UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 20182021

OR

For the transition period from to

Commission File Number 001-37587

CytomX Therapeutics, Inc.

(Exact Name of Registrant as Specified in Its Charter)

(650) (650) 515-3185

(Registrant’s telephone number, including area code)3

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐No☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐No☒

Indicate by check mark whether the issuer (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes☒ No ☐

Indicate by check mark whether the registrant has submitted electronically, every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes☒ No ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ☒

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of June 30, 2018,2021, the last business day of the registrant’s most recently completed second fiscal quarter, the aggregate market value of the registrant’s common stock held by non-affiliates of the registrant was approximately $876.4$408.3 million, based on the closing price of the registrant’s common stock on the Nasdaq Global Select Market on June 30, 20182021 of $22.86$6.33 per share. Shares of the registrant’s common stock held by each officer and director and each person known to the registrant to own 10% or more of the outstanding common stock of the registrant have been excluded in that such persons may be deemed affiliates. This determination of affiliate status is not a determination for other purposes.

As of January 31, 2019, 45,111,2822022, 65,392,758 shares of the registrant’s common stock, $0.00001 par value per share, were outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

CYTOMX THERAPEUTICS, INC.

ANNUAL REPORT ON FORM 10-K

TABLE OF CONTENTS

Forward-Looking Statements

This Annual Report on Form 10-K contains certain forward-looking statements that involve risks and uncertainties. These forward-looking statements reflect our current views with respect to, among other things, future events and our financial performance. These statements are often, but not always, made through the use of words or phrases such as “may,” “might,” “should,” “could,” “predict,” “potential,” “believe,” “expect,” “continue,” “will,” “anticipate,” “seek,” “estimate,” “intend,” “plan,” “projection,” “would,” “annualized” and “outlook,” or the negative version of those words or other comparable words or phrases of a future or forward-looking nature. These forward-looking statements are not historical facts, and are based on current expectations, estimates and projections about our industry, management’s beliefs and certain assumptions made by management, many of which, by their nature, are inherently uncertain and beyond our control. Accordingly, we caution you that any such forward-looking statements are not guarantees of future performance and are subject to risks, assumptions, estimates and uncertainties that are difficult to predict. Although we believe that the expectations reflected in these forward-looking statements are reasonable as of the date made, actual results may prove to be materially different from the results expressed or implied by the forward-looking statements.

A number of important factors could cause our actual results to differ materially from those indicated in these forward-looking statements, including those factors identified in “Risk Factors” or “Management’s Discussion and Analysis of Financial Condition and Results of Operations” or the following:

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Any forward-looking statements in this Annual Report on Form 10-K reflect our current views with respect to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under Part I, Item 1A. Risk Factors and discussed elsewhere in this Annual Report on Form 10-K. Given these uncertainties, you should not place undue reliance on these forward-looking statements. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

This Annual Report on Form 10-K also contains estimates, projections and other information concerning our industry, our business and the markets for certain drugs and therapeutic biologics, including data regarding the estimated size of those markets, their projected growth rates and the incidence of certain medical conditions. Information that is based on estimates, forecasts, projections or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained these industry, business, market and other data from reports, research surveys, studies and similar data prepared by third parties, industry, medical and general publications, government data and similar sources. In some cases, we do not expressly refer to the sources from which these data are derived.

Except where the context otherwise requires, in this Annual Report on Form 10-K, “we,” “us,” “our” and the “Company” refer to CytomX Therapeutics, Inc.

Trademarks

This Annual Report on Form 10-K includes trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included in this Annual Report on Form 10-K are the property of their respective owners.

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PART I

PART I

OverviewItem 1. Business

Overview

We are a clinical-stage, oncology-focused biopharmaceutical company withdedicated to destroying cancer differently. We aim to build a visioncommercial enterprise to maximize our impact on the treatment of transforming lives with safer, more effective therapies. We arecancer. By pioneering a novel class of conditionally activated biologic candidates, powered by our Probody® therapeutic technology platform, we lead the field of conditionally activated oncology therapeutics and have established conditional activation as a strategic area of biologics research and development. Our goal is to transcend the limits of current cancer treatments by successfully leveraging therapeutic targets and strategies that were once thought to be inaccessible.

Our proprietary, unique and versatile Probody technology platform is designed to enable conditional activation of biologic therapeutic candidates within the tumor microenvironment while minimizing drug activity in healthy tissues and circulation. Our industry-leading platform is built on a strong foundation of tumor biology expertise including deep knowledge of tumor-associated enzymes known as proteases. Proteases are tightly controlled in normal tissues but often poorly regulated and active in tumor microenvironments where they play important roles in cancer cell migration, invasion and metastasis. Leveraging our deep scientific knowledge, we conceived of and constructed our Probody therapeutic platform which allows us to genetically engineer biologic therapeutic candidates to contain protease-cleavable masks. Our masking strategy is designed to reduce binding of biologic drugs to their targets until the mask is removed by proteases in the tumor microenvironment, providing more selective targeting of the tumor. We believe this innovative approach has the potential to improve cancer treatment in three ways:

We are employing our leading, conditional activation platform technology to address some of the biggest challenges today in oncology biologics research and development. These include the validation of potential new targets for antibody-drug conjugates (“ADCs”), opening solid tumor opportunities for T-cell engaging bispecific antibodies (“TCBs”), and increasing the therapeutic window for immune modulators such as cytokines and checkpoint inhibitors (“CPIs”).

We have utilized our multi-modality Probody platform to build a promising pipeline of potential first-in-class and best-in-class therapeutics that encompasses six novel product candidates, four of which are currently in multiple Phase 2 clinical studies in nine cancer indications. These include the conditionally activated ADCs praluzatamab ravtansine (CX-2009, targeting CD166) and CX-2029 (targeting CD71), and the Probody immune CPIs pacmilimab (CX-072, targeting PD-L1) and BMS-986249 (targeting CTLA-4).

Underscoring our commitment to destroying cancer differently, we have recently advanced a new Probody modality into the clinic. CX-904 is our first conditionally activated TCB, targeting the epidermal growth factor receptor (“EGFR”) on tumor cells and the CD3 receptor on T cells. In January 2022, the investigational antibodynew drug application (“IND”) for the program was allowed to proceed by the U.S. Food and Drug Administration (“FDA”). We are in the process of initiating a first-in-human Phase 1 study of CX-904 in patients with advanced solid tumors and expect to dose the first patient in the first half of 2022. We are also developing CX-2043, our third conditionally activated ADC directed toward epithelial cell adhesion molecule, EpCAM/Trop-1, currently in preclinical studies, as well as other discovery stage programs across multiple modalities.

Our Corporate Strategy

We are utilizing our industry-leading, proprietary, versatile, and tunable Probody platform to create a robust pipeline of biologic therapeutics to improve the lives of people with cancer and to build a long-term, multi-product, commercial biopharmaceutical company. We aim to achieve this goal by:

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Our Pipeline of Conditionally Activated Product Candidates

We are leveraging our Probody platform to build a robust pipeline of potential first-in-class and best-in-class anti-cancer therapies. We currently retain worldwide development and commercialization rights to two of our most advanced Probody therapeutics in the clinic, praluzatamab ravtansine and pacmilimab. Additionally, we are advancing multiple partnered development programs in the clinic, including CX-2029 in collaboration with AbbVie, BMS-986249 and BMS-986288 partnered with Bristol Myers Squibb, and the Amgen-partnered CX-904. The table below depicts the current status of our conditionally activated product candidates that are in clinical and preclinical development:

CytomX Pipeline of Conditionally Activated Probody Therapeutics

Praluzatamab Ravtansine (CX-2009): A Potentially First-in-Class Conditionally Activated ADC Targeting CD-166

With more than ten ADCs approved in the United States, this drug class is now well established as an effective therapeutic strategy for the treatment of cancer. The Probody therapeutic approach is designed to more specifically target antibody therapeutics to the tumor microenvironment and minimize drug activity in healthy tissue and in circulation. We believe this approach has the potential to make meaningful enhancements to the combined efficacy and safety profile of antibody therapeutics, known as the “therapeutic window” and also to enable new targeted therapies. We believe that Probody therapeutics have the potential to create or widen the therapeutic window for certain antibody therapeutics, allowing for the development of new approaches to the treatment of cancer. WeHowever, conventional ADCs are utilizing our Probody Platform to develop a pipeline, shown below, of potential best-in-class immunotherapies against clinically-validated targets and potential first-in-class therapeutics against novel, difficult to drug targets. Furthermore, we believe the Probody therapeutic approach has the potential to enable safer, more effective combination therapy for cancer.

CytomX pipeline of Probody Therapeutics

We believe there is a significant opportunity in localizing antibody therapeutics to the tumor microenvironment, and therefore the market opportunity for Probody therapeutics could be large.  Cancer is the second leading cause of mortality in the United States and accounts for nearly one in every five deaths. Early cancer research and treatment relied on relatively non-specific and highly toxic small molecule chemotherapies. Over the last twenty years, a new paradigm of cancer treatment has emerged that is focused on more targeted therapies, including monoclonal antibody modalities, which represent some of the most effective and top-selling therapies on the market today. In 2017, half of the top 10 best-selling drugs on the market were monoclonal antibodies.  More recently, immuno-oncology has emerged as a promising new field of cancer therapy that aims to enhance anti-tumor immune responses by, for example, overcoming suppressive mechanisms that cancer cells have developed to evade the immune system. In addition, new classes of monoclonal antibody-based therapeutics have also reached the market. These new classes include Antibody Drug Conjugates (“ADCs”), bispecific antibodies, and Chimeric Antigen Receptor (“CAR”) based cellular therapies. We have demonstrated that our Probody therapeutic technology can be applied to many antibody modalities, including antibodies against immuno-oncology targets, ADCs, and bispecific antibodies, and therefore we believe that significant opportunities exist for CytomX to develop and capture market share with innovative anti-cancer treatments.

Our most advanced product candidate is CX-072, a wholly owned Probody therapeutic targeting programmed cell death ligand 1 (“PD-L1”), a clinically and commercially validated immuno-oncology target.  In normal physiology, PD-L1 plays a role in suppressing the immune system in healthy tissue, preventing autoimmunity. Tumors can co-opt this inhibitory function by upregulating PD-L1 expression and evading anti-cancer immune surveillance. Inhibitors of the PD-L1 pathway have therefore been designed and developed that restore anti-cancer immune surveillance and such inhibitors have demonstrated anti-cancer activity in a wide variety of cancer types. Regulatory approval has been granted for PD-L1 inhibitors and/or programmed cell death 1 (“PD-1”) inhibitors in a wide range of cancers, including advanced melanoma, renal cell cancers, non-small cell lung cancer, and bladder cancers.

While PD-L1 inhibitors have been shown to enhance anti-cancer immunity, systemic administration of inhibitors of the PD-L1 pathway can result in impairment of normal immune tolerance of healthy tissues, and severe immune-related toxicities can emerge. These toxicities can be particularly serious when PD-L1 inhibitors are combined with other anti-cancer agents.  Our PD-L1 Probody therapeutic, CX-072, is designed to uncouple the anti-cancer activity of PD-L1 inhibitors from the associated autoimmune toxicities by inhibiting PD-L1 in the tumor microenvironment with minimal engagement in healthy tissue.   We are currently evaluating CX-072 in a Phase 1/2 study that we call PROCLAIM-CX-072. This study is designed to assess the safety, activity, and translational biology of CX-072 as a single agent and in combination with other anticancer therapies. We disclosed initial clinical proof of concept data on CX-072 at various oncology conferences in 2018.  In February 2019, we disclosed additional clinical safety and efficacy data on CX-072 at a Research and Development Day hosted by CytomX management (“CytomX R&D Day”).

Our second most advanced product candidate is CX-2009, a wholly owned Probody Drug Conjugate (“PDC”) directed against CD166, a novel drug target.  Probody Drug Conjugates are CytomX-designed Probody therapeutic versions of a class of drugs called Antibody ADCs, which are antibodies that have been conjugated to a small molecule cytotoxic agent via a labile chemical linker.  Several ADCs have been approved for the treatment of cancer in the United States and elsewhere, including Kadcyla™, which targets HER2 positive metastatic breast cancer, and Adcetris™, which targets CD30 in Classical Hodgkin Lymphoma.  To avoid target-related toxicity, traditional ADCs have historically been limitedrestricted to targeting proteins that are expressed highly in tumors, but that are also absentwith little or poorly expressedno expression in healthy tissues. Very fewtissues, in order to avoid undesirable on-target toxicities. Few cancer-associated proteins have this desired profile.  Because ourdesirable profile, thereby limiting the utility of conventional ADCs.

Our therapeutic strategy with conditionally activated ADCs is to leverage targets to achieve binding to tumor cells, and to effect cancer cell killing via a cytotoxic payload conjugated to the antibody. Our Probody therapeutics areplatform is designed to minimize bindingreduce on-target toxicities that otherwise may occur with conventional ADCs. We do not mask the cytotoxic payload in our conditionally activated ADCs, and therefore some payload-related toxicities are expected. Furthermore, payload toxicities may offer an indication that therapeutically active levels of potent anti-cancerthe drug conjugate are being achieved.

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Praluzatamab ravtansine,our wholly-owned lead product candidate, is a potential first-in-class conditionally activated ADC directed toward CD166. CD166 is a tumor target previously considered undruggable with a conventional ADC therapy due to normal tissues, we believe we can address a new class of targets with attractive molecular features that were previously unsuitable because ofits high expression on normal tissues. CD166tissues, but that has been validated as a potential target at CytomX. Praluzatamab ravtansine is conjugated with the potent microtubule inhibiting payload DM4, a chemotherapeutic agent in the maytansine class, licensed from ImmunoGen.

We have completed a Phase 1 dose-finding, multi-cohort study involving heavily-pretreated patients. These first-in-human data were published in the peer-reviewed journal Clinical Cancer Research in February 2022, in which we reported encouraging anti-cancer activity in patients with triple-negative breast cancer (“TNBC”) and hormone receptor-positive (“HR+”), human epidermal growth factor receptor 2 (“HER2”)-non-amplified breast cancer, among others. In particular, clinical benefit rates ("CBR") in breast cancer of 41% and 28% were observed at 16 and 24 weeks (“CBR16” and “CBR 24”), respectively, with all four patients with TNBC who achieved CBR16 maintaining it at CBR24. Praluzatamab ravtansine was generally well tolerated at doses up to 7 mg/kg administered every three weeks, with mostly DM4-related toxicities, including ocular, neuropathic, and hepatic.

Observed Responses and Durability in Breast Cancer with Praluzatamab Ravtansine (CX-2009) at Doses ≥4 mg/kg Q3W as of August 31, 2020

In December 2020, we initiated a three-arm, Phase 2 study of praluzatamab ravtansine in HER2-non amplified breast cancer. The first two arms, Arms A and B, will evaluate praluzatamab ravtansine as monotherapy, with Arm A focusing on patients with HR+, HER2-non-amplified breast cancer and Arm B in patients with TNBC. Arm C will study praluzatamab ravtansine in combination with pacmilimab in patients with TNBC. We expect initial data for Arms A and B to be available in the second half of 2022.

According to the American Cancer Society, an exampleestimated 287,850 new cases of invasive breast cancer are expected to be diagnosed in women in the United States in 2022, making it the most frequently diagnosed cancer in women. HR+/HER2‒ and TNBC subtypes, collectively HER2-non-amplified, is the largest segment of breast cancer, accounting for greater than 80% of patients with advanced breast cancer. Patients with HR+ breast cancer are treated with hormone-based therapy, which can be single-agent or combination therapy (including CDK4/6 or mTOR inhibition). If their cancer progresses, patients may require more aggressive cytotoxic chemotherapy and this kindlate-stage disease setting represents a significant unmet need for more efficacious treatment options. For TNBC, given this tumor subtype lacks estrogen or progesterone receptors and the HER2 protein, chemotherapy is the main systemic treatment option. The combination of target. CD166immune CPI and chemotherapy has recently been approved by the FDA for patients with advanced, previously-untreated TNBC that expresses the PD-L1 marker. For patients who have tried at least 2 other drug treatments, the ADC, sacituzumab govitecan, might be an option. Despite these recent advances, significant need exists for novel treatment options for these patients.

CX-2029: A Potentially First-in-Class Conditionally Activated ADC Targeting CD71, The Transferrin Receptor

Our second lead conditionally activated ADC is CX-2029, which we are advancing in a global co-development collaboration with AbbVie. This program is intended to open a therapeutic window for successful targeting of CD71, also known as the transferrin receptor 1 (“TfR1”). CD71 is a cell surface protein essential for iron uptake in dividing cells and is highly and homogenously expressed in multiple different tumors types, which makes ita number of solid and hematologic cancers. However, given its central role in iron metabolism, CD71 is present on most healthy cells and is

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thought to be an attractiveundruggable target for a Probody drug conjugate therapeutic; however,with conventional ADCs. CX-2029 is conjugated with the high expression of CD166 on normal tissues makes this a difficult target to drug with a traditional ADC.  CX-2009 is our Probody therapeutic directed to CD166 and conjugated to a cytotoxic agent. CX-2009 is currently intubulin inhibitor, monomethyl auristatin E (“MMAE”), as the dose escalation portion of a Phase 1/2 study thatpayload.

In 2020, we call PROCLAIM-CX-2009. In February 2019, we disclosed initial clinical data on CX-2009 atcompleted the CytomX R&D Day.

In addition to our wholly owned programs, we have entered into several strategic collaborations with leading oncology-focused pharmaceutical companies, such as AbbVie Inc., through its subsidiary AbbVie Ireland Unlimited Company (“AbbVie”), Amgen, Inc. (“Amgen”) and Bristol-Myers Squibb Company (“BMS”). The most advanced program from our partnerships is a CTLA-4 Probody therapeutic which BMS is currently advancing through the dose escalationdose-escalation phase of a Phase 1/2 clinical trial.  We are also treating patients in PROCLAIM-CX-2029, aan ongoing Phase 1/2 clinical study, for which we received a $40 million milestone payment from AbbVie. We published these first-in-human data in the peer-reviewed journal Clinical Cancer Research in June 2021. A total of 45 patients with advanced solid tumors were enrolled to receive CX-2029 intravenously every three weeks at dose levels ranging from 0.1 mg/kg to 5 mg/kg. At doses of 0.25 mg/kg to 5 mg/kg, more than 90% of CX-2029 circulated predominantly as the intact species. CX-2029 was generally well tolerated at doses up to 3 mg/kg, with infusion related reactions, anemia, and neutropenia as the most common dose-dependent adverse events. Neutropenia is commonly associated with the MMAE payload. The etiology of anemia is under investigation and is likely multifactorial. The MMAE payload is also known to be associated with anemia, and preclinical studies have shown that reduction of red blood cell precursors has been observed in response to targeting CD71, which is known to play a PDC targetingrole in early erythroid development. Anemia was managed with transfusions and supportive care. Additionally, no CX-2029 treatment related deaths were reported, and no patient withdrew from the highly expressed target, CD71dose-escalation phase of the clinical trial due to anemia.

Encouraging preliminary clinical activity was observed at doses of 2 mg/kg and higher. Notably, three of four patients with squamous non-small cell lung carcinoma (“sqNSCLC”) had stable disease (“SD”) or better, including two confirmed partial responses (“PRs”) (at doses of 3 and 5 mg/kg); and seven of eight patients with head and neck squamous cell carcinoma (“HNSCC”) had SD or better, including one confirmed PR at 3 mg/kg.

Observed Responses and Durability in sqNSCLC and HNSCC with CX-2029 at Doses ≥2 mg/kg Q3W as of August 14, 2020

In November 2020, we expanded this study into a four-cohort Phase 2 expansion, designed to evaluate CX-2029 as a monotherapy in patients with sqNSCLC, HNSCC, esophageal and gastro-esophageal junction cancers, and diffuse large B-cell lymphoma (“DLBCL”). Preliminary data for the sqNSCLC and HNSCC cohorts were disclosed in December 2021. As of the data cutoff on October 29, 2021, 23 patients with sqNSCLC and 29 patients with HNSCC had received at least one dose of CX-2029 (safety population), of whom 16 sqNSCLC patients and 25 HNSCC patients had at least one post baseline assessment (efficacy-evaluable population). For the sqNSCLC cohort, an objective response rate (“ORR”) by local investigator of 18.8% was observed in the 16 efficacy-evaluable patients, including two confirmed PRs and one unconfirmed PR that confirmed seven days after the data cutoff. Two of these responses were ongoing as of the data cutoff and the third had a response duration of 5.6 months. The disease control rate (“DCR”),

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which includes patients with a complete response, PR, or stable disease, was 87.5%. The sqNSCLC cohort continues to enroll patientstowards the goal of 25 efficacy-evaluable patients. In the 25 efficacy-evaluable patients with HNSCC, the ORR was 4.0%, with a 56.0% DCR, including one unconfirmed PR which will not confirm. The HNSCC cohort has completed enrollment.

The preliminary safety profile of CX-2029 in the Phase 2 expansion was consistent with previous Phase 1 observations, with no new safety signals identified. The most common treatment-related adverse events (“TRAEs”) in 10% or more of patients (All Grade, Grade 3) were anemia (78.8%, 67.3%), infusion related reactions (69.2%, 3.8%), fatigue (19.2%, 1.9%), and nausea (13.5%, 0.0%), and decreased neutrophil count (13.6%, 9.6% (plus one Grade 4 event 1.9%)). The most common reason for treatment discontinuation was disease progression (44.2%), three patients (5.8%) discontinued for a treatment-related adverse event (anemia; 2 Grade 2, 1 Grade 3). TRAEs leading to dose interruption or reduction were 40.4% and 34.6%, respectively. Thirteen patients, eight with sqNSCLC and five with HNSCC, were still on treatment as of the data cut off. Patient enrollment continues in the CX-2029 expansion phase and we plan to provide certain additional data updates in 2022.

Lung cancer is the leading cause of death from all cancers globally, resulting in more than 1.8 million deaths per year. Greater than 80% of lung cancers are NSCLC and the main subtypes of NSCLC are adenocarcinoma, squamous cell carcinoma, and large cell carcinoma, with squamous cell representing approximately 30%. While a number of immune CPIs have partneredbeen approved by the FDA for NSCLC treatment, patients who failed these agents have limited treatment options, representing a potentially significant opportunity for CX-2029 to address. Head and neck cancers include cancers in the larynx, throat, lips, mouth, nose, and salivary glands, and represent the 6th most common cancer worldwide, resulting in 350,000 deaths annually, whereas it is the 8th most commonly diagnosed cancer in the United States, accounting for approximately 11,500 deaths annually. The most common types of esophageal cancer are adenocarcinoma and squamous cell carcinoma, with AbbVie.squamous cell accounting for about 90% of the global annual incidence of 456,000. DLBCL is the most common aggressive subtype of non-Hodgkin lymphoma, constituting up to 40% of cases globally and more than 18,000 people diagnosed with the malignancy each year in the United States. Despite recent advances in cancer treatment, including the advent of immuno-oncology therapy, significant unmet need remains for these four cancer types.

In October 2018, we filed an investigational new drug application (“IND”) on CX-188,

Pacmilimab (CX-072): A Probody Therapeutic Targeting PD-L1

Our most advanced wholly-owned immuno-oncology product candidate is pacmilimab, a wholly owned Probody therapeutic targeting PD-1,against PD-L1, a clinically and commercially validated anti-cancercancer target. The CX-188 INDPD pathway consists principally of two targets: PD-1, which is typically expressed on T-cells, and PD-L1, which is typically expressed on the tumor cells as well as on healthy tissue. In healthy tissue, PD-1 and PD-L1 work together to negatively regulate immune response and maintain tolerance between the immune system and healthy tissue. Tumors, however, upregulate PD-L1 to evade immune surveillance by the host’s immune system. Therefore, development of antibodies against PD-1 and PD-L1 have become a key focal point in cancer drug development, with multiple PD-1 antibodies including nivolumab (Opdivo®), pembrolizumab (Keytruda®), and cemiplimab (Libtayo®) and multiple PD-L1 antibodies including atezolizumab (Tecentriq®), durvalumab (Imfinzi®), and avelumab (Bavencio®) approved by the FDA. There continue to be many other PD pathway inhibitors in clinical development. In addition to assessment as single agents, PD-1 and PD-L1 antibodies have been studied extensively as the centerpiece of oncology combination therapies.

While inhibitors of the PD-L1 and/or PD-1 pathway offer the potential for clinical benefit in patients with a wide-variety of cancer types, there are a number of risks imposed by administration of these agents. According to U.S. labels for Opdivo, Keytruda, Tecentriq, Bavencio, and Imfinzi, the most common side effects (defined as either >15% or >20%, depending upon the agent) that were observed with commercially available anti-PD-L1 and anti-PD-1 agents include: fatigue, decreased appetite, nausea, vomiting, diarrhea, dyspnea, constipation, cough, musculoskeletal pain, back pain, abdominal pain, arthralgia, urinary tract infection, upper respiratory tract infection, peripheral edema, infusion-related reaction, rash, asthenia, pruritus, headache, and pyrexia.

Combining a PD pathway inhibitor with another anti-cancer agent often results in significantly greater toxicity than monotherapy alone. One example is the combination of atezolizumab and paclitaxel protein-bound, or nab-paclitaxel, which was clearedapproved in the United States for the treatment of adult patients with unresectable locally advanced or metastatic TNBC whose tumors express ≥ 1% of PD-L1, as determined by an FDA approved test. According to data reported in 2018 in The New England Journal of Medicine, the combination of atezolizumab at a dose of 840 mg and nab-paclitaxel at a dose of 100 mg per square meter of body-surface resulted in Grade 3/4 treatment related adverse events (“TRAEs”) in 48.7% of the patients treated versus 42.2% in the placebo-nab-paclitaxel group, and drug discontinuations in 6.4% of the patients treated, compared to 1.4% in the placebo group.

We believe that a locally activated Probody therapeutic targeting PD-L1 has the potential to maintain the anti-tumor activity of the PD pathway blockade while reducing the autoimmunity that results from blocking such pathway systemically. As such, we believe that pacmilimab has the potential to enable combination therapies that cannot be appropriately dosed because of synergistic toxicity, and ultimately that pacmilimab may have the potential to play an important role in combination therapy. Pacmilimab may also ultimately prove to be a safer monotherapy than existing PD inhibitors which could have specific applications in certain clinical settings.

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In July 2021, we published two manuscripts in the Journal for ImmunoTherapy of Cancer: (1) pacmilimab monotherapy at the recommended Phase 2 dose of 10 mg/kg every 14 days in 114 patients and (2) paclimimab in combination with ipilimumab in 27 patients; all patients were heavily-pretreated. Both studies demonstrated a low rate of immune-mediated toxicity. Additionally, pacmilimab monotherapy showed signs of anti-tumor activity in patients not selected for high PD-L1 expression but had tumors that are sensitive to immune checkpoint inhibition, including TNBC, anal squamous cell carcinoma, cutaneous squamous cell carcinoma, and tumors with high mutational burden.

Based on this potentially differentiated profile of a favorable tolerability and clear evidence of anti-cancer activity, we are studying pacmilimab in combination with praluzatamab ravtansine in a Phase 2 study in TNBC and continue to evaluate additional combination partners for pacmilimab.

BMS-986249 and BMS-986288

In collaboration with our partner, Bristol Myers Squibb, we are developing BMS-986249 and BMS-986288, Probody versions of ipilimumab. Ipilimumab, sold under the brand name Yervoy®, is a monoclonal antibody that targets CTLA-4, a checkpoint protein receptor that downregulates the immune system. In the United States, ipilimumab has been approved by the FDA to treat melanoma as a single agent and in November 2018.  Due tocombination with nivolumab, an anti-PD-1 antibody, for colorectal cancer, hepatocellular carcinoma, malignant pleural mesothelioma, NSCLC, and renal cell carcinoma. While treatment with ipilimumab as a recent program and portfolio prioritization, we have decided to indefinitely postpone clinical trialsmonotherapy or in combination with nivolumab has resulted in clinically meaningful anti-tumor activity in these malignancies, highlighted by the recently updated median overall survival of 72.1 months for CX-188.  We may elect to initiate clinical trials for CX-188the combination in the future.Phase 3 study of nivolumab or nivolumab plus ipilimumab versus ipilimumab alone in previously-untreated advanced melanoma ("CheckMate 067"), ipilimumab has a narrow therapeutic window and the FDA approved label has a warning about potential severe and fatal immune-related adverse events. We believe our CTLA-4-targeting Probody therapeutic may be able to effectively localize the anti-CTLA-4 antibody activity to the tumor microenvironment, thereby limiting systemic toxicities normally seen with ipilimumab, which could improve the benefit/risk profile of anti-CTLA-4 containing treatment regimens.

In an ongoing Phase 1/2 study conducted by Bristol Myers Squibb in patients with advanced cancers, Bristol Myers Squibb reported at ASCO 2020 preliminary data indicating that escalating doses of BMS-986249 ranging from 240 mg to 2400 mg (approximately 3 to 30 mg/kg of ipilimumab) were found to be generally well tolerated, either as a single agent or in combination with nivolumab. In February 2020, Bristol Myers Squibb initiated a randomized Phase 2 study cohort expansion in combination with nivolumab in patients with previously-untreated unresectable stage III-IV melanoma which resulted in a $10 million milestone payment from Bristol Myers Squibb. This study has been modified to include three additional single-arm cohorts: advanced hepatocellular carcinoma, metastatic castration-resistant prostate cancer, and unresectable locally advanced or metastatic TNBC.

For BMS-986288, a Probody version of non-fuscosylated ipilimumab, Bristol Myers Squibb is evaluating its safety and efficacy alone and in combination with nivolumab in an ongoing Phase 1/2 study in patients with selected advanced solid tumors.

CX-904

We have also extended our Probody platform to the new and promising modality of T-cell engaging bispecific antibodies (“TCBs”). Conventional TCBs are a highly potent therapeutic modality designed to direct the activity of cytotoxic T-cellsT cells to tumors. TCBs such as the BiTE® molecule, Blincyto®, a CD19-directed TCB commercialized by Amgen, have shown clinical activity in hematologic malignancies, but development of TCBs for solid tumor indications is proving challenging. Due to their high potency, TCBs can target normal tissues with low antigen expression, resultingwhich may result in significant on-target, off-tumor toxicity that can limit dosing to low levels. As a result, it has been difficult to reach the level of drug exposure required for efficacy without excessive toxicity.challenges. We believe that thesuch challenges could be addressed using our Probody platform is potentially capable ofby localizing the activity of TCBs to the tumor microenvironment and avoid on-target, off-tumor toxicity.  thereby improving the therapeutic window for TCBs in solid tumors.

Our most advanced program in the TCBthis modality is an Epidermal Growth Factor Receptor-CD3CX-904, a conditionally activated epidermal growth factor receptor-CD3 (“EGFR-CD3”EGFRxCD3”) T-cell bispecific,TCB, which is currently in lead optimization stage, andwe partnered with Amgen. In preclinical studies, CytomX’s Probody EGFRxCD3 bispecific therapeutics demonstrated anti-tumor activity and better tolerability when compared to EGFRxCD3 bispecifics without Probody masking. Additionally, while we believe our preclinical studies show that we have the potential to reach a favorable therapeutic index, clinical data will be necessary to specify an acceptable dose. In January 2022, the IND for CX-904 was allowed to proceed by the FDA. We are in the process of initiating a first-in-human Phase 1 study in patients with advanced solid tumors and expect to dose the first patient in the first half of 2022.

Our broad

Preclinical Product Candidates and Research

We are actively broadening the potential application of our Probody therapeuticplatform technology platform and leadto multiple other product candidates, are supportedincluding additional potential first-in-class conditionally activated ADC product candidates, investigational TCBs and cytokines.

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Anti-Trop-1 (EpCAM) Conditionally Activated ADC Program

Trop-1 or epithelial cell adhesion molecule (“EpCAM”) is a target that is highly expressed on a wide variety of tumor types. It has been, however, a difficult target to drug due to its wide expression on normal tissues. An EpCAM-targeting conditionally activated ADC program, CX-2043, was originally developed by more than a decade of thorough scientific researchImmunoGen utilizing our Probody technology and strong intellectual property. We are a leaderImmunoGen’s next-generation linker chemistry and novel maytansinoid payload, DM21. At the 2018 European Antibody Congress and the 2019 American Association for Cancer Research Annual Meeting, ImmunoGen reported pre-clinical data from this program showing CX-2043 elicited potent tumor regression in the emerging field of localizing antibody therapeutics tomultiple tumor models, while minimizing on-target toxicities outside the tumor microenvironment as evidenced by. In late 2019, we in-licensed exclusive worldwide development and commercialization rights to CX-2043, for which we are working towards submitting an IND.

Cytokines

Our work with cytokines stems from the fact that systemic toxicity and poor exposure have limited the clinical success of this important and highly potent class of immune modulators. While significant progress has been made in recent years with the approval of interleukin-2, a prototypical immune modulator, for the treatment of metastatic renal cell carcinoma and metastatic melanoma, many efforts to improve its therapeutic window have not been successful. By leveraging our patent estateProbody platform, we have recently created a protease-activatable version of approximately 100 issued patents (someinterferon alpha-2b, which has shown an improved therapeutic window in preclinical studies.

T-cell engaging Bispecific Antibodies

In addition to our work on CX-904, we are advancing a program of which are co-ownedT-cell engaging bispecific antibodies, both ourselves, and with a third party)our partners, Amgen and 250 pending patent applications (someAstellas. This program includes novel antibody formats and leverages our deep expertise in masking and extensive and growing knowledge of which are co-owned with a third party). We also have an exclusive license from University of California, Santa Barbara (“UCSB”) to three patent families covering screening tools to identify masks and substrates.the tumor protease microenvironment.

The successful development of our product candidates involves a lengthy and expensive process with an uncertain outcome, and preliminary or interim results of our studies may not be predictive of the final results from those trials and the results of earlier studies and trials may not be predictive of future trial results. This is due to the numerous risks and uncertainties associated with the development of product candidates. If our Probody therapeutic technology and product candidates generally prove to be ineffective, unsafe or commercially unviable, it would have a material and adverse effect on our business, financial condition, results of operations and prospects.See “Risk Factors” for a discussion of the risks and uncertainties associated with our product candidates and our research and development projects.

Our Corporate Strategy

We are utilizing our proprietary and differentiated Probody platform to develop a leading pipeline of novel, innovative anti-cancer therapies to improve the lives of people with cancer and to build a long-term, multi-product, commercial stage biotechnology company.  We aim to achieve this goal by:

Our Probody Platform

Localization of therapeutic antibody activity of biologics within disease tissue is of increasing interest in the biopharmaceutical industry due to the desire to maximize the activity of antibody-based drugs whilstbiologics while reducing their toxicities. At CytomX, weWe call our approach to therapeutic antibody localization of biologics our Probody platform. A Probody therapeutic candidate consists of three components: an active anti-cancer antibody,biologic, a mask for the antibody,biologic, and a protease-cleavable linker which connects the mask to the antibody.biologic. The mask is a peptide designed to disguise the active binding site of the antibodybiologic to prevent the therapeuticit from binding to the target present on healthy tissue. Probody therapeutics therapeutic candidates

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are produced as a single protein by standard antibodybiologic production methodology. The following graphic depicts the three components of a Probody therapeutic:therapeutic candidate:

Depiction of the structure of a Probody therapeutic candidate and a protease interacting with the Probody to cleave the linker and activate the molecule

When a Probody therapeutic candidate enters a tumor, it encounters proteases, which are enzymes that cleave proteins and have increased activity in the tumor microenvironment. The proteases in the tumor cleave the linker, releasing the mask and allowing the antibodybiologic to bind to the target on the tumor. The following graphic depicts the activation ofway a Probody therapeutic candidate is designed to be activated by proteases:

Depiction of how a Probody therapeutic is designed to enter the tumor microenvironment (left), be activated by protease cleavage to remove the mask (middle), thereby enabling the released antibodybiologic to bind to the tumor target (right)

Proteases play an essential role in many aspects of normal physiology, such as digestion of food in the gastrointestinal tract, wound healing and metabolic function. However, uncontrolled protease activity can lead to destruction of essential proteins and tissues. Therefore, proteases are normally very tightly regulated by multiple mechanisms, with only small amounts of extracellular protease activity being detectable in healthy tissues. In contrast, it has been well documented that proteases are not only present, but also activated, in virtually all types of tumors, playing a key role in tumor growth, invasion and metastasis. Probody therapeutics are designed to be activated in this protease-rich tumor microenvironment, but not in healthy tissue where proteases are under tight control as depicted in the figure below:

Probody therapeutics are designed to remain masked and inactive in healthy tissue (right) but be unmasked and activated in diseased tissue, such as in tumors (left)

Probody therapeutics are designed to limit toxicitycontrol. Consequently, we believe that cantoxicities that arise from the binding of an antibodya biologic therapeutic to a target in healthy tissues can be reduced, while preserving biological activity inagainst the tumor where it is desired.desired can be preserved. We and our partners have demonstrated the applicabilitypotential of our Probody platform across multiple monoclonal antibody modalities, including ADCs, cancer immunotherapy, ADCs,TCBs, and T-cell-recruiting bispecifics.cytokines.

We have designed protease-cleavable linkers so that several activated proteases within the tumor microenvironment can cleave them. Using this approach, we believe Probody therapeutics can be cleaved and activated by at least one protease across a large number of tumor types. This concept has been validated by the translational data that we have generated from clinical studies for our CX-072 and CX-2009 programs, which suggests that Probody therapeutics are sufficiently activated in the tumor microenvironment, and once activated, behave like the underlying parenteral antibody.  We have also presented initial clinical data for our CX-072 and CX-2009 programs that indicate that the Probody therapeutic remains sufficiently masked, and therefore inert, in systemic circulation.  These features of the Probody platform, now validated with clinical data, suggest that we can potentially develop differentiated therapies which can widen therapeutic window for validated targets such as PD-L1 and enable a therapeutic window for broadly expressed targets such as CD166.10

Key Advantages of Our Probody Platform

CytomX’s leadership in conditional activation is built on a decade-long expertise in tumor biology and its customizable Probody platform

We believe that our Probody Platformplatform provides the following key advantages:

Our Lead Product Candidates

We are leveragingBMS-986249, our Probody platform to build a leading pipeline of innovative and differentiated anti-cancer therapies. We currently retain worldwide development and commercialization rights to our two most advanced Probody therapeutics in the clinic, CX-072 and CX-2009.  In addition, we have multiple partnered development programs including BMS 986249, an anti-CTLA-4 Probody program with BMS, and CX-2029, an anti-CD71 PDC program in collaboration with AbbVie.  

CX-072 (PD-L1 Probody therapeutic)

Overview and Limitations of Existing Therapies

Our most advanced product candidate is CX-072, a wholly owned Probody therapeutic targeting PD-L1, a clinically and commercially validated cancer target.  The PD pathway consists principally of two targets: PD-1, which is typically expressed on T-cells, and PD-L1, which is typically expressed on the tumor cells as well as on healthy tissue. In healthy tissue, PD-1 and PD-L1 work together to negatively regulate immune response and maintain tolerance between the immune system and healthy tissue.  Tumors, however, upregulate PD-L1 to evade immune surveillance by the host’s immune system.  Therefore, development of antibodies against PD-1 and PD-L1 have become a key focal point in cancer drug development, with three PD-1 antibodies nivolumab (Opdivo™), pembrolizumab (Keytruda™), and cemiplimab (Libtayo™) and three PD-L1 antibodies atezolizumab (Tecentriq™), durvalumab (Imfinzi™), and avelumab (Bavencio™) approved as of February 2018, with many other PD pathway inhibitors in clinical development. In addition to assessment as single agents, PD-1 and PD-L1 antibodies have been studied extensively as the centerpiece of oncology combination therapies.  According to the Cancer Research Institute, as of November 2017, there were in excess of 1,000 combination studies ongoing with a PD-1 or PD-L1 therapeutic.  

While inhibitorsversion of the PD-L1 and/or PD-1 pathway offer the potential for clinical benefit in patients withanti-CTLA4 therapeutic, ipilimumab, was generally well tolerated at high doses ranging from 240 mg to 2400 mg (approximately 3 to 30 mg/kg of ipilimumab), either as a wide-variety of cancer types, there are a number of risks imposed by administration of these agents.  According to U.S. Labels for Opdivo, Keytruda, Tecentriq, Bavencio, and Imfinzi, the most common side effects (defined as either >15%single agent or >20%, depending upon the agent) that were observed with commercially available anti-PD-L1 and anti-PD-1 agents include: fatigue, decreased appetite, nausea, vomiting, diarrhea, dyspnea, constipation, cough, musculoskeletal pain, back pain, abdominal pain, arthralgia, urinary tract infection, upper respiratory tract infection, peripheral edema, infusion-related reaction, rash, asthenia, pruritus, headache, and pyrexia.

Based on our analysis of publicly available data, we believe that while in general, the addition of second or third combination partners to PD-L1 or PD-1 inhibitors can result in increased anti-cancer activity, there is often a corresponding increase in the toxicity of these combinations.  For example, according to the New England Journal of Medicine, the most common adverse reactions (greater than or equal to 20%) in patients with melanoma receiving nivolumab with ipilimumab were fatigue, rash, diarrhea, nausea, and pruritus. In some cases, administration of an inhibitor of the PD-L1 pathway with another type of anti-cancer agent in combination have resulted in severe toxicities that have prevented further developmentwith nivolumab. The approved doses of the combination.  In these cases, the toxicity levels caused by the multiple agents in the periphery creates an unacceptable risk to patients, despite theipilimumab commonly used today are 1 mg/kg and 3 mg/kg.

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Neutrophil counts in monkeys treated with CD71 ADC or PDC

Taken together, we believe that CX-2029 has the potential to create a therapeutic window for a CD71 targeting therapeutic.  CX-2029 is currently being studied in a Phase 1/2 clinical trial (PROCLAIM-CX-2029) that is being conducted by CytomX.  

Preclinical Product Candidates

We are actively pursuing the application of our Probody platform technology to multiple other product candidates. These include other product candidates directed against other immunotherapy targets, additional first-in-class PDC product candidates, and T-Cell Engaging bispecific product candidates. Below are selected examples of product candidates that we are pursuing.

CX-188, PD-1 Probody Therapeutic

We have advanced CX-188, our wholly-owned PD-1 Probody therapeutic to the clinical stage.  PD-1 is the receptor for the PD-L1 ligand responsible for inhibiting T-cell activation. It is the target for various immuno-oncology products, including nivolumab (Opdivo) and pembrolizumab (Keytruda).  As with PD-L1, inhibiting PD-1 elicits T-cell anti-tumor responses in a variety of different cancers, and also induces systemic autoimmunity and toxicity. In 2018 we filed an IND for CX-188 and the IND was cleared by the FDA in November 2018.   We have decided to indefinitely postpone clinical trials for CX-188 due to program and portfolio prioritization.  We may elect in the future to initiate clinical trials for CX-188.

Probody T-Cell Engaging Bispecific Platform

We believe that our Probody platform can be applied to T-cell engaging bispecific antibodies (“TCBs”).  TCBs are a highly potent therapeutic modality, designed to direct the activity of cytotoxic T-cells to tumors. TCBs such as Blincyto, a CD19-directed TCB commercialized by Amgen, have shown clinical activity in hematologic malignancies, but development of TCBs for solid tumor indications is proving challenging. Due to their high potency, TCBs can target normal tissues with low antigen expression, resulting in significant on-target, off-tumor toxicity that can limit dosing to low levels. As a result, it has been difficult to reach the level of drug exposure required for efficacy without excessive toxicity. Therefore, novel methods are needed to enable the potent anti-tumor activity of TCBs while limiting toxicity due to cytokine release and the resulting damage to healthy tissues.

Our most advanced asset in this modality is a T cell-engaging Bispecific Probody therapeutic (“Pb-TCB”) targeting EGFR and CD3. In in vitro preclinical studies, we have demonstrated that the unmasked EGFR-CD3 TCB (diamonds) can exhibit potent dose-dependent tumor cell killing, while the masked EGFR-CD3 Pb-TCB (filled squares) reduced cytotoxicity by more than 100,000-fold, as shown in the figure below. A TCB which does not bind EGFR (open squares) does not kill tumor cells, demonstrating that the activity of the TCB is target dependent.

Cytotoxicity of HT-29 tumor cells induced by unmasked, active EGFR-CD3 bispecific antibody (red) and by masked EGFR-CD3 bispecific Probody therapeutic (blue). An inactive control is shown in blue squares

However, in established tumor models, we have demonstrated that Pb-TCBs can induce tumor regressions. As the figure below shows, in the HT29 xenograft model, the Pb-TCB at 0.5 mg/kg (open squares) demonstrated significant anti-tumor activity, and at 1.5 mg/kg (closed squares) was able to induce complete tumor regression. A control treated with inactive PBS buffer (“PBS”) is also shown (circles).  

Example of pre-clinical anti-tumor activity of a Probody TCB at 2 different doses (microgram/kg) in a mouse model, compared to vehicle control (PBS, black). Asterisks indicate statistical significance compared to control.

In nonhuman primates, the EGFR-CD3 Pb-TCB has a significantly higher maximum tolerated dose than the unmasked TCB.  Cynomologus monkeys were able to tolerate a dose of 4,000 microgram/kg of the Pb-TCB, while the maximum tolerated dose of the unmasked TCB was 60 microgram/kg.  Furthermore, as shown in the figure below, the tolerated exposure of the Pb-TCB (blue symbols) was greater than 10,000-fold higher than that of the unmasked TCB (red symbols).  

Concentration in plasma over time of 60 or 180 micrograms/kg single dose of an unmasked, active EGFR-CD3 TCB (red) and of 2000 micrograms/kg as a single dose of a masked EGFR-CD3 Probody therapeutic TCB (blue).

Taken together, we believe our Probody Platform has the potential to enable the development of T-cell engaging bispecific therapeutics against broadly expressed targets such as EGFR.  Our EGFR-CD3 Pb-TCB program is partnered with Amgen, and as of February 2019, is in the pre-clinical lead optimization stage.

Our Collaborations

We believe that the Probody platform has broad applicability across a number ofmany cancer types, biological targets and antibody formats.modalities. We have leveraged strategic partnering to (a) extend the reach of our therapeutic opportunity, and (b) bring in significant non-dilutive capital into the Company. Since 2013, we have entered into collaborations with AbbVie, Amgen, BMSAstellas, Bristol Myers Squibb and ImmunoGen, among others, to enable development of certain Probody therapeutics. In constructing each of these collaborations, our primary objectives were to collaborate with leading biopharmaceutical players to validaterealize the potential of Probody therapeutics, totherapeutics; gain meaningful near-term funding and/or technology access to enable advancement of CytomX’s wholly ownedour wholly-owned Probody therapeutics pipeline,pipeline; broaden the number of Probody therapeutics that ultimately reach the clinic,clinic; and to retain significant milestones, royalties, and in some cases product rights, for long term upside.their long-term potential.

AbbVie Ireland Unlimited Company

In April 2016, we entered into two agreements with AbbVie, a CD71 Co-Development and Licensing Agreement (the “CD71 Agreement”) and athe Discovery Collaboration and Licensing Agreement (the “Discovery Agreement” andDiscovery Agreement, together with the CD71 Agreement are collectively referred to as the “AbbVie Agreements”). Under the terms of the CD71 Agreement, we and AbbVie are co-developing CX-2029, a Probody Drug Conjugateconditionally activated antibody-drug conjugate (“PDC”ADC”) against CD71, and we are responsible for pre-clinical and early clinical development. AbbVie will be responsible for later development and commercialization, with global late-stage development costs shared between the two companies. We will assume 35% of the net profits or net losses related to later development unless we opt-out. If we opt-out from participation of co-development of CX-2029, AbbVie will have sole right and responsibility for the further development, manufacturing and commercialization of such CX-2029.

Under the CD71 Agreement, we received an upfront payment of $20.0 million in April 2016, and wea milestone payment of $40.0 million in May 2020 for completion of the dose-escalation phase of the ongoing Phase 1/2 study. We are currently eligible to receive up to $470.0$430.0 million in development, regulatory and commercial milestone payments and royalties on ex-US sales in the high teens to low twenties if we participate in the co-development of the CX-2029 subject to a reduction in such royalties if we opt-out from the co-development of the CD71 PDC.conditionally activated ADC. Our share of later stage co-development costs for CX-2029 is capped, provided that AbbVie may offset our co-development cost above the capped amounts from future payments such as milestone payments and royalties.

Under the terms of the Discovery Agreement, AbbVie receivesreceived exclusive worldwide rights to develop and commercialize PDCconditionally activated ADCs against up to two targets, one of which was selected in March 2017.2017 and the second of which was selected in July 2019. We shall perform research services to discover the Probody therapeutics and create PDCsconditionally activated ADCs for the nominated collaboration targets. From that point, AbbVie shall have sole right and responsibility for development and commercialization of products comprising or containing such PDCsconditionally activated ADCs (“Discovery Licensed Products”).

Under the Discovery Agreement, we received an upfront payment of $10.0 million in April 2016 and may receivewe received an additional upfront payment of $10.0 million in July 2019 upon the selection by AbbVie of the second target and the satisfaction of certain performance conditions under the CD71 Agreement. AbbVie has not selected the second target, but the performance conditions under the CD71 Agreement were met in September 2016. We are also eligible to receive up to $275.0$265.0 million infor each target nomination,in development, regulatory and commercial milestone payments andas well as royalties in the high singlesingle-digits to low teens from commercial sales of any resulting PDCs. conditionally activated ADCs.

Amgen, Inc.

In September 2017, we entered into a Collaboration and License Agreement (the “Amgen Agreement”) with Amgen. Pursuant to the Amgen Agreement, we received an upfront payment of $40.0 million in October 2017. Concurrent with the entry into the Amgen Agreement, Amgen purchased 1,156,069 shares of our common stock for $20.0 million.million.

Under the terms of the Amgen Agreement, we and Amgen are co-developing a Probodyconditionally activated T-cell engaging bi-specificbispecific therapeutic targeting EGFR (“EGFR Products”). We are responsible for early-stage development of EGFR Products and all related costs (up to certain pre-set costs and certain limits based on clinical study size). Amgen will be responsible for late-stage development, commercialization, and all related costs of EGFR Products. Following early-stage development, we will have the right to elect to participate financially in the global co-development of EGFR Products with Amgen, during which we would bear certain of the worldwide development costs for EGFR Products and Amgen would bear the rest of such costs (the “EGFR Co-Development Option”). If we exercise our EGFR Co-Development Option, we will share in somewhat less than 50% of the profit and losses from sales of such EGFR Products in the U.S., subject to certain caps, offsets, and deferrals. If we choose not to exercise our EGFR Co-Development Option, we will not bear any costs of later stage development. We are eligible to receive up to $455.0$460.0 million in development, regulatory, and commercial milestone payments for EGFR Products, and royalties in the low-double digit to mid-teen

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percentage of worldwide commercial sales, provided that if we exercise our EGFR Co-Development option, we shall only receive royalties in the low-double digit to mid-teen percentage of commercial sales outside of the United States.

In October 2021, we and Amgen executed an amendment to the Amgen Agreement primarily to (1) extend the target selection date for Amgen to select its additional targets for research and development, and (2) reduce the total number of milestone events and increase the total amount of milestone payments for EGFR Products.

Amgen also has the right to select a total of up to three targets, including the two additional targets discussed below. We and Amgen will collaborate in the research and development of Probodyconditionally activated T-cell engaging bi-specificsbispecifics products directed against such targets. Amgen has selected one such target (the “Amgen Other Product”). If Amgen exercises its option within a specified period of time, it can select two such additional targets (the “Amgen Option Products” and, together with the Amgen Other Product, the “Amgen Products”). Except with respect to preclinical activities to be conducted by us, Amgen will be responsible, at its expense, for the development, manufacture, and commercialization of all Amgen Products. If Amgen exercises all of its options and advances all three of the Amgen Products, we are eligible to receive up to $950.0 million in upfront, development, regulatory, and commercial milestones and tiered high single-digit to low-teen percentage royalties.

We have the option to select, from programs specified in the Amgen Agreement, an existing pre-clinical stage T-cell engaging bispecific product from the Amgen pre-clinical pipeline. We will be responsible, at our expense, for converting this program to a Probodyconditionally activated T-cell engaging bispecific product, and thereafter, be responsible for development, manufacturing, and commercialization of the product (“CytomX Product”). Amgen is eligible to receive up to $203.0 million in development, regulatory, and commercial milestone payments for the CytomX Product, and tiered mid-single digit to low double-digit percentage royalties.

Bristol-MyersAstellas Pharma Inc

In March 2020, we entered into a Collaboration and License Agreement (the “Astellas Agreement”) with Astellas, pursuant to which we and Astellas will collaborate on the research, development and commercialization of T-cell engaging bispecific antibody products (“Products”) directed to CD3 and selected tumor antigen targets using our Probody® platform and other proprietary technology. Under the Astellas Agreement, we granted Astellas an exclusive, worldwide, royalty-bearing license to develop and commercialize Products in all fields. Astellas may select up to four targets to develop, with an option to expand to six targets. We will lead preclinical research and discovery activities up to clinical candidate selection for Products directed against up to four targets. Astellas will lead preclinical and clinical development of and regulatory approval for all Products. Astellas will be responsible for commercializing each Product, provided that we will have the option to elect to co-commercialize certain Products with Astellas in the United States, subject to the terms of a separate commercialization agreement to be entered into between us and Astellas.

Under the terms of the Astellas Agreement, we received an upfront payment of $80 million, and Astellas will be responsible for funding the cost of preclinical research and discovery activities of both parties for all Products and for funding the cost of development and commercialization of all Products worldwide. If Astellas exercises its option to expand to six targets, we will be eligible to receive future preclinical, clinical and commercial milestones of approximately $2.5 billion. Astellas will pay us tiered royalties on global net sales of Products from high single-digit to mid-teens percentages, subject to certain reductions. Astellas’ royalty obligations continue with respect to each country and each Product until the later of (i) the date on which such Product is no longer covered by certain intellectual property rights, (ii) the 10th anniversary of the first commercial sale of such product in such country, and (iii) the loss of regulatory exclusivity for such Product in such country.

In addition, for a specified number of targets, at a pre-specified time prior to the initiation of the first pivotal study of a Product directed against such target, we will have an option to elect to co-fund certain subsequently initiated clinical trials for such Product. If we opt in, we would be responsible for a pre-determined portion of the costs of such trials, subject to specified caps, deferrals and offsets. We would then have the option to elect to co-commercialize such Products in the United States. For any such Products, in lieu of royalties in the United States, we will receive less than 40% of the profits for such Products in the United States and tiered low double-digit to mid-teens percentage royalties on net sales of such Products outside of the United States, subject to certain reductions.

Bristol Myers Squibb Company

In May 2014, we and BMSBristol Myers Squibb entered into a Collaboration and License Agreement (the “BMS Agreement”) to discover and develop compounds for use in human therapeutics aimed at multiple immuno-oncology targets using our Probody therapeutic technology.

Under the terms of the BMS Agreement, we granted BMSBristol Myers Squibb exclusive worldwide rights to develop and commercialize Probody therapeutics for up to four oncology targets, two of which were selected upon the execution of the BMS Agreement. Pursuant to the BMS Agreement, we received an upfront payment of $50.0 million and were initially entitled to receive contingent

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payments of up to an aggregate of $1,217.0 million in development, regulatory and commercial milestone payments, which can be reduced by any such payments received or by any termination of targets being pursued. We are entitled to royalty payments in the mid-single digitmid-single-digit to low double digitsdouble-digits percentage from potential future sales. We also receive research and development service fees. BMSBristol Myers Squibb has terminated certain targets from the BMS Agreement, as described below.

In January 2016, BMSBristol Myers Squibb selected the third target pursuant to the BMS Agreement and paid us $10.0 million. In December 2016, BMSBristol Myers Squibb selected the fourth and its final target pursuant to the BMS Agreement and paid us $15.0 million. In December 2016, BMSBristol Myers Squibb selected BMS-986249, a CTLA-4 Probody therapeutic, as a clinical candidate pursuant to the BMS Agreement, which triggered a $2.0 million pre-clinical milestone payment to us. In November 2017, BMSBristol Myers Squibb received acceptance of the IND for BMS-986249 from the FDA, which triggered a $10.0 million milestone payment to us. Bristol Myers Squibb recently advanced BMS-986249 into a randomized Phase 2 cohort expansion in patients with metastatic melanoma in combination with the PD-1 inhibitor nivolumab as part of the larger clinical trial, triggering, in February 2020, a $10.0 million milestone payment from Bristol Myers Squibb to us. This study has been modified to include three additional single-arm cohorts: advanced hepatocellular carcinoma, metastatic castration-resistant prostate cancer, and unresectable locally advanced or metastatic TNBC.

In September 2019, Bristol Myers Squibbinitiated the dose escalation phase of a Phase 1/2a clinical trial of a second anti-CTLA-4-directed therapeutic, BMS-986288, based on a modified version of ipilimumab, administered as monotherapy and in combination with nivolumab in patients with selected advanced solid tumors.

In March 2017, we and BMSBristol Myers Squibb entered into Amendment Number 1 to Extend Collaboration and License Agreement (the “Amendment”(“Amendment 1”). The Amendment grants BMS1 granted Bristol Myers Squibb exclusive worldwide rights to develop and commercialize Probody therapeutics for up to six additional oncology targets and two non-oncology targets.

Under the terms of the Amendment 1, we will continuecontinued to collaborate with BMSBristol Myers Squibb to discover and conduct preclinical development of Probody therapeutics against targets selected by BMS.

Bristol Myers Squibb. Pursuant to the Amendment 1, we received an upfront payment of $200.0 million and we will bewere eligible to receive up to an aggregate of $3,586.0 million as follows: (i) up to $116.0 million in development milestone payments per target or up to $928.0 million if the maximum of eight targets are selected for the first product modality; (ii) up to $124.0 million in milestonecontingent payments for the first commercial sale in various territories for up to three indications per target program or up to $992.0 million if the maximum of eight targets are selected for the first product modality; (iii) up to $60.0 million indevelopment, regulatory and sales milestone payments per target or up to $480.0 million if maximum of eight targets are selected for the first product modality; and (iv) up to $56.3 million in development milestone payments or up to $450.0 million if the maximum of eight targets are selected for the second product modality; (v) up to $62.0 million in milestone payments for the first commercial sale in various territories for up to three indications per target program or up to $496.0 million if the maximum of eight targets are selected for the second product modality; (iii) up to $30.0 million in sales milestone payments per target or up to $240.0 million if maximum of eight targets are selected for the second product modality.milestones. We arewere also entitled to tiered mid-single to low double-digit percentage of royalties from potential future sales.

In January 2019, BMS provided us notificationFebruary 2021, we and Bristol Myers Squibb entered into Amendment Number 2 to amend the Collaboration and License Agreement (“Amendment 2”), as amended by Amendment 1. Subsequent to Amendment 2, Bristol Myers Squibb has the exclusive worldwide rights to develop and commercialize Probody therapeutics for up to five oncology targets. Under the terms of terminationAmendment 2, the period for target selection has been extended and we will continue to collaborate with Bristol Myers Squibb to discover and conduct preclinical development of threeProbody therapeutics against targets selected by Bristol Myers Squibb. Pursuant to Amendment 2, we are eligible to receive contingent payments for development, regulatory and sales milestones of the targets in the BMS Agreement.up to an aggregate of $1,779.0 million. We are still in the processalso entitled to tiered mid-single- to low double-digit percentage of evaluating the related financial impact.  The termination of these targets does not affect BMS-986249, which, as of February 2019, continues to be explored in a Phase 1/2 clinical study that is being conducted by BMS.  The termination of these targets also does not affect the Amendment, which remains in full force and effect.  royalties from potential future sales.

ImmunoGen, Inc.Inc.

In January 2014, CytomX and ImmunoGen entered into the Research Collaboration Agreement (the “ImmunoGen Research Agreement”). The ImmunoGen Research Agreement provides us with the right to use ImmunoGen’s ADC technology in combination with our Probody therapeutic technology to create a PDCconditionally activated ADC directed at one specified target under a research license, and to subsequently obtain an exclusive, worldwide development and commercialization license to use ImmunoGen’s ADC technology to develop and commercialize such PDCs.conditionally activated ADCs. Under the agreement, we provided ImmunoGen with the rights to CytomX’sour Probody therapeutic technology to create PDCsconditionally activated ADCs directed at two targets under the research license and to subsequently obtain exclusive, worldwide development and commercialization licenses to develop and commercialize such PDCs.conditionally activated ADCs. In February 2016, we exercised our option to obtain a development and commercialization license for CX-2009praluzatamab ravtansine (CX-2009) pursuant to the terms of the ImmunoGen Research Agreement (the “CX-2009 License”). In February 2017, ImmunoGen exercised its option to obtain a development and commercialization license for the first of its two targets. ImmunoGen discontinued this program in July 2017 and substitution rights for this program terminated in February 2017. ImmunoGen exercised its second option to obtain a development and commercialization license pursuant to the ImmunoGen Research Agreement (the “ImmunoGen 2017 License”) for a target, epithelial cell adhesion molecule (EPCAM),EpCAM, in December 2017. At the end of 2019, as a result of a strategic restructuring by ImmunoGen and its decision to out-license certain programs, we obtained a worldwide, exclusive, sublicensable license to the EpCAM conditionally activated ADC program from ImmunoGen (the “ImmunoGen 2019 License”) and the ImmunoGen 2017 and continues research work on this program.license ended.

Under the terms of the ImmunoGen Research Agreement, both we and ImmunoGen were required to perform research activities on behalf of the other party for no monetary consideration. Each party iswas solely responsible for the development, manufacturing and commercialization of any products resulting from the exclusive development and commercialization license obtained by such party under the agreement. In consideration for the ImmunoGen 2017praluzatamab ravtansine License,, we are entitled to receive up to $30.0 million in development and regulatory milestone payments per the research program target, up to $50.0 million in sales milestone payments per target and royalties in the mid-single digit percentage on the commercial sales of any resulting product. In consideration for the CX-2009 License, ImmunoGen is entitled to receive up to $60.0 million

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in development and regulatory milestone payments, up to $100.0 million in sales milestone payments and royalties in the mid to high single digitssingle-digits percentage on the commercial sales of any resulting product. In August 2017, we made a milestone payment of $1.0 million to ImmunoGen for the first patient dosing with CX-2009.praluzatamab ravtansine and in February 2020, we triggered a $3.0 million milestone payment to ImmunoGen for the first dosing of a patient in the praluzatamab ravtansine Phase 2 clinical trial. Under the ImmunoGen 2019 License, we gained rights to the EpCAM conditionally activated ADC program and, in return, we made an upfront payment, and we will pay certain clinical development, approval and commercialization milestone payments if achieved and royalties on product sales.

Pfizer PDC CollaborationManufacturing

In May 2013, we entered into a collaboration with Pfizer for up to four targets which was terminated in March 2018.

Manufacturing

Our Probody therapeutic candidates are designed to be produced as fully recombinant antibody prodrugs. Our Probody therapeutic candidates are also designed to maintain the manufacturability benefits of antibodies and leverage well established technologies used for antibody production. We conduct cell line development and process development both in-house and in collaboration with contract development and manufacturing organizations (“CMO”). CMOs are responsible for manufacturing of drug substance and clinical drug product materials.

Our lead Chinese hamster ovary cell line has been successfully used for manufacturing several antibodies and requires minimal process optimization to establish a process to support early phase manufacturing. We utilize well established production steps typically part of a platform manufacturing process for antibodies. The CMOCMOs we have selected hashave a strong track record in manufacturing therapeutic biologics, including antibodies. All activities from cell line development to formulated drug product are performed at one location to maintain aggressive timelines and minimize delays that can result from engaging multiple parties for manufacturing. Similarly, for our PDCconditionally activated ADC projects we have selected CMOs with strong expertise in clinical/commercial drug conjugate manufacturing and with capabilities for toxin conjugation and fill-finish. Furthermore, our two lead PDCconditionally activated ADC programs incorporate toxin payloads that have an established clinical and regulatory history.

To date, we have generally been able to successfully manufacture CX-072, CX-2009praluzatamab ravtansine (CX-2009), CX-2029, and CX-2029pacmilimab (CX-072) for our ongoing early stageearly-stage clinical trials.  However,trials with contract manufacturers. Our partner, Bristol Myers Squibb, has also been successful in independently manufacturing drug product for BMS-986249 and BMS-986288. Furthermore, in order to conduct later stagelater-stage clinical trials of our product candidates, including CX-072, CX-2009praluzatamab ravtansine, CX-2029, and CX-2029,pacmilimab, and eventually, if approved, commercial products, we will need to manufacture them in larger quantities. We, or any manufacturing partners, may be unable to successfully increase the manufacturing scale and capacity for any of our product candidates in a timely or cost-effective manner, or at all. For example, we are currently working with our CMOs to change our manufacturing processes and formulations, as well as scaling up for large drug manufacturing capability for praluzatamab ravtansine and to increasepacmilimab and increasing the term of stability for CX-072pacmilimab drug product for late stagelate-stage clinical trials and commercialization. However, we may have to start late stagelate-stage trials with our early clinical trial drug product and switch to the late stagelate-stage or commercial drug product mid trial. In such event, the FDA will require us to complete bridging studies to compare the earlier stage material with the late stagelate-stage or commercial material to assure comparability between the earlier trial material and the late stagelate-stage or commercial material. Changing the formulation and scale up process is a complicated and difficult task. While we believe we can complete the process successfully, there can be no assurances that the changes we make to the drug product and manufacturing process will be successful or completed in a timely manner or that the FDA will not require additional development steps or studies from those we believe are necessary. If we are unable scale up our manufacturing capabilities with respect to CX-072praluzatamab ravtansine, pacmilimab or any of our other product candidates, increase the life of drug stability of CX-072pacmilimab or such other product candidates, or successfully complete the FDA’s bridging requirements, we may not be able to successfully obtain FDA approval and commercialize CX-072pacmilimab or such other product candidates in a timely manner or at all.

The supply chain for the manufacturing of our product candidates is complicated and can involve many parties. We do not own manufacturing facilities for producing such supplies and rely on third-party contract manufacturers to manufacture our clinical trial and preclinical study product supplies. Our clinical trial manufacturing contractors and suppliers are our sole source for their respective manufacturing and supplies. Failure of any of these contractors could affect our ability to have clinical trial material available when needed. This could result in a substantial delay of our clinical trials. For example, for each of CX-072 CX-2009praluzatamab ravtansine, CX-2029, pacmilimab and CX-2029,CX-904, our manufacturing supply chain includes several contract manufacturers, and failure by any of these manufacturers could result in interruptions of our clinical studies. We do not have any long-term contracts and we do not currently have an alternative to any of our third-party contract manufacturers. Consequently, there can be no assurance that our preclinical and clinical development product supplies will not be limited, interrupted, or of satisfactory quality or continue to be available at acceptable prices. In particular, any replacement of any of our third-party contract manufacturers could require significant effort and expertise because there may be a limited number of qualified replacements. In addition, we may encounter issues with transferring technology to a new third-party manufacturer, and we may encounter regulatory delays if we need to move the manufacturing of our products from one third-party manufacturer to another. For example, we were dependent on ImmunoGen under our collaboration for certain steps in the manufacturing of clinical quantities of CX-2009.praluzatamab ravtansine. At the end of 2018, ImmunoGen closed their clinical manufacturing facility in Norwood, MA. This siteMassachusetts which provided clinical manufacturing support for the CX-2009praluzatamab ravtansine program. We have initiatedcompleted the transfer of the drug substance manufacturing process from ImmunoGen to a contract manufacturer, where we have an existing relationship and with expertise in the manufacture of antibody

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drug conjugates at a clinical and commercial scale. To date,While the manufacturing transfer process is still ongoing and has not yet been completed. However,completed, there can be no assurancesassurance that we will not experience a disruption toin the supply of CX-2009 in connection withpraluzatamab ravtansine as a result of such transfer or that we will not experience any other disruption in the transfer will be successful.manufacturing of praluzatamab ravtansine.

In-Licenses

In-Licenses

License from UCSB

In August 2010, we entered into an agreement with UCSB, that grants us an exclusive license, with the right to sublicense, under the patent rights owned by UCSB covering mask and screening technologies relating to the identification and discovery of pro-protein biologics, including masks and substrates, for the identification of pro-proteins, for use in the fields of therapeutics, in vivo diagnostics, and prophylactics (the “UCSB Agreement”). The UCSB Agreement also grants us an exclusive license, with the right to sublicense, under UCSB’s interest in certain patent rights we co-own with UCSB covering Probody antibodies and other pro-proteins in the fields of therapeutics, in vivo diagnostics and prophylactics.

We had no upfront payment obligations under the agreement. In April 2019, we amended the UCSB Agreement and in connection with the amendment, we paid UCSB $1.0 million and issued 150,000 shares of our common stock to UCSB. We are obligated to pay to UCSB royalties on net sales of licensed products in the low single digit percentages, subject to annual minimum amounts as well as certain reductions. We are required to make milestone payments to UCSB on the accomplishment of certain milestones totaling up to $1,075 million for each of the first two indications for each licensed product consisting of a molecule or compound covered by the licensed patent rights. We were also obligated to make a payment to UCSB upon the first occurrence of an IPO or change of control. If the Company sublicenses its rights under the UCSB Agreement, it must pay UCSB a percentage of our total sublicense revenues ranging from the mid-single to mid-teen percentages, which total amount would be first reduced by the aggregate amount of certain research and development related expenses incurred by the Company and other permitted deductions.

LicenseLicenses from ImmunoGen

In February 2016, we exercised our option to obtain a worldwide, exclusive, sublicensable license from ImmunoGen for development and commercialization of products directed against the target selected by us under our research collaboration agreement with ImmunoGen. Additionally, in December 2019, we obtained a worldwide, exclusive, sublicensable license to ImmunoGen’s EpCAM conditionally activated ADC program. See the description of the license agreementagreements set forth under the caption “Our Collaborations—ImmunoGen, Inc.” in this Item 1 of this Annual Report on Form 10-K.

Competition

CytomX is pioneering a new class of antibody therapeutics – the Probody therapeutic platform. The biotechnology and biopharmaceutical industries, including the ADC and the immuno-oncology subsector,subsectors, are characterized by rapid evolution of technologies, fierce competition and strong defense of intellectual property. Any product candidates that we successfully develop and commercialize will have to compete with existing therapies and new therapies that may become available in the future. While we believe that our proprietary Probody platform and scientific expertise in the field of biologics and immuno-oncology provide us with competitive advantages, a wide variety of institutions, including large biopharmaceutical companies, specialty biotechnology companies, academic research departments and public and private research institutions, are actively developing potentially competitive products and technologies. We face substantial competition from biotechnology and biopharmaceutical companies developing biopharmaceutical products, particularly with respect to inADC and immuno-oncology therapeutics, where competition is intense and rapidly evolving. These competitors generally fall within the following categories:

Masking and conditional activation: Several companies, including Akriveia,AbbVie, Adagene, Amgen, Amunix, BioAtla, Halozyme, Harpoon, Maverick Therapeutics, Pandion Therapeutics, Revitope, Roche, Seagen, Takeda, Werewolf, and RocheXilio are exploring antibody masking and/or conditional activation strategies, which could compete with our Probody Platform.platform.

Antibody-drug conjugates: Several large pharmaceutical companies, such as AbbVie, Daiichi Sankyo, Gilead, Pfizer, Roche, and Takeda are developing ADCs. Two mid-sized companies, ImmunoGen and Seagen are also leaders in this space. In addition, numerous smaller companies have ongoing efforts in the space.

Cancer immunotherapies: Cancer immunotherapy is one of the most competitive and fastest growing segments of the pharmaceutical industry. Almost every large pharmaceutical company is developing cancer immunotherapies, including Amgen, AstraZeneca, PLC, BMS,Bristol Myers Squibb, Celgene, GlaxoSmithKline, plc, Merck, & Co., Inc., Novartis, AG, Pfizer, Roche, Holding Ltd and Sanofi SA.Sanofi. In addition, many large and mid-sized biotech companies such as BeiGene, Incyte, TESARO, Inc., Nektar, and Alkermes have ongoing efforts in cancer immunotherapy. Finally, numerous smallNumerous smaller companies are also working in the space.

Antibody drug conjugates: Several large pharmaceutical companies, such as AbbVie, Daiichi Sankyo, Pfizer, Roche, and Takeda are developing ADCs.  Three mid-sized companies, ImmunoGen, Seattle Genetics, and Immunomedics are also leaders in this space.  Finally, numerous small companies have ongoing efforts in the space.

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T-cell engaging bispecifics: Several large pharmaceutics companies, such as Amgen, Novartis, and Roche, have on-going efforts in the spacefield of TCBs. In additional, several mid-sized biotech companies such as MacrogenicsMacroGenics and Xencor, as well as numerous smaller companies, including Janux, have ongoing efforts in TCBs.  Finally, numerous small companies have ongoing efforts in the space.

Many of our competitors, either alone or with strategic partners, have substantially greater financial, technical and human resources than we do. Accordingly, our competitors may be more successful than us in obtaining approval for treatments and achieving widespread market acceptance, rendering our treatments obsolete or non-competitive. Accelerated merger and acquisition activity in the biotechnology and biopharmaceutical industries may result in even more resources being concentrated among a smaller number of our competitors. These companies also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical study sites and patient registration for clinical studies and acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. Our commercial opportunity could be substantially limited in the event that our competitors develop and commercialize products that are more effective, safer, less toxic, more convenient or less expensive than our comparable products. In geographies that are critical to our commercial success, competitors may also obtain regulatory approvals before us, resulting in our competitors building a strong market position in advance of our products’ entry. We believe the factors determining the success of our programs will be the efficacy, safety and convenience of our product candidates.

Intellectual Property

We strive to protect and enhance the proprietary technology, inventions, and improvements that are commercially important to our business, including seeking, maintaining, and defending patent rights, whether developed internally or licensed from third parties. Our policy is to seek to protect our proprietary position by, among other methods, pursuing and obtaining patent protection in the United States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements, platforms and product candidates that are important to the development and implementation of our business. Our patent portfolio is intended to cover, but is not limited to, our technology platforms, our product candidates and components thereof, their methods of use and processes for their manufacture, our proprietary reagents and assays, and any other inventions that are commercially important to our business. We also rely on trade secret protection of our confidential information and know-how relating to our proprietary technology, platforms and product candidates, continuing innovation, and in-licensing opportunities to develop, strengthen, and maintain our proprietary position in our Probody platform and product candidates. We expect to rely on data exclusivity, market exclusivity, patent term adjustment and patent term extensions when available. Our commercial success may depend in part on our ability to obtain and maintain patent and other proprietary protection for our technology, inventions, and improvements; to preserve the confidentiality of our trade secrets; to maintain our licenses to use intellectual property owned or controlled by third parties; to defend and enforce our proprietary rights, including our patents; to defend against and challenge the assertion by third parties of their purported intellectual property rights; and to operate without the unauthorized infringement of valid and enforceable patents and other proprietary rights of third parties.

We believe that we have a strong global intellectual property position and substantial know-how and trade secrets relating to our Probody therapeutic technology, platform and product candidates. Our patent portfolio as of February 15, 2019January 6, 2022 contains at least 100 issued160 granted patents (some of which are co-owned with a third party) and 250at least 390 pending patent applications (some of which are co-owned with a third party). We have exclusively licensed UCSB’s interest in the co-owned patent family covering Probody and other pro-protein technology in the fields of therapeutics, in vivo diagnostics and prophylactics.

These patents and patent applications include claims directed to:

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In addition, we have exclusively licensed a patent portfolio of patent families from UCSB patents and patent applications that cover compositions and methods related to screening for and identification of masks and protease-cleavable linkers that we incorporatehave incorporated into our Probody therapeutics and may incorporate into future Probody therapeutics.

As for the Probody platform, product candidates and processes we develop and commercialize, in the normal course of business, we intend to pursue, where appropriate, patent protection or trade secret protection relating to compositions, methods of manufacture, assay methods, methods of use, treatment of indications, dosing and formulations. We may also pursue patent protection with respect to product development processes and technology.

We continually assess and refine our intellectual property strategy as we develop new platform technologies and product candidates. To that end, we are prepared to file additional patent applications if our intellectual property strategy requires such filings, or where we seek to adapt to competition or seize business opportunities. Further, we are prepared to file patent applications, as we consider appropriate under the circumstances, relating to the new technologies that we develop. In addition to filing and prosecuting patent applications in the United States, we often file counterpart patent applications in the European Union and in additional countries where we believe such foreign filing is likely to be beneficial, including but not limited to any or all of Australia, Brazil, Canada, China, Europe, Hong Kong, India, Indonesia, Israel, Japan, Malaysia, Mexico, New Zealand, Russia or Eurasian Patent Organization, Singapore, South Africa and South Korea.beneficial.

Our currently issued patents will likely expire on dates ranging from 2028 to 2035,2037, unless we receive patent term extension or adjustment as might be available under applicable law. If patents are issued on our pending patent applications, the resulting patents are projected to expire on dates ranging from 2028 to 2039,2041, unless we receive patent term extension or adjustment. However, the actual protection afforded by a patent varies on a product-by-product basis, from country-to-country, and depends upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions, the availability of legal remedies in a particular country, and the validity and enforceability of the patent.

All of our patents and patent applications are subject to risks and uncertainties under U.S. and foreign law. We also rely on trademark registration to protect our trademarks. For a more comprehensive discussion of risks related to our proprietary technology, inventions, improvements, platforms and product candidates, please see the section entitled “Risk Factors—Risks Related to Intellectual Property.”

We intend to file applications for trademark registrations in connection with our product candidates in various jurisdictions, including the U.S. The USPTO previously accepted the PROBODY mark under an intent-to-use trademark application. Because we were unable to show use for that mark within three years of acceptance, the mark became abandoned. We have re-filed for trademark protection of the PROBODY mark with the USPTO. We also have filed for trademark protection of the CYTOMX and IHZ marks as well as the CytomX Logo with the USPTO. Both the PROBODY and IHZ marks were allowed by the USPTO in 2016. The PROBODY mark was registered in class 5 by the USPTO in 2017.

We also rely on trade secret protection for our confidential and proprietary information. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our exclusive property. In many cases our confidentiality and other agreements with consultants, outside scientific collaborators, sponsored researchers and other advisors require them to assign or grant us licenses to inventions they invent as a result of the work or services they render under such agreements or grant us an option to negotiate a license to use such inventions.

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Government Regulation and Product Approval

Governmental authorities in the U.S., at the federal, state and local level, and other countries extensively regulate, among other things, the research, development, testing, manufacture, labeling, packaging, promotion, storage, advertising, distribution, marketing and export and import of products such as those we are developing. Our therapeuticproduct candidates are subject to regulation in the U.S. as biologics, which must be approved by the FDA through the NDA or BLA process before they may be legally marketed in the U.S. and will be subject to similar requirements in other countries prior to marketing in those countries. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources.

U.S. Government Regulation

In the U.S., the FDA regulates drugsbiologics under the Federal Food, Drug, and Cosmetic Act (“FDCA”) and in the case of therapeutic biologics, the Public Health ServicesService Act (“PHSA”), and their respective implementing regulations. Failure to comply with the applicable U.S. requirements at any time during the product development or approval process, or after approval, may subject an applicant to administrative or judicial sanctions, any of which could have a material adverse effect on us. These sanctions could include:

NDA and BLA approval processesApproval Process

The process required by the FDA before a therapeuticbiologic may be marketed in the U.S. generally involves the following:

Preclinical and Clinical Studies

Once a biopharmaceuticalbiologic product candidate is identified for development, it enters the preclinical or nonclinical testing stage. Nonclinical tests include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies. An IND sponsor must submit the results of the nonclinical tests, together with manufacturing information and analytical data, to the FDA as part of the IND. Some nonclinical testing may continue even after the IND is submitted. In addition to including the results of the nonclinical studies, the IND will also include a protocol detailing, among other things, the objectives of the clinical trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated if the first phase lends itself to an efficacy determination.evaluation. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, places the IND on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin. A clinical hold may occur at any time during the life of an IND and may affect one or more specific studies or all studies conducted under the IND.

All clinical trials must be conducted under the supervision of one or more qualified investigators in accordance with GCPs. They must be conducted under protocols detailing the objectives of the trial, dosing procedures, research subject selection and exclusion criteria and the safety and effectiveness criteria to be evaluated. Each protocol, and any subsequent material amendment to the protocol, must be submitted to the FDA as part of the IND. While the IND is active and before approval, progress reports detailingsummarizing the statusresults of the clinical trials and nonclinical studies performed since the last progress report must be submitted at least annually to the FDA, and written IND safety reports must be submitted to the FDA annually. Sponsors also must report to the FDAand investigators for serious and unexpected suspected adverse reactionsevents, findings from other studies suggesting a significant risk to humans exposed to the same or similar drugs, findings from animal or in vitro testing suggesting a timely manner,significant risk to humans, and any clinically important increase in the rateincreased incidence of a serious suspected adverse reaction overcompared to that listed in the protocol or investigation brochure or any findings from other studies or animal or in vitro testing that suggest a significant risk in humans exposedinvestigator brochure.

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Furthermore, an independent IRB for each site proposing to the product candidate. An institutional review board (“IRB”) atconduct each institution participating in the clinical trial must review and approve the protocol before aplan for any clinical trial commencesand its informed consent form before the clinical trial begins at that institutionsite and must also approve the information regarding the trial and the consent form that must be provided to each research subject or the subject’s legal representative, monitor the study until completedcompletion. Some studies also include oversight by an independent group of qualified experts organized by the clinical study sponsor, known as a data safety monitoring board, which provides authorization for whether or not a study may move forward at designated check points based on access to certain data from the study and otherwise complymay halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. Depending on its charter, this group may determine whether a trial may move forward at designated check points based on access to certain data from the trial. The FDA or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with IRB regulations.the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. There are also requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries.

Human clinical trials are typically conducted in three sequential phases that may overlap or be combined.

A pivotal study is aPost-approval trials, sometimes referred to as “Phase 4” clinical study that adequately meets regulatory agency requirements for the evaluation of a product candidate’s efficacy and safety such that it cantrials, may be conducted after initial marketing approval. These trials are used to justifygain additional experience from the approvaltreatment of patients in the product. Generally, pivotal studies are also Phase 3 studies butintended therapeutic indication. In certain instances, FDA may be Phase 2 studies ifmandate the trial design provides a reliable assessmentperformance of clinical benefit, particularly in situations where there is an unmet medical need. Humansuch “Phase 4” clinical trials are inherently uncertain, and Phase 1, Phase 2 and Phase 3 testing may not be successfully completed. The FDA or the sponsor may suspendas a clinical trial at any timecondition of approval for a variety of reasons, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the product candidate has been associated with unexpected serious harm to patients.BLA

During the development of a new biologic product candidate, sponsors are given opportunities to meet with the FDA at certain points; specifically, prior to the submission of an IND, at the end of Phase 2 and before a BLA or NDA is submitted. Meetings at other times may be requested. These meetings can provide an opportunity for the sponsor to share information about the data gathered to date and for the FDA to provide advice on the next phase of development. Sponsors typically use the meeting at the end of Phase 2 to discuss their Phase 2 clinical results and present their plans for the pivotal Phase 3 clinical trial that they believe will support the approval of the new therapeutic. If a Phase 3 clinical trial is the subject of discussion at the end of Phase 2 meeting with the FDA, a sponsor may be able to request a Special Protocol Assessment (“SPA”), the purpose of which is to reach agreement with the FDA on the Phase 3 clinical trial protocol design and analysis that will form the primary basis of an efficacy claim.

Post-approval trials, sometimes referred to as “Phase 4” clinical trials, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, FDA may mandate the performance of such “Phase 4” clinical trials.

According to published guidance on the SPA process, a sponsor that meets the prerequisites may make a specific request for a SPA and provide information regarding the design and size of the proposed clinical trial. The FDA is supposed to evaluate the protocol within 45 days of the request to assess whether the proposed trial is adequate, which evaluation may result in discussions and a request for additional information. A SPA request must be made before the proposed trial begins, and all open issues must be resolved before the trial begins. Although the FDA will assess protocols that have already begun, these assessments will not be subject to the 45-day review applicable to SPAs. If a written agreement is reached, it will be documented and made part of the record. The agreement will be binding on the FDA and may not be changed by the sponsor or the FDA after the trial begins except with the written agreement of the sponsor and the FDA or if the FDA determines that a substantial scientific issue essential to determining the safety or efficacy of the product candidate was identified after the testing began.

Concurrent with clinical trials, sponsors usually complete additional animal safety studies, develop additional information about the chemistry and physical characteristics of the product candidate and finalize a process for manufacturing commercial quantities of the product candidate in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and the manufacturer must develop methods for testing the quality,safety, purity and potency of the product candidate. To help reduce the risk of the introduction of adventitious agents with use of biological products, the PHSA emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other criteria, the sponsor must develop methods for testing the identity, strength, quality, potency and purity of the final biological product. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the biologicalbiologic product candidate does not undergo unacceptable deterioration over its shelf life. Additionally, for both NDA and

Submission of a BLA products, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its proposed shelf-life.FDA

The results of product development, nonclinical studies and clinical trials, along with descriptions of the manufacturing process, analytical tests and other control mechanisms, proposed labeling and other relevant information are submitted to the FDA as part of an NDA ora BLA requesting approval to market the product.product for one or more indications.

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Under the Prescription Drug User Fee Act (“PDUFA”) as amended, each BLA or NDA must be accompanied by a significant user fee. The FDA adjusts the PDUFA user fees on an annual basis. PDUFA also imposes an annual productprogram fee for products and an annual establishment fee on facilities used to manufacture prescription biological or drugmarketed products. Fee waivers or reductions are available in certain circumstances, such as where a waiver is necessary to protect the public health, where the fee would present a significant barrier to innovation, or where the applicant is a small business submitting its first human therapeutic application for review.

Within 60 days following submission of the application, the FDA reviews a BLA or NDA submitted to determine if it is substantially complete before the agency accepts it for filing. The FDA may refuse to file any BLA or NDA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA or NDA must be resubmitted with the additional information. The resubmitted application also is subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review of the BLA or NDA.BLA. The FDA reviews thea BLA to determine, among other things, whether the proposed product is safe, pure and potent and/or effective for its intended use, and has an acceptable purity profile, and in the case of an NDA, whether the product is safe and effective for its intended use, andfacility in each case, whether the productwhich it is being manufactured, processed, packaged, or held meets standards designed to assure the product’s continued safety, purity and potency in accordance with cGMP. The FDA may refer applications for novel products or products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

During the product approval process, the FDA also will determine whether a risk evaluation and mitigation strategies (“REMS”) plan is necessary to assure the safe use of the product. If the FDA concludes a REMS plan is needed, the sponsor of the BLA or NDA must submit a proposed REMS plan. The FDA will not approve a BLA or NDA without a REMS plan, if required. The FDA has authority to require a REMS plan under the Food and Drug Administration Amendments Act of 2007 (the “FDAAA”) when necessary to ensure that the benefits of a drug or therapeutic biologic outweigh the risks. In determining whether a REMS plan is necessary, the FDA must consider the size of the population likely to use the drug or therapeutic biologic, the seriousness of the disease or condition to be treated, the expected benefit of the drug or therapeutic biologic, the duration of treatment, the seriousness of known or potential adverse events, and whether the drug or therapeutic biologic is a new molecular entity. A REMS plan may be required to include various elements, such as a medication guide or patient package insert, a communication plan to educate health care providers of the risks, limitations on who may prescribe or dispense the drug or therapeutic biologic, or other measures that the FDA deems necessary to assure the safe use of the drug or therapeutic biologic. In addition, the REMS plan must include a timetable to assess the strategy at 18 months, three years, and seven years after the strategy’s approval.

The FDA may also require a REMS plan for a drug or therapeutic biologic that is already on the market if it determines, based on new safety information, that a REMS plan is necessary to ensure that the product’s benefits outweigh its risks.

Before approving a BLA, or NDA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving a BLA, or NDA, the FDA will typically inspect one or more clinical sites to assure that the clinical trials were conducted in compliance with IND trial requirements and GCP requirements. To assure cGMP and GCP compliance, an applicant must incur significant expenditure of time, money and effort in the areas of training, record keeping, production and quality control.

Notwithstanding the submission of relevant data and information,After the FDA may ultimately decide thatevaluates the BLA or NDA does not satisfy its regulatory criteria for approval and deny approval. Data obtained from clinical trials are not always conclusive and the FDA may interpret data differently than we interpret the same data. If the agency decides not to approve the BLAmanufacturing facilities, it issues either an approval letter or NDA in its present form, the FDA will issue a complete response letter. An approval letter thatauthorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally describes all of the specific deficiencies in the BLA or NDA identified by the FDA. The deficiencies identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. Additionally, the complete response letter may include recommended actions that the applicant might take to place the application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the BLA, or NDA, addressing all of the deficiencies identified in the letter, or withdraw the application.

Even if a product receives regulatory approval, the approval may be significantly limited to specific indications and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings or precautions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing, or dispensing in the form

As a condition of a risk management plan, or otherwise limit the scope of any approval. In addition,BLA approval, the FDA may require posta Risk Evaluation and Mitigation Strategy (“REMS”) to ensure that the benefits of the drug outweigh its risks. If the FDA determines a REMS is necessary prior to or during review of the application, the sponsor must submit a REMS as part of its application, and the FDA will not approve a BLA without a REMS, if required. A REMS program may be required to include various elements, such as a medication guide or patient package insert, a communication plan to educate healthcare providers of the product’s risks, or other elements to assure safe use, such as limitations on who may prescribe or dispense the drug, dispensing only under certain circumstances, special monitoring and the use of patient registries. In addition, all REMS programs must include a timetable to periodically assess the strategy following implementation.

Further, product approval may require substantial post-approval testing and surveillance to monitor the product’s safety and efficacy, and the FDA has the authority to prevent or limit further marketing of a product based on the results of these post-marketing programs. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are identified following initial marketing. Moreover, changes to the conditions established in an approved application, including changes in indications, labeling or manufacturing processes or facilities may require submission and FDA approval of a new supplement before the changes can be implemented. A supplement for a new indication typically requires clinical trials, sometimesdata, and the FDA uses similar procedures in reviewing supplements as it does in reviewing original applications.

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Companion Diagnostics

Some of our product candidates may require use of an in vitro diagnostic to identify appropriate patient populations. These diagnostics, often referred to as “Phase 4”companion diagnostics, are regulated as medical devices. In the United States, the FDCA and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, pre-clinical and clinical trials, designed to further assess a biological product’s safetytesting, premarket clearance or approval, registration and effectiveness,listing, manufacturing, labeling, storage, advertising and testingpromotion, sales and surveillance programs to monitor the safety of approved products that have been commercialized.

Companion Diagnostics

The FDA issued a final guidance document in July 2014 addressing agency policy in relation to in vitrodistribution, export and import, and post-market surveillance. Unless an exemption applies, companion diagnostic tests.tests require marketing clearance or approval from the FDA prior to commercial distribution. The guidance explains that for some drugstwo primary types of FDA marketing authorization applicable to a medical device are premarket notification, also called 510(k) clearance, and therapeutic biologics, thepremarket approval (“PMA”).

If use of a companion diagnostic test is essential for theto safe and effective use of a biologic product, then the FDA generally will require approval or clearance of the diagnostic contemporaneously with the approval of the biologic product. According to FDA guidance, for novel product candidates such as drugs and therapeutic biologics, a companion diagnostic device and its corresponding product candidate should be approved or cleared contemporaneously by FDA for the use indicated in the product such as when the uselabeling. The guidance also explains that a companion diagnostic device used to make treatment decisions in clinical trials of a product candidate generally will be considered an investigational device unless it is limitedemployed for an intended use for which the device is already approved or cleared. If used to make critical treatment decisions, such as patient selection, the diagnostic device generally will be considered a specific patient subpopulation that cansignificant risk device under the FDA’s Investigational Device Exemption (“IDE”) regulations. Thus, the sponsor of the diagnostic device will be identified by usingrequired to comply with the test.IDE regulations. According to the guidance, if a diagnostic device and a drug or biologic product candidate are to be studied together to support their respective approvals, both products can be studied in the same investigational study, if the study meets both the requirements of the IDE regulations and the IND regulations. The guidance provides that depending on the details of the study plan and subjects, a sponsor may seek to submit an IND alone, or both an IND and an IDE.

The FDA generally requires companion diagnostics intended to select the patients who will respond to cancer treatment to obtain approval of a PMA for that diagnostic contemporaneously with approval of the therapeutic product. The PMA process, including the gathering of clinical and pre-clinical data and the submission to and review by the FDA, generally will not approve suchcan take several years or longer. It involves a product ifrigorous premarket review during which the companion diagnostic is not also approved or cleared for the appropriate indication,applicant must prepare and accordingly the therapeutic product and the companion diagnostic should be developed and approved or cleared contemporaneously. However,provide the FDA may decide that it is appropriate to approve such a product without an approved or cleared in vitro companion diagnostic device whenwith reasonable assurance of the drug or therapeutic biologic is intended to treat a serious or life-threatening condition for which no satisfactory alternative treatment existsdevice’s safety and effectiveness and information about the FDA determines that the benefits from the use of a product with an unapproved or uncleared in vitro companion diagnostic device are so pronounced as to outweigh the risks from the lack of an approved or cleared in vitro companion diagnostic device. The FDA encourages sponsors considering developing a therapeutic product that requires a companion diagnostic to request a meeting with both relevant device and therapeutic product review divisionsits components regarding, among other things, device design, manufacturing and labeling. PMA applications are also subject to ensure thatan application fee. In addition, PMAs for certain devices must generally include the product development plan will product sufficient dataresults from extensive pre-clinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of both the therapeutic productdevice for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic produces reproducible results when the same sample is tested multiple times by multiple users at multiple laboratories. In addition, as part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (“QSR”) which imposes elaborate testing, control, documentation and the companion diagnostic. Because the FDA’s policy on companion diagnostics is set forth only in guidance, this policy is subject to change andother quality assurance requirements.

PMA approval is not legally binding.

Expedited Reviewguaranteed, and Approval

The FDA has various programs, including Fast Track, priority review, accelerated approval and breakthrough therapy designation, which are intended to expedite or simplify the process for reviewing therapeutic candidates, or provide for the approval of a product candidate on the basis of a surrogate endpoint. Even if a product candidate qualifies for one or more of these programs, the FDA may later decide that the product candidate no longer meets the conditions for qualification or that the time period for FDA review or approval will be lengthened. Generally, therapeutic candidates that are eligible for these programs are those for serious or life-threatening conditions, those with the potential to address unmet medical needs and those that offer meaningful benefits over existing treatments. For example, Fast Track is a process designed to facilitate the development and expedite the review of therapeutic candidates to treat serious or life-threatening diseases or conditions and fill unmet medical needs. Priority review is designed to give therapeutic candidates that offer major advances in treatment or provide a treatment where no adequate therapy exists an initial review within eight months as comparedultimately respond to a standard review timePMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA’s evaluation of twelve months.

Although Fast Track and priority review dothe PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA’s evaluation of the PMA or manufacturing facilities is not affect the standards for approval,favorable, the FDA will attemptdeny approval of the PMA or issue a not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is necessary to facilitate earlymake the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case the PMA approval may be delayed for several months or years while the trials are conducted and frequent meetingsthen the data submitted in an amendment to the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution. Once granted, PMA approval may be withdrawn by the FDA if compliance with post approval requirements, conditions of approval or other regulatory standards are not maintained or problems are identified following initial marketing.

After a sponsordevice is placed on the market, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the United States.

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Expedited Development and Review Programs

The FDA offers a number of expedited development and review programs for qualifying product candidates.

A product candidate may be eligible for Fast Track designated product candidate and expedite review of the application for a product candidate designated for priority review. Accelerated approval, whichdesignation if it is described in Subpart H of 21 CFR Part 314, provides for an earlier approval for a new product candidate that is (1) intended to treat a serious or life-threatening disease or condition; (2) generallycondition and demonstrates the potential to address unmet medical needs for the disease or condition. Fast Track designation applies to the combination of the product candidate and the specific indication for which it is being studied. The sponsor of a Fast Track product candidate has opportunities for frequent interactions with the review team during product development and, once a BLA is submitted, the product candidate may be eligible for Priority Review. A Fast Track product candidate may also be eligible for Rolling Review, where the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the sponsor provides a meaningful advantageschedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA.

A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for Breakthrough Therapy designation to expedite its development and review. A product candidate can receive Breakthrough Therapy designation if preliminary clinical evidence indicates that the product candidate may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

After a BLA is submitted for a product candidate, including a product candidate with a Fast Track designation and/or Breakthrough Therapy designation, the BLA may be eligible for other types of FDA programs intended to expedite the FDA review and approval process, such as Priority Review and Accelerated Approval. A BLA is eligible for Priority Review if the product candidate has the potential to provide a significant improvement in the treatment, diagnosis or prevention of a serious disease or condition compared available therapies;products. Priority review designation means the FDA’s goal is to take action on the marketing application within six months of the 60-day filing date, compared to ten months under standard review.

Additionally, product candidates studied for their safety and (3) demonstrateseffectiveness in treating serious or life-threatening diseases or conditions may receive Accelerated Approval upon a determination that the product candidate has an effect on either a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, (“IMM”) andthat is reasonably likely to predict an effect on IMMirreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. A surrogate endpoint is a laboratory measurement or physical sign used as an indirect or substitute measurement representing a clinically meaningful outcome. As a condition of approval,Accelerated Approval, the FDA maywill generally require that athe sponsor of a product candidate receiving accelerated approvalto perform adequate and well-controlled post-marketing clinical studies to verify and describe the predictedanticipated effect on irreversible morbidity or mortality or other clinical endpoint, and the productbenefit. Products receiving Accelerated Approval may be subject to acceleratedexpedited withdrawal procedures.

procedures if the sponsor fails to conduct the required post-marketing studies or if such studies fail to verify the predicted clinical benefit. In the Food and Drug Administration Safety and Innovation Act (the “FDASIA”), which was signed into law in July 2012, the U.S. Congress encouragedaddition, the FDA to utilize innovative and flexible approaches to the assessment of therapeutic candidates under accelerated approval. The law required the FDA to issue related guidance and also promulgate confirming regulatory changes. In May 2014, the FDA published a final Guidance for Industry titled “Expedited Programs for Serious Conditions—Drugs and Biologics,” which provides guidance on FDA programs that are intended to facilitate and expedite development and review of new therapeutic candidates as well as threshold criteria generally applicable to concluding that a product candidate is a candidate for these expedited development and review programs.

In addition to the Fast Track, accelerated approval and priority review programs discussed above, the FDA’s “Expedited Programs” guidance also describes the Breakthrough Therapy designation. The FDA defines a Breakthrough Therapycurrently requires as a therapeutic that is intended, alone or in combination with one or more other therapeutics, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates thatfor Accelerated Approval pre-approval of promotional materials, which could adversely impact the therapeutic may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. A therapeutic designated as a Breakthrough Therapy is eligible for accelerated approval. The FDA must take certain actions, such as holding timely meetings and providing advice, intended to expeditetiming of the development and reviewcommercial launch of an application for approval of a Breakthrough Therapy. Even if a product qualifies for one or more of these programs, the FDA may later decide that the product no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened. A request for Breakthrough Therapy designation should be submitted concurrently with, or as an amendment to, an IND, but ideally no later than the end of Phase 2 meeting.product.

Patent Term Restoration and Marketing Exclusivity

Depending upon the timing, duration and specifics of FDA approval of the use of our therapeutic candidates, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Act. The Hatch-Waxman Act permits a patent restoration term of up to five years as compensation for patent term lost during product development and the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product candidate’s approval date. The patent term restoration period is generally one half of the time between the effective date of an IND and the submission date of an NDA,a BLA, plus the time between the submission date of an NDAa BLA and the approval of that application, except that the review period is reduced by any time during which the applicant failed to exercise due diligence. Only one patent applicable to an approved product candidate is eligible for the extension and the application for extension must be made prior to expiration of the patent. The USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we intend to apply for restorations of patent term for some of our currently owned or licensed patents to add patent life beyond their current expiration date, depending on the expected length of clinical trials and other factors involved in the submission of the relevant NDA.BLA.

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Biosimilars and Exclusivity

The Affordable Care Act, signed into law in 2010, includes the FDCA also can delay the submission or the approval of certain applications. The FDCA provides a five-year period of non-patent marketing exclusivity within the U.S. to the first applicant to gain approval of an NDA for a new chemical entity. A product candidate is a new chemical entity if the FDA has not previously approved any other new product candidate containing the same active moiety, which is the molecule or ion responsible for the action of the product candidate substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application (an “ANDA”), or a 505(b)(2) NDA submitted by another company for another version of such product candidate where the applicant does not own or have a legal right of reference to all the data required for approval. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement of one of the patents listed with the FDA by the innovator NDA holder. The FDCA also provides three years of marketing exclusivity for an NDA, or supplement to an existing NDA, if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application. Examples of such new clinical investigations include those with respect to new indications, dosages or strengths of an existing product candidate. This three-year exclusivity covers only the modification for which the product received approval on the basis of the new clinical investigations and does not prohibit the FDA from approving ANDAs for product candidates containing the active agent for the original indication or condition of use. Five-year exclusivity will not delay the submission or approval of another company’s full NDA. However, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

The Biologics Price Competition and Innovation Act (the “BPCIA”(“BPCIA”) amended, which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. The FDA has issued several guidance documents outlining an approach to review and approval of biosimilars. Biosimilarity, which requires that there be no clinically meaningful differences between the PHSAbiological product and the reference product in terms of safety, purity, and potency, can be shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to authorizethe reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA to approve similar versions of innovative biologics, commonly known as biosimilars. A competitor seekinguntil four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar must file an applicationproduct may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to establishdemonstrate the safety, purity and potency of its molecule as highly similar to an approved innovator biologic, among other requirements.product. The BPCIA however, barsalso created certain exclusivity periods for biosimilars approved as interchangeable products. At this juncture, it is unclear whether products deemed “interchangeable” by the FDA from approving biosimilar applications for 12 years after an innovatorwill, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law.

A biological product receives initial marketing approval.can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity protection or patent term, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant Orphan Drug Designation to therapeutic candidates intended to treat a rare disease or condition, which is generally a disease or condition that affects either (1) fewer than 200,000 individuals in the U.S., or (2) more than 200,000 individuals in the U.S. and for which there is no reasonable expectation that the cost of developing and making available in the U.S. a product candidate for this type of disease or condition will be recovered from sales in the U.S. for that product candidate. Orphan drug designation entitles the applicant to incentives, which may include grant funding towards clinical study costs, tax advantages, and waivers of FDA user fees. Orphan Drug Designation must be requested before submitting an NDA.a BLA. After the FDA grants Orphan Drug Designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan Drug Designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product candidate that has Orphan Drug Designation subsequently receives the first FDA approval for the disease for which it has such designation, the product candidate is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications to market the same product candidate for the same indication for seven years, except under limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for seven years.which the drug was designated. Orphan drug exclusivity however, could also block the approval of one of our therapeutic candidates for seven years if a competitor obtains approval of the same product candidate as defined bydoes not prevent the FDA or if our product candidate is determined to be contained within the competitor’s product candidatefrom approving a different drug for the same disease or condition, or the same drug for a different disease or condition. Among the other benefits of orphan drug designation are tax credits for certain research and a waiver of the NDA application user fee.

A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication or disease.

for which it received orphan designation. In addition, the orphan drug credit is available for qualifying costs incurred betweenexclusive marketing rights in the dateUnited States may be lost if the FDA designateslater determines that the request for designation was materially defective or, as noted above, if a drug as ansecond applicant demonstrates that its product is clinically superior to the approved product with orphan drug andexclusivity or the date the FDA approves the drug. The recent tax reform legislation, which was signed into law on December 22, 2017, reduced the amountmanufacturer of the qualified clinical research costs for a designated orphanapproved product that a sponsor may claim as a credit from 50%is unable to 25%.

Pediatric Exclusivity and Pediatric Use

Under the Best Pharmaceuticals for Children Act (the “BPCA”), certain therapeutic candidates may obtain an additional six months of exclusivity if the sponsor submits information requested in writing by the FDA, referred to as a Written Request, relating to the use of the active moietyassure sufficient quantities of the product candidate in children. Althoughto meet the FDA may issue a Written Request for studies on either approvedneeds of patients with the rare disease or unapproved indications, it may only do so where it determines that information relating to that use of a product candidate in a pediatric population, or part of the pediatric population, may produce health benefits in that population.condition

In addition, thePediatric Studies

The Pediatric Research Equity Act (“PREA”), requires a sponsor to conduct pediatric studies for most therapeutic candidates and biologics, for a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration. Under PREA, original NDAs, BLAs and supplements thereto must contain a pediatric assessment unless the sponsor has received a deferral or waiver. The required assessment must assess the safety and effectiveness of the product candidate for the claimed indications in all relevant pediatric subpopulations and support dosing and administration for each pediatric subpopulation for which the product

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candidate is determined to be safe, pure and effective.potent. The sponsor or FDA may request a deferral of pediatric studies for some or all of the pediatric subpopulations. A deferral may be granted for several reasons, including a finding that the product candidate or biologic is ready for approval for use in adults before pediatric studies are complete or that additional safety or effectiveness data needs to be collected before the pediatric studies begin. The law requires the FDA to send a PREA Non-Compliance letter to sponsors who have failed to submit their pediatric assessments required under PREA, have failed to seek or obtain a deferral or deferral extension or have failed to request approval for a required pediatric formulation. It further requires the FDA to post the PREA Non- Compliance letter and sponsor’s response.

As part of the FDASIA, the U.S. Congress made a few revisions to the BPCA and PREA, which were slated to expire on September 30, 2012, and made both laws permanent.

Post-Approval Requirements

Once ana BLA approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements is not maintained or if problems occur after the biologic product candidate reaches the market. Later discovery of previously unknown problems with a product candidate may result in restrictions on the product candidate or even complete withdrawal of the product candidate from the market. After approval, some types of changes to the approved product, candidate, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further FDA review and approval. In addition, the FDA may under some circumstances require testing and surveillance programs to monitor the effect of approved therapeutic candidatesproduct that have been commercialized, and the FDA under some circumstances has the power to prevent or limit further marketing of a product candidate based on the results of these post-marketing programs.

Any therapeutic candidates manufactured or distributed by us pursuant to FDA approvals are subject to continuing regulation by the FDA, including, among other things:

TherapeuticBiologic manufacturers and other entities involved in the manufacture and distribution of approved therapeutic products are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and some state agencies for compliance with cGMPs and other laws. The FDA periodically inspects manufacturing facilities to assess compliance with cGMP, which imposes extensive procedural, substantive and record-keeping requirements. In addition, changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require FDA approval before being implemented. FDA regulations would also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon us and any third-party manufacturers that we may decide to use if our product candidates are approved. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance.

New LegislationOnce an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and Regulations

From timestandards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to time, legislation is drafted, introducedcomply with regulatory requirements, may result in mandatory revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

The FDA closely regulates the marketing, labeling, advertising and passedpromotion of drug products. A company can make only those claims relating to safety and efficacy that are approved by the FDA and in Congressaccordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe, in their independent professional medical judgment, legally available products for uses that could significantly changeare not described in the statutory provisions governing the testing, approval, manufacturingproduct’s labeling and marketing of products regulatedthat differ from those tested by us and approved by the FDA. In addition to new legislation,Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA regulationsdoes not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the subject of off-label use of their products. However, companies may share truthful and policies are often revised or interpreted by the agency in waysnot misleading information that may significantly affect our business and our products. It is impossible to predict whether further legislative changes will be enacted or whether FDA regulations, guidance, policies or interpretations changed or what the effect of such changes, if any, may be.otherwise consistent with a product’s FDA-approved labelling.

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Regulation Outside of the U.S.

In addition to regulations in the U.S., we will be subject to regulations of other jurisdictions governing any clinical trials and commercial sales and distribution of our therapeutic candidates. Whether or not we obtain FDA approval for a product, we must obtain approval by the comparable regulatory authorities of countries outside of the U.S. before we can commence clinical trials in such countries and approval of the regulators of such countries or economic areas, such as the European Union, before we may market products in those countries or areas. The approval process and requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from place to place, and the time may be longer or shorter than that required for FDA approval.

Under European Union regulatory systems, a company can consider applying for marketing authorization in several European Union member states by submitting its marketing authorization application(s) under a centralized, decentralized or mutual recognition procedure. The centralized procedure provides for the grant of a single marketing authorization that is valid for all European Union member states. The centralized procedure is compulsory for medicines derived from biotechnology, orphan medicinal products, or those medicines with an active substance not authorized in the European Union on or before May 20, 2004 intended to treat acquired immune deficiency syndrome (“AIDS”), cancer, neurodegenerative disorders or diabetes and optional for those medicines containing a new active substance not authorized in the European Union on or before May 20, 2004, medicines which are highly innovative, or medicines to which the granting of a marketing authorization under the centralized procedure would be in the interest of patients at the European Union-level. The decentralized procedure provides for recognition by European Union national authorities of a first assessment performed by one of the member states. Under this procedure, an identical application for marketing authorization is submitted simultaneously to the national authorities of several European Union member states, one of them being chosen as the “Reference Member State”, and the remaining being the “Concerned Member States”. The Reference Member State must prepare and send drafts of an assessment report, summary of product characteristics and the labelling and package leaflet within 120 days after receipt of a valid marketing authorization application to the Concerned Member States, which must decide within 90 days whether to recognize approval. If any Concerned Member State does not recognize the marketing authorization on the grounds of potential serious risk to public health, the disputed points are eventually referred to the European Commission, whose decision is binding on all member states. The mutual recognition procedure is similar to the decentralized procedure except that a medicine must have already received a marketing authorization in at least one of the member states, and that member state acts as the Reference Member State.

As in the U.S., we may apply for designation of a product candidate as an orphan drug for the treatment of a specific indication in the European Union before the application for marketing authorization is made.

Orphan drugs in the European Union enjoy economic and marketing benefits, including up to ten years of market exclusivity for the approved indication unless another applicant can show that its product is safer, more effective or otherwise clinically superior to the orphan-designated product, the marketing authorization holder is unable to supply sufficient quantity of the medicinal product or the marketing authorization holder has given its consent.

Coverage and Reimbursement

Sales of our products will depend, in part, on the extent to which our products will be covered by third-party payors, such as government health programs, commercial insurance and managed healthcare organizations. These third-party payors are increasingly reducing reimbursements for medical products and services. Additionally, the containment of healthcare costs has become a priority of federal and state governments and the prices of therapeutics have been a focus in this effort. The U.S. government, state legislatures and foreign governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit our net revenue and results. If these third- party payors do not consider our products to be cost-effective compared to other therapies, they may not cover our products after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow us to sell our products on a profitable basis.

Healthcare Reform

The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act (together, the “ACA”) has had a significant impact on the health care industry. The ACA expanded coverage for the uninsured while at the same time containing overall healthcare costs. With regard to biopharmaceutical products, the ACA, among other things, addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected, increased the minimum Medicaid rebates owed by manufacturers under the Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, established annual fees and taxes on manufacturers of certain branded prescription drugs, and a new Medicare Part D coverage gap discount program, in which manufacturers must agreehad to offer 50% point-of-sale discounts, which, through subsequent legislative amendments, will bewas increased to

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70% starting in 2019,, off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D.

Since its enactment, there have been judicial, executive and Congressional challenges to certain aspects of the ACA. On June 17, 2021, the U.S. Supreme Court dismissed the most recent judicial challenge to the ACA brought by several states without specifically ruling on the constitutionality of the ACA. Prior to the Supreme Court’s decision, President Biden issued an executive order initiating a special enrollment period from February 15, 2021 through August 15, 2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also instructed certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare.

In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted that impact payment methodologies and reimbursement amounts. On August 2, 2011, the Budget Control Act of 2011 among other things, created measures for spending reductions by Congress, which led to aggregate reductions to Medicare payments to providers of 2% per fiscal year starting in April 2013, and, due to subsequent legislative amendments, will stay in effect through 20272030, with the exception of a temporary suspension from May 1, 2020 through March 31, 2022, unless additional Congressional action is taken. On January 2, 2013, President Obama signed into law the American Taxpayer Relief Act of 2012 (the “ATRA”) was signed into law which, among other things, also reduced Medicare payments to several types of providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years.

Recently, there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed bills designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. For example, the 21st Century Cures Act changed the reimbursement methodology for infusion drugs and biologics furnished through durable medical equipment in an attempt to remedy over- and underpayment of certain products. Furthermore, the Build Back Better Act, if enacted, would introduce substantial drug pricing reforms, including the establishment of a drug price negotiation program within the U.S. Department of Health and Human Services that would require manufacturers to charge a negotiated “maximum fair price” for certain selected drugs or pay an excise tax for noncompliance, and the establishment of rebate payment requirements on manufacturers of certain drugs payable under Medicare Parts B and D. If the Build Back Better Act is not enacted, similar or other drug pricing proposals could appear in future legislation. Individual states in the United States have also become increasingly aggressive in passing legislation and implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

We expect that the current presidential administration and U.S. Congress will continue to seek to modify, repeal, or otherwise invalidate all, or certain provisions of, the ACA. Since taking office, President Trump has continued to support the repeal of all or portions of the ACA.  On October 12, 2017, President Trump issued an executive order that expands the use of association health plans and allows anyone to purchase short-term health plans that provided temporary, limited insurance. This executive order also calls for the halt of federal payments to health insurers for cost-sharing reductions previously available to lower-income Americans to afford coverage. There is still uncertainty with respect to the impact this executive order could have on coverage and reimbursement for healthcare items and services covered by plans that were authorized by the ACA. In addition, most recently, the Tax Cuts and Jobs Act was enacted, which, among other things, removes penalties for not complying with the ACA’s individual mandate to carry health insurance. We cannot predict the extent of the impact of any such changes to any of these laws on us.

Finally, in some foreign countries, the proposed pricing for a product candidate must be approved before it may be lawfully marketed. The requirements governing therapeutic pricing vary widely from country to country. For example, the European Union provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. A member state may approve a specific price for the medicinal product, or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of our product candidates. Historically, therapeutic candidates launched in the European Union do not follow price structures of the U.S. and generally tend to be significantly lower.

Other Healthcare Laws

We may also be subject to healthcare regulation and enforcement by the federal government and the states and foreign governments where we may market our product candidates, if approved. These laws include, without limitation, state and federal anti-kickback, fraud and abuse, false claims, privacyphysician and security, physician sunshineother health care provider payment and drug pricing transparency laws and regulations.

The federal Anti-Kickback Statute prohibits, among other things, any person from knowingly and willfully offering, soliciting, receiving or providing remuneration, directly or indirectly, to induce either the referral of an individual, for an item or service or the purchasing or ordering of a good or service, for which payment may be made under federal healthcare programs such as the Medicare and Medicaid programs. The Anti-Kickback Statute is subject to evolving interpretations. In the past, the government has enforced the Anti-Kickback Statute to reach large settlements with healthcare companies based on sham consulting and other financial arrangements with physicians. A person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal False Claims Act. The majority of states also have anti-kickback laws, which establish similar prohibitions and, in some cases, may apply to items or services reimbursed by any third-party payor, including commercial insurers.

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Additionally, the civil False Claims Act prohibits knowingly presenting or causing the presentation of a false, fictitious or fraudulent claim for payment to the U.S. government, knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the U.S. government, or from knowingly making a false statement to avoid, decrease or conceal an obligation to pay money to the U.S. government. In addition, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal False Claims Act. Actions under the False Claims Act may be brought by the Attorney General or as a qui tam action by a private individual in the name of the government. Violations of the False Claims Act can result in very significant monetary penalties and treble damages. The federal government is using the False Claims Act, and the accompanying threat of significant liability, in its investigation and prosecution of pharmaceutical and biotechnology companies throughout the U.S., for example, in connection with the promotion of products for unapproved uses and other sales and marketing practices. The government has obtained multi-million and multi-billion-dollar settlements under the False Claims Act in addition to individual criminal convictions under applicable criminal statutes. Given the significant size of actual and potential settlements, it is expected that the government will continue to devote substantial resources to investigating healthcare providers’ and manufacturers’ compliance with applicable fraud and abuse laws.

The U.S. federal Health Insurance Portability and Accountability Act of 1996 (“HIPAA”), created new federal criminal statutes that prohibit among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

There has also been a recent trend of increased federal and state regulation of payments made to physicians and other healthcare providers. The ACA, among other things, imposes new reporting requirements on drug manufacturers for payments made by them to physicians (as defined by statute), certain non-physician practitioners including physician assistants and nurse practitioners and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members. Failure to submit required information may result in civil monetary penalties for all payments, transfers of value or ownership or investment interests that are not timely, accurately and completely reported in an annual submission. Certain states also mandate implementation of compliance programs and compliance with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government, impose restrictions on drug manufacturer marketing practices and/or require the tracking and reporting of pricing and marketing information as well as gifts, compensation and other remuneration or items of value provided to physicians and other healthcare professionals and entities.

We may also be subject to data privacy and security regulation by both the federal government and the states in which we conduct our business. HIPAA, as amended by the Health Information TechnologyPenalties for Economic and Clinical Health Act (“HITECH”) and their respective implementingviolating any of such laws or any other governmental regulations including the final omnibus rule published on January 25, 2013, imposes specified requirements relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s privacy and security standards directly applicable to “business associates,” defined as independent contractors or agents of covered entities that create, receive, maintain or transmit protected health information in connection with providing a service for or on behalf of a covered entity. HITECH also increased theapply include, without limitation, administrative, civil and criminal penalties, that may be imposed against covered entities, business associates and possibly other persons, and gave state attorneys general new authority to file civil actions for damages, fines, disgorgement, the curtailment or injunctionsrestructuring of operations, exclusion from participation in federal courtsand state healthcare programs, integrity oversight and reporting obligations to enforceresolve allegations of non-compliance and imprisonment.

Data Privacy and Security Laws

Numerous state, federal and foreign laws, regulations and standards govern the collection, use, access to, confidentiality and security of health-related and other personal information, and could apply now or in the future to our operations or the operations of our partners. In the United States, numerous federal HIPAA laws and seek attorney’s fees and costs associated with pursuing federal civil actions. In addition, state laws and non-USregulations, including data breach notification laws, health information privacy and security laws and consumer protection laws and regulations (particularly EUgovern the collection, use, disclosure, and protection of health-related and other personal information. In addition, certain foreign laws regarding personal data relating to individuals based in Europe) govern the privacy and security of health informationpersonal data, including health-related data. For example, the General Data Protection Regulation (“GDPR”) imposes strict requirements for processing the personal data of individuals within the European Economic Area (“EEA”). Companies that must comply with the GDPR face increased compliance obligations and risk, including more robust regulatory enforcement of data protection requirements and potential fines for noncompliance of up to €20 million or 4% of the annual global revenues of the noncompliant company, whichever is greater. Further, from January 1, 2021, companies have had to comply with the GDPR and also the United Kingdom GDPR (“UK GDPR”), which, together with the amended UK Data Protection Act 2018, retains the GDPR in certain circumstances, manyUK national law. The UK GDPR mirrors the fines under the GDPR, i.e., fines up to the greater of which differ from€20 million (£17.5 million) or 4% of global turnover. Privacy and security laws, regulations, and other obligations are constantly evolving, may conflict with each other to complicate compliance efforts, and can result in investigations, proceedings, or actions that lead to significant ways, thus complicating compliance efforts.civil and/or criminal penalties and restrictions on data processing.

Environment

Our third-party manufacturers are subject to inspections by the FDA for compliance with cGMP and other U.S. regulatory requirements, including U.S. federal, state and local regulations regarding environmental protection and hazardous and controlled substance controls, among others. Environmental laws and regulations are complex, change frequently and have tended to become

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more stringent over time. We have incurred, and may continue to incur, significant expenditures to ensure we are in compliance with these laws and regulations. We would be subject to significant penalties for failure to comply with these laws and regulations.

Our Company Origins and Team

Our Probody platform technology has its origins in work performed at the University of California, Santa Barbara (“UCSB”), by our scientific founder Professor Patrick Daugherty. Since our inception, we have continued developing and adding to this technology and aspire to design a pipeline of Probody therapeutics that will better the lives of cancer patients. We have assembled an experienced and talented group of individuals dedicated to the advancement of cancer care. Our chief executive officer and chairman, Dr. Sean McCarthy, leads a team that draws on robust experience in all phases of product discovery, clinical development and commercialization. Our clinical development team is led by Dr. Amy Peterson, president and chief operating officer, and Dr. Alison Hannah, chief medical officer. Our research and preclinical development team is led by Dr. Michael Kavanaugh, chief scientific officer,Marcia Belvin, head of research, and includes renowned and established researchers, and our clinical development team is led by Dr. Rachel Humphrey, chief medical officer.researchers. Our management team members have significant experience in oncology with previous experience at AstraZeneca, BMS,BeiGene, Chiron, Five Prime,Genentech, Maxygen, Medivation, Millennium, Novartis, SGX and other companies.

EmployeesHuman Capital

As of December 31, 2018,2021, we had 137174 full-time employees and 24 part-time employees. Of these employees, 102137 were primarily engaged in research and development activities. None of our employees are represented by a labor union or covered by collective bargaining agreements and we consider our employee relations to be good. Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and additional employees. The principal purposes of our equity incentive plans are to attract, retain and motivate selected employees, consultants and directors through the granting of stock-based compensation awards and cash-based performance bonus awards.

Corporate Information

Our operations commenced in February 2008 when our predecessor entity was formed. We were incorporated in Delaware in September 2010. We maintain our executive offices at 151 Oyster Point Blvd., Suite 400, South San Francisco, California 94080, and our main telephone number is (650) 515-3185.

We were an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012.  Based on our public float at June 30, 2018, we ceased to be an emerging growth company at December 31, 2018 and, accordingly, we are required to comply with the auditor attestation requirements of Section 404 to include an opinion from our independent registered public accounting firm on the effectiveness of our internal controls over financial reporting for our 2018 Annual Report on Form 10-K.

We view our operations and measure our business as one reportable segment operating in the United States. See Note 2 to our audited financial statement included elsewhere in this Annual Report on Form 10-K for additional information. Additional information required by this item is incorporated herein by reference to PART II. Item 6 of this Annual Report on Form 10-K.

Our research and development expenses were $103.9$114.2 million, $92.3$112.9 million, and $54.8$131.6 million for the years ended December 31, 2018, 20172021, 2020, and 2016,2019, respectively. Please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations-Research and Development Expenses” for additional detail regarding our research and development activities.

We maintain a website at www.cytomx.com, which contains information about us. The information in, or that can be accessed through, our website is not part of this Annual Report on Form 10-K. Our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K and amendments to those reports are available, free of charge, on or through our website as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. The SEC maintains an Internet site that contains reports, proxy and information statements and other information regarding our filings at www.sec.gov.

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PART II – OTHEROTHER INFORMATION

Item 1A.Risk Factors

Risk Factors Summary

We are providing the following summary of risk factors contained in this Annual Report on Form 10-K to enhance the readability and accessibility of our risk factor disclosures in accordance with SEC rules. Please carefully review the full risk factors pertaining to this summary and to additional general risk factors contained in this Annual Report on Form 10-K in their entirety for additional information regarding the material factors that make an investment in our securities speculative or risky. These risks and uncertainties include, but are not limited to, the following:

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Risk Factors

You should consider carefully the risks and uncertainties described below, together with all of the other information in this Annual Report on Form 10-K, including our financial statements and the related notes and “Management’s Discussion and Analysis of Financial Condition and Results of Operations.” If any of the following risks are realized, our business, financial condition, results of operations and prospects could be materially and adversely affected. The risks described below are not the only risks facing the Company. Risks and uncertainties not currently known to us or that we currently deem to be immaterial also may materially adversely affect our business, financial condition, results of operations and/or prospects.

Risks Related to Our Business

The COVID-19 pandemic or any future pandemic could adversely impact our business, including our research, clinical trials, and financial condition.

In December 2019, a novel strain of coronavirus, COVID-19, was reported to have surfaced in Wuhan, China. Since then,COVID-19 has spread to multiple countries, including the United States and European and Asia-Pacific countries, including countries in which we have planned or active clinical trial sites, including for praluzatamab ravtansine (CX-2009). As COVID-19 and its variants continue to spread around the globe, we will likely continue to experience disruptions that could severely impact our business, research, including research for our partners or research of our partners, and clinical trials, including ongoing or planned clinical trials for praluzatamab ravtansine, CX-2029 and clinical trials of our partners, including Bristol Myers Squibb. These disruptions and impacts may include:

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For example, in March 2020, we announced the temporary pause in new patient enrollment and new site activation in our Phase 2 clinical trial of praluzatamab ravtansine as a result of the COVID-19 pandemic, primarily due to delays in patient enrollment and clinical site initiations, and the termination of the Phase 2 clinical trial of pacmilimab (CX-072) in combination with ipilimumabafter a re-evaluation of the evolving clinical, competitive and commercial landscapes in immuno-oncology, taken together with impact of the COVID-19 pandemic. Since then, we have revised our strategy for developing praluzatamab ravtansine, including redesigning the study. While enrollment is ongoing for our Phase 2 clinical trial for praluzatamab ravtansine and the Phase 2 expansion cohorts for CX-2029, we cannot be certain of the continuing impact of the COVID-19 pandemic, including COVID-19 variants on clinical trial planning, or that site initiation, patient recruitment or other clinical trial activities will not continue to be delayed, discontinued or otherwise impacted.

Furthermore, the COVID-19 pandemic and government limitations on activities may continue to impact our ability to conduct research, including limiting our ability to obtain research materials and equipment, limiting access to our laboratories to conduct research, limiting the ability or willingness of employees to work at our facilities and limiting our ability to complete research and experiments in a timely basis or at all. For example, in March 2020 we initiated a mandatory work-from-home program, limiting onsite activity to a substantially reduced level of laboratory research activities. Although we have gradually increased levels of such laboratory research activities, we continue to operate in a hybrid, work-from-home environment and there can be no assurance that we will be able to continue to increase or maintain current levels of such activity. The COVID-19 pandemic and government limitations could further impact our ability to conduct business generally, including making timely payments, filing timely governmental and other business reports and filings, and otherwise comply with our obligations.

Any of the potential business, research and clinical impacts arising as a result of the COVID-19 pandemic could cause us to default on our obligations to our collaborative partners, including our specific research and development obligations, potentially resulting in termination of one or more collaborations, and could materially and adversely affect our business, financial condition, results of operation and prospects.

In addition, the spread of COVID-19 may negatively impact the trading price of shares of our common stock and could further severely impact our ability to raise additional capital on a timely basis or at all.

The global outbreak of COVID-19 continues to rapidly evolve, including with the discovery of new variants/mutations of the virus. The extent to which the COVID-19 pandemic continues to impact our business, including our clinical trials, research and financial condition will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the ultimate geographic spread of the disease, the duration of the outbreak, travel restrictions and social distancing in the United States and other countries, business closures or business disruptions and the effectiveness of actions taken in the United States and other countries to contain and treat the disease.

We are a clinical-stage biopharmaceutical company with a limited operating history and have not generated any revenue from product sales. We have a history of losses, expect to continue to incur significant losses for the foreseeable future and may never achieve or maintain profitability, which could result in a decline in the market value of our common stock.

We are a clinical-stage biopharmaceutical company with a limited operating history, developing a novel class of therapeutic antibody product candidates, based on our proprietary biologic Probody technology platform. Since our inception, we have devoted our resources to the development of Probody therapeutics. We have had significant operating losses since our inception. As of December 31, 2018,2021 and December 31, 2017,2020, we had an accumulated deficit of $315.0$533.7 million and $219.5$450.1 million, respectively. Substantially all of our losses have resulted from expenses incurred in connection with our research and development programs and from general and administrative costs associated with our operations.

Though we have developed our Probody platform, our technologies and product candidates are in early stages of development, and we are subject to the risks of failure inherent in the development of product candidates based on novel technologies. We have not yet demonstrated our ability to successfully complete any mid or late-stage clinical trials, including large-scale, pivotal clinical trials, obtain regulatory approvals, arrange for a third party to manufacture a commercial scalecommercial-scale product candidate, or conduct sales and marketing activities necessary for successful commercialization. Typically, it takes many years to develop one product candidate from the time it enters initial preclinical studies to when it is available for treating patients. Consequently, any predictions made about our future success or viability may not be as accurate as they could be if we had a longer operating history. We will need to transition from a company with a research and development focus to a company capable of supporting commercial activities. We may not be successful in such a transition.

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Furthermore, we have never generated any revenue from product sales, and have not obtained regulatory approval for any of our product candidates. We also do not expect to generate any revenue from product sales for the foreseeable future, and we expect to continue to incur significant operating losses for the foreseeable future due to the cost of research and development, preclinical studies and clinical trials and the regulatory approval process for our product candidates. We expect our net losses to increase substantially as we continue clinical development of our lead programs and advance additional programs into clinical development. In particular, we expect our losses to increase substantially as we continue to enroll patients in our ongoing Phase 1/2 clinical trialstrial of CX-072,praluzatamab ravtansine (CX-2009), our conditionally activated ADC candidate directed against PD-L1, CX-2009,CD166, as monotherapy or in combination with pacmilimab (CX-072) in patients with breast cancer, as we enroll patients in our PDC candidate directed against CD-166,Phase 2 expansion trial of CX-2029, and our PDCconditionally activated ADC candidate directed against CD71 in collaboration with AbbVie Inc., as we enroll patients in our Phase 1 clinical trial of CX-904, our conditionally activated T-cell-engaging bispecific antibody candidate against the epidermal growth factor receptor (“EGFR”) in collaboration with Amgen, Inc., and as we advance into later trials and new trials for these and other programs. However, the amount of our future losses is uncertain. Our ability to achieve profitability, if ever, will depend on, among other things, our, or our collaborators, successfully developing product candidates, obtaining regulatory approvals to market and commercialize product candidates, manufacturing any approved products on commercially reasonable terms, establishing a sales and marketing organization or suitable third-party alternatives for any approved product and raising sufficient funds to finance business activities. If we, or our collaborators, are unable to develop our technologies and commercialize one or more of our product candidates or if sales revenue from any product candidate that receives approval is insufficient, we will not achieve profitability, which could have a material and adverse effect on our business, financial condition, results of operations and prospects.

We expect that we will need to raise substantial additional funds to advance development of our product candidates and we cannot guarantee that this additional funding will be available on acceptable terms or at all. Failure to obtain this necessary capital when needed may force us to delay, limit or terminate our product development and commercialization of our current or future product candidates.

The development of biopharmaceutical product candidates is capital-intensive. To date, we have used substantial funds to develop our technology and product candidates and will require significant funds to conduct our ongoing clinical trials as well as to further our research and development, preclinical testing and future clinical trials of additional product candidates, to seek regulatory approvals for our product candidates and to manufacture and market any products that are approved for commercial sale. In addition, we have incurred and will continue to incur additional costs associated with operating as a public company.

As of December 31, 2018,2021, we had $436.1$305.2 million in cash, cash equivalents and short-term investments. We believe that our existing capital resources will be sufficient to fund our planned operations into 2021.at least for the next twelve months from the date the financial statements included in this report are issued. Our future capital requirements and the period for which we expect our existing resources to support our operations may vary significantly from what we expect. Our monthly spending levels vary based on our ongoing clinical trials, new and ongoing research and development and other corporate activities. For example, we expect our monthly spending to increase substantially as we continue to enroll patients in our ongoing Phase 1/2 clinical trialstrial of CX-072, CX-2009, andpraluzatamab ravtansine (CX-2009) as monotherapy or in combination with pacmilimab (CX-072) in patients with breast cancer, as we enroll patients in our Phase 2 expansion trial of CX-2029, and as we advance into later trials and new trials for other programs.enroll patients in our Phase 1 clinical trial of CX-904. Because the length of time and activities associated with conducting our clinical trials and successfully researching and developing our product candidates is highly uncertain, we are unable to estimate the actual funds we will require for development and, once any product candidate is approved, any subsequent marketing and commercialization activities.

The timing and amount of our operating expenditures will depend largely on:

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If we are unable to obtain funding on a timely basis or on acceptable terms, we may have to delay, reduce or terminate our research and development programs and preclinical studies or clinical trials, limit strategic opportunities or undergo reductions in our workforce or other corporate restructuring activities. We also could be required to seek funds through arrangements with collaborators or others that may require us to relinquish rights to some of our technologies or product candidates that we would otherwise pursue on our own. We do not expect to realize revenue from sales of products or royalties from licensed products in the foreseeable future, if at all, and unless and until our product candidates are clinically tested, approved for commercialization and successfully marketed. To date, we have financed our operations primarily through sales of our common stock, sale of our convertible preferred securities prior to our IPO and payments received under our collaboration agreements, including, most recently, the Collaboration and License Agreement that we entered into with AmgenAstellas in September 2017.March 2020. We will be required to seek additional funding in the future and currently intend to do so through additional collaborations, public or private equity offerings or debt financings, credit or loan facilities or a combination of one or more of these funding sources. Our ability to raise additional funds will depend on financial, economic and other factors, many of which are beyond our control.control, including the COVID-19 pandemic. Additional funds may not be available to us on acceptable terms or at all. If we raise additional funds by issuing equity securities, our stockholders will suffer dilution and the terms of any financing may adversely affect the rights of our stockholders. In addition, as a condition to providing additional funds to us, future investors may demand, and may be granted, rights superior to those of existing stockholders. Debt financing, if available, is likely to involve restrictive covenants limiting our flexibility in conducting future business activities, and, in the event of insolvency, debt holders would be repaid before holders of our equity securities received any distribution of our corporate assets.

Clinical development involves a lengthy and expensive process with an uncertain outcome, and results of earlier studies and trials may not be predictive of future trial results. We may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our product candidates.

As is the case with all oncology drugs, our product candidates in clinical development or preclinical development go through a long process and have a high risk of failure. We commenced enrollment of our Phase 1/2 clinical trial of CX-072, our candidate directed against PD-L1,failure, including termination for cancer and treated our first patient in January 2017. We also initiated our Phase 1/2 clinical trial of CX-2009, our PDC candidate directed against CD-166, for cancer in June 2017, and initiated our Phase 1/2 clinical trial of CX-2029, our PDC candidate directed against CD71 in collaboration with AbbVie, for cancer in June 2018. In addition, Bristol-Myers Squibb Company (“BMS”) commenced enrollment of a Phase 1/2 clinical trial for BMS-986249, a Probody therapeutic directed against CTLA-4, in 2018.strategic reasons. It is impossible to predict when or if any of our or our partner’s product candidates will prove effectivesafe, pure and safepotent (or effective) in humans or will receive regulatory approval. Before obtaining marketing approval from regulatory authorities for the sale of any product candidate, we or our partners must complete extensive clinical trials to demonstrate the safety, purity and efficacypotency (or efficacy) of our product candidates in humans. Commencement of clinical trials for programs beyond CX-072, CX-2009,praluzatamab ravtansine, CX-2029, BMS-986249, BMS-986288, and BMS-986249pacmilimab and CX-904 is subject to finalizing the trial design and filingsubmission of an IND or similar filing withsubmission to the FDA or similar foreign regulatory authority.global health authorities. In addition, even if we file oursubmit an IND or a comparable submissionssubmission in other jurisdictions for these or other product candidates, including CX-2043, the FDA or other regulatory authorities could disagree that we have satisfied their requirements to commence our clinical trials or disagree with our study design, which may require us to complete additional preclinical studies or amend our protocols or impose stricter conditions on the commencement of clinical trials and may delay our ability to begin Phase 1 clinical trials, causing an increase in the amount of time and expense required to develop our product candidates.candidates including CX-2043. As a result of the foregoing, the research and development, preclinical studies and clinical testing of any product candidate is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time during the development process.

Further, we or our collaborators may also experience delays in completing ongoing clinical trials, completing preclinical studies or initiating further clinical trials of our product candidates.candidates, including, for example, among other things, as a result of the COVID-19 pandemic. We do not know whether our or our collaborators’ ongoing clinical trials or preclinical studies will be completed on schedule or at all, or whether planned clinical trials or preclinical studies will begin on time, need to be redesigned, enroll patients on time or be completed on schedule, if at all. We or our collaborators may have insufficient internal resources to complete ongoing clinical trials or initiate clinical trials for our other product candidates. The development programs for our product candidates may also be delayed for a variety of reasons, including delays related to:

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In addition, the results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy traits despite having progressed through preclinical studies and initial clinical trials. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or safety profiles, notwithstanding promising results in earlier trials.

Our product candidates are in early stages of development and may fail or suffer delays that materially and adversely affect their commercial viability. If we are unable to advance our product candidates through clinical development, obtain regulatory approval and ultimately commercialize such product candidates, or experience significant delays in doing so, our business will be materially harmed.

We are very early in our development efforts, with only threefour product candidates, CX-072, CX-2009praluzatamab ravtansine (CX-2009), CX-2029, pacmilimab (CX-072), and CX-2029,CX-904 currently in early stageearly-stage clinical development. In addition, BMSBristol Myers Squibb is currently evaluating BMS-986249, a CTLA-4-directed Probody therapeutic in a randomized cohort expansion trial of a Phase 1/2 clinical trial that it initiated in January 2018.2018, and BMS-986288, a second anti-CTLA-4 Probody, in a Phase 1/2 trial it initiated in 2019. We have no products on the market and our ability to achieve and sustain profitability depends on obtaining regulatory approvals for and successfully commercializing our product candidates, either alone or with third parties. Before obtaining regulatory approval for the commercial distribution of our product candidates, we or our collaborator must conduct extensive preclinical tests and clinical trials to demonstrate sufficient safety, purity and efficacypotency (or efficacy) of our product candidates in patients.

As a result, we may not have the financial resources to continue development of, or to modify existing or enter into new collaborations for, a product candidate if we experience any issues that delay or prevent regulatory approval of, or our ability to commercialize, product candidates, including:

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We could find that the therapeutics we or our collaborators pursue are not safe, or efficacious or that the safety.pure, potent (or efficacious). Further, a clinical trial may be suspended or terminated by us, our collaborators, the IRBs of the institutions in which such trials are being conducted, the Data Safety Monitoring Board for such trial or by the FDA or other regulatory authorities due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a drug or therapeutic biologic, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. Furthermore, we expect to rely on our collaborators, CROs and clinical trial sites to ensure proper and timely conduct of our clinical trials and while we expect to enter into agreements governing their committed activities, we have limited influence over their actual performance.

If we or our collaborators experience delays in the completion of, or termination of, any clinical trial of our product candidates, the commercial prospects of our product candidates will be harmed, and our ability to generate product revenues or receive royalties from any of these product candidates will be delayed. In addition, any delays in completing our clinical trials will increase our costs, slow down our product development and approval process and jeopardize our ability to commence product sales and generate revenues. Furthermore, if one or more of our product candidates or our Probody therapeutic technology generally prove to be ineffective, unsafe or commercially unviable, the development of our entire platform and pipeline could be delayed, potentially permanently. Any of these occurrences may materially and adversely affect our business, financial condition, results of operations and prospects. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our product candidates.

For example, in March 2020, we made the strategic decision to terminate our Phase 2 clinical trial evaluating pacmilimab in combination ipilimumab in melanoma. This decision followed a re-evaluation of the evolving clinical, competitive and commercial landscapes in immuno-oncology, taken together with the impact of the COVID-19 pandemic.

Interim, “top-line,” and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publicly disclose preliminary or top-line data from our preclinical studies and clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. For example, in December 2021 we announced preliminary data on two of the four expansion cohorts for CX-2029. We can make no assurances that the ultimate trial results for these two cohorts will be consistent with or better or worse than that reported data. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. Further, as a result of the COVID-19 pandemic or for other reasons, we may not be able to collect accurate or complete data at the time we collect such preliminary data, including as a result of the inability of sites to properly record data due to staffing limitations or the inability of patients to visit sites at scheduled times, the inability of CROs to access site data or for other reasons. As a result, the top-line or preliminary results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Top-line data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, top-line data should be viewed with caution until the final data are available.

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From time to time, we may also disclose interim data from our preclinical studies and clinical trials. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available or as patients from our clinical trials continue other treatments for their disease. Adverse differences between preliminary, top-line, or interim data and final data could significantly harm our business prospects.

Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product and our company in general. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and you or others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure.

Our product candidates may cause undesirable side effects at any time during or after the clinical trial process that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any.any, including withdrawal from the market.

Undesirable side effects caused by our product candidates could cause us, our collaborators or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other regulatory authorities. As is the case with all oncology drugs, there may be immediate or late side effects associated with the use of our product candidates (e.g. CX-072, CX-2009and CX-2029), praluzatamab ravtansine (CX-2009), CX-2029, and pacmilimab (CX-072)). For example, in June 2018 we announced initial clinical data on CX-072 at the Annual Meeting of the American Society of Clinical Oncology (“ASCO”) and in February 2019 we announced updated clinical data regarding CX-072 and our first clinical data on CX-2009. While CX-072 has generally been well tolerated to date, thereThere can be no guarantyassurance that unexpected adverse events will not occur later in this trialour ongoing trials or in otherfuture trials involving our product candidates or the product candidates of our collaborators. The data described at ASCO showUndesirable side effects may appear in later trials that were not observed in our earlier trials or may be more severe in later trials than earlier trials.

In May 2020, we reported that the administration of monotherapy CX-072 waspacmilimab had been generally well tolerated with the majority of treatment-related adverse events (“TRAEs”) as Grade 1/2. However, Grade 3/4 TRAEs wereAt that time, we also reported in two patients (neutropenia and thrombocytopenia in a patient with thymic cancer (3 mg/kg) and transaminase elevation in a patient with breast cancer (30 mg/kg)) but both events were successfully managed with therapeutic intervention including steroids and discontinuation of CX-072.  In addition, the results showed that the administration of CX-072 in combination with ipilimumab was well tolerated with the majority of TRAEs as Grade 1/2.  Of the 16 treated patients, five (31%) reported a Grade 3/4 TRAE, a rate similar to that reported previously for 3 mg/kg ipilimumab monotherapy. These events included: Grade 3 colitis (n=1), Grade 3 dyspnea/pneumonitis (n=1), Grade 3 headache/Grade 3 hyponatremia (n=1), and Grade 3 amylase/Grade 4 lipase (n=1).  A Grade 3 TRAE in one patient was designated as non-treatment related post data cutoff. A dose limiting toxicity of Grade 3 dyspnea was reported in one patient. On October 22, 2018, we presented follow-up data at the 2018 Annual Meeting of the European Society of Medical Oncology in Munich, Germany.114 monotherapy patients treated with 10 mg/kg every two weeks and who were evaluable for safety, ten (9%) patients experienced a grade ≥3 TRAE, and two (2%) experienced grade ≥3 immune-related adverse events (“irAEs”), with two (2%) TRAEs leading to treatment discontinuation. In this presentation,June 2019, we also disclosed initial data on immune related adverse events (irAE) and infusion related reactions (IRR).  Of the 46 patients treated, 3 (7%) developed Grade 3/4 irAEs and 2 (4%) developed Grade 3/4 IRRs.  Of the 20 patients treated in the combination with ipilimumab, 2 (10%) developed Grade 3/4 irAEs and 0 (0%) developed Grade 3/4 IRRs.

In February 2019, we announced updated data on the ongoing monotherapy clinical trial for CX-072 focused on our dose expansion cohort of 10 mg/kg.  While the safety data we reported at 10 mg/kg is trending toward a similar or better profile than data presented previously, that rate may change with time as more patients are enrolled in the ongoing studies. We also reported at the 10 mg/kg dose, anthe anti-drug antibody (“ADA”) rate ofwas approximately 62%, The rate across all dose levels, including lower dose levels in our trial, is approximately 77% at the data cutoff.  We. While we do not believe this ADA is impacting our ability to reach targeted drug exposures. However,exposures, we cannot provide assurance that the rate will not change or that it will not later limit drug exposure or cause severe adverse events. We also cannot provide assurance that the rates and the types of adverse events will not increase with time as more patients are treated in ongoing or future studies.

In February 2019, we announced data on the ongoing clinical trial for CX-2009.  While CX-2009Administration of pacmilimab in combination with ipilimumab has been generally well tolerated to date, 23 / 76 (30.3%with the majority of TRAEs as Grade 1/2. In October 2019, we reported that of the 27 patients treated across all combination doses, Grade 3/4 TRAEs were reported in nine (33%) patients and Grade 3/4 irAEs were reported in six (22%) patients. Of the 20 patients treated with ipilimumab at 3 mg/kg at varying doses of pacmilimab, Grade 3/4 TRAEs were reported in five (25%) patients and Grade 3/4 irAEs were reported in three (15%) patients. We cannot provide assurance that these rates and the types of adverse events will not increase over time with more patients being treated in future studies of our product candidates.

Administration of praluzatamab ravtansine has also been generally well tolerated with most reported TRAEs being Grade 1/2. In May 2020, we announced that 34/92 (37%) patients experienced a Grade 3/4 TRAE. The most common adverse event observed was ocular toxicity, an anticipated toxicity associated with the DM4 payload. Other Grade 3/4 TRAEs included liver function test abnormalities, gastrointestinal disorders and nervous system disorders. Currently,We cannot guarantee that these rates and the types of adverse events will not increase over time with more patients being treated in ongoing or future studies.

In May 2020, we announced that CX-2029 was generally well tolerated at doses up to 3 mg/kg with the most common TRAEs being infusion related reactions, anemia and neutropenia/leukopenia. Grade 3 or greater hematologic TRAEs, anemia and neutropenia, were dose optimizationdependent, with anemia being managed with transfusions and supportive care. In December 2021, we announced preliminary data on two of four expansion cohorts for CX-2029, including that the most common Grade 3 TRAEs in 10% or more of patients were anemia (67.3%) and decreased neutrophil count (9.6% (plus one Grade 4 event 1.9%)). The etiology of anemia remains under investigation and is underwaylikely to furtherbe multi-factorial. While the MMAE payload is known to inform dose selection.be associated with anemia, preclinical studies have shown that reduction of red blood cell precursors has been observed in response to targeting CD71, which is known to play a role in early erythroid development. Although we believe these TRAEs are manageable, there can be no assurance that the rate or severity of any of these side effects will not increase over time with more patients being treated in ongoing or future studies.

The results of our or our collaborators’ future clinical trials or the clinical trials of our collaborators could reveal a high and unacceptable severity of adverse side effects, including immune system related adverse events or increased toxicity, and it is possible that patients enrolled in such clinical trials could respond in unexpected ways. ways or otherwise have unexpected adverse events. For instance,example, in 2022 we are in the process of

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initiating a first-in-human Phase 1 clinical trial with CX-904 and, while we believe our preclinical studies indicate the potential to reach a favorable therapeutic index, clinical data will be necessary to specify an acceptable dose. We cannot provide assurance that we will reach an acceptable dose for CX-904.

Additionally, the Phase 1/2 clinical trial of CX-072 is being conducted in patients with advanced cancers, including metastatic or locally advanced unresectable solid tumors or lymphomas, who have failed other approved therapies for their disease, and as such, it may be difficult to establish safety and efficacy in this type of patient population. In addition, certain arms of our clinical trial of CX-072 enroll patients with tumor types that are not known to be responsive to PD-L1 agents and therefore may be less likely to show effectiveness. Because certain PD-1 and PD-L1 agents are already approved for the treatment of some tumor types, we cannot test CX-072 on those tumor types and will not be able to obtain clinical information about how CX-072 acts in these tumors. Comparing safety and efficacy of CX-072 against other PD-L1 or PD-1 antibodies (either in development or in the market) may be difficult since our Phase 1/2 study is enrolling a different patient population than other studies.   Furthermore, a portion of our Phase 1/2 clinical trial of CX-072 includes the administration of CX-072 in combination with Yervoy (ipilimumab) or Zelboraf(vemurafenib), which could exacerbate immune system related adverse events, cause increased toxicity or otherwise lead to unexpected adverse events. The Phase 1/2 clinical trial of

BMS-986249 being conducted by BMSBristol Myers Squibb includes the administration of the product candidate at relatively high dosage levels, which could further exacerbate such risks. In our Phase 1/2 clinical trials of CX-2009with praluzatamab ravtansine and CX-2029, we are targeting CD-166CD166 and CD71, respectively, targets that are broadly expressed on normal tissue, which could create unacceptable toxicity or fail to result in anti-tumor activity. For instance, CD71 which is a metabolic protein with high levels of expression in healthy tissues, and the consequences of targeting such protein in humans are unknown. Any future clinical trials of our product candidates could face similar or heightened risks depending on the modality. Similarly, the combination of EGFR and CD3 has been shown to induce significant toxicities in preclinical animal studies due to the widespread expression of each target.

In the event that our clinical trials or the clinical trials of our collaborators reveal these or othersevere adverse side effects, our trials or theour collaborators’ clinical trials of our collaborators could be suspended or terminated and the FDA or comparable foreign regulatory authorities could impose a clinical hold, order us to cease further development of or deny approval of our product candidates for any or all targeted indications. Such side effects could also affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. For example, in our Phase 1/2 clinical trial of praluzatamab ravtansine, some patients stopped treatment due to ocular toxicity. While we are using ocular toxicity prophylactic measures in our Phase 2 clinical trial, we cannot be assured that such measures will be effective. In addition, any of these occurrences with respect to one of our product candidates could negatively affect our or any collaborator’s ability to enroll patients and seek regulatory approval for other product candidates that we have developed using our Probody platform, which could also result in a collaborator terminating any program utilizing our Probody platform and the termination of such collaborative relationship. Any of these occurrences may materially and adversely affect our business, financial condition, results of operations and prospects. Further, clinical trials by their nature utilize a sample of the potential patient population. With a limited number of patients and limited duration of exposure, rare and severe side effects of our product candidates may only be uncovered with a significantly larger number of patients exposed to the product candidate.

In the event that any of our product candidates receives regulatory approval and we, our collaborators or others identify undesirable side effects caused by such product or any other Probody therapeutics, any of the following adverse events could occur, which could result in the loss of significant revenue to us and materially and adversely affect our results of operations and business:

In addition, adverse side effects caused by any drugs of other companies utilizing the same or similar anti-bodiesantibodies of our product candidates, or that are similar in nature to our product candidates could delay or prevent regulatory approval of our product candidates, limit the commercial profile of an approved label for our product candidates, or result in significant negative consequences following marketing approval.

We believe that any of these events could prevent us from achieving or maintaining market acceptance of our product candidates and could substantially increase the costs of commercializing our product candidates, if approved, and significantly impact our ability to successfully commercialize our product candidates and generate revenues.

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If we experience delays or difficulties in the enrollment of patients in clinical trials, our receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate or continue clinical trials for our product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials as required by the FDA or similar regulatory authorities outside the United States. Patient enrollment, a significant factor in the timing of clinical trials, is affected by many factors, including:

For example, in March 2020, we announced a temporary pause in new patient enrollment and new site activation in our Phase 2 clinical trial of praluzatamab ravtansine as a result of the COVID-19 pandemic. We revised our strategy for praluzatamab ravtansine and in December 2020, we initiated a new Phase 2 clinical trial of praluzatamab ravtansine, for which we anticipated to report initial clinical data in the fourth quarter of 2021. However, in August 2021, we announced that primarily due to the COVID-19 pandemic, we anticipate initial clinical data from that trial in 2022. There can be no assurances that the COVID-19 pandemic will not continue to have a significant impact on our ability to complete our ongoing clinical trials and enroll patients in any planned or future clinical trials.

In addition, competing clinical trials and clinicians’ and patients’ perceptions as to the potential advantages of the product candidate being studied in relation to other available therapies, including any new drugs or therapeutic biologics that may be approved for the indications we are investigating, could affect our ability to enroll a sufficient number of eligible patients in our clinical trials. For example, in our Phase 1/2 clinical trial of CX-072, which is directed against PD-L1, we are only permitted to enroll patients with cancer types for which there are no PD inhibitors available for sale.  As thereThere are currently several PD-1 and/or PD-L1 agents approved for a growing list of cancer types along with hundredsthousands of clinical trials exploring the use of PD-1 and PD-L1 agents, thereagents. There can be no assurance that patientsfurther trials with pacmilimab (CX-072) or our other drug candidates will choose to enroll in ournot be adversely affected by a limited patient population. Our clinical trial. In addition, any armstrials of our Phase 1/2 clinical trial of CX-072 for indications with small population sizes could be particularly difficult to enroll. Furthermore, the part of our Phase 1/2 clinical trial of CX-072 in which patients are treated with the combination of CX-072praluzatamab ravtansine and vemurafenib can only enroll those patients who do not have access to MEK inhibitors because the emerging standard of care in jurisdictions where MEK inhibitors are available in combination with a BRAF inhibitor (such as vemurafenib), which may have an impact on enrollment in this part of the trial. Our Phase 1/2 clinical trial of CX-2009 studiesCX-2029 study patients who have one or a select number of seven specific tumor types rather than patients suffering from any cancer, which may limitlimits the rate of enrollment of the trial. AsIn addition, some of our clinical trials seek to treat indications with thesmall population sizes which could be particularly difficult to enroll. Our clinical trials of CX-072, our Phase 1/2 clinical trials of CX-2009praluzatamab ravtansine and CX-2029 are also competing with hundredsthousands of clinical trials with alternative anti-cancer drugs in a similar class (e.g. antibody drugantibody-drug conjugates), and certain arms of the clinical trialtrials may be difficult to enroll due to the emerging standard of care for such indications in certain jurisdictions, including the United States. Likewise, our clinical trial of CX-904 is also competing with thousands of other anti-cancer clinical trials. Any clinical trials of our product candidates initiated by our collaborators, including BMS’Bristol Myers Squibb’s ongoing Phase 1/2 clinical trial, face similar and additional risks relating to enrollment. We or our collaborators could also encounter delays in the development of any of our product candidates if prescribing physicians encounter unresolved ethical issues associated with enrolling patients in clinical trials of our product candidates in lieu of prescribing existing treatments that have established safety and efficacy profiles. Any delays relating to patient enrollment could cause significant delays in the timing of our or our collaborators’ clinical trials, or the clinical trials of our collaborators, which may materially and adversely affect our business, financial condition, results of operations and prospects.

Our approach to the discovery and development of our therapeutic treatments is based on novel technologies that are unproven and may not result in marketable products.

We plan to continue to develop a pipeline of product candidates using our proprietary Probody platform. We believe that product candidates (including cancer immunotherapies, PDCsconditionally activated ADCs and bispecific antibodies) identified with our product discovery platform may offer an improved therapeutic approach by taking advantage of unique conditions in the tumor microenvironment, thereby reducing the dose-limiting toxic effects associated with traditional antibody products, which can also attack healthy tissue. However, the scientific research that forms the basis of our efforts to develop product candidates based on our Probody platform is ongoing, including the research resulting from our ongoing Phase 1/2 clinical trials for CX-072, CX-2009praluzatamab ravtansine (CX-2009), CX-2029, pacmilimab (CX-072) and CX-2029.CX-904.

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We may ultimately discover that our Probody platform and any product candidates resulting from it do not possess certain properties required for therapeutic effectiveness or protection from toxicity. For example, when Probody therapeutics are administered to human subjects, protease levels in tumors may not be sufficient and the peptide mask may not be cleaved, which would limit the potential efficacy of the antibody. In addition, if the peptide mask is inappropriately released, for example, due to an inflammatory disease, it may reduce the potential to limit toxicity of the anti-cancer agent or result in unforeseen events when administered in humans. Binding of the peptide mask to the antigen bindingantigen-binding domain of the Probody may not be constant, which could lead to intermittent periods when the antigen bindingantigen-binding domain or antibody portion is unmasked. Furthermore, Probody product candidates may not remain stable in the human body for the period of time required for the drug to reach and to bind to the target tissue. In addition, product candidates based on our Probody platform may demonstrate different chemical and pharmacological properties in patients than they do in laboratory studies. Although our Probody platform and certain product candidates have demonstrated successful results in animal studies, they may not demonstrate the same chemical and pharmacological properties in humans and may interact with human biological systems in unforeseen, ineffective or harmful ways. Our understanding of the molecular pharmacology of Probody therapeutics, that is, the precise manner and sequence in which they are activated and behave in vivo, is incomplete. Probody therapeutics are complex biological molecules and we are evaluating the performance of this new technology in cancer patients for the first time. Many specific elements of Probody therapeutic function may contribute to their overall safety and efficacy profile including, but not limited to, the removal of only one mask from the dually maskeddually-masked antibody, the removal of both masks from the dually maskeddually-masked antibody, the binding strength of masks for the underlying antibody, and the binding strength of the underlying antibody for its target. We have no directlimited structural evidence for how masks interact with antibodies. It may take many years before we develop a full understanding of Probody

pharmacology, and we may never know precisely how they function in vivo.As with any new biologic or product developed on a novel platform, we have a limited understanding of the immunogenicity profile of Probody therapeutics. As a result, our Probody product candidates may trigger immune responses, such as ADA,anti-drug antibody (“ADA”), that may inhibit the ability of the antibody to reach the target tissue, inhibit the ability of the antibody to bind to its target, cause adverse side effects in humans or cause hypersensitivity reactions. For example, we reported in February 2019 that in our ongoing CX-2019pacmilimab trial at the 10 mg/kg dose, the anti-drug antibody (“ADA”)ADA rate was approximately 62%. Across all dose levels, including lower dose levels in our trial, the rate is approximately 77% at the data cutoff. We do not believe the ADA rate is impacting our ability to reach targeted drug exposures. However, we cannot provide assurance that it will not later limit drug exposure or cause severe adverse events. Problems that are specific to our Probody platform may have an unfavorable impact on all of our product candidates. As a result, we may never succeed in developing a marketable product and we may never become profitable, which would cause the value of our common stock to decline.

In addition, the scientific evidence to support the feasibility of developing product candidates against novel, difficult to drug targets, is both preliminary and limited. For example, our understanding of the expression of CD166 and CD71 in both healthy and diseased tissues is still developing. As a result, we cannot provide any assurance that we will be able to successfully identify and advance any product candidates to target novel, difficult to drugdifficult-to-drug targets.

We believe the only clinical experience that the FDA and foreign regulatory authorities have with Probody-based therapeutics in oncology comes from CX-072, CX-2009,praluzatamab ravtansine, CX-2029, BMS-986249, BMS-986288, and BMS-986249.pacmilimab. We believe that the FDA and foreign regulatory authorities, have no clinical experience in other disease areas, and such limited experience may increase the complexity, uncertainty and length of the regulatory approval process for our product candidates and may keep us from commencing first-in-human trials in certain countries. As there is limited historical precedent for the regulatory clearance of Probody-based therapeutics in oncology, there is a higher degree of risk that the FDA or other regulatory authorities could disagree that we or our collaborators have satisfied their requirements to commence clinical trials for some product candidates or disagree with our study designs, which may require us to complete additional preclinical studies or amend our protocols or impose stricter conditions on the commencement of clinical trials. In addition, local clinical practice in other countries may affect whether we or our collaborators are able to initiate a clinical trial there. As a result, we and our collaborators may never receive approval to market and commercialize any product candidate. Even if we or our collaborators obtain regulatory approval, the approval may be for targets, disease indications or patient populations that are not as broad as we or they intended or desired or may require labeling that includes significant use or distribution restrictions or safety warnings. We or our collaborators may be required to perform additional or unanticipated clinical trials to obtain approval or be subject to post-marketing testing requirements to maintain regulatory approval. If one or more of our product candidates or our Probody technology generally prove to be ineffective, unsafe or commercially unviable, our entire platform and pipeline wouldmay have little, if any, value, which would have a material and adverse effect on our business, financial condition, results of operations and prospects.

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The market may not be receptive to our product candidates based on a novel therapeutic modality, and we may not generate any future revenue from the sale or licensing of product candidates.

Even if regulatory approval is obtained for a product candidate, we may not generate or sustain revenue from sales of the product due to factors such as whether the product can be sold at a competitive cost and whether it will otherwise be accepted in the market. The product candidates that we are developing are based on our Probody platform, which is a new technology and therapeutic approach. Market participants with significant influence over acceptance of new treatments, such as physicians and third-party payors, may not adopt a product or treatment based on our Probody platform and technologies, and we may not be able to convince the medical community and third-party payors to accept and use, or to provide favorable reimbursement for, any product candidates developed by us or our collaborators. This may be particularly true for any of our product candidates (including CX-072and BMS-986249)BMS-986249, BMS-986288, and pacmilimab (CX-072) for which there are existing approved therapies, such as approved agents targeting PD-L1, PD-1, or CTLA-4. Market acceptance of our product candidates will depend on, among other factors:

If any product candidate we commercialize fails to achieve market acceptance, it could have a material and adverse effect on our business, financial condition, results of operations and prospects.

We have entered, and may in the future seek to enter, into collaborations with third parties for the development and commercialization of our product candidates using our Probody platform. If we fail to enter into such collaborations, or such collaborations are not successful, we may not be able to capitalize on the market potential of our Probody platform and resulting product candidates.

Since 2013, we have entered into collaborations with AbbVie, Amgen, BMS,Astellas, Bristol Myers Squibb, ImmunoGen, and Pfizer and others to develop certain Probody therapeutics. We may in the future seek third-party collaborators for development and commercialization of other therapeutic technologies or product candidates. Biopharmaceutical companies are our prior and likely future collaborators for any marketing, distribution, development, licensing or broader collaboration arrangements. With respect to our existing collaboration agreements, and what we expect will be the case with any future collaboration agreements, we have and would expect to have limited control over whether such collaborations pursue the development of our product candidates or the amount and timing of resources that such collaborators dedicate to the development or commercialization of our product candidates. For instance, in March 2018, Pfizer terminated the collaboration agreement we had entered into with them in May 2013. Such collaboration agreement had entitled Pfizer to nominate up to four research targets and since 2013, we had collaborated with Pfizer on three of such targets. However, no program was ever advanced beyond the lead optimization stage pursuant to the agreement, and Pfizer had previously elected not to select a fourth target and had decided to discontinue its epidermal growth factor receptor Probody Drug Conjugate.conditionally activated ADC. In July 2017, ImmunoGen discontinued the preclinical evaluation of one of its two programs being developed under our collaboration and in December 2019, licensed the other program to us, terminating their license agreement from us. In addition, in January 2019, BMSBristol Myers Squibb terminated its programs for three targets it had selected under our agreement with them. As a result, there can be no assurances that any of the programs covered by our existing or future collaborations will be developed further. Further, our ability to generate revenues from our existing and future arrangements will depend on our collaborators’ abilities to successfully perform the functions assigned to them in these arrangements. Additionally, some of our collaborations may require us to share in certain development and commercialization expenses. If we cannot afford to share such expenses when required, our rights under such collaborations may be adversely affected, including potentially that our collaboratorcollaborators may terminate the relevant agreement.

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Overall, collaborations involving our product candidates currently pose, and will continue to pose, the following risks to us:

As a result of the foregoing, our current and any future collaboration agreements may not lead to development or commercialization of our product candidates in the most efficient manner or at all and may not result in the realization of the benefits we expected to achieve upon our entry into such agreements. Any failure to successfully develop or commercialize our product candidates pursuant to our current or any future collaboration agreements could have a material and adverse effect on our business, financial condition, results of operations and prospects.

If our collaborators cease development efforts under our collaboration agreements, or if any of those agreements are terminated, these collaborations may fail to lead to commercial products and we may never receive milestone payments or future royalties under these agreements.

Substantially all of our revenue to date has been derived from our existing collaboration agreements, including, most recently, the Amgen Agreementagreement that we entered into with AmgenAstellas in September 2017,March 2020, and a significant portion of our future revenue and cash resources is expected to be derived from these agreements or other similar agreements we may enter into in the future. Revenue from research and development collaborations depend upon continuation of the collaborations, reimbursement of development costs, the achievement of milestones and royalties, if any, derived from future products developed from our research. If our development partners do not select additional targets and we are unable to successfully advance the development of our product candidates or achieve milestones, revenue and cash resources from milestone payments under our collaboration agreements will be substantially less than expected.

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In addition, to the extent that any of our collaborators were to terminate a collaboration agreement, we may decide to independently develop these product candidates to the extent we retain development rights. Such development could include funding preclinical or clinical trials, assuming marketing and distribution costs and defending intellectual property rights. Alternatively, in certain instances, we may choose to abandon product candidates altogether. For instance, in March 2018, Pfizer terminated theour 2013 collaboration agreement we had entered into with them, in May 2013, and in January 2019, BMSBristol Myers Squibb terminated its programs for three targets that it had selected under our agreement with them. AnyThe termination of the foregoingany of our collaboration agreements or individual programs within a collaboration agreement could result in a change to our business plan and may have a material adverse effect on our business, financial condition, results of operations and prospects. If a collaboration is terminated, we would not be eligible to receive the milestone, royalty or other payments that would have been payable under the collaboration agreement. For example, as a result of ImmunoGen’s decision to out-license the EpCAM program and our licensing of the program from them in 2019, their license for the program from us ended and we will not receive milestone or other payments from them.

If we do not achieve our projected development and commercialization goals in the timeframes we announce and expect, the commercialization of any of our product candidates may be delayed, and our business will be harmed.

For planning purposes, we sometimes estimate the timing of the accomplishment of various scientific, clinical, regulatory and other product development objectives. These milestones may include our expectations regarding the commencement or completion of scientific studies and clinical trials, the submission of regulatory filings, or commercialization objectives. From time to time, we may publicly announce the expected timing of some of these milestones, such as the completion of an ongoing clinical trial, the initiation of other clinical programs, receipt of marketing approval, or a commercial launch of a product. The achievement of many of these milestones may be outside of our control. All of these milestones are based on a variety of assumptions which may cause the timing of achievement of the milestones to vary considerably from our estimates, including:

For example, in March 2020, we announced the temporary pause in new patient enrollment and new site activation in our Phase 2 clinical trial of praluzatamab ravtansine (CX-2009) as a result of the COVID-19 pandemic and the termination of the Phase 2 clinical trial of pacmilimab (CX-072) in combination with ipilimumab after a re-evaluation of the evolving clinical, competitive and commercial landscapes in immuno-oncology, taken together with the impact of the COVID-19 pandemic. Further, we continue to see an impact as a result of the COVID-19 pandemic on our efforts, including ongoing clinical trial site activation and patient enrollment for praluzatamab ravtansine.

If we fail to achieve announced milestones in the timeframes we expect, the commercialization of any of our product candidates may be delayed, and our business and results of operations may be harmed.

We may not successfully engage in strategic transactions, including any additional collaborations we seek, which could adversely affect our ability to develop and commercialize product candidates, impact our cash position, increase our expense and present significant distractions to our management.

Since commencing operations, we have entered into several collaboration agreements, including most recently, the Amgen Agreementagreement that we entered into with AmgenAstellas in September 2017.March 2020. From time to time, we may consider strategic transactions, such as additional collaborations, acquisitions of companies, asset purchases and out- or in-licensing of product candidates or technologies. In particular, we will evaluate and, if strategically attractive, seek to enter into additional collaborations, including with major biotechnology or biopharmaceutical companies. The competition for collaborators is intense, and the negotiation process is time-consuming and complex. Any new

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collaboration may be on terms that are not optimal for us, and we may not be able to maintain any new collaboration if, for example, development or approval of a product candidate is delayed, sales of an approved product candidate do not meet expectations or the collaborator terminates the collaboration. Any such collaboration, or other strategic transaction, may require us to incur non-recurring or other charges, increase our near- and long-term expenditures and pose significant integration or implementation challenges or disrupt our management or business. These transactions would entail numerous operational and financial risks, including exposure to unknown liabilities, disruption of our business and diversion of our management’s time and attention in order to manage a collaboration or develop acquired products, product candidates or technologies, incurrence of substantial debt or dilutive issuances of equity securities to pay transaction consideration or costs, higher than expected collaboration, acquisition or integration costs, write-downs of assets or goodwill or impairment charges, increased amortization expenses, difficulty and cost in facilitating the collaboration or combining the operations and personnel of any acquired business, impairment of relationships with key suppliers, manufacturers or customers of any acquired business due to changes in management and ownership and the inability to retain key employees of any acquired business. Accordingly, although there can be no assurance that we will undertake or successfully complete any transactions of the nature described above, any transactions that we do complete may be subject to the foregoing or other risks and have a material and adverse effect on our business, financial condition, results of operations and prospects. The termination by a collaborator of a collaboration may cause a decrease in the price of our stock. Conversely, any failure to enter any additional collaboration or other strategic transaction that would be beneficial to us could delay the development and potential commercialization of our product candidates and have a negative impact on the competitiveness of any product candidate that reaches market.

If we are unable to successfully develop companion diagnostic tests for certain of our product candidates, or experience significant delays in doing so, we may not realize the full commercial potential of our product candidates.

Because we are focused on precision medicine, in which predictive biomarkers will be used to identify the right patients for our product candidates, we believe that our success may depend, in part, on the development of companion diagnostic tests. To successfully develop a companion diagnostic test, we would need to address a number of scientific, technical and logistical challenges. However, we have little experience in the development of companion diagnostic tests and may not be successful in developing appropriate tests to pair with any of our product candidates. Companion diagnostic tests are subject to regulation by the FDA and similar regulatory authorities outside the United States as medical devices and require separate regulatory approval prior to commercialization. Given our limited experience in developing companion diagnostic tests, we could seek to rely on third parties to design, manufacture, obtain regulatory approval for any companion diagnostic tests for our product candidates. However, we and such collaborators may encounter difficulties in developing and obtaining approval for the companion diagnostic tests, including issues relating to selectivity/specificity, analytical validation, reproducibility, or clinical validation. Any delay or failure by us or our collaborators to develop or obtain regulatory approval of the companion diagnostic tests could delay or prevent approval of our product candidates. As a result, our business would be harmed, possibly materially.

We rely on third parties to conduct all of our clinical trials and certain of our preclinical studies and intend to continue to do so, and if such third parties do not perform as contractually required, fail to satisfy regulatory or legal requirements or miss expected deadlines, our development programs could be delayed with material and adverse effects on our business, financial condition, results of operations and prospects.

We do not have the ability to independently conduct clinical trials. As such, we currently rely and intend to continue to rely on third-party clinical investigators, CROs, clinical data management organizations and consultants to help us design, conduct, supervise and monitor clinical trials of our product candidates. As a result, we will have less control over the timing, quality and other aspects of our clinical trials than we would have had we conducted them on our own. These investigators, CROs and consultants are not our employees and we have limited control over the amount of time and resources that they dedicate to our programs. These third parties may have contractual relationships with other entities, some of which may be our competitors, which may draw time and resources from our programs. The third parties with which we contract might not be diligent, careful or timely in conducting our preclinical studies or clinical trials, resulting in the preclinical studies or clinical trials being delayed or unsuccessful. Furthermore, our third-party contractors, including CROs are being and may continue to be impacted in their ability to conduct our work as a result of the COVID-19 pandemic.

If we cannot contract with acceptable third parties on commercially reasonable terms, or at all, or if these third parties do not carry out their contractual duties, satisfy legal and regulatory requirements for the conduct of preclinical studies or clinical trials or meet expected deadlines, our clinical development programs could be delayed and otherwise adversely affected. In all events, we will be responsible for ensuring that each of our preclinical studies and clinical trials are conducted in accordance with the general investigational plan and protocols for the trial. The FDA requires preclinical studies to be conducted in accordance with good laboratory practices (“GLPs”) and clinical trials to be conducted in accordance with good clinical practices (“GCPs”), including for designing, conducting, recording and reporting the results of preclinical studies and clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of clinical trial participants are protected. Our reliance

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on third parties that we do not control will not relieve us of these responsibilities and requirements. Any adverse development or delay in our clinical trials could have a material and adverse effect on our business, financial condition, results of operations and prospects.

We are currently conducting and will continue to conduct clinical trials and will contract with third-party manufacturers in foreign countries, which could expose us to risks that could have a material adverse effect on the success of our business.

We have enrolled or are planning to enroll patients in our clinical trials outside the United States, including in Europe, Australia and South Korea. The acceptance of study data from clinical trials conducted outside the U.S. or another jurisdiction by the FDA or comparable foreign regulatory authority may be subject to certain conditions or may not be accepted at all. In cases where data from foreign clinical trials are intended to serve as the sole basis for marketing approval in the U.S., the FDA will generally not approve the application on the basis of foreign data alone unless (i) the data are applicable to the U.S. population and U.S. medical practice; (ii) the trials were performed by clinical investigators of recognized competence and pursuant to GCP regulations; and (iii) the data may be considered valid without the need for an on-site inspection by the FDA, or if the FDA considers such inspection to be necessary, the FDA is able to validate the data through an on-site inspection or other appropriate means. In addition, even where the foreign study data are not intended to serve as the sole basis for approval, the FDA will not accept the data as support for an application for marketing approval unless the study is well-designed and well-conducted in accordance with GCP requirements and the FDA is able to validate the data from the study through an onsite inspection if deemed necessary. Many foreign regulatory authorities have similar approval requirements. In addition, such foreign trials would be subject to the applicable local laws of the foreign jurisdictions where the trials are conducted. There can be no assurance that the FDA or any comparable foreign regulatory authority will accept data from trials conducted outside of the U.S. or the applicable jurisdiction. If the FDA or any comparable foreign regulatory authority does not accept such data, it would result in the need for additional trials, which could be costly and time-consuming, and which may result in current or future product candidates that we may develop not receiving approval for commercialization in the applicable jurisdiction.

Conducting clinical trials outside the United States also exposes us to additional risks, including risks associated with additional foreign regulatory requirements; foreign exchange fluctuations; patient monitoring and compliance; compliance with foreign manufacturing, customs, shipment and storage requirements; the severity of the COVID-19 pandemic in such jurisdictions; and cultural differences in medical practice and clinical research. We are also subject to risks associated with doing business globally, including commercial, political, and financial risks. In addition, we are subject to potential disruption caused by military conflicts; potentially unstable governments or legal systems; civil or political upheaval or unrest; local labor policies and conditions; possible expropriation, nationalization, or confiscation of assets; problems with repatriation of foreign earnings; economic or trade sanctions; closure of markets to imports; anti-American sentiment; terrorism or other types of violence in or outside the United States; health pandemics; and a significant reduction in global travel. For example, pandemics and public health emergencies, such as the COVID-19 pandemic, have disrupted and delayed and could in the future disrupt or delay enrollment in our clinical trials in Europe, South Korea and elsewhere. Our success will depend, in part, on our ability to overcome the challenges we encounter with respect to these risks and other factors affecting U.S. companies with global operations. If our global clinical trials or foreign third-party suppliers were to experience significant disruption due to these risks or for other reasons, it could have a material adverse effect on our business, financial condition, results of operations and prospects.

Because we have no long termlong-term contracts with and rely on third-party manufacturing and supply partners, most of which are sole source suppliers, our supply of research and development, preclinical and clinical development materials may become limited or interrupted or may not be of satisfactory quantity or quality.

We rely on third-party contract manufacturers to manufacture our clinical trial and preclinical study product supplies.supplies which, in addition to having other issues, could be adversely impacted by the COVID-19 pandemic. Most of our clinical trial manufacturing contractors and suppliers are our sole source for their respective manufacturing and supplies. Failure of any of these contractors could put our ability to have clinical trial material available when needed. This could result in a substantial delay of our clinical trials. For example, for each of CX-072 CX-2009praluzatamab ravtansine (CX-2009), CX-2029, pacmilimab (CX-072), and CX-2029,CX-904, our manufacturing supply chain includes several contract manufacturers, and failure by any of these manufacturers could result in interruptions of our clinical studies. For example, in November 2019, one of our contract manufacturers that manufactures pacmilimab experienced a production failure. If we had not been able to assure sufficient supplies of clinical trial drug product after the production failure, we may have been required to suspend any ongoing trials and postpone future trials. Although we have taken sufficient steps to assure our current supply of pacmilimab clinical trial drug product for our ongoing clinical trial and planned clinical trials, there can be no assurance that we will not have future production failures, which could affect our ability to conduct our trials for praluzatamab ravtansine, CX-2029, pacmilimab, CX-904 or any other clinical trial drug candidates on our planned timeline or at all. We do not own manufacturing facilities for producing such supplies and do not have any long termlong-term contracts and we do not currently have an alternative to any of our third-party contract manufacturers. There can be no assurance that our preclinical and clinical development product supplies will not be limited, interrupted, or of satisfactory quality or continue to be available at acceptable prices. In particular, any replacement of any of our third-party contract manufacturers could require significant effort and expertise because there may be a limited number of qualified replacements. In addition, we may encounter issues with transferring technology to a new third-party manufacturer, and we

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may encounter regulatory delays if we need to move the manufacturing of our products from one third-party manufacturer to another. For example, we were dependent on ImmunoGen under our collaboration for certain steps in the manufacturing of clinical quantities of CX-2009.praluzatamab ravtansine. At the end of 2018, ImmunoGen closed their clinical manufacturing facility in Norwood, MA. This site provided clinical manufacturing support for the CX-2009praluzatamab ravtansine program. We have initiated thecompleted transfer of the drug substance manufacturing process from ImmunoGen to a CMO, where we have an existing relationship and which has expertise in the manufacture of antibody drugantibody-drug conjugates at a clinical and commercial scale. To date,While the manufacturing transfer process is still ongoing and has not yet been completed. However,completed, there can be no assurancesassurance that we will not experience a disruption toin the supply of CX-2009 in connection withpraluzatamab ravtansine as a result of such transfer or that we will not experience any other disruption in the transfer will be successful.manufacture of praluzatamab ravtansine.

The manufacturing process for a product candidate is subject to FDA and foreign regulatory authority review. Suppliers and manufacturers must meet applicable manufacturing requirements and undergo rigorous facility and process validation tests required by regulatory authorities in order to comply with regulatory standards, such as current Good Manufacturing Practices (“cGMPs”). In the event that any of our manufacturers fails to comply with such requirements or to perform its obligations to us in relation to quality, timing or otherwise, such as the pacmilimab manufacturing production failure our contract manufacturer experienced in November 2019, or if our supply of components or other materials becomes limited or interrupted for other reasons, such as one of our manufacturers going out of business, we may be forced to manufacture the materials ourselves, for which we currently do not have the capabilities or resources, or enter into an agreement with another third party, which we may not be able to do on reasonable terms, if at all. In some cases, the technical skills or technology required to manufacture our product candidates may be unique or proprietary to the original manufacturer and we may have difficulty transferring such skills or technology to another third party and a feasible alternative may not exist. These factors would increase our reliance on such manufacturer or require us to obtain a license from such manufacturer in order to have another third party manufacture our product candidates. If we are required to change manufacturers for any reason, we will be required to verify that the new manufacturer maintains facilities and procedures that comply with quality standards and with all applicable regulations and guidelines. The delays associated with the verification of a new manufacturer could negatively affect our ability to develop product candidates in a timely manner or within budget.

We expect to continue to rely on third-party manufacturers if we receive regulatory approval for any product candidate. To the extent that we have existing, or enter into future, manufacturing arrangements with third parties, we will depend on these third parties to perform their obligations in a timely manner consistent with contractual and regulatory requirements, including those related to quality control and assurance. If we are unable to obtain or maintain third-party manufacturing for product candidates, or to do so on commercially reasonable terms, we may not be able to develop and commercialize our product candidates successfully. We may find that our third-party manufacturer is unable to scale up the process in order to produce commercial quantities of our products. Our or a third party’s failure to execute on our manufacturing requirements and comply with cGMPs could adversely affect our business in a number of ways, including:

The supply chain for the manufacturing of our product candidates is complicated and can involve many parties. This is especially the case for our clinical stage Probody Drug Conjugates, CX-2009clinical-stage conditionally activated ADCs, praluzatamab ravtansine, CX-2029 and CX-2029.CX-904. If we were to experience any supply chain issues, our product supply could be seriously disrupted. In addition, we expect the logistical challenges associated with our supply chain to grow more complex as additional product candidates commence any clinical trials.

We, or third-party manufacturers, may be unable to successfully scale-up manufacturing of our product candidates in sufficient quality and quantity, which would delay or prevent us from developing our product candidates and commercializing approved products, if any.

It may prove more challenging than we anticipate to manufacture products that incorporate our Probody therapeutic technology. In order to conduct clinical trials of our product candidates, including our Phase 1/2 clinical trials for CX-072, CX-2009praluzatamab ravtansine (CX-2009), CX-2029, pacmilimab (CX-072), and CX-2029,CX-904 we will need to manufacture them in large quantities. To date, we have generally been able to successfully manufacture CX-072, CX-2009praluzatamab ravtansine, CX-2029, and CX-2029pacmilimab for our ongoing early stageearly-stage clinical trials. However, in November 2019, we had a production failure at one of our contract manufacturers that manufactured pacmilimab for our Phase 1/2

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clinical trial and for our future trials. If we had not been able to assure sufficient supplies of clinical trial drug product after the production failure, we may have been required to suspend any ongoing trials and postpone future trials. Although we have taken sufficient steps to assure our current supply of pacmilimab clinical trial drug product for our planned clinical trials, there can be no assurance that we will not have future production failures, which could affect our ability to conduct our trials for praluzatamab ravtansine, CX-2029, pacmilimab, CX-904 or any other clinical trial drug candidates on our planned timeline or at all. Furthermore, in order to conduct later stage clinical trials of our product candidates, including CX-072, CX-2009 and CX-2029,such as our Phase 2 clinical trial for praluzatamab ravtansine, and eventually, if approved, commercial products, we will need to manufacture them in larger quantities. We, or any manufacturing partners, may be unable to successfully increase the manufacturing scale and capacity for any of our product candidates in a timely or cost-effective manner, or at all. For example, we are currently working with our CMOs to change our manufacturing processes and formulations as well as scaling up for larger drug manufacturing capability, and to increase the term of stability for CX-072including praluzatamab ravtansine drug product for late stagelate-stage clinical trials and commercialization. However, we may have to start late stagelate-stage trials with our early clinical trial drug product and switch to late stagelate-stage or commercial drug product mid trial. In such event, the FDA will require us to complete bridging studies to compare the earlier stage material with late stagelate-stage or commercial material to assure comparability between the earlier trial material and the latelate- stage or commercial material. Changing formulation and scalescaling up the process is a complicated and difficult task. While we believe we can complete this process successfully, there can be no assurances that the changes we make to the drug product and manufacturing process will be successful or completed in a timely manner or that the FDA will not require additional development steps or studies from those we believe are necessary. If we are not able to scale up our manufacturing capabilities with respect to CX-072praluzatamab ravtansine, pacmilimab or any of our other product candidates, increase the life of drug stability of CX-072 or such other product candidates, or successfully complete the FDA’s bridging requirements, we may not be able to successfully obtain FDA approval and commercialize CX-072 or such other product candidates in a timely manner or at all.

Additionally, we were dependent on ImmunoGen under our collaboration for certain steps in the manufacturing of clinical quantities of CX-2009.praluzatamab ravtansine. At the end of 2018, ImmunoGen closed their clinical manufacturing facility in Norwood, Massachusetts, which provided clinical manufacturing support for the CX-2009praluzatamab ravtansine program. We have initiatedcompleted the transfer of the drug substance manufacturing process from ImmunoGen to a contract manufacturer, where we have an existing relationship and with expertise in the manufacture of antibody drug conjugates at a clinical and commercial scale. However,While the manufacturing transfer process has been completed, there can be no assurancesassurance that we will not experience a disruption toin the supply of CX-2009praluzatamab ravtansine in connection with such transfer.  To date,transfer or that we will not experience any other disruption in the manufacturing transfer process is still ongoing and has not yet been completed.of praluzatamab ravtansine. In addition, for CX-2029, the manufacturing of additional clinical quantities could be particularly difficult because we are relying on three different parties to manufacture supplies. If we, or any manufacturing partners, are unable to successfully scale up the manufacture of our product candidates in sufficient quality and quantity, the development, testing, and clinical trials of that product candidate may be delayed or infeasible, and regulatory approval or commercial launch of any resulting product may be delayed or not obtained, which could significantly harm our business.

We may acquire assets or form strategic alliances in the future, and we may not realize the benefits of such acquisitions.

As we continue to mature our Probody platform and our clinical stage pipeline, we may seek to acquire and/or in-license other oncology products, product candidates, programs or companies that we consider complimentary to our efforts. Such efforts may never result in a transaction and any future growth through acquisition or in-licensing will depend upon the availability of suitable products, product candidates, programs or companies for acquisition or in-licensing on acceptable prices, terms and conditions. Even if appropriate opportunities are available, we may not be able to acquire rights to them on acceptable terms, or at all. The competition to acquire or in-license rights to promising products, product candidates, programs and companies is fierce, and many of our competitors are large, multinational pharmaceutical and biotechnology companies with considerably more financial, development and commercialization resources, personnel, and experience than we have. In order to compete successfully in the current business climate, we may have to pay higher prices for assets than may have been paid historically, which may make it more difficult for us to realize an adequate return on any acquisition. In addition, even if we succeed in identifying promising products, product candidates, programs or companies, we may not have the ability to develop, obtain regulatory approval for and commercialize such opportunities, or the financial resources necessary to pursue them.

Even if we are able to successfully identify and acquire or in-license new products, product candidates, programs or companies, we may not be able to successfully manage the risks associated with integrating any products, product candidates, programs or companies into our business or the risks arising from anticipated and unanticipated problems in connection with an acquisition or in-licensing. Further, while we seek to mitigate risks and liabilities of potential acquisitions through, among other things, due diligence, there may be risks and liabilities that such due diligence efforts fail to discover, that are not disclosed to us, or that we inadequately assess. Any failure in identifying and managing these risks and uncertainties effectively would have a material adverse effect on our business. In any event, we may not be able to realize the anticipated benefits of any acquisition or in-licensing for a variety of reasons, including the possibility that a product candidate fails to advance to clinical development, proves not to be safe or effective in clinical trials, or fails to reach its forecasted commercial potential or that the integration of a product, product candidate, program or company gives rise to unforeseen difficulties and expenditures. Any failure in identifying and managing these risks and uncertainties would have a material adverse effect on our business.

In addition, acquisitions create other uncertainties and risks, particularly when the acquisition takes the form of a merger or other business consolidation. We may encounter unexpected difficulties, or incur unexpected costs, in connection with transition activities and integration efforts, which include:

If we fail to integrate or otherwise manage an acquired business successfully and in a timely manner, resulting operating inefficiencies could increase our costs more than we planned, could negatively impact the market price of our common stock and could otherwise distract us from execution of our strategy. Failure to maintain effective financial controls and reporting systems and procedures could also impact our ability to produce timely and accurate financial statements.

We may expend our limited resources to pursue a particular product candidate and fail to capitalize on product candidates that may be more profitable or for which there is a greater likelihood of success.

Because we have limited financial and managerial resources, we focus on specific product candidates and indications, including CX-072, CX-2009praluzatamab ravtansine (CX-2009), CX-2029, pacmilimab (CX-072), and CX-2029.CX-904. As a result, we may forgo or delay pursuit of opportunities with those products in other indications or with other product candidates that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs, including CX-2043, and product candidates for specific indications may not yield any commercially viable product candidates. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

We may experience difficulties in managing our growth and expanding our operations successfully.

We will need to grow our organization substantially to continue development and pursue the potential commercialization of CX-072, CX-2009 andpraluzatamab ravtansine (CX-2009), CX-2029, pacmilimab (CX-072), CX-904 and our other product candidates, including CX-2043, as well as function as a public company. As we increase the number of our product candidates entering and advancing through preclinical studies and clinical trials, we will need to expand our development, regulatory and manufacturing capabilities or contract with additional organizations to provide these capabilities for us. In addition, we expect our collaborations to require greater resources as the development of our product candidates under such agreements progresses. In the future, we expect to also have to manage additional relationships with collaborators or partners, suppliers and other organizations. In particular, if the third-partiesthird parties on which we currently rely are not capable of delivering services or supplies in a manner that is sufficient to meet our requirements as we expand our operations, we could be required to contract with new third parties and there can be no assurances that the services or supplies of such third parties will be available on commercially reasonable terms, or at all. Furthermore, our ability to manage our operations and

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future growth will require us to continue to increase headcount as well as improve our operational, financial and management controls, reporting systems and procedures. We may not be able to implement improvements to our management information and control systems in an efficient or timely manner and may discover deficiencies in existing systems and controls.

We face competition from entities that have developed or may develop product candidates for cancer, including companies developing novel treatments and technology platforms. If these companies develop technologies or product candidates more rapidly than we do or their technologies are more effective, our ability to develop and successfully commercialize product candidates may be adversely affected.

The development and commercialization of drugs and therapeutic biologics is highly competitive. We compete with a variety of multinational biopharmaceutical companies and specialized biotechnology companies, as well as technology being developed at universities and other research institutions. Our competitors have developed, are developing or will develop product candidates and processes competitive with our product candidates. Competitive therapeutic treatments include those that have already been approved and accepted by the medical community and any new treatments that enter the market. We believe that a significant number of products are currently under development, and may become commercially available in the future, for the treatment of conditions for which we may try to develop product candidates. For instance,Additionally, there is intense and rapidly evolving competition in the biotechnology, biopharmaceutical and antibody and immunoregulatory therapeutics fields, and our competitors include larger and better funded biopharmaceutical, biotechnological and therapeutics companies. In addition, these companies compete with us in recruiting scientific and managerial talent.

We believe that while our Probody platform, its associated intellectual property and our scientific and technical know-how, give us a competitive advantage in this space, competition from many sources remains. The clinical development pipeline for cancer includes small molecules, antibodies and therapies from a variety of groups. In addition, numerous compounds are in clinical development for cancer treatment. As a result, our success will partially depend on our ability to develop and protect therapeutics that are safer and more effective than competing products. Our commercial opportunity and success will be reduced or eliminated if competing products that are safer, more effective, or less expensive than the therapeutics we develop or if we are unable to utilize our Probody therapeutic technology to differentiate our Probody therapeutics from the products of our competitors. For instance, if any of our lead product candidates, including, CX-072, CX-2009praluzatamab ravtansine and CX-2029 are approved, they will compete with a range of therapeutic treatments that are either in development or currently marketed. A variety of oncology drugs and therapeutic biologics are currently on the market or in clinical development. The market for immunotherapies like CX-072pacmilimab (CX-072) is, in particular, highly competitive and the field is changing quickly. In March 2020, we made the strategic decision to terminate our Phase 2 study evaluating pacmilimab in combination ipilimumab. This decision followed a re-evaluation of the evolving clinical, competitive and commercial landscapes in immuno-oncology, taken together with the impact of the COVID-19 pandemic. Given the amount of time required to successfully develop and obtain regulatory approval for each of our product candidates, it is therefore possible that by the time we obtain any such approval, if ever, and commence sales, we may no longer be able to differentiate such product candidate from those of our competitors.

We face substantial competition from pharmaceutical companies developing products in immuno-oncology,oncology, including companies such as Amgen, AstraZeneca PLC, BMS, Celgene,Bristol Myers Squibb, GlaxoSmithKline plc, Merck & Co., Inc. Novartis AG, Pfizer, Roche Holding Ltd. and Sanofi SA. Many large and mid-sized biotech companies, including BeiGene, Incyte, TESARO, Inc., Nektar, and Alkermes have ongoing efforts in cancer immunotherapy. Finally, numerous small companies are also working in the space. Several companies, including Akriveia,Adagene, Amgen, Amunix, BioAtla, Halozyme, Maverick Therapeutics, PandionHarpoon Therapeutics, Revitope, Roche, Seagen, Takeda, Werewolf Therapeutics, and Seattle GeneticsXilio are exploring antibody masking and/or conditional activation strategies, which could compete with our Probody Platform.platform. We are also aware of several companies that are developing ADCs, such as AbbVie, Immunomedics,ADC Therapeutics, Daiichi Sankyo, Gilead, ImmunoGen, Mersana Therapeutics, Pfizer, Roche Holding Ltd. AndSeagen and Takeda.  In addition, two mid-sized companies, ImmunoGen and Seattle Genetics, Inc. are also leaders in the development of ADCs and we are aware of numerous small companies with ongoing efforts in this field. Furthermore, several large pharmaceutical companies, including Amgen, Novartis AG and Roche Holding Ltd., are developing T-cell engaging immunotherapies, and we are aware of several mid-sized biotech companies, such as MacrogenicsMacroGenics and Xencor, and small companies with ongoing efforts to develop T-cell engaging immunotherapies. Any of these companies may be well-capitalizedwell capitalized and may have significant clinical experience. In addition, these companies include our collaborators.

Many of our competitors have significantly greater financial, technical, manufacturing, marketing, sales and supply resources or experience than we do. If we successfully obtain approval for any product candidate, we will face competition based on many different factors, including the safety and effectiveness of our products, the ease with which our products can be administered and the extent to which patients accept relatively new routes of administration, the timing and scope of regulatory approvals for these products, the availability and cost of manufacturing, marketing and sales capabilities, price, reimbursement coverage and patent position. Competing products could present superior treatment alternatives, including by being more effective, safer, less expensive or marketed and sold more effectively than any products we may develop. Competitive products may make any products we develop less differentiated or noncompetitive before we recover the expense of developing and commercializing our product candidates. Such competitors could also recruit our employees, which could negatively impact our level of expertise and our ability to execute our business plan.

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Any inability to attract and retain qualified key management and technical personnel would impair our ability to implement our business plan.

Our success largely depends on the continued service of key management, advisors and other specialized personnel, including Sean A. McCarthy, D.Phil., our chief executive officer and chairman, and Amy C. Peterson, M.D., our president and chief executive officer, W. Michael Kavanaugh, M.D., our chief scientific officer and Rachel W. Humphrey, M.D., our chief medicaloperating officer. The loss of one or more members of our management team or other key employees or advisors could delay our research and development programs and have a material and adverse effect on our business, financial condition, results of operations and prospects. The relationships that our key managers have cultivated within our industry make us particularly dependent upon their continued employment with us. We are dependent on the continued service of our technical personnel because of the highly technical nature of our product candidates and technologies and the specialized nature of the regulatory approval process. Because our management team and key employees are not obligated to provide us with continued service, they could terminate their employment with us at any time without penalty. In particular, as a result of the COVID-19 pandemic, the ability of employees to engage in a remote working environment has increased the competitive landscape across the country for us in seeking qualified employees. Employees are now able to consider opportunities across the country and it may be more difficult to hire employees. Furthermore, it is more difficult to engage employees in Company culture and build working rapport when they are working remotely. As a result, it may be more difficult to retain employees on a long-term basis. Our future success will depend in large part on our continued ability to attract and retain other highly qualified scientific, technical and management personnel, as well as personnel with expertise in clinical testing, manufacturing, governmental regulation and commercialization. We face competition for personnel from other companies, universities, public and private research institutions, government entities and other organizations, especially as job opportunities in the biotechnology industry have recently increased significantly in the San Francisco Bay Area.Area and across the country.

If any of our product candidates are approved for marketing and commercialization and we are unable to develop sales, marketing and distribution capabilities on our own or enter into agreements with third parties to perform these functions on acceptable terms, we will be unable to commercialize successfully any such future products.

We currently have no sales, marketing or distribution capabilities or experience. If any of our product candidates is approved, we will need to develop internal sales, marketing and distribution capabilities to commercialize such products, which would be expensive and time-consuming, or enter into collaborations with third parties to perform these services. If we decide to market our products directly, we will need to commit significant financial and managerial resources to develop a marketing and sales force with technical expertise and supporting distribution, administration and compliance capabilities. If we rely on third parties with such capabilities to market our products or decide to co-promote products with collaborators, we will need to establish and maintain marketing and distribution arrangements with third parties, and there can be no assurance that we will be able to enter into such arrangements on acceptable terms or at all. In entering into third-party marketing or distribution arrangements, any revenue we receive will depend upon the efforts of the third parties and there can be no assurance that such third parties will establish adequate sales and distribution capabilities or be successful in gaining market acceptance of any approved product. If we are not successful in commercializing any product approved in the future, either on our own or through third parties, our business, financial condition, results of operations and prospects could be materially and adversely affected.

Our future growth may depend, in part, on our ability to operate in foreign markets, where we would be subject to additional regulatory burdens and other risks and uncertainties.

Our future growth may depend, in part, on our ability to develop and commercialize our product candidates in foreign markets for which we may rely on collaboration with third parties. We are not permitted to market or promote any of our product candidates before we receive regulatory approval from the applicable regulatory authority in that foreign market, and we may never receive such regulatory approval for any of our product candidates. To obtain separate regulatory approval in many other countries we must comply with numerous and varying regulatory requirements of such countries regarding safety and efficacy and governing, among other things, clinical trials and commercial sales, pricing and distribution of our product candidates, and we cannot predict success in these jurisdictions. If we obtain approval of our product candidates and ultimately commercialize our product candidates in foreign markets, we would be subject to the risks and uncertainties, including the burden of complying with complex and changing foreign regulatory, tax, accounting and legal requirements and the reduced protection of intellectual property rights in some foreign countries. We may need to rely on third parties to market, distribute and sell our products in foreign markets.

Price controls imposed in foreign markets may adversely affect our future profitability.

In some countries, particularly member states of the European Union, the pricing of prescription drugs is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after receipt of marketing approval for a product. In addition, there can be considerable pressure by governments and other stakeholders on prices and reimbursement levels, including as part of cost containment measures. Political, economic and regulatory developments may further complicate pricing negotiations, and pricing negotiations may continue after reimbursement has been obtained. Reference pricing used by various European Union member states and parallel distribution, or arbitrage between low-priced and high-priced member states, can further reduce prices. In some countries, we or future collaborators may be required to conduct a clinical trial or other studies that compare the cost-effectiveness of our Probody therapeutic candidates to other available therapies in order to obtain or maintain reimbursement or pricing approval. Publication of discounts by third-party payors or authorities may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries. If reimbursement of any product candidate approved for marketing is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business, financial condition, results of operations or prospects could be materially and adversely affected. We currently do not know how the exit of the United Kingdom from the European Union will affect the pricing of prescription drugs, either in the United Kingdom or in the remaining European Union member states.

Our business entails a significant risk of product liability and our ability to obtain sufficient insurance coverage could have a material and adverse effect on our business, financial condition, results of operations and prospects.

We are exposed to significant product liability risks inherent in the development, testing, manufacturing and marketing of therapeutic treatments, including as a result of the clinical testing of CX-072, CX-2009,praluzatamab ravtansine (CX-2009), CX-2029, BMS-986249, BMS-986288,

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pacmilimab (CX-072) and BMS-986249CX-904 and any of our other product candidates we or those of our collaborators may conduct clinical trials for.collaborators. Product liability claims could delay or prevent completion of our development programs. If we succeed in marketing product candidates, such claims could result in an FDA investigation of the safety and effectiveness of our product candidates, our manufacturing processes and facilities (or the manufacturing processes and facilities of our third-party manufacturer)manufacturers) or our marketing programs and potentially a recall of our products or more serious enforcement action, limitations on the approved indications for which they may be used or suspension or withdrawal of approvals. Regardless of the merits or eventual outcome, liability claims may also result in decreased demand for our products, injury to our reputation, costs to defend the related litigation, a diversion of management’s time and our resources, substantial monetary awards to trial participants or patients and a decline in our stock price. We currently have insurance that we believe is appropriate for our stage of development and may need to obtain higher levels of insurance prior to marketing any of our product candidates. Any insurance we have or may obtain may not provide sufficient coverage against potential liabilities. Furthermore, clinical trial and product liability insurance is becoming increasingly expensive. As a result, we may be unable to obtain sufficient insurance at a reasonable cost to protect us against losses caused by product liability claims that could have a material and adverse effect on our business, financial condition, results of operations and prospects.

Our employees and independent contractors may engage in misconduct or other improper activities, including noncompliance with regulatory standards and requirements.

We are exposed to the risk of fraud or other misconduct by our employees or independent contractors. Misconduct by these parties could include intentional failures to comply with FDA regulations, provide accurate information to the FDA, comply with manufacturing standards we may establish, comply with federal and state data privacy, security, fraud and abuse, and other healthcare laws and regulations, report financial information or data accurately or disclose unauthorized activities to us. In particular, sales, marketing and business arrangements in the healthcare industry are subject to extensive laws and regulations intended to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing,

discounting, marketing and promotion, sales commission, customer incentive programs and other business arrangements. Activities subject to these laws could also involve the improper use or misrepresentation of information obtained in the course of clinical trials, which could result in regulatory sanctions and cause serious harm to our reputation. It is not always possible to identify and deter misconduct by employees and other third parties, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws or regulations. Additionally, we are subject to the risk that a person or government could allege such fraud or other misconduct, even if none occurred. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a material and adverse effect on our business, financial condition, results of operations and prospects, including the imposition of significant fines or other sanctions.

Our information technology systems, or those of our CROs or other contractors or consultants we may utilize, may fail, suffer disruptions or suffer security breaches, which could result in a material disruption of our product development programs.

Our information technology and other internal infrastructure systems and those of our CROs and contractors and consultants, including corporate firewalls, servers, leased lines and connection to the Internet, face the risk of systemic failure and may be vulnerable to damage from computer viruses, unauthorized access, natural disasters, terrorism, war and telecommunication and electrical failures. Such events could cause interruptions of our operations. For instance, the loss of data from any current or future clinical trial or data from any preclinical studies involving our product candidates could result in delays in our development and regulatory filing efforts and significantly increase our costs. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data, or inappropriate disclosure of confidential or proprietary information, we could incur liability, recovery of our data could take a prolonged period of time, and the development of our research or product candidates could be delayed.

Cybersecurity breaches could expose us to liability, damage our reputation, compromise our confidential information or otherwise adversely affect our business.

We maintain sensitive company data on our computer networks, including our intellectual property and proprietary business information. We face a number of threats to our networks from unauthorized access, security breaches and other system disruptions. Despite our security measures, our infrastructure may be vulnerable to attacks by hackers or other disruptive problems. Any such security breach may compromise information stored on our networks and may result in significant data losses or theft of our intellectual property or proprietary business information. A cybersecurity breach could adversely affect our reputation and could result in other negative consequences, including disruption of our internal operations, increased cyber security protection costs, lost revenues or litigation.

If we do not comply with laws regulating the protection of the environment and health and human safety, our business could be adversely affected.

Our research and development activities involve the use of hazardous materials and various chemicals. We maintain quantities of various flammable and toxic chemicals in our facilities in South San Francisco, California that are required for our research and development activities. We are subject to federal, state and local laws and regulations governing the use, manufacture, storage, handling and disposal of these hazardous materials. We believe our procedures for storing, handling and disposing these materials in our South San Francisco facilities comply with the relevant guidelines of South San Francisco, the state of California and the Occupational Safety and Health Administration of the U.S. Department of Labor. Although we believe that our safety procedures for handling and disposing of these materials comply with the standards mandated by applicable regulations, the risk of accidental contamination or injury from these materials cannot be eliminated. If an accident occurs, we could be held liable for resulting damages, which could be substantial. We are also subject to numerous environmental, health and workplace safety laws and regulations, including those governing laboratory procedures, exposure to blood-borne pathogens and the handling of animals and biohazardous materials. Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of these materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological or hazardous materials. Additional federal, state and local laws and regulations affecting our operations may be adopted in the future. We may incur substantial costs to comply with, and substantial fines or penalties if we violate, any of these laws or regulations.

Our current operations are concentrated in one location, and we or the third parties upon whom we depend may be adversely affected by earthquakes or other natural disasters and our business continuity and disaster recovery plans may not adequately protect us from a serious disaster.

Our current operations are located in our facilities in South San Francisco, California. Any unplanned event, such as flood, fire, explosion, earthquake, extreme weather condition, medical epidemics, power shortage, telecommunication failure or other natural or manmade accidents or incidents that result in us being unable to fully utilize our facilities, or the manufacturing facilities of our third-party contract manufacturers, may have a material and adverse effect on our ability to operate our business, particularly on a daily basis, and have significant negative consequences on our financial and operating conditions. Loss of access to these facilities may result in increased costs, delays in the development of our product candidates or interruption of our business operations. Earthquakes or other natural disasters could further disrupt our operations and have a material and adverse effect on our business, financial condition, results of operations and prospects. If a natural disaster, power outage or other event occurred that prevented us from using all or a significant portion of our headquarters, that damaged critical infrastructure, such as our research facilities or the manufacturing facilities of our third-party contract manufacturers, or that otherwise disrupted operations, it may be difficult or, in certain cases, impossible, for us to continue our business for a substantial period of time. For example, in March 2020, the COVID-19 pandemic caused us to restrict access to our facility and initiate a work-from-home program limiting onsite activity to a substantially reduced level of laboratory research activities. Although we have gradually increased levels of our laboratory research activities, we continue to operate in a hybrid, work-from-home environment and there can be no assurance that we will be able to continue to increase or maintain current levels of such activity or that the COVID-19 pandemic will not continue to impact our ability to conduct business.

The disaster recovery and business continuity plans we have in place may prove inadequate in the event of a serious disaster or similar event. We may incur substantial expenses as a result of the limited nature of our disaster recovery and business continuity plans, which could have a material and adverse effect on our business. As part of our risk management policy, we maintain insurance coverage at levels that we believe are appropriate for our business. However, in the event of an accident or incident at these facilities, we cannot assure you that the amounts of insurance will be sufficient to satisfy any damages and losses. If our facilities, or the manufacturing facilities of our third-party contract manufacturers, are unable to operate because of an accident or incident or for any

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other reason, even for a short period of time, any or all of our research and development programs may be harmed. Any business interruption may have a material and adverse effect on our business, financial condition, results of operations and prospects.

Our reported financial results may be adversely affected by changes in accounting principles generally accepted in the U.S.

We prepare our financial statements in conformity with accounting principles generally accepted in the U.S. These accounting principles are subject to interpretation by the Financial Accounting Standards Board (“FASB”) and the SEC. A change in these policies or interpretations could have a significant effect on our reported financial results, may retroactively affect previously reported results, could cause unexpected financial reporting fluctuations, and may require us to make costly changes to our operational processes and accounting systems. For example, in May 2014, the FASB issued Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606), which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU replaced most existing revenue recognition guidance in the U.S. GAAP when it became effective. The new standard was effective at the beginning of our fiscal year 2018 with early adoption permitted for our fiscal year 2017. We evaluated the impact of ASU 2014-09 on our financial statements and adoption of the standard had a significant impact on our financial statements and retroactively affected the accounting treatment of transactions completed before adoption. Additionally, for the purpose of revenue recognition, we are required to estimate research service periods as well as the related cost to completion, of our research development program. Such estimates are inherently uncertain and may result in changes in estimates to financial statements in subsequent periods.

Our ability to utilize our net operating loss carryforwards and certain other tax attributes may be limited.

Under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended (the “IRC”), if a corporation undergoes an “ownership change” (generally defined as a greater than 50 percentage points change (by value) in the ownership of its equity over a rolling three-year period), the corporation’s ability to use its pre-change net operating loss carryforwards and certain other pre-change tax attributes to offset its post-change income and taxes may be limited. California has similar rules. We haveFor example, we performed an IRC Section 382 analysis in 2017 and determined there was an ownership change in 2017, that resulted in Section 382 limitations. The ownership change limited our ability to utilize net operating losses against taxable income in 2018 for both federal and California tax purposes. The remaining net operating losses and credit will be available in future years before expiration during their respective carryforward periods. We may experience ownership changes in the future as a result of shifts in our stock ownership, some of which are outside our control, and our ability to utilize net operating loss carryforwards could be limited by an “ownership change” as described above, which could result in additional increased tax liability to our company.the Company.

Recent U.S. tax legislation and future changes to applicable U.S. or foreign tax laws and regulations may have a material adverse effect on our business, financial condition and results of operations.

We are subject to income and other taxes in the U.S. and foreign jurisdictions. Changes in laws and policy relating to taxes or trade may have an adverse effect on our business, financial condition and results of operations. For example, the U.S. government recently enacted significant tax reform, and certain provisions of the new law may adversely affect us. Changes include, but are not limited to, a federal corporate tax rate decrease from 34% to 21% for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a more generally territorial system, and a one-time transition tax on the mandatory deemed repatriation of foreign earnings. The legislation is unclear in many respects and could be subject to potential

amendments and technical corrections and will be subject to interpretations and implementing regulations by the Treasury and Internal Revenue Service, any of which could mitigate or increase certain adverse effects of the legislation. In addition, it is unclear how these U.S. federal income tax changes will affect state and local taxation. Generally, future changes in applicable U.S. or foreign tax laws and regulations, or their interpretation and application could have an adverse effect on our business, financial conditions and results of operations.

Risks Related to Intellectual Property

If we are not able to obtain and enforce patent protection for our technologies or product candidates, development and commercialization of our product candidates may be adversely affected.

Our success depends in part on our ability to obtain and maintain patents and other forms of intellectual property rights, including in-licenses of intellectual property rights of others, for our product candidates, methods used to manufacture our product candidates and methods for treating patients using our product candidates, as well as our ability to preserve our trade secrets, to prevent third parties from infringing upon our proprietary rights and to operate without infringing upon the proprietary rights of others. We have a substantial number of issued patents and pending patent applications, some of which are co-owned with a third party, covering our Probody platforms and products as well as methods of use and production thereof; we have exclusively licensed UCSB’s interest in the patent family co-owned with UCSB that covers Probody and other pro-protein technology in the fields of therapeutics, in vivo diagnostics and prophylactics. In addition, we have exclusively licensed a patent portfolio of three patent families from UCSB that includes patents and patent applications that cover compositions and methods related to the screening for and identification of the masks and protease-cleavable linkers that we incorporate into our Probody candidates. We may not be able to apply for patents on certain aspects of our product candidates in a timely fashion or at all. Our existing issued and granted patents and any future patents we obtain may not be sufficiently broad to prevent others from using our technology or from developing competing products and technology. There is no guarantee that any of our pending patent applications will result in issued or granted patents, that any of our issued or granted patents will not later be found to be invalid or unenforceable or that any issued or granted patents will include claims that are sufficiently broad to cover our product candidates or to provide meaningful protection from our competitors. Moreover, the patent position of biotechnology and biopharmaceutical companies can be highly uncertain because it involves complex legal and factual questions. We will be able to protect our proprietary rights from unauthorized use by third parties only to the extent that our current and future proprietary technology and product candidates are covered by valid and enforceable patents or are effectively

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maintained as trade secrets. If third parties disclose or misappropriate our proprietary rights, it may materially and adversely affect our position in the market.

The U.S. Patent and Trademark Office (“USPTO”) and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other provisions during the patent process. There are situations in which noncompliance can result in abandonment or lapse of a patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. In such an event, competitors might be able to enter the market earlier than would otherwise have been the case. The standards applied by the USPTO and foreign patent offices in granting patents are not always applied uniformly or predictably. For example, there is no uniform worldwide policy regarding patentable subject matter or the scope of claims allowable in biotechnology and biopharmaceutical patents. As such, we do not know the degree of future protection that we will have on our proprietary products and technology. While we will endeavor to try to protect our product candidates with intellectual property rights such as patents, as appropriate, the process of obtaining patents is time-consuming, expensive and sometimes unpredictable.

In addition, there are numerous recent changes to the patent laws and proposed changes to the rules of the USPTO that may have a significant impact on our ability to protect our technology and enforce our intellectual property rights. For example, the America Invents Act (“AIA”) enacted within the last several years involves significant changes in patent legislation. The Supreme Court has ruled on several patent cases in recent years, some of which cases either narrow the scope of patent protection available in certain circumstances or weaken the rights of patent owners in certain situations. The recent decision by the Supreme Court in Association for Molecular Pathology v. Myriad Genetics, Inc. precludes a claim to a nucleic acid having a stated nucleotide sequence that is identical to a sequence found in nature and has not been modified. We currently are not aware of an immediate impact of this decision on our patents or patent applications because we are developing product candidates that contain modifications, such as our Probody substrates and masks, that we believe are not found in nature. However, this decision has yet to be clearly interpreted by courts and by the USPTO. We cannot assure you that the interpretations of this decision or subsequent rulings will not adversely impact our patents or patent applications. In addition to increasing uncertainty with regard to our ability to obtain patents in the future, this combination of events has created uncertainty with respect to the value of patents, once obtained. Depending on decisions by the U.S. Congress, the federal courts and the USPTO, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

Once granted, patents may remain open to opposition, interference, re-examination, post-grant review, inter partiespartes review, nullification or derivation action in court or before patent offices or similar proceedings for a given period after allowance or grant, during which time third parties can raise objections against such initial grant. In the course of such proceedings, which may continue for a protracted period of time, the patent owner may be compelled to limit the scope of the allowed or granted claims thus attacked, or may lose the allowed or granted claims altogether. In addition, there can be no assurance that:

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Other companies or organizations may challenge our or our licensors’ patent rights or may assert patent rights that prevent us from developing and commercializing our products.

Probody therapeutics are a relatively new scientific field. We have obtained grants and issuances of Probody therapeutic patents and have licensed one patent family comprising several of these patents from a third party on an exclusive basis for therapeutics applications. The issued patents and pending patent applications in the United States and in key markets around the world that we own or license claim many different methods, compositions and processes relating to the discovery, development, manufacture and commercialization of antibody and immunoregulatory therapeutics. Specifically, we own and have licensed a portfolio of patents, patent applications and other intellectual property covering Probody compositions of matter as well as their methods of manufacturing and use.

As the field of antibody and immunoregulatory therapeutics matures, patent applications are being processed by national patent offices around the world. There is uncertainty about which patents will issue, and, if they do, as to when, to whom, and with what claims. In addition, third parties may attempt to invalidate our intellectual property rights.

Even if our rights are not directly challenged, disputes could lead to the weakening of our intellectual property rights. Our defense against any attempt by third parties to circumvent or invalidate our intellectual property rights could be costly to us, could require significant time and attention of our management and could have a material and adverse effect on our business, financial condition, results of operations and prospects or our ability to successfully compete.

There are many issued and pending patents that claim aspects of our product candidates and modifications that we may need to apply to our product candidates. There are also many issued patents that claim antibodies or portions of antibodies that may be relevant for Probody products we wish to develop. Thus, it is possible that one or more organizations will hold patent rights to which we will need a license. If those organizations refuse to grant us a license to such patent rights on reasonable terms, we may not be able to market products or perform research and development or other activities covered by these patents.

We may not be able to protect our intellectual property rights throughout the world.

Obtaining a valid and enforceable issued or granted patent covering our technology in the U.S. and worldwide can be extremely costly. In jurisdictions where we have not obtained patent protection, competitors may use our technology to develop their own products and further, may export otherwise infringing products to territories where we have patent protection, but where it is more difficult to enforce a patent as compared to the U.S. Competitor products may compete with our future products in jurisdictions where we do not have issued or granted patents or where our issued or granted patent claims or other intellectual property rights are not sufficient to prevent competitor activities in these jurisdictions. The legal systems of certain countries, particularly certain developing countries, make it difficult to enforce patents and such countries may not recognize other types of intellectual property protection, particularly that relating to biopharmaceuticals. This could make it difficult for us to prevent the infringement of our patents or marketing of competing products in violation of our proprietary rights generally in certain jurisdictions. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial cost and divert our efforts and attention from other aspects of our business.

We generally file a provisional patent application first (a priority filing) at the USPTO. An international application under the Patent Cooperation Treaty (“PCT”) is usually filed within twelve months after the priority filing. Based on the PCT filing, national and regional patent applications may be filed in the United States, Europe, Japan, Australia and Canada and, depending on the individual case, also in any or all of, inter alia, Brazil, China, Hong Kong, India, Indonesia, Israel, Malaysia, Mexico, New Zealand, Russia or Eurasian Patent Organization, Singapore, South Africa, South Korea and other jurisdictions. We have so far not filed for patent protection in all national and regional jurisdictions where such protection may be available. In addition, we may decide to abandon national and regional patent applications before grant. Finally, the grant proceeding of each national or regional patent is an independent proceeding which may lead to situations in which applications might in some jurisdictions be refused by the relevant registration authorities, while granted by others. It is also quite common that depending on the country, various scopes of patent protection may be granted on the same product candidate or technology.

The laws of some jurisdictions do not protect intellectual property rights to the same extent as the laws in the U.S., and many companies have encountered significant difficulties in protecting and defending such rights in such jurisdictions. If we or our licensors encounter difficulties in protecting, or are otherwise precluded from effectively protecting, the intellectual property rights important for our business in such jurisdictions, the value of these rights may be diminished and we may face additional competition from others in those jurisdictions. Many countries have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In addition, many countries limit the enforceability of patents against government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of such patent. If we or any of our licensors are forced to grant a license to third parties with respect to any patents relevant to our business, our competitive position in the relevant jurisdiction may be impaired and our business and results of operations may be adversely affected.

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We or our licensors, or any future strategic partners may become subject to third party claims or litigation alleging infringement of patents or other proprietary rights or seeking to invalidate patents or other proprietary rights, and we may need to resort to litigation to protect or enforce our patents or other proprietary rights, all of which could be costly, time consuming, delay or prevent the development and commercialization of our product candidates, or put our patents and other proprietary rights at risk.

We or our licensors, or any future strategic partners may be subject to third-party claims for infringement or misappropriation of patent or other proprietary rights. We are generally obligated under our license or collaboration agreements to indemnify and hold harmless our licensors or collaborators for damages arising from intellectual property infringement by us. For example, in March 2020, Vytacera Bio, LLC filed a patent infringement lawsuit against the Company in the U.S. District Court for the District of Delaware. The lawsuit alleges that the Company’s use, offers to sell, and/or sales of the Probody technology platform for basic research applications constitutes infringement. The complaint seeks unspecified monetary damages. The Company believes that the lawsuit is without merit and intends to vigorously defend itself. However, there can be no assurance that a court might not rule against us in these proceedings. Even if we are successful in defending against such claim, this litigation could divert management’s attention, as well as our resources, from our business and any claims paid out of our cash reserves would harm our financial condition and operating results.

If we or our licensors, or any future strategic partners are found to infringe a third-party patent or other intellectual property rights, we could be required to pay damages, potentially including treble damages, if we are found to have willfully infringed. In addition, we or our licensors, or any future strategic partners may choose to seek, or be required to seek, a license from a third party, which may not be available on acceptable terms, if at all. Even if a license can be obtained on acceptable terms, the rights may be non-exclusive, which could give our competitors access to the same technology or intellectual property rights licensed to us. If we fail to obtain a required license, we or our collaborators may be unable to effectively market product candidates based on our technology, which could limit our ability to generate revenue or achieve profitability and possibly prevent us from generating revenue sufficient to sustain our operations. In addition, we may find it necessary to pursue claims or initiate lawsuits to protect or enforce our patent or other intellectual property rights. The cost to us in defending or initiating any litigation or other proceeding relating to patent or other proprietary rights, even if resolved in our favor, could be substantial, and litigation would divert our management’s attention. Some of our competitors may be able to sustain the costs of complex patent litigation more effectively than we can because they have substantially greater resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could delay our research and development efforts and limit our ability to continue our operations.

If we were to initiate legal proceedings against a third party to enforce a patent covering one of our products or our technology, the defendant could counterclaim that our patent is invalid or unenforceable. In patent litigation in the U.S., defendant counterclaims alleging invalidity or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, for example, lack of novelty, obviousness or non-enablement. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the USPTO, or made a misleading statement, during prosecution. The outcome following legal assertions of invalidity and unenforceability during patent litigation is unpredictable. With respect to the validity question, for example, we cannot be certain that there is no invalidating prior art, of which we and the patent examiner were unaware during prosecution. If a defendant were to prevail on a legal assertion of invalidity or unenforceability, we would lose at least part, and perhaps all, of the patent protection on one or more of our products or certain aspects of our platform technology. Such a loss of patent protection could have a material and adverse effect on our business, financial condition, results of operations and prospects. Patents and other intellectual property rights also will not protect our technology if competitors design around our protected technology without legally infringing, misappropriating or otherwise violating our patents or other intellectual property rights.

Intellectual property rights of third parties could adversely affect our ability to commercialize our product candidates, and we might be required to litigate or obtain licenses from third parties in order to develop or market our product candidates. Such litigation or licenses could be costly or not available on commercially reasonable terms.

Because the antibody landscape is still evolving, including the masked antibody landscape, it is difficult to conclusively assess our freedom to operate without infringing on third-party rights. There are numerous companies that have pending patent applications and issued patents broadly covering antibodies generally or covering antibodies directed against the same targets as, or targets similar to, those we are pursuing. There are many issued patents and patent applications covering antibodies targeted against PD-1 and PD-L1, and the intellectual property covering PD-1 and PD-L1 antibodies has been the subject of litigation and licensing, especially regarding how broadly certain claims should be construed. If the claims were to be construed broadly by the courts, we may need to obtain a license to some of such intellectual property, covering PD-1 and/or PD-L1 antibodies, which would decrease the profits we would realize from the sale of such products. An increasing number of third parties are filing masked antibody patent applications, several of which contain claims that are patterned after our own patent claims. Our competitive position may suffer if patents issued to third parties or other third-party intellectual property rights cover our products or product candidates or elements thereof, or our manufacture or uses relevant to our development plans. In such cases, we may not be in a position to develop or commercialize products or product candidates unless we successfully pursue litigation to nullify or invalidate the third-party intellectual property

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right concerned, or enter into a license agreement with the intellectual property right holder, if available on commercially reasonable terms. There may be issued patents of which we are not aware, held by third parties that, if found to be valid and enforceable, could be alleged to be infringed by our Probody therapeutic technologies. There also may be pending patent applications of which we are not aware that may result in issued patents, which could be alleged to be infringed by our Probody therapeutic technologies. If such an infringement claim should be brought and be successful, we may be required to pay substantial damages, be forced to abandon our product candidates or seek a license from any patent holders. No assurances can be given that a license will be available on commercially reasonable terms, if at all.

It is also possible that we have failed to identify relevant third-party patents or applications. For example, U.S. applications filed before November 29, 2000, and certain U.S. applications filed after that date that will not be filed outside the U.S. remain confidential until patents issue. Patent applications in the U.S. and elsewhere are published approximately 18 months after the earliest filing for which priority is claimed, with such earliest filing date being commonly referred to as the priority date. Therefore, patent applications covering our products or platform technology could have been filed by others without our knowledge. Additionally, pending patent applications that have been published can, subject to certain limitations, be later amended in a manner that could cover our platform technologies, our products or the use of our products. Third-party intellectual property right holders may also actively bring infringement claims against us. We cannot guarantee that we will be able to successfully settle or otherwise resolve such infringement claims. If we are unable to successfully settle future claims on terms acceptable to us, we may be required to engage in or continue costly, unpredictable and time-consuming litigation and may be prevented from or experience substantial delays in marketing our products. If we fail in any such dispute, in addition to being forced to pay damages, we may be temporarily or permanently prohibited from commercializing any of our product candidates that are held to be infringing. We might, if possible, also be forced to redesign product candidates so that we no longer infringe the third-party intellectual property rights. Any of these events, even if we were ultimately to prevail, could require us to divert substantial financial and management resources that we would otherwise be able to devote to our business.

Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities.

Litigation, including the ongoing patent infringement lawsuit brought by Vytacera Bio, LLC (“Vytacera”) against us, or other legal proceedings relating to intellectual property claims, with or without merit, is unpredictable and generally expensive and time consuming and is likely to divert significant resources from our core business, including distracting our technical and management personnel from their normal responsibilities. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. Such litigation or proceedings could substantially increase our operating losses and reduce the resources available for development activities or any future sales, marketing or distribution activities.

We may not have sufficient financial or other resources to adequately conduct such litigation or proceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources and more mature and developed intellectual property portfolios. Accordingly, despite our efforts, we may not be able to prevent third parties from infringing upon, misappropriating or misappropriatingotherwise violating or from successfully challenging our intellectual property rights. For example, although we believe the Vytacera lawsuit is without merit and we intend to vigorously defend ourselves, we cannot provide any assurance that we will be successful. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a material and adverse effect on our ability to compete in the marketplace.

If we fail to comply with our obligations under any license, collaboration or other agreements, we may be required to pay damages and could lose our rights to intellectual property rights that are necessary for developing and protecting our product candidates or we could lose certain rights to grant sublicenses.

Our licenses from Amgen, ImmunoGen and UCSB impose, and any future licenses we enter into are likely to impose, various development, commercialization, funding, diligence, sublicensing, insurance, patent prosecution and enforcement and/or other obligations on us, including various payment obligations such as milestone and royalty payments and payments based on sublicensing revenues. Our rights under our agreements with our licensors or collaborators may be limited or modified according to their terms. Additionally, if we breach any of these obligations, or use the intellectual property licensed to us in an unauthorized manner, we may be required to pay damages and the licensor may have the right to terminate the license, which could result in us being unable to develop, manufacture and sell products that are covered by the licensed technology or enable a competitor to gain access to the licensed technology. Moreover, our licensors and collaborators may own or control intellectual property that has not been licensed to us and, as a result, we may be subject to claims, regardless of their merit, that we are infringing, misappropriating or otherwise violating the licensor’s rights. In addition, while we cannot currently determine the amount of the royalty or sublicense revenue

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payment obligations we would be required to pay on development or sales of future products, if any, the amounts may be significant. The amount of our future royalty or sublicense revenue payment obligations will depend on the technology and intellectual property we use in products that we successfully develop and commercialize, if any. Therefore, even if we successfully develop and commercialize products, we may be unable to achieve or maintain profitability.

Our intellectual property agreements with our licensors, collaborators and third parties may be subject to disagreements over contract interpretation, which could narrow the scope of, or result in termination of, our rights to the relevant intellectual property or technology or increase our financial or other obligations to such third parties.

Certain provisions in our intellectual property agreements may be susceptible to multiple interpretations. For example, we may disagree with our licensors or collaborators regarding whether, when and to what extent various obligations under these agreements apply to certain of our product candidates and products, including various payment, development, commercialization, funding, diligence, sublicensing, insurance, patent prosecution and enforcement and/or other obligations. The resolution of any contract interpretation disagreement that may arise could affect the scope of our rights to the relevant intellectual property or technology, or affect financial or other obligations under the relevant agreement. In either case, such disagreement could have a material adverse effect on our business, financial condition, results of operations and prospects.

In addition, while it is our policy to require our employees and contractors who may be involved in the conception or development of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who in fact conceives or develops intellectual property that we regard as our own. Our assignment agreements may not be self‑executing or may be breached, and we may be forced to bring claims against third parties, or defend claims they may bring against us, to determine the ownership of what we regard as our intellectual property.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patent protection for certain aspects of our product candidates, we also consider trade secrets, including confidential and unpatented know-how, important to the maintenance of our competitive position. We protect trade secrets and confidential and unpatented know-how, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to such knowledge, such as our employees, corporate collaborators, outside scientific collaborators, CROs, contract manufacturers, consultants, advisors and other third parties. We also enter into confidentiality and invention or patent assignment agreements with our employees and consultants that obligate them to maintain confidentiality and assign their inventions to us.

Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts in the U.S. and certain foreign jurisdictions are less willing or unwilling to protect trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed.

We may be subject to claims that we or our employees or consultants have wrongfully used or disclosed alleged trade secrets of our employees’ or consultants’ former employers or their clients. These claims may be costly to defend and if we do not successfully do so, we may be required to pay monetary damages and may lose valuable intellectual property rights or personnel.

Many of our employees were previously employed at universities or biotechnology or biopharmaceutical companies, including our competitors or potential competitors. Although no claims against us are currently pending, we may be subject to claims that these employees or we have inadvertently or otherwise used or disclosed trade secrets or other proprietary information of their former employers. Litigation may be necessary to defend against these claims. If we fail in defending such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. A loss of key research personnel or their work product could hamper our ability to commercialize, or prevent us from commercializing, our product candidates, which could severely harm our business. Even if we are successful in defending against these claims, litigation could result in substantial costs and be a distraction to management.

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If our trademarks and trade names are not adequately protected, then we may not be able to build name recognition in our markets of interest and our business may be adversely affected.

Our trademarks or trade names may be challenged, infringed, circumvented or declared generic or determined to be infringing on other marks. We may not be able to protect our rights to these trademarks and trade names or may be forced to stop using these names, which we need for name recognition by potential partners or customers in our markets of interest. If we are unable to establish name recognition based on our trademarks and trade names, we may not be able to compete effectively and our business may be adversely affected.

Risks Related to Government Regulation

We may be unable to obtain or be delayed in obtaining U.S. or foreign regulatory approval and, as a result, be unable or delayed in being able to commercialize our product candidates.

Our product candidates that we are currently developing are regulated as therapeutic biologics that are subject to requirements for review and approval of a BLA by the FDA’s Center for Drug Evaluation and Research (“CDER”). Therefore, our product candidates are subject to extensive governmental regulations relating to, among other things, research, testing, development, manufacturing, safety, efficacy, approval, recordkeeping, reporting, labeling, storage, packaging, advertising and promotion, pricing, marketing and distribution of drugs and therapeutic biologics. Rigorous preclinical testing and clinical trials and an extensive regulatory approval process are required to be successfully completed in the U.S. and in many foreign jurisdictions before a new drug or therapeutic biologic can be marketed. Satisfaction of these and other regulatory requirements is costly, time consuming, uncertain and subject to unanticipated delays. For example, at this time it is impossible to predict whether the COVID-19 pandemic will cause regulatory delays in the U.S. or foreign jurisdictions. It is possible that none of the product candidates we may develop will obtain the regulatory approvals necessary for us or our existing or future collaborators to begin selling them.

As a company, we have limited experience in conducting and managing the clinical trials necessary to obtain regulatory approvals, including approval by the FDA. The time required to obtain FDA and other approvals is unpredictable but typically takes many years following the commencement of clinical trials, depending upon the type, complexity and novelty of the product candidate. The standards that the FDA and its foreign counterparts use when regulating us require judgment and can change, which makes it difficult to predict with certainty how they will be applied. Any analysis we perform of data from preclinical and clinical activities is subject to confirmation and interpretation by regulatory authorities, which could delay, limit or prevent regulatory approval. We may also encounter unexpected delays or increased costs due to new government regulations, for example, from future legislation or administrative action, or from changes in FDA policy during the period of product development, clinical trials and FDA regulatory review. Further, government shutdowns, such as the recentpartial U.S. federal government shutdown in late 2018 or the uncertainty of Great Britain’United Kingdom’s departure

from the European Union may impact our ability to access government agencies in a timely manner or otherwise impact our ability to move our product candidates through the regulatory process. It is impossible to predict whether legislative changes will be enacted, or whether FDA or foreign regulations, guidance or interpretations will be changed, or what the impact of such changes, if any, may be.

Because the product candidates we are developing may represent a new class of therapeutic biologics, the FDA and its foreign counterparts have not yet established any definitive policies, practices or guidelines in relation to these product candidates. While we believe the product candidates that we are currently developing are regulated as therapeutic biologics that are subject to requirements for review and approval of a BLA by the FDA’s Center for Drug Evaluation and Research (“CDER”), the FDA could decide to regulate them as drugs that are subject to requirements for review and approval of an NDA by CDER or as biological products that are subject to requirements for review and approval of a BLA by the FDA’s Center for Biologics Evaluation and Research (“CBER”). The lack of policies, practices or guidelines may hinder or slow review by the FDA of any regulatory filings that we may submit. Moreover, the FDA may respond to theseour submissions by defining requirements we may not have anticipated. Such responses could lead to significant delays in the clinical development of our product candidates. In addition, because there may be approved treatments for some of the diseases for which we may seek approval, in order to receive regulatory approval, we may need to demonstrate through clinical trials that the product candidates we develop to treat these diseases, if any, are not only safe and effective, but safer or more effective than existing products. Furthermore, in recent years, there has been increased public and political pressure on the FDA with respect to the approval process for new drugs and therapeutic biologics, and the FDA’s standards, especially regarding product safety, appear to have become more stringent.

Any delay or failure in obtaining required approvals could have a material and adverse effect on our ability to generate revenues from the particular product candidate for which we are seeking approval. Furthermore, any regulatory approval to market a product may be subject to limitations on the approved uses for which we may market the product or the labeling or other restrictions. In addition, the FDA has the authority to require a risk evaluation and mitigation strategies (“REMS”) planREMS as part of an NDA ora BLA or after approval, which may impose further requirements or restrictions on the distribution or use of an approved drug or biologic, such as limiting prescribing to certain physicians or medical centers that have undergone specialized training, limiting treatment to patients who meet certain safe-use criteria and requiring treated patients to enroll in a registry. These limitations and restrictions may limit the size of the market for the product and affect reimbursement by third-party payors.

We are also subject to numerous foreign regulatory requirements governing, among other things, the conduct of clinical trials, manufacturing and marketing authorization, pricing and third-party reimbursement. The foreign regulatory approval process varies among countries and may include all of the risks associated with FDA approval described above as well as risks attributable to the

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satisfaction of local regulations in foreign jurisdictions. Moreover, the time required to obtain approval may differ from that required to obtain FDA approval. Approval by the FDA does not ensure approval by regulatory authorities outside the U.S. and vice versa.

Even if we receive regulatory approval for any of our product candidates, we will be subject to ongoing regulatory obligations and continued regulatory review, which may result in significant additional expense. Additionally, our product candidates, if approved, could be subject to labeling and other restrictions and market withdrawal and we may be subject to penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our products.

Any regulatory approvals that we or our collaborators obtain for our product candidates may also be subject to limitations on the approved indicated uses for which a product may be marketed or to the conditions of approval, or contain requirements for potentially costly post-marketing testing, including “Phase 4” clinical trials, and surveillance to monitor the safety and efficacy of the product candidate. In addition, if the FDA or a comparable foreign regulatory authority approves any of our product candidates, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, import, export, advertising, promotion and recordkeeping for the product will be subject to extensive and ongoing regulatory requirements. These requirements include submissions of safety and other post-marketing information and reports, registration, as well as continued compliance with cGMPs and good clinical practices for any clinical trials that we conduct post-approval. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with our third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things:

The FDA’s policies may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. For example, in December 2016, the 21st Century Cures Act, or “Cures Act”, was signed into law.  The Cures Act, among other things, is intended to modernize the regulation of drugs and biologics and to spur innovation, but its ultimate implementation is unclear.candidates If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained and we may not achieve or sustain profitability, which would adversely affect our business.

We also cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or abroad. For example, certainIf we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may be subject to enforcement action, and we may not achieve or sustain profitability.

Our product candidates for which we intend to seek approval as biologic products may face competition sooner than anticipated.

The Affordable Care Act includes a subtitle called the Biologics Price Competition and Innovation Act of 2009 (“BPCIA”), which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. Under the BPCIA, an application for a highly similar or “biosimilar” product may not be submitted to the FDA until four years following the date that the reference product was first approved by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first approved. During this 12-year period of exclusivity, another company may still market a competing version of the Trump administrationreference product if the FDA approves a full BLA for the competing product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of their product.

We believe that any of our product candidates approved as a biological product under a BLA should qualify for the 12-year period of exclusivity. However, there is a risk that this exclusivity could be shortened due to congressional action or otherwise, or that the FDA will not consider our product candidates to be reference products for competing products, potentially creating the opportunity for competition sooner than anticipated. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. Moreover, the extent to which a biosimilar, once approved, will be substituted for any one of

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our businessreference products in a way that is similar to traditional generic substitution for non-biological products is not yet clear, and industry.  Namely, the Trump administration has taken several executive actions, including the issuance ofwill depend on a number of Executive Orders,marketplace and regulatory factors that are still developing.

Disruptions at the FDA and other government agencies caused by funding shortages or global health concerns could impose significant burdens on,hinder their ability to hire, retain or deploy key leadership and other personnel, or otherwise materially delay,prevent new or modified products from being developed, approved or commercialized in a timely manner or at all, which could negatively impact our business.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, statutory, regulatory, and policy changes, the FDA’s ability to engage in routine regulatoryhire and oversight activities such as implementing statutes through rulemaking, issuanceretain key personnel and accept the payment of guidance,user fees, and review and approval of marketing applications.  It is difficult to predict how these requirements will be implemented, and the extent to which they will impactother events that may otherwise affect the FDA’s ability to exerciseperform routine functions. Average review times at the FDA have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is inherently fluid and unpredictable. Disruptions at the FDA and other agencies may also slow the time necessary for therapeutic biologics or modifications to approved therapeutic biologics to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA, have had to furlough FDA employees and stop critical activities.

Separately, in response to the COVID-19 pandemic, in March 2020, the FDA announced its intention to postpone most inspections of foreign manufacturing facilities, and on March 18, 2020, the FDA temporarily postponed routine surveillance inspections of domestic manufacturing facilities. Subsequently, in July 2020, the FDA resumed certain on-site inspections of domestic manufacturing facilities subject to a risk-based prioritization system. The FDA utilized this risk-based assessment system to assist in determining when and where it was the safest to conduct prioritized domestic inspections. Additionally, on April 15, 2021, the FDA issued a guidance document in which the FDA described its plans to conduct voluntary remote interactive evaluations of certain drug manufacturing facilities and clinical research sites, among other facilities. According to the guidance, the FDA may request such remote interactive evaluations where the FDA determines that remote evaluation would be appropriate based on mission needs and travel limitations. In May 2021, the FDA outlined a detailed plan to move toward a more consistent state of inspectional operations, and in July 2021, the FDA resumed standard inspectional operations of domestic facilities and was continuing to maintain this level of operation as of September 2021. More recently, the FDA has continued to monitor and implement changes to its inspectional activities to ensure the safety of its employees and those of the firms it regulates as it adapts to the evolving COVID-19 pandemic. Regulatory authorities outside the United States may adopt similar restrictions or other policy measures in response to the COVID-19 pandemic. If a prolonged government shutdown occurs, or if global health concerns continue to prevent the FDA or other regulatory authority. If these executive actions impose constraintsauthorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact the ability of the FDA or other regulatory authorities to timely review and process our regulatory submissions, which could have a material adverse effect on FDA’s ability to engage in oversight and implementation activities in the normal course, our business may be negatively impacted.business.

Healthcare legislative reform measures may have a material and adverse effect on our business and results of operations.

In the United States, there have been and continue to be a number of legislative initiatives to contain healthcare costs. For example, in March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act (together, the “ACA”), was passed, which substantially changed the way healthcare is financed by both governmental and private insurers, and significantly impacts the U.S. pharmaceutical industry. The ACA, among other things, subjected therapeutic biologics to potential competition by lower-cost biosimilars, addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs and therapeutic biologics that are inhaled, infused, instilled, implanted or injected, increased the minimum Medicaid rebates owed by manufacturers under the Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, established annual fees and taxes on manufacturers of certain branded prescription drugs and therapeutic biologics, and created a new Medicare Part D coverage gap discount program, in which manufacturers must agree to offer 50% point-of-sale discounts, which, through subsequent legislative amendments, will bewas increased to 70% starting in 2019, off negotiated prices of applicable brand drugs and therapeutic biologics to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs and therapeutic biologics to be covered under Medicare Part D.

Since its enactment, there have been judicial, executive and Congressional challenges to certain aspects of the ACA, and we expect there will be additional challenges and amendmentsACA. On June 17, 2021, the U.S. Supreme Court dismissed the most recent judicial challenge to the ACA inbrought by several states without specifically ruling on the future. The current Presidential Administration and U.S. Congress will likely continue to seek to modify, repeal, or otherwise invalidate all, or certain provisionsconstitutionality of the ACA. Since taking office,Prior to the Supreme Court’s decision, President Trump has continued to support the repeal of all or portions of the ACA.  On October 12, 2017, President TrumpBiden issued an executive order that expandsinitiating a special enrollment period from February 15, 2021 through August 15, 2021 for purposes of obtaining health insurance coverage through the use of association health plans and allows anyone to purchase short-term health plans that provide temporary, limited insurance. ThisACA marketplace. The executive order also calls for the halt of federal paymentsinstructed certain governmental agencies to health insurers for cost-sharing reductions previously availablereview and reconsider their existing policies and rules that limit access to lower-income Americans to afford coverage. Therehealthcare. It is still uncertainty with respect to the impact this executive order could have on coverage and reimbursement forunclear how healthcare items and services coveredreform measures enacted by plans that were authorizedCongress or implemented by the ACA.  In addition, the Tax Cuts and Jobs Act was enacted, which, among other things, removes penalties for not complying with the Affordable Care Act’s individual mandate to carry health insurance. On January 22, 2018, President Trump signed a continuing resolution on appropriations for fiscal year 2018 that delayed the implementation of certain mandated fees under the Affordable Care Act, including the so-called “Cadillac” tax on certain high cost employer-sponsored insurance plans, the annual fee imposed on certain health insurance providers based on market share, and the medical device excise tax on non-exempt medical devices. Congress may consider other legislation to repeal or replace other elements of the Affordable Care Act. It is uncertain the extent to whichBiden administration, if any, such changes maywill impact our business or financial condition.business.

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In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted to reduce healthcare expenditures. The Budget Control Act of 2011, among other things, included aggregate reductions of Medicare payments to providers of 2% per fiscal year. These reductions went into effect on April 1, 2013 and, due to subsequent legislative amendments to the statute, will remain in effect through 20272030, with the exception of a temporary suspension from May 2, 2020 through March 31, 2022, unless additional Congressional action is taken. On January 2, 2013, the American Taxpayer Relief Act of 2012 was signed into law, which among other things, further reduced Medicare payments to several types of providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the

government to recover overpayments to providers from three to five years. If federal spending is further reduced, anticipated budgetary shortfalls may also impact the ability of relevant agencies, such as the FDA or the National Institutes of Health to continue to function at current levels. Amounts allocated to federal grants and contracts may be reduced or eliminated. These reductions may also impact the ability of relevant agencies to timely review and approve research and development, manufacturing, and marketing activities, which may delay our ability to develop, market and sell any products we may develop.

Moreover, payment methodologies, including payment for companion diagnostics, may be subject to changes in healthcare legislation and regulatory initiatives. For example, in March 2018, the Centers for Medicare & Medicaid Services (“CMS”) has begun bundling the Medicare payments for certain laboratory tests ordered while a patient received services in a hospital outpatient setting and, beginning in 2018, CMS will pay for clinical laboratory services based on a weighted average of reported prices that private payors, Medicare Advantage plans, and Medicaid Managed Care plans pay for laboratory services. Further, in March 2018, CMS finalized a national coverage determination extending coverage under the Medicare program for certain diagnostic laboratory tests using next generation sequencing (“NGS”) that are approved by the FDA as a companion in vitro diagnostic and used in a cancer with an FDA-approved companion diagnostic indication. Under the national coverage determination, diagnostic tests that meet these criteria are covered only in patients with recurrent, metastatic, relapsed, refractory or stages III or IV cancer if the test has an FDA-approved or cleared indication for use in that patient’s cancer and results are provided to the treating physician for management of the patient using a report template to specify treatment options. Although the Medicare program increasingly is used as a model for how private payors and other governmental payors develop their coverage and reimbursement policies, it is difficult to predict at this time what third-party payors will decide with respect to the coverage and reimbursement for any companion diagnostics associated with our product candidates.

In addition, recently there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed bills designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. For example, the 21st Century Cures Act changed the reimbursement methodology for infusion drugs and biologics furnished through durable medical equipment in an attempt to remedy over- and underpayment of certain products. Furthermore, the Build Back Better Act, if enacted, would introduce substantial drug pricing reforms, including the establishment of a drug price negotiation program within the U.S. Department of Health and Human Services that would require manufacturers to charge a negotiated “maximum fair price” for certain selected drugs or pay an excise tax for noncompliance, and the establishment of rebate payment requirements on manufacturers of certain drugs payable under Medicare Parts B and D. If the Build Back Better Act is not enacted, similar or other drug pricing proposals could appear in future legislation. Individual states in the United States have also become increasingly active in passing legislation and implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regional healthcare authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescription drug and other healthcare programs. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our product candidates or companion diagnostics or additional pricing pressures.

If we or our collaborators, manufacturers or service providers fail to comply with healthcare laws and regulations, we or they could be subject to enforcement actions, which could affect our ability to develop, market and sell our products and may harm our reputation.

Although we do not currently have any products on the market, onceif and when we begin commercializing our product candidates, we will be subject to additional healthcare statutory and regulatory requirements and enforcement by the federal government and the states and foreign governments in which we conduct our business. Healthcare providers, physicians and third-party payors play a primary role in the recommendation and prescription of any product candidates for which we obtain marketing approval. Our future arrangements with third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute our product candidates for which we obtain marketing approval. In addition, we may be subject to patient data privacy and security regulation by both the U.S. federal government and the states in which we conduct our business. Restrictions under applicable federal and state healthcare laws and regulations, include the following:

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Ensuring that our future business arrangements with third-partiesthird parties comply with applicable healthcare laws and regulations could involve substantial costs. It is possible that governmental authorities will conclude that our business practices do not comply with current or future statutes, regulations, agency guidance or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any such requirements, we may be subject to penalties, including civil or criminal penalties, monetary damages, the curtailment or restructuring of our operations, loss of eligibility to obtain approvals from the FDA, or exclusion from participation in government contracting, healthcare reimbursement or other government programs, including Medicare and Medicaid, any of which could adversely our financial results. Although effective compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, these risks cannot be entirely eliminated. Any action against us for an alleged or suspected violation could cause us to incur significant legal expenses and could divert our management’s attention from the operation of our business, even if our defense is successful. In addition, achieving and sustaining compliance with applicable laws and regulations may be costly to us in terms of money, time and resources.

If we or future collaborators, manufacturers or service providers fail to comply with applicable federal, state or foreign laws or regulations, we could be subject to enforcement actions, which could affect our ability to develop, market and sell our products successfully and could harm our reputation and lead to reduced acceptance of our products by the market. These enforcement actions include, among others:

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If we fail to comply with U.S. and foreign regulatory requirements, regulatory authorities could limit or withdraw any marketing or commercialization approvals we may receive and subject us to other penalties that could materially harm our business.

Even if we receive marketing and commercialization approval of a product candidate, we will be subject to continuing regulatory requirements, including in relation to adverse patient experiences with the product and clinical results that are reported after a product is made commercially available, both in the U.S. and any foreign jurisdiction in which we seek regulatory approval. The FDA has significant post-market authority, including the authority to require labeling changes based on new safety information and to require post-market studies or clinical trials to evaluate safety risks related to the use of a product or to require withdrawal of the product from the market. The FDA also has the authority to require a REMS plan after approval, which may impose further requirements or restrictions on the distribution or use of an approved drug or therapeutic biologic. The manufacturer and manufacturing facilities we use to make a future product, if any, will also be subject to periodic review and inspection by the FDA and other regulatory agencies, including for continued compliance with cGMP requirements. The discovery of any new or previously unknown problems with our third-party manufacturers, manufacturing processes or facilities may result in restrictions on the product, manufacturer or facility, including withdrawal of the product from the market. If we rely on third-party manufacturers, we will not have control over compliance with applicable rules and regulations by such manufacturers. Any product promotion and advertising will also be subject to regulatory requirements and continuing regulatory review. If we or our collaborators, manufacturers or service providers fail to comply with applicable continuing regulatory requirements in the U.S. or foreign jurisdictions in which we seek to market our products, we or they may be subject to, among other things, fines, warning letters, holds on clinical trials, delay of approval or refusal by the FDA to approve pending applications or supplements to approved applications, suspension or withdrawal of regulatory approval, product recalls and seizures, administrative detention of products, refusal to permit the import or export of products, operating restrictions, injunction, civil penalties and criminal prosecution.

We face regulation and potential liability relatedActual or perceived failures to the privacy,comply with applicable data protection, privacy and information security which may require significant resourceslaws, regulations, standards and mayother requirements could adversely affect our business, results of operations, and financial performance.condition.

The regulatory environment surrounding informationdata privacy and security data collection and privacy is increasingly demanding. We are or may in the future be subject to numerous U.S. federal and state laws and non-U.S. regulations governing the protectioncollection, use, disclosure, retention, and security of personal and confidential information of our clinical subjects, clinical investigators, employees and vendors/business contacts, includingcontacts. Implementation standards and enforcement practices are likely to remain uncertain for the foreseeable future, and we cannot yet determine the impact future laws, regulations, standards, or perception of their requirements may have on our business. This evolution may create uncertainty in relationour business, affect our ability to medical records, credit card dataoperate in certain jurisdictions or to collect, store, transfer use and share personal information, necessitate the acceptance of more onerous obligations in our contracts, result in liability or impose additional costs on us. The cost of compliance with these laws, regulations and standards is high and is likely to increase in the future. Any failure or perceived failure by us to comply with federal, state or foreign laws or regulations, our internal policies and procedures or our contracts governing our processing of personal information could result in negative publicity, government investigations and enforcement actions, claims by third parties and damage to our reputation, any of which could have a material adverse effect on our business, results of operation, and financial condition.

In the United States, HIPAA imposes, among other things, certain standards relating to the privacy, security, transmission and breach reporting of individually identifiable health information. We may obtain health information from third parties (including research institutions from which we obtain clinical trial data) that are subject to privacy and security requirements under HIPAA. Depending on the facts and circumstances, we could be subject to significant penalties if we violate HIPAA. Certain states have also adopted comparable privacy and security laws and regulations, some of which may be more stringent than HIPAA. Such laws and regulations will be subject to interpretation by various courts and other governmental authorities, thus creating potentially complex compliance issues for us and our future customers and strategic partners. For example, the California Consumer Privacy Act (“CCPA”) went into effect on May 25, 2018,January 1, 2020. The CCPA creates individual privacy rights for California consumers, including the European General Data Protection Regulation, or GDPR, became effective, implementingexpanded right to access and delete their personal information, opt out of certain personal information sharing, and receive detailed information about how their personal information is used. The CCPA provides for civil penalties for violations, as well as a private right of action for data breaches that is expected to increase data breach litigation. Further, the California Privacy Rights Act (“CPRA”) recently passed in California. The CPRA significantly amends the CCPA and will impose additional data protection obligations on covered businesses, including additional consumer rights processes, limitations on data uses, new audit requirements for higher risk data, and

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opt outs for certain uses of sensitive data. It will also create a new California data protection agency authorized to issue substantive regulations and could result in increased privacy and information security enforcement. The majority of the provisions will go into effect on January 1, 2023, and additional compliance investment and potential business process changes may be required. Similar laws have passed in Virginia and Colorado, and have been proposed in other states and at the federal level, reflecting a trend toward more stringent privacy legislation in the United States. The enactment of such laws could have potentially conflicting requirements that would make compliance challenging. In the event that we are subject to or affected by HIPAA, the CCPA, the CPRA or other domestic privacy and data protection laws, any liability from failure to comply with the requirements of these laws could adversely affect our financial condition.

Our operations abroad may also be subject to increased scrutiny or attention from data protection authorities. For example, the GDPR went into effect in relation to our use ofMay 2018, and imposes stringent requirements for processing the personal data relating toof individuals located inwithin the E.U. (and E.E.A.). TheEEA. Companies that must comply with the GDPR repeals the Data Protection Directive (95/46/EC)face increased compliance obligations and is directly applicable in all E.U. member states. The GDPR significantly increased fining levels torisk, including more robust regulatory enforcement of data protection requirements and potential fines for noncompliance of up to 4% total worldwide annual turnover or up to €20 million, (whicheverwhichever is higher) for non-compliance with its requirements. We will behigher. Among other requirements, the GDPR regulates transfers of personal data subject to the GDPR to third countries that have not been found to provide adequate protection to such personal data, including the United States; in July 2020, the Court of Justice of the European Union (“CJEU”) limited how organizations could lawfully transfer personal data from the EU/EEA to the United States by invalidating the EU-US Privacy Shield Framework for purposes of international transfers and imposing further restrictions on the use of standard contractual clauses (“SCCs”). The European Commission issued revised SCCs on June 4, 2021 to account for the decision of the CJEU and recommendations made by the European Data Protection Board. The revised SCCs must be used for relevant new data transfers from September 27, 2021; existing standard contractual clauses arrangements must be migrated to the revised clauses by December 27, 2022. The new SCCs apply only to the transfer of personal data outside of the EEA and not the United Kingdom; the United Kingdom’s Information Commissioner’s Office launched a public consultation on its draft revised data transfers mechanisms in August 2021. There is some uncertainty around whether the revised clauses can be used for all types of data transfers, particularly whether they can be relied on for data transfers to non-EEA entities subject to the GDPR. As supervisory authorities issue further guidance on personal data export mechanisms, including circumstances where the standard contractual clauses cannot be used, or start taking enforcement action, we could suffer additional costs, complaints and/or regulatory investigations or fines, and/or if we are otherwise unable to transfer personal data between and among countries and regions in which we operate, it could affect the manner in which we provide our products and services, the geographical location or segregation of our relevant systems and operations, and could adversely affect our financial results.

Further, from January 1, 2021, we have an E.U. presencehad to comply with the GDPR and also the UK GDPR, which, together with the amended UK Data Protection Act 2018, retains the GDPR in UK national law. The UK GDPR mirrors the fines under the GDPR, i.e., fines up to the greater of €20 million (£17.5 million) or “establishment” (e.g., E.U. based subsidiary or operations), when conducting clinical trials with E.U. based4% of global turnover. The relationship between the United Kingdom and European Union in relation to certain aspects of data subjects (whetherprotection law remains unclear, including how data transfers between European Union member states and the trials are conducted directly by us or through a clinical vendor or collaborator) or offering approved products or services (if relevant) to E.U. based data subjects (regardless of whether involving our E.U. based subsidiary or operations).

The GDPR sets out a number of requirements that must be complied with when handling the personal data of such E.U. based data subjects including: providing expanded disclosures about how their personal dataUnited Kingdom will be used; higher standards for organizationstreated. These changes may lead to demonstrate that they have obtained valid consent or have another legal basis in place to justify their data processing activities; the obligation to appoint data protection officers in certain circumstances; new rights for individuals to be “forgotten” and rights to data portability, as well as enhanced current rights (e.g., access requests); the principal of accountability and demonstrating compliance through policies, procedures, training and audit; the new mandatory data breach regime. In particular, medical or health data, genetic data and biometric data where the latter is used to uniquely identify an individual (even, in certain situations, where such data is key coded) are all classified as “special category” data under GDPR and afford greater protection and require additional compliance obligations. Further, E.U. member states have a broad right to impose additional conditions – including restrictions – on thesecosts and could increase our overall risk. The European Commission has adopted an adequacy decision in favor of the United Kingdom, enabling data

categories. This is because the GDPR allows E.U. transfers from EU member states to derogate from the requirements ofUnited Kingdom without additional safeguards. However, the GDPR mainlyUK adequacy decision will automatically expire in regard to specific processing situations (including special category dataJune 2025 unless the European Commission re-assesses and processing for scientificrenews or statistical purposes). As the E.U. member states reframe their national legislation to harmonize with the GDPR, we will need to monitor compliance with all relevant E.U. member states' laws and regulations, including where permitted derogations from the GDPR are introduced.extends that decision.

We will also be subject to evolving E.U. laws on data export, where we transfer data outside the E.U. (or E.E.A.) to group companies or third parties. The GDPR only permits exports of data outside the E.U. (and E.E.A.) where there is a suitable data transfer solution in place to safeguard personal data (e.g., the EU Commission approved Standard Contractual Clauses). Some of the approved current data transfer mechanisms are under review in the E.U. courts and by the E.U. Commission and therefore we need to monitor this space for any future changes.

Where we rely on third parties to carry out a number of services for us, including processing personal data on our behalf, we are required under GDPR to enter into contractual arrangements to help ensure that these third parties only process such data according to our instructions and have sufficient security measures in place. Any security breach or non-compliance with our contractual terms or breach of applicable law by such third parties could result in enforcement actions, litigation, fines and penalties or adverse publicity and could cause our customers to lose trust in us, which could have an adverse impact on our reputation and business.

In recent years, U.S. and European lawmakers and regulators have expressed concern over electronic marketing and the use of third-party cookies, web beacons and similar technology for online behavioral advertising. In the E.U., marketing is defined broadly to include any promotional material andEuropean Union, the rules specifically on e-marketing are currently set out in the ePrivacy Directive, which will be replaced by a new ePrivacy Regulation. While the ePrivacy Regulation was originally intended to be adopted on May 25, 2018 (alongside the GDPR), it is still going through the European legislative process and commentators now expect it to be adopted during the middle or second half of 2019.process. The current draft of the ePrivacy Regulation imposes strict opt-in e-marketing rules with limited exceptions tofor business to business communications, and significantly increases fining powersfines for non-compliance. Regulation of cookies and web beacons may lead to the same levels as GDPR (see above).  broader restrictions on our online activities, including our efforts to understand our users’ internet usage and promote ourselves to them.

WeAlthough we work to comply with applicable laws, regulations and standards, our contractual obligations and other legal obligations, these requirements are evolving and may find it necessary or desirablebe modified, interpreted and applied in an inconsistent manner from one jurisdiction to join self-regulatory bodiesanother, and may conflict with one another or other privacy-related organizations, particularly relatinglegal obligations with which we must comply. Any failure or perceived failure by us or our employees, representatives, contractors, consultants, collaborators, or other third parties to biopharmacy and/comply with such requirements or scientific research, that require compliance with their rules pertaining toadequately address privacy and data security.

The introduction of the GDPR, and any resultant changes in E.U. member states’ national laws and regulations and the ePrivacy Regulation, will increase our compliance obligations and will necessitate the review and implementation of policies and processes relating to our collection and use of data. This increase in compliance obligations could also lead to an increase in compliance costs which may have an adverse impact on our business, financial condition or results of operations.

If any person, including any of our employees, clinical vendors or collaborators or those with whom we share such information, negligently disregards or intentionally breaches our established controls with respect to our clinical subject, clinical investigator or employee data, or otherwise mismanages or misappropriates that data, we could be subject to significant monetary damages, regulatory enforcement actions, fines and/or criminal prosecution in one or more jurisdictions. As above, under the GDPR there are significant new punishments for non-compliance whichsecurity concerns, even if unfounded, could result in a penalty of up to 4% of a firm’s global annual revenue. In addition, a data breach could result in negative publicity which could damage our reputation and have an adverse effect on our business, financial condition or results of operations.

We strive to comply with all applicable laws, but they may conflict with each other, and by complying with the laws or regulations of one jurisdiction, we may find that we are violating the laws or regulations of another jurisdiction. Despite our efforts, we may not have fully complied in the past and may not in the future. If we become liable under laws or regulations applicable to us, we could be required to pay significant fines, penalties and penalties,damage to our reputation, may be harmed and we may be forced to change the way we operate. ThatThis could requireresult in additional cost and liability to us, to incur significant expenses or to discontinue certain services, which could negatively affect our business.business, results of operation, and financial condition.

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Even if we are able to commercialize any product candidate, such product candidate may become subject to unfavorable pricing regulations or third-party coverage and reimbursement policies, which would harm our business.

The regulations that govern regulatory approvals, pricing and reimbursement for new drugs and therapeutic biologics vary widely from country to country. Some countries require approval of the sale price of a drug or therapeutic biologic before it can be marketed. In many countries, the pricing review period begins after marketing approval is granted. In some foreign markets, prescription biopharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain regulatory approval for a product in a particular country, but then be subject to price regulations that delay our commercial launch of the product, possibly for lengthy time periods and negatively impact the revenues we are able to generate from the sale of the product in that country. Adverse pricing limitations may hinder our ability to recoup our investment in one or more product candidates, even if our product candidates obtain regulatory approval.

Our ability to commercialize any products successfully also will depend in part on the extent to which coverage and reimbursement for these products and related treatments will be available from government authorities, private health insurers and other organizations. Even if we succeed in bringing one or more products to the market, these products may not be considered cost-effective, and the amount reimbursed for any products may be insufficient to allow us to sell our products on a competitive basis. Because our programs are in the early stages of development, we are unable at this time to determine their cost effectiveness or the likely level or method of reimbursement. Increasingly, the third-party payors who reimburse patients or healthcare providers, such as government and private insurance plans, are requiring that drug companies provide them with predetermined discounts from list prices, and are seeking to reduce the prices charged or the amounts reimbursed for biopharmaceutical products. If the price we are able to charge for any products we develop, or the reimbursement provided for such products, is inadequate in light of our development and other costs, our return on investment could be adversely affected. There may be significant delays in obtaining reimbursement for newly-approved drugs or therapeutic biologics, and coverage may be more limited than the purposes for which the drug or therapeutic biologic is approved by the FDA or similar regulatory authorities outside of the United States. Moreover, eligibility for reimbursement does not imply that any drug or therapeutic biologic will be reimbursed in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim reimbursement levels for new drugs or therapeutic biologics, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement rates may be based on payments allowed for lower-cost drugs or therapeutic biologics that are already reimbursed, may be incorporated into existing payments for other services and may reflect budgetary constraints or imperfections in Medicare data. Net prices for drugs or therapeutic biologics may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs or therapeutic biologics from countries where they may be sold at lower prices than in the U.S. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement rates. Our inability to promptly obtain coverage and adequate reimbursement rates from both government-funded and private payors for new drugs or therapeutic biologics that we develop and for which we obtain regulatory approval could have a material and adverse effect on our operating results, our ability to raise capital needed to commercialize products and our financial condition.

A Breakthrough Therapy Designation by the FDAWe may seek and fail to obtain fast track or breakthrough therapy designations for any of our current or future product candidatescandidates. If we are successful, these programs may not lead to a faster development or regulatory review or approval process, and it doesthey do not increase the likelihood that our product candidatesguarantee we will receive marketing approval.

approval for any product candidate. We may also seek a Breakthrough Therapy Designationto obtain accelerated approval for some of our product candidates. A breakthrough therapy is defined as a product that is intended, alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. For products that have been designated as breakthrough therapies, interaction and communication between the FDA and the sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. Products designated as breakthrough therapies by the FDA can also be eligible for accelerated approval.

Designation as a breakthrough therapy is within the discretion of the FDA. Accordingly, even if we believe one of our product candidates meets the criteria for designation as a breakthrough therapy, the FDA may disagree and instead determine not to make such designation. In any event, the receipt of a Breakthrough Therapy Designation for a product candidate may not result in a faster development process, review or approval compared to products considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. In addition, even if one or more of our product candidates qualify as breakthrough therapies,but the FDA may later decidedisagree that we have met the products no longer meet the conditionsrequirements for qualification and rescind the breakthrough designation.such approval.

A Fast Track Designation by the FDA for any of our product candidates may not actually lead to a faster development or regulatory review or approval process.

We may seek Fast Track Designation for some of our product candidates. If a product is intended for the treatment of a serious or life-threatening condition and the product demonstratespreclinical or clinical data demonstrate the potential to address an unmet medical needsneed for this condition, the product sponsor may apply for fast track designation. Fast Track Designation.track designation provides increased opportunities for sponsor meetings with the FDA during preclinical and clinical development, in addition to the potential for rolling review of a BLA, if the sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA. The FDA has broad discretion whether or not to grant this designation, so even if we believe a particular product candidate is eligible for this designation, we cannot assure you that the FDA would decide to grant it. Even if we do receive Fast Track Designation,fast track designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures. The FDA may withdraw Fast Track Designationrescind the fast track designation if it believes that the designation is no longer supported by data from our clinical development program.

We may also seek breakthrough therapy designation for any product candidate that we develop. A breakthrough therapy is defined as a drug that is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over currently approved therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. Like fast track designation, breakthrough therapy designation is within the discretion of the FDA. Accordingly, even if we believe a product candidate we develop meets the criteria for designation as a breakthrough therapy, the FDA may disagree and instead determine not to make such designation. In any event, the receipt of breakthrough therapy designation for a product candidate may not result in a faster

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We may seek Orphan Drug Designation for some of our product candidates, and we may be unsuccessful or may be unable to maintain the benefits associated with Orphan Drug Designation, including the potential for market exclusivity.

As part of our business strategy, we may seek Orphan Drug Designation for our product candidates, and we may be unsuccessful. Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs and therapeutic biologics for relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a drug or therapeutic biologic as an orphan drug if it is a drug or therapeutic biologic intended to treat a rare disease or condition, which is generally defined as a patient population of fewer than 200,000 individuals annually in the United States, or a patient population greater than 200,000 in the United States where there is no reasonable expectation that the cost of developing the drug or therapeutic biologic will be recovered from sales in the United States. In the United States, Orphan Drug Designation entitles a party to financial incentives such as opportunities for grant funding toward clinical trial costs, tax advantages and user-fee waivers. In addition, if a product that has Orphan Drug Designation subsequently receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan drug exclusivity, which means that the FDA may not approve any other applications, including a full NDA or BLA, to market the same product for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or where the manufacturer is unable to assure sufficient product quantity.

Even if we obtain Orphan Drug Designation for our product candidates in specific indications, we may not be the first to obtain marketing approval of these product candidates for the orphan-designated indication due to the uncertainties associated with developing pharmaceutical products. In addition, exclusive marketing rights in the United States may be limited if we seek approval for an indication broader than the orphan-designated indication or may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition. Further, even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different drugs or therapeutic biologics with different active moieties can be approved for the same condition. Even after an orphan product is approved, the FDA can subsequently approve the same drug or therapeutic biologic with the same active moiety for the same condition if the FDA concludes that the later drug or therapeutic biologic is safer, more effective or makes a major contribution to patient care. Orphan Drug Designation neither shortens the development time or regulatory review time of a drug or therapeutic biologic nor gives the drug or therapeutic biologic any advantage in the regulatory review or approval process. In addition, while we may seek Orphan Drug Designation for our product candidates, we may never receive such designations.

Tax reform legislation passed in 2017 reduced the amount of the qualified clinical research costs for a designated orphan product that a sponsor may claim as a credit from 50% to 25%. Thus, further limiting the advantage and may impact our future business strategy of seeking the Orphan Drug Designation.

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Risks Related to Ownership of Our Common Stock

Our quarterly operating results may fluctuate significantly or may fall below the expectations of investors or securities analysts, each of which may cause our stock price to fluctuate or decline.

We expect our operating results to be subject to quarterly fluctuations. Our net loss and other operating results will be affected by numerous factors, including:

If our quarterly operating results fall below the expectations of investors or securities analysts, the price of our common stock could decline substantially. Furthermore, any quarterly fluctuations in our operating results may, in turn, cause the price of our stock to fluctuate substantially. We believe that quarterly comparisons of our financial results are not necessarily meaningful and should not be relied upon as an indication of our future performance.

Our stock price may be volatile and purchasers of our common stock could incur substantial losses.

Our stock price is volatile. Since our initial public offering (“IPO”), our stock had highlow and lowhigh sales prices in the range of $9.01$3.60 and $35.00 per share. The market price for our common stock may be influenced by many factors, including the other risks described in this section titled “Risk Factors” and the following:

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In addition, theThe stock markets in general, and the markets for pharmaceutical, biopharmaceutical and biotechnology stocks in particular, have experienced extreme volatility, including as a result of the COVID-19 pandemic, that has been often unrelated to the operating performance of the issuer. These broad market and industry factors may seriously harm the market price of our common stock, regardless of our operating performance.

In addition, the spread of COVID-19 may negatively impact the trading price of shares of our common stock and could further severely impact our ability to raise additional capital on a timely basis or at all.

The future issuance of equity or of debt securities that are convertible into equity will dilute our share capital.

We may choose to raise additional capital in the future, depending on market conditions, strategic considerations and operational requirements. To the extent that additional capital is raised through the issuance of shares or other securities convertible into shares, our stockholders will be diluted. On February 27, 2020, we entered into an Open Market Sale Agreement (the “Sales Agreement”) with Jefferies LLC (“Jefferies”), to sell shares of our common stock, par value $0.00001 per share, with aggregate gross sales proceeds of up to $75,000,000, from time to time, through an at the market offering under which Jefferies will act as sales agent. We have issued securities under the Sales Agreement and may do so in the future. In addition, in January and February 2021, we sold 16,428,571 shares of our common stock at $7.00 per share in an underwritten public offering. Future issuances of our common stock or other equity securities pursuant to the Sales Agreement or otherwise, or the perception that such sales may occur, could adversely affect the trading price of our common stock and impair our ability to raise capital through future offerings of shares or equity securities. No prediction can be made as to the effect, if any, that future sales of common stock or the availability of common stock for future sales will have on the trading price of our common stock.

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The employment agreements with our executive officers may require us to pay severance benefits to officers in connection with termination of employment or upon a change of control of us, which could harm our financial condition.

Each of our executive officers is entitled to receive a lump sum payment equal to nine monthsone year or one yearmore of his or her base salary as well as continued medical and dental coverage for a period of nine monthsone year or onemore plus a prorated portion of his or her target annual bonus for the calendar year in which his or her employment is terminated following his or her termination of employment due to good reason or without cause. In the event of a change in control and a termination of employment without cause or due to good reason, each of our executive officers would similarly receive nine monthsone year or one yearmore of his or her base salary as well as continued medical and dental coverage for a period of nine monthsone year or one year,more, as well as an additional lump sum payment equal to three-fourths100% or 100%more of his or her target annual bonus for the calendar year in which his or her employment is terminated and full vesting of his or her outstanding option awards. The accelerated vesting of options could result in dilution to our existing stockholders and harm the market price of our common stock. Furthermore, the payment of these severance benefits could harm our financial condition. In addition, these potential severance payments may discourage or prevent third parties from seeking a business combination with us.

An active market for our common stock may not be maintained.

Prior to our IPO in October 2015, there had been no public market for shares of our common stock. Our stock began trading on Thethe Nasdaq Global Select Market in 2015, and we can provide no assurance that we will be able to maintain an active trading market on The Nasdaq Global Select Market or any other exchange in the future. If an active market for our common stock is not maintained, it may be difficult for our stockholders to sell shares without depressing the market price for the shares or at all. An inactive market may also impair our ability to raise capital by selling shares and may impair our ability to acquire other businesses, applications or technologies using our shares as consideration.

If securities or industry analysts do not publish research or reports about our business, or if they issue adverse or misleading opinions regarding our stock, our stock price and trading volume could decline.

The trading market for our common stock will be influenced by the research and reports that industry or securities analysts publish about us or our business. If any of the analysts who cover us issue an adverse or misleading opinion regarding us, our business model, our intellectual property or our stock performance, or if our target studies and operating results fail to meet the expectations of analysts, our stock price would likely decline. If one or more of these analysts cease coverage of us or fail to publish reports on us regularly, we could lose visibility in the financial markets, which in turn could cause our stock price or trading volume to decline.

Our principal stockholders and management own a significant percentage of our stock and will be able to exert significant control over matters subject to stockholder approval.

As of December 31, 2018,2021, our executive officers, directors, holders of 5% or more of our capital stock based on publicly available filings made with the SEC and their respective affiliates beneficially owned approximately 44.9%39% of our outstanding common stock. Therefore, these stockholders have the ability to influence us through this ownership position. These stockholders may be able to determine all matters requiring stockholder approval. For example, these stockholders may be able to control elections of directors, amendments of our organizational documents, or approval of any merger, sale of assets, or other major corporate transaction. This may prevent or discourage unsolicited acquisition proposals or offers for our common stock that our stockholders may feel are in their best interest.

Anti-takeover provisions in our charter documents and under Delaware law could make an acquisition of us, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.

Provisions in our amended and restated certificate of incorporation and our amended and restated bylaws may delay or prevent an acquisition of us or a change in our management. In addition, these provisions may frustrate or prevent any attempts by our stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Because our board of directors is responsible for appointing the members of our management team, these provisions could in turn affect any attempt by our stockholders to replace current members of our management team. These provisions include:

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Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, as amended, which prohibits a person who owns in excess of 15 percent of our outstanding voting stock from merging or combining with us for a period of three years after the date of the transaction in which the person acquired in excess of 15 percent of our outstanding voting stock, unless the merger or combination is approved in a prescribed manner. These provisions would apply even if the proposed merger or acquisition could be considered beneficial by some stockholders.

We incur increased costs as a result of operating as a public company, and our management is required to devote substantial time to new compliance initiatives and corporate governance practices.

As a public company, we incur significant legal, accounting and other expenses. The Sarbanes-Oxley Act, the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of The Nasdaq Global Select Market and other applicable securities rules and regulations impose various requirements on public companies, including establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Our management and other personnel need to devote a substantial amount of time to these compliance initiatives. Moreover, these rules and regulations increase our legal and financial compliance costs and make some activities more time consuming and costly. For example, we expect that these rules and regulations may make it more difficult and more expensive for us to obtain director and officer liability insurance, which in turn could make it more difficult for us to attract and retain qualified members of our board of directors. However, these rules and regulations are often subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices.

If we are not able to comply with the requirements of Section 404 of the Sarbanes-Oxley Act of 2002 in a timely manner or with adequate compliance, we may be subject to sanctions by regulatory authorities.

Section 404 of the Sarbanes-Oxley Act of 2002 requires that we evaluate and determine the effectiveness of our internal controls over financial reporting and provide a management report on the internal control over financial reporting. If we have a material weakness in our internal controls over financial reporting, we may not detect errors on a timely basis and our financial statements may be materially misstated. We evaluate our internal controls systems to allow management to report on the effectiveness of the operation of our internal controls. Based on our market capitalization at June 30, 2018, we ceased to be an emerging growth company at December 31, 2018 and, accordingly, are now required to have an opinion from our independent registered public accounting firm on the effectiveness of our internal controls over financial reporting for our 2018 Annual Report and future annual reports.

However, if we are not able to comply with the requirements of Section 404, in a timely manner, or if we or our independent registered public accounting firm identify deficiencies in our internal controls that are deemed to be material weaknesses, we could be subject to sanctions or investigations by The Nasdaq Global Select Market, the SEC or other regulatory authorities, which would entail expenditure of additional financial and management resources and could materially adversely affect our stock price. Deficient internal controls could also cause us to fail to meet our reporting obligations or cause investors to lose confidence in our reported financial information, which could have a negative effect on our stock price.

Because we do not anticipate paying any cash dividends on our capital stock in the foreseeable future, capital appreciation, if any, will be your sole source of gain.

We have never declared or paid cash dividends on our capital stock. We currently intend to retain all of our future earnings, if any, to finance the growth and development of our business. As a result, capital appreciation, if any, of our common stock will be your sole source of gain for the foreseeable future.

We may incur significant costs from class action litigation due to our expected stock volatility.

Our stock price may fluctuate for many reasons, including as a result of public announcements regarding the progress of our development efforts or the development efforts of future collaborators or competitors, the addition or departure of our key personnel, variations in our quarterly operating results and changes in market valuations of biopharmaceutical and biotechnology companies.

This risk is especially relevant to us because biopharmaceutical and biotechnology companies have experienced significant stock price volatility in recent years. When the market price of a stock has been volatile as our stock price may be, holders of that stock have occasionally brought securities class action litigation against the company that issued the stock. If any of our stockholders were to bringFor example, in May 2020, a putative securities class action lawsuit was brought against us (“Class Action Lawsuit”). While the Class Action Lawsuit was voluntarily dismissed without prejudice by the plaintiff and his attorneys in January 2021, a similar lawsuit or another lawsuit could be filed in the

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future. Stockholder lawsuits of this type against us, even if the lawsuitit is without merit, we could cause us to incur substantial costs defending the lawsuit. The lawsuit could also divert the time and attention of our management.

Our amended and restated bylaws designate the Court of Chancery of the State of Delaware as the sole and exclusive forum for certain types of actions and proceedings that may be initiated by our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

Our amended and restated bylaws provide that, subject to limited exceptions, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or proceeding brought on our behalf, any action asserting a claim of breach of a fiduciary duty owed by any of our directors, officers or other employees to us or our stockholders, any action asserting a claim against us arising pursuant to any provision of the Delaware General Corporation Law, as amended, our amended and restated certificate of incorporation or our amended and restated bylaws, any action to interpret, apply, enforce or determine the validity of our amended and restated certificate of incorporation or our amended and restated bylaws or any other action asserting a claim against us that is governed by the internal affairs doctrine. Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and to have consented to the provisions of our amended and restated certificate of incorporation described above. This choice of forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers or other employees, which may discourage such lawsuits against us and our directors, officers and employees. Alternatively, if a court were to find these provisions of our amended and restated certificate of incorporation inapplicable to, or unenforceable in respect of, one or more of the specified types of actions or proceedings, we may incur additional costs associated with resolving such matters in other jurisdictions, which could adversely affect our business and financial condition.

General Risk Factors

We may acquire assets or form strategic alliances in the future, and we may not realize the benefits of such acquisitions.

As we continue to mature our Probody platform and our clinical stage pipeline, we may seek to acquire and/or in-license other oncology products, product candidates, programs or companies that we consider complimentary to our efforts. Such efforts may never result in a transaction and any future growth through acquisition or in-licensing will depend upon the availability of suitable products, product candidates, programs or companies for acquisition or in-licensing on acceptable prices, terms and conditions. Even if appropriate opportunities are available, we may not be able to acquire rights to them on acceptable terms, or at all. The competition to acquire or in-license rights to promising products, product candidates, programs and companies is fierce, and many of our competitors are large, multinational pharmaceutical and biotechnology companies with considerably more financial, development and commercialization resources, personnel, and experience than we have. In order to compete successfully in the current business climate, we may have to pay higher prices for assets than may have been paid historically, which may make it more difficult for us to realize an adequate return on any acquisition. In addition, even if we succeed in identifying promising products, product candidates, programs or companies, we may not have the ability to develop, obtain regulatory approval for and commercialize such opportunities, or the financial resources necessary to pursue them.

Even if we are able to successfully identify and acquire or in-license new products, product candidates, programs or companies, we may not be able to successfully manage the risks associated with integrating any products, product candidates, programs or companies into our business or the risks arising from anticipated and unanticipated problems in connection with an acquisition or in-licensing. Further, while we seek to mitigate risks and liabilities of potential acquisitions through, among other things, due diligence, there may be risks and liabilities that such due diligence efforts fail to discover, that are not disclosed to us, or that we inadequately assess. Any failure in identifying and managing these risks and uncertainties effectively would have a material adverse effect on our business. In any event, we may not be able to realize the anticipated benefits of any acquisition or in-licensing for a variety of reasons, including the possibility that a product candidate fails to advance to clinical development, proves not to be safe or effective in clinical trials, or fails to reach its forecasted commercial potential or that the integration of a product, product candidate, program or company gives rise to unforeseen difficulties and expenditures. Any failure in identifying and managing these risks and uncertainties would have a material adverse effect on our business.

In addition, acquisitions create other uncertainties and risks, particularly when the acquisition takes the form of a merger or other business consolidation. We may encounter unexpected difficulties, or incur unexpected costs, in connection with transition activities and integration efforts, which include:

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If we fail to integrate or otherwise manage an acquired business successfully and in a timely manner, resulting operating inefficiencies could increase our costs more than we planned, could negatively impact the market price of our common stock and could otherwise distract us from execution of our strategy. Failure to maintain effective financial controls and reporting systems and procedures could also impact our ability to produce timely and accurate financial statements.

Our future growth may depend, in part, on our ability to operate in foreign markets, where we would be subject to additional regulatory burdens and other risks and uncertainties.

Our future growth may depend, in part, on our ability to develop and commercialize our product candidates in foreign markets for which we may rely on collaboration with third parties. We are not permitted to market or promote any of our product candidates before we receive regulatory approval from the applicable regulatory authority in that foreign market, and we may never receive such regulatory approval for any of our product candidates. To obtain separate regulatory approval in many other countries we must comply with numerous and varying regulatory requirements of such countries regarding safety and efficacy and governing, among other things, clinical trials and commercial sales, pricing and distribution of our product candidates, and we cannot predict success in these jurisdictions. If we obtain approval of our product candidates and ultimately commercialize our product candidates in foreign markets, we would be subject to the risks and uncertainties, including the burden of complying with complex and changing foreign regulatory, tax, accounting and legal requirements and the reduced protection of intellectual property rights in some foreign countries. We may need to rely on third parties to market, distribute and sell our products in foreign markets.

Our information technology systems, or those of our CROs or other contractors or consultants we may utilize, may fail, suffer disruptions or suffer security breaches, which could result in a material disruption of our product development programs.

We are increasingly dependent on information technology systems and infrastructure, including mobile technologies, to operate our business. In the ordinary course of our business, we collect and store confidential and sensitive electronic information on our networks and in our data centers. This information includes, among other things, our intellectual property and proprietary information, the confidential information of our collaborators and licensees, and the personally identifiable information of our employees. It is important to our operations and business strategy that this electronic information remains secure and is perceived to be secure. Our information technology and other internal infrastructure systems and those of our CROs and contractors and consultants are vulnerable to damage and interruption from computer viruses, unauthorized access, natural disasters, terrorism, war, telecommunication and electrical failures, hacking, cyberattacks, phishing attacks and other social engineering schemes, malicious code, employee theft or misuse, human error, fraud, denial or degradation of service attacks, sophisticated nation-state and nation-state-supported actors or unauthorized access or use by persons inside our organization, or persons with access to systems inside our organization. A system interruption or security breach that leads to disclosure or modification of or prevents access to personally identifiable information or other protected information could harm our reputation, compel us to comply with federal and/or state breach notification laws and foreign law equivalents, subject us to mandatory corrective action, require us to verify the correctness of database contents and otherwise subject us to liability under laws and regulations that protect personal data, resulting in increased costs or loss of revenue. Similarly, the loss of clinical trial data from completed or ongoing or planned clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data.

Attacks upon information technology systems are also increasing in their frequency, levels of persistence, sophistication and intensity, and are being conducted by sophisticated and organized groups and individuals with a wide range of motives and expertise. As a result

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of the COVID-19 pandemic and resulting shelter-in-place and stay-at-home restrictions, we may also face increased cybersecurity risks due to our dependency on remote working technology and electronic monitoring of clinical trial sites, which may create additional opportunities for cybercriminals to exploit vulnerabilities. Furthermore, because the techniques used to obtain unauthorized access to, or to sabotage, systems change frequently and often are not recognized until launched against a target, we may be unable to anticipate these techniques or implement adequate preventative measures. We may also experience security breaches that may remain undetected for an extended period. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data, or inappropriate disclosure of confidential or proprietary information, we could incur liability, recovery of our data could take a prolonged period of time, and the development of our research or product candidates could be delayed.

As cyber threats continue to evolve, we may be required to expend significant additional resources to continue to modify or enhance our protective measures or to investigate and remediate any information security vulnerabilities. While we have implemented security measures to protect our data security and information technology systems, such measures may not prevent such events. Significant disruptions of our information technology systems or breaches of data security could have a material adverse effect on our business, financial condition and results of operations.

If we do not comply with laws regulating the protection of the environment and health and human safety, our business could be adversely affected.

Our research and development activities involve the use of hazardous materials and various chemicals. We maintain quantities of various flammable and toxic chemicals in our facilities in South San Francisco, California that are required for our research and development activities. We are subject to federal, state and local laws and regulations governing the use, manufacture, storage, handling and disposal of these hazardous materials. We believe our procedures for storing, handling and disposing these materials in our South San Francisco facilities comply with the relevant guidelines of South San Francisco, the state of California and the Occupational Safety and Health Administration of the U.S. Department of Labor. Although we believe that our safety procedures for handling and disposing of these materials comply with the standards mandated by applicable regulations, the risk of accidental contamination or injury from these materials cannot be eliminated. If an accident occurs, we could be held liable for resulting damages, which could be substantial. We are also subject to numerous environmental, health and workplace safety laws and regulations, including those governing laboratory procedures, exposure to blood-borne pathogens and the handling of animals and biohazardous materials. Although we maintain workers’ compensation insurance to cover us for costs and expenses, we may incur due to injuries to our employees resulting from the use of these materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological or hazardous materials. Additional federal, state and local laws and regulations affecting our operations may be adopted in the future. We may incur substantial costs to comply with, and substantial fines or penalties if we violate, any of these laws or regulations.

Changes in U.S. or foreign tax laws or regulations that are applied adversely to us may have a material adverse effect on our business, cash flow, financial condition or results of operations.

New income, sales, use or other tax laws, statutes, rules, regulations or ordinances could be enacted at any time, which could adversely affect our business and financial condition. Further, existing tax laws, statutes, rules, regulations or ordinances could be interpreted, changed, modified or applied adversely to us. For example, legislation enacted in 2017, informally titled the Tax Cuts and Jobs Act (the “Tax Act”), enacted many significant changes to the U.S. tax laws. Future guidance from the Internal Revenue Service and other tax authorities with respect to the Tax Act may affect us, and certain aspects of the Tax Act could be repealed or modified in future legislation. Changes in applicable tax rules, including changes to corporate tax rates, the realization of net deferred tax assets relating to our operations, the taxation of foreign earnings, and the deductibility of expenses under future reform legislation could have a material impact on the value of our deferred tax assets, could result in significant one-time charges, and could increase our future tax expense.

If securities or industry analysts do not publish research or reports about our business, or if they issue adverse or misleading opinions regarding our stock, our stock price and trading volume could decline.

The trading market for our common stock will be influenced by the research and reports that industry or securities analysts publish about us or our business. If any of the analysts who cover us issue an adverse or misleading opinion regarding us, our business model, our intellectual property or our stock performance, or if our target studies and operating results fail to meet the expectations of

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analysts, our stock price would likely decline. If one or more of these analysts cease coverage of us or fail to publish reports on us regularly, we could lose visibility in the financial markets, which in turn could cause our stock price or trading volume to decline.

Item 1B. Unresolved Staff Comments

None