TG Therapeutics 424B5 Prospectus supplement for primary offering

TABLE OF CONTENTS

The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to these securities has been filed with the Securities and Exchange Commission and is effective. This preliminary prospectus supplement is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-233636

Subject to completion, dated December 14, 2020

PRELIMINARY PROSPECTUS SUPPLEMENT
(to Prospectus dated September 5, 2019)

$200,000,000

[MISSING IMAGE: lg_tgtherapeutics-4clr.jpg]

Common Stock

We are offering shares of our common stock, $0.001 par value per share, in this offering, with an aggregate offering price of $200,000,000. At an assumed offering price of $42.27, the last reported sale price of our common stock on December 11, 2020, we would expect to issue and sell 4,731,488 shares of our common stock.

Our common stock is traded on the Nasdaq Capital Market under the symbol “TGTX.” On December 11, 2020, the last reported sale price of our common stock on the Nasdaq Capital Market was $42.27 per share.

Per share

Total

Public offering price

Underwriting discount and commissions(1)

Proceeds to TG Therapeutics, Inc., before expenses

(1)

See “Underwriting” beginning on page S-66 of this prospectus supplement for additional information regarding underwriting compensation.

We have granted the underwriters an option for a period of up to 30 days from the date of this prospectus supplement to purchase up to an aggregate of additional shares of our common stock at the price per share set forth above, representing an aggregate amount of approximately $30,000,000. If the underwriters exercise the option in full, the total proceeds to us, before offering expenses, will be approximately $ . See “Underwriting” beginning on page S-66.

Investing in our common stock involves risks. You should carefully consider all of the information set forth in this prospectus supplement, the accompanying base prospectus and the documents incorporated by reference in this prospectus supplement before deciding to invest in our common stock. Please see “Risk factors” on page S-6 of this prospectus supplement and in the documents incorporated by reference in this prospectus supplement and the accompanying base prospectus to read about factors you should consider before buying shares of our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement. Any representation to the contrary is a criminal offense.

The underwriters expect to deliver the shares of common stock against payment on or about December , 2020.

Joint Book-Running Managers

J.P. Morgan Goldman Sachs & Co. LLC Evercore ISI Cantor

The date of this prospectus supplement is December , 2020

TABLE OF CONTENTS

Table of contents

Prospectus supplement

Prospectus

S-i

TABLE OF CONTENTS

About this prospectus supplement

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this common stock offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference herein and therein. The second part, the accompanying prospectus, provides more general information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between the information contained in this prospectus supplement and the information contained in the accompanying prospectus or any document incorporated by reference therein filed prior to the date of this prospectus supplement, you should rely on the information in this prospectus supplement; provided that, if any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement.

We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference herein were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.

Neither we nor the underwriters have authorized anyone to provide information different from that contained in this prospectus supplement and the accompanying prospectus, including any free writing prospectus that we have authorized for use in this offering. When you make a decision about whether to invest in our common stock, you should not rely upon any information other than the information in this prospectus supplement or the accompanying prospectus, including any free writing prospectus that we have authorized for use in this offering. Neither the delivery of this prospectus supplement or the accompanying prospectus, including any free writing prospectus that we have authorized for use in this offering, nor the sale of our common stock means that information contained in this prospectus supplement and the accompanying prospectus, including any free writing prospectus that we have authorized for use in this offering, is correct after their respective dates. It is important for you to read and consider all information contained in this prospectus supplement and the accompanying prospectus, including the information incorporated by reference into this prospectus supplement and the accompanying prospectus, and any free writing prospectus that we have authorized for use in connection with this offering in making your investment decision. You should also read and consider the information in the documents to which we have referred you in the sections entitled “Where you can find more information” and “Incorporation of certain information by reference” in this prospectus supplement.

We are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the common stock in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement and the accompanying prospectus must inform themselves about, and observe any restrictions relating to, the offering of the common stock and the distribution of this prospectus supplement and the accompanying prospectus outside the United States. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

Unless otherwise stated, all references in this prospectus supplement to “we,” “us,” “our,” “TG,” the “Company” and similar designations refer to TG Therapeutics, Inc. and our subsidiaries. This prospectus supplement contains trademarks and trade names of TG Therapeutics, Inc., including our name and logo. Other service marks, trademarks and trade names referred to in this document are the property of their respective owners.

S-ii

TABLE OF CONTENTS

Forward-looking statements

Certain matters discussed in this prospectus supplement may constitute forward-looking statements for purposes of the Securities Act of 1933, as amended (the “Securities Act”), and the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from the future results, performance or achievements expressed or implied by such forward-looking statements. In some cases, you can identify forward-looking statements by words such as “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will,” “would” or the negative of these words or other comparable terminology, although not all forward-looking statements contain these identifying words. All written or oral forward-looking statements attributable to us are expressly qualified in their entirety by these cautionary statements. In addition, with respect to all of our forward-looking statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include, but are not limited to, statements about our:

•

expectations for increases or decreases in expenses;

•

expectations for the clinical and pre-clinical development, manufacturing, regulatory approval, and commercialization of our pharmaceutical product candidates or any other products we may acquire or in-license;

•

use of clinical research centers and other contractors;

•

expectations as to the timing of commencing or completing pre-clinical and clinical trials and the expected outcomes of those trials;

•

expectations for incurring capital expenditures to expand our research and development and manufacturing capabilities;

•

expectations for generating revenue or becoming profitable on a sustained basis;

•

expectations or ability to enter into marketing and other partnership agreements;

•

expectations or ability to enter into product acquisition and in-licensing transactions;

•

expectations or ability to build our own commercial infrastructure to manufacture, market and sell our drug candidates;

•

products being accepted by doctors, patients or payors;

•

ability to compete against other companies and research institutions;

•

ability to secure adequate protection for our intellectual property;

•

ability to attract and retain key personnel;

•

availability of reimbursement for our products;

•

estimates of the sufficiency of our existing cash and cash equivalents and investments to finance our operating requirements, including expectations regarding the value and liquidity of our investments;

•

stock price and its volatility;

•

expectations for future capital requirements; and

•

potential impact of the coronavirus (COVID-19) pandemic and government measures to control it.

The forward-looking statements contained in this prospectus supplement reflect our views and assumptions only as of the date this prospectus supplement is signed. New risks and uncertainties arise from time to time, and it is impossible for us to predict these events or how they may affect us. Except as required by law, we assume no responsibility for updating any forward-looking statements. You should, however, review the factors and risks we describe in the reports we will file from time to time with the Securities and Exchange Commission (the “SEC”) after the date of this prospectus supplement. See “Where you can find more information” and “Incorporation of certain information by reference.”

S-iii

TABLE OF CONTENTS

Summary risk factors

Our business is subject to a number of risks of which you should be aware before making an investment decision. These risks include the following:

We are a biopharmaceutical company with a limited operating history and have not generated any revenue from drug sales. We have incurred significant operating losses since our inception and anticipate that we will incur continued losses for the foreseeable future.

If we are unable to obtain regulatory approval for our most advanced drug candidates or other drug candidates and ultimately cannot commercialize our most advanced drug candidates or other drug candidates, or experience significant delays in doing so, our business will be materially harmed.

We will need to raise substantial additional funding. If we are unable to raise capital when needed, we would be forced to delay, reduce or eliminate some of our drug development programs or commercialization efforts.

Our level of indebtedness and debt service obligations could adversely affect our financial condition, and may make it more difficult for us to fund our operations.

Because the results of preclinical studies and early clinical trials are not necessarily predictive of future results, any product candidate we advance into clinical trials may not have favorable results in later clinical trials, if any, or receive regulatory approval. Moreover, 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.

Clinical drug development involves a lengthy and expensive process, with an uncertain outcome. We may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of our drug candidates.

We may seek accelerated approval for some of our product candidates but may not be able to obtain it as the sufficiency of our clinical trial results for accelerated approval are subject to the FDA’s discretion.

Our drug candidates may cause undesirable side effects 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 product candidates we may advance through clinical development are subject to extensive regulation, which can be costly and time consuming, cause unanticipated delays or prevent the receipt of the required approvals.

A fast track or breakthrough therapy designation by the FDA may not actually lead to a faster development or regulatory review or approval process.

We have received orphan drug designation for some of our drug candidates for specified indications, and we may seek orphan drug designation for additional indications and some other of our drug candidates. However, we may be unsuccessful in obtaining or may be unable to maintain the benefits associated with orphan drug designation, including the potential for market exclusivity.

The incidence and prevalence for the target patient populations of our drug candidates have not been established with precision. If the market opportunities for our drug candidates are smaller than we estimate or if any approval that we obtain is based on a narrower definition of the patient population, our revenue and ability to achieve profitability will be adversely affected, possibly materially.

We face substantial competition for treatments for our target indications, which may result in others commercializing drugs before or more successfully than we do resulting in the reduction or elimination of our commercial opportunity.

•

Product liability lawsuits against us could cause us to incur substantial liabilities and could limit commercialization of any drug candidates that we may develop.

S-iv

TABLE OF CONTENTS

•

We are subject to new legislation, regulatory proposals and managed care initiatives that may increase our costs of compliance and adversely affect our ability to market our products, obtain collaborators and raise capital.

•

Major public health issues, and specifically the pandemic caused by COVID-19, could have an adverse impact on our financial condition and results of operations and other aspects of our business.

•

If any product candidate for which we receive regulatory approval does not achieve broad market acceptance among physicians, patients, healthcare payors, and the medical community, the revenues that we generate from its sales will be limited.

•

We rely on third parties to generate clinical, preclinical and other data necessary to support the regulatory applications needed to conduct clinical trials and file for marketing approval. We rely on third parties to help conduct our planned clinical trials. If these third parties do not perform their services as required, we may not be able to obtain regulatory approval for or commercialize our product candidates when expected or at all.

•

We contract with third parties for the manufacture of our drug candidates for pre-clinical development and clinical trials, and we expect to continue to do so for commercialization. This reliance on third parties increases the risk that we will not have sufficient quantities of our drug candidates or such quantities at an acceptable cost or quality, which could delay, prevent or impair our development or commercialization efforts.

•

Our success depends upon our ability to obtain and protect our intellectual property and proprietary technologies and if the scope of our patent protection obtained is not sufficiently broad, our competitors could develop and commercialize technology and drugs similar or identical to ours, and our ability to successfully commercialize our technology and drugs may be impaired.

•

Because we have in-licensed our product candidates from third parties, any dispute with or non-performance by our licensors will adversely affect our ability to develop and commercialize the applicable product candidates.

•

Obtaining and maintaining patent protection depends on compliance with various procedural, document submission, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

•

We may need to license certain intellectual property from third parties, and such licenses may not be available or may not be available on commercially reasonable terms.

•

If we or our partners are sued for infringing intellectual property rights of third parties, it will be costly and time consuming, and an unfavorable outcome in that litigation would have a material adverse effect on our business.

•

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

•

We will need to develop and expand our business, and we may encounter difficulties in managing this development and expansion, which could disrupt our operations.

•

Our stock price is, and we expect it to remain, volatile, which could limit investors ability to sell stock at a profit.

The foregoing is only a summary of some of our risks. These and other risks are discussed more fully in the section entitled “Risk Factors” beginning on page S-6, in the section entitled “Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2019 and our Quarterly Reports for the periods ended March 31, 2020, June 30, 2020 and September 30, 2020, each as filed with the SEC on May 11, 2020, August 10, 2020 and November 9, 2020, respectively, which are incorporated herein by reference in their entirety, as well as any amendment or update to our risk factors reflected in subsequent filings with the SEC, and elsewhere in this prospectus supplement (our “Risk Factors”).

S-v

TABLE OF CONTENTS

Prospectus supplement summary

This summary highlights information contained elsewhere or incorporated by reference in this prospectus supplement and the accompanying prospectus and in the documents we incorporate by reference. This summary does not contain all of the information that you should consider before deciding to invest in our common stock. You should read this entire prospectus supplement and the accompanying prospectus carefully, including the “Risk factors” section contained in this prospectus supplement and our consolidated financial statements and the related notes and the other documents incorporated by reference herein, which are described under “Incorporation of certain information by reference” and “Where you can find more information” included in this prospectus supplement.

Our business

We are a biopharmaceutical company dedicated to developing and delivering medicines for patients with B-cell mediated diseases, including chronic lymphocytic leukemia (CLL), non-Hodgkin lymphoma (NHL) and multiple sclerosis (MS). We have developed a robust B-cell directed research and development (“R&D”) platform for identification of key B-cell pathways of interest and rapid clinical testing. Currently, we have five B-cell targeted drug candidates in clinical development, with the two lead therapies, ublituximab (TG-1101) and umbralisib (TGR-1202), in pivotal trials for CLL and NHL, with ublituximab also in pivotal trials for MS. Ublituximab is a novel anti-CD20 monoclonal antibody (mAb) that has been glycoengineered for enhanced potency. Umbralisib is an oral, once daily, dual inhibitor of PI3K-delta and CK1-epsilon. When used together in combination therapy, ublituximab and umbralisib are referred to as “U2”. Additionally, in early clinical development we have an anti-PD-L1 monoclonal antibody cosibelimab (TG-1501), an oral Bruton’s Tyrosine Kinase (BTK) inhibitor referred to as TG-1701, and an anti-CD47/CD19 bispecific antibody referred to as TG-1801.

We also actively evaluate complementary products, technologies and companies for in-licensing, partnership, acquisition and/or investment opportunities. To date, we have not received approval for the sale of any of our drug candidates in any market and, therefore, have not generated any product sales from our drug candidates.

Our products under development

We have leveraged our B-cell platform to develop a robust drug pipeline of targeted orally available, potent and selective small molecule kinase inhibitors and intravenously delivered immunotherapies that leverage the patients’ own immune system to fight cancer. We currently own worldwide development and commercial rights, subject to certain limited geographical restrictions, to all of our preclinical and clinical programs. The following table summarizes our most advanced drug candidates:

Clinical Drug Candidate (molecular target)	Initial Target Disease	Stage of Development (trial name)
Ublituximab/TG-1101 (anti-CD20 mAb)	Chronic Lymphocytic Leukemia	Phase 3 trial (UNITY-CLL) Phase 2b trial (ULTRA-V)
	Relapsing Multiple Sclerosis	Phase 3 trials (ULTIMATE I and II)
Umbralisib/TGR-1202 (PI3K-delta inhibitor)	Chronic Lymphocytic Leukemia	Phase 3 trial (UNITY-CLL) Phase 2b trial (ULTRA-V)
	Marginal Zone Lymphoma	Phase 2b trial (UNITY-NHL)
	Follicular Lymphoma/Small Lymphocytic Lymphoma	Phase 2b trial (UNITY-NHL)
Cosibelimab/TG-1501 (anti-PDL1 mAb)	B-cell cancers	Phase 1 trial
TG-1701 (BTK inhibitor)	B-cell cancers	Phase 1 trial
TG-1801 (anti-CD47/CD19 bispecific Ab)	B-cell cancers	Phase 1 trial

S-1

TABLE OF CONTENTS

Phase 3 and registration directed clinical trial highlights:

We have several Phase 3 and registration-directed Phase 2b clinical trials ongoing that may support marketing applications for approval. Our most advanced trials, UNITY-NHL MZL & FL single agent cohorts, UNITY-CLL, and the ULTIMATE I & II trials, have all completed enrollment and have either completed their primary analysis or are nearing completion. Accordingly, we would expect to see minimal impact on the conduct and our proposed timelines for these three trials related to the COVID-19 pandemic. However, as the pandemic evolves, we will continue to evaluate each trial, monitor potential implications, and work closely with our investigational sites, CROs, and vendors to develop continuity plans.

The following are highlights from our current Phase 3 trials and registration-directed Phase 2b clinical trials:

•

UNITY-NHL Phase 2b Trial: UNITY-NHL is a global Phase 2b registration-directed clinical trial designed to evaluate the efficacy and safety of single-agent umbralisib and U2 combinations in patients with previously treated NHL. The marginal zone lymphoma (MZL), follicular lymphoma (FL), and small lymphocytic lymphoma (SLL) single agent umbralisib cohorts of this trial are fully enrolled. The primary objective of these cohorts is to assess the efficacy of single agent umbralisib as measured by Overall Response Rate (ORR).

•

UNITY-NHL MZL and FL Single Agent Umbralisib Cohorts: The MZL cohort enrolled adult patients who had at least one prior line of therapy that included an anti-CD20 monoclonal antibody. In February 2019, we announced that the MZL cohort met the primary endpoint of ORR as determined by an Independent Review Committee (IRC) for all treated patients (n=69). The results met our target guidance of 40-50% ORR. Previously, in January 2019, the U.S. Food and Drug Administration (“FDA”) granted Breakthrough Therapy Designation (BTD) to umbralisib for the treatment of adult patients with MZL who have received at least one prior anti-CD20 regimen. In April 2019, the FDA granted orphan drug designation to umbralisib for the treatment of patients with any of the three types of marginal zone lymphoma: nodal, extranodal, and splenic MZL. The FL/SLL cohort enrolled adult patients who had two or more prior lines of therapy that included an anti-CD20 monoclonal antibody and an alkylating agent. In October 2019, we announced that the FL patients within this cohort met the primary endpoint of ORR as determined by IRC for all treated FL patients (n=118). The results met our target guidance of 40-50% ORR. In January of 2020, we received guidance from the FDA allowing submission of a single New Drug Application (NDA) for MZL and FL indications, and we initiated a rolling submission of an NDA to the FDA for umbralisib in MZL and FL. In March 2020, we announced that the FDA granted orphan drug designation to umbralisib for the treatment of FL. In June 2020, we announced the completion of the rolling NDA submission for MZL and FL, and in August 2020 we announced the FDA accepted the NDA. The MZL indication, under BTD, has been accepted for Priority Review and has a Prescription Drug User Fee Act (PDUFA) goal date of February 15, 2021. The FL indication has been accepted for standard review with a PDUFA goal date of June 15, 2021. On November 4, 2020, accepted abstracts for the 2020 American Society of Hematology Virtual Conference were released with the final data from the UNITY-NHL, MZL and FL cohorts, which we previously announced top-line results for in February and October 2019, respectively. Highlights from the abstract are as follows:

•

A total of 208 patients with iNHL received at least 1 dose of umbralisib, including 69 marginal zone lymphoma (MZL), 117 follicular lymphoma (FL), and 22 small lymphocytic lymphoma (SLL) patients ;

•

MZL patients were relapsed/refractory to ≥1 prior lines of treatment, including an anti-CD20. At a median follow up of 27.8 months, the following was observed:

•

“Any Tumor Reduction” rates for MZL of 90.6%, FL of 83.5% and SLL of 89.5%.

•

49.3% ORR with 15.9% Complete response (CR) rate.

•

Median PFS was not reached, with an estimated 12-month PFS rate of 64.2%; no patients who achieved a CR have experienced disease progression to date.

S-2

TABLE OF CONTENTS

•

FL patients were relapsed or refractory to ≥2 prior lines, including an anti-CD20 and an alkylating agent. At a median follow up of 27.5 months the following was observed:

•

45.3% ORR with 5.1% achieving a CR.

•

Median PFS was 10.6 months, with an estimated 12-month PFS rate of 45.9%.

•

The most common AEs of > Grade 3 were neutropenia (11.5%), diarrhea (10.1%) and increased ALT/AST (7.2%). Other AEs of interest included pneumonitis (all Grades 1.4%, > Grade 3 1.0%) and colitis (all Grades 1.4%, >Grade 3 0.5%).

•

Conclusion: Umbralisib achieved meaningful clinical activity in a heavily pretreated iNHL population. The safety profile was manageable, with a relatively low incidence of immune-mediated toxicities and AE-related discontinuations.

•

UNITY-NHL Additional Cohorts: There are additional exploratory disease cohorts of the UNITY-NHL trial focused on diffuse large B cell lymphoma (DLBCL) and mantle cell lymphoma (MCL). In total, there are currently four cohorts in the UNITY-NHL trial, including MZL, FL/SLL, DLBCL, and MCL. Each cohort is evaluated separately from the others. The MZL, MCL and FL cohorts are currently enrolling additional patients exploring the combination of U2.

•

UNITY-CLL Phase 3 Trial Evaluating Umbralisib plus Ublituximab (U2): UNITY-CLL is a global Phase 3 randomized controlled clinical trial comparing the U2 combination to an active control arm of obinutuzumab plus chlorambucil in patients with both treatment-naïve and relapsed or refractory CLL. Two additional arms evaluating single agent ublituximab and single agent umbralisib were also enrolled for purposes of evaluating the contribution of each in the U2 combination regimen. The primary endpoint for this study is progression free survival (PFS) which we intend to use to support a Biologics License Application (BLA) submission for approval of the U2 combination in CLL. The study completed enrollment in October 2017 with over 600 patients across the four treatment arms, with approximately 420 patients in the U2 and the active control arms combined. This trial is conducted under a Special Protocol Assessment (SPA) with the FDA. On May 5, 2020, we announced the UNITY-CLL trial met its primary endpoint at a prespecified interim analysis demonstrating a statistically significant improvement in PFS (p<0.0001) and will be stopped early for superior efficacy. In October 2020, we announced that the FDA granted Fast Track Designation to U2 for CLL. On November 4, 2020, accepted abstracts for the 2020 ASH Virtual Conference were released with the final data from the UNITY-CLL study, which we previously announced top-line results for in May of 2020. Highlights from this abstract are as follows:

•

421 patients were randomized to the U2 (n=210) or O+Chl (n=211) arms; 57% of patients were treatment-naïve and 43% had R/R CLL.

•

At a median follow-up of 36.2 months, U2 significantly prolonged progression-free survival (PFS) vs O+Chl (median 31.9 months vs 17.9 months; hazard ratio 0.546 (p<0.0001)).

•

PFS improvement with U2 vs O+Chl was consistent across all subgroups examined including treatment naïve patients (median 38.5 months vs 26.1 months, hazard ratio 0.482) and relapsed/refractory patients (median 19.5 months vs 12.9 months, hazard ratio 0.601).

•

Overall response rate (ORR) was significantly higher with U2 compared to O+Chl (83.3% vs 68.7%; p<0.001).

•

Grade 3/4 Adverse Events (AE) of interest regardless of causality (U2 vs O+Chl) included neutropenia (30.6% vs 34.7%), thrombocytopenia (3.4% vs 13.1%), diarrhea (12.1% vs 2.5%), infusion related reaction (1.9% vs 3.5%), elevated AST/ALTs (8.3% vs 2%), colitis (3.4% vs 0%) and pneumonitis (2.9% vs 0%).

•

Conclusion: U2 exhibited a well-tolerated safety profile, and significantly improved PFS vs. standard of care chemoimmunotherapy in patients with treatment naïve and relapsed/refractory CLL.

S-3

TABLE OF CONTENTS

•

ULTIMATE I & II Trials Evaluating Single Agent Ublituximab in RMS: ULTIMATE I and ULTIMATE II are two independent Phase 3 trials. Each trial is a global, randomized, multi-center, double-blinded, double-dummy, active-controlled study comparing ublituximab to teriflunomide in subjects with relapsing forms of Multiple Sclerosis (RMS). The primary endpoint for each study is Annualized Relapse Rate (ARR) following 96 weeks of treatment, which we intend to use to support a submission for approval of ublituximab in RMS. These trials are both being conducted under a SPA with the FDA. Full enrollment was completed in October 2018, with approximately 1,100 subjects enrolled in both studies combined.

On December 10, 2020, we announced that both studies met their primary endpoint with ublituximab treatment demonstrating a statistically significant reduction in ARR over a 96-week period (p<0.005 in each trial). Ublituximab treatment resulted in an ARR of <0.10 in each of ULTIMATE I & II, with a relative reduction in ARR of approximately 60% and 50%, respectively, over teriflunomide. The ULTIMATE I & II studies investigated the safety and efficacy of a one-hour 450mg infusion of ublituximab every six months, following the Day 1 infusion (150mg over four hours). Further analyses of the ULTIMATE I & II studies including safety and secondary endpoints will be conducted and detailed data will be presented at an upcoming medical congress, targeted in first half of 2021. Additionally, data from these studies are intended to support a Biologics License Application (BLA) submission for ublituximab in RMS targeted in mid-year 2021.

•

ULTRA-V Phase 2b Trial Evaluating U2 plus Venetoclax in CLL: ULTRA-V is a Phase 2 open-label, multicenter, registration-directed clinical trial designed to investigate the efficacy and safety of U2 in combination with venetoclax in subjects with treatment-naïve and relapsed or refractory CLL. The primary endpoints for this study are ORR and Complete Response (CR) rate. This trial is currently enrolling.

Recent developments

On November 9, 2020, we launched an at the market offering of shares of the Company’s common stock, $0.001 par value per share, having an aggregate offering price of up to $400,000,000 from time to time pursuant to the At Market Issuance Sales Agreement by and among the Company and Jefferies LLC, Cantor Fitzgerald & Co., and B. Riley Securities, Inc. (formerly B. Riley FBR, Inc.), dated March 20, 2020 (the “ATM”).

Company information

Our principal executive offices are located at 2 Gansevoort St., 9th Floor, New York, New York 10014, and our telephone number is 212-554-4484. We maintain a website on the Internet at www.tgtherapeutics.com and our e-mail address is info@tgtxinc.com. Our website, and the information contained on it, are not to be considered part of this prospectus supplement or the accompanying prospectus. For further information regarding us and our financial information, you should refer to our recent filings with the SEC. See “Where you can find more information” and “Incorporation of certain information by reference.”

Under the terms of our term loan facility, Hercules (as defined below) or its nominee has the right to purchase shares of common stock being offered in this offering at the public offering price and on the same terms as the other purchasers in this offering.

S-4

TABLE OF CONTENTS

The offering

Issuer

TG Therapeutics, Inc.

Common stock offered by us

Common stock to be outstanding after the offering

Option to Purchase Additional Shares

Use of Proceeds

We intend to use the net proceeds of this offering for the continued development of ublituximab (TG-1101) and umbralisib (TGR-1202), the potential in-license, acquisition, development and commercialization of other pharmaceutical products, and for general corporate purposes. See “Use of proceeds” on page S- 61.

Risk factors

See “Risk factors” beginning on page S- 6 for a discussion of factors that you should consider before buying shares of our common stock.

Nasdaq Capital Market Symbol

TGTX

The number of shares of common stock to be outstanding after the offering assumes no exercise of the underwriters’ option to purchase additional shares of common stock and is based on 128,918,552 shares of common stock outstanding as of September 30, 2020.

The number of shares of common stock to be outstanding after this offering does not take into account as of September 30, 2020:

•

2,529,133 shares of common stock issuable upon the exercise of outstanding stock options with a weighted average exercise price of $6.99 per share;

•

17,814 shares of common stock issuable upon the conversion of outstanding notes payable with a weighted average conversion price of $1,125 per share;

•

an aggregate of 5,054,913 shares of common stock reserved for future issuance under our stock option and incentive plans; and

•

147,058 shares of common stock issuable upon the exercise of outstanding warrants with a weighted average exercise price of $4.08 per share.

Further, the number of shares of common stock to be outstanding after this offering does not take into account 2,582,678 shares of common stock issued pursuant to sales under our ATM through December 9, 2020.

S-5

TABLE OF CONTENTS

Risk factors

Investment in our common stock involves risks. Before deciding whether to invest in our common stock, you should consider carefully the risk factors discussed below and those contained in the section entitled “Risk Factors” contained in our Annual Report on Form 10-K for the year ended December 31, 2019 and our Quarterly Reports for the periods ended March 31, 2020, June 30, 2020 and September 30, 2020, each as filed with the SEC on May 11, 2020, August 10, 2020 and November 9, 2020, respectively, which are incorporated herein by reference in their entirety, as well as any amendment or update to our risk factors reflected in subsequent filings with the SEC. If any of the risks or uncertainties described in our SEC filings actually occurs, our business, financial condition, results of operations or cash flow could be materially and adversely affected. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. The risks and uncertainties we have described are not the only ones facing our company. Additional risks not currently known to us or that we currently deem to be immaterial may adversely impact our business in the future. Additionally, many of these risks and uncertainties are currently elevated by and may or will continue to be elevated by the COVID-19 pandemic.

Risks related to this offering

Future sales or other issuances of our common stock could depress the market for our common stock.

Sales of a substantial number of shares of our common stock, or the perception by the market that those sales could occur, could cause the market price of our common stock to decline or could make it more difficult for us to raise funds through the sale of equity in the future.

In connection with this offering, we have entered into a lock-up agreement for a period of 60 days following this offering, subject to certain exceptions, and our directors and officers and certain of our significant stockholders have entered into lock-up agreements for a period of 45 days following this offering, subject to certain exceptions. We and our directors and officers may be released from lock-up prior to the expiration of the respective lock-up period at the sole discretion of J.P. Morgan Securities LLC. See “Underwriting.” Upon expiration or earlier release of the lock-up, we and our directors and officers may sell shares into the market, which could adversely affect the market price of shares of our common stock.

Future issuances of common stock could further depress the market for our common stock.

If we make one or more significant acquisitions in which the consideration includes stock or other securities, our stockholders’ holdings may be significantly diluted. In addition, stockholders’ holdings may also be diluted if we enter into arrangements with third parties permitting us to issue shares of common stock in lieu of certain cash payments upon the achievement of milestones.

Our stock price is, and we expect it to remain, volatile, which could limit investors’ ability to sell stock at a profit.

The trading price of our common stock is likely to be highly volatile and subject to wide fluctuations in price in response to various factors, many of which are beyond our control. These factors include:

•

publicity regarding actual or potential clinical results relating to products under development by our competitors or us;

•

delay or failure in initiating, completing or analyzing nonclinical or clinical trials or the unsatisfactory design or results of these trials;

•

achievement or rejection of regulatory approvals by our competitors or us;

•

announcements of technological innovations or new commercial products by our competitors or us;

•

developments concerning proprietary rights, including patents;

•

developments concerning our collaborations;

S-6

TABLE OF CONTENTS

•

regulatory developments in the United States and foreign countries;

•

economic or other crises and other external factors, including the effect of the COVID-19 pandemic on the global economy and its potential to negatively affect the hospitals and clinical sites in which we conduct any of our clinical trials, and patients’ willingness to access those sites to continue the trials, which could have a material adverse effect on our business, our results of operations or our financial condition;

•

period-to-period fluctuations in our revenues and other results of operations;

•

changes in financial estimates by securities analysts; and

•

sales of our common stock by us.

We will not be able to control many of these factors, and we believe that period-to-period comparisons of our financial results will not necessarily be indicative of our future performance.

In addition, the stock market in general, and the market for biotechnology companies in particular, has experienced extreme price and volume fluctuations that may have been unrelated or disproportionate to the operating performance of individual companies. These broad market and industry factors may seriously harm the market price of our common stock, regardless of our operating performance.

Certain anti-takeover provisions in our charter documents and Delaware law could make a third-party acquisition of us difficult. This could limit the price investors might be willing to pay in the future for our common stock.

Provisions in our amended and restated certificate of incorporation and restated bylaws could have the effect of making it more difficult for a third party to acquire, or of discouraging a third party from attempting to acquire, or control us. These factors could limit the price that certain investors might be willing to pay in the future for shares of our common stock. Our amended and restated certificate of incorporation allows us to issue preferred stock without the approval of our stockholders, including pursuant to our shareholder rights plan. The issuance of preferred stock could decrease the amount of earnings and assets available for distribution to the holders of our common stock or could adversely affect the rights and powers, including voting rights, of such holders. In certain circumstances, such issuance could have the effect of decreasing the market price of our common stock. Our shareholder rights plan could be used by our board to deter any third party offer to acquire a significant portion of our common stock, even an offer at a premium to the market price. Our restated bylaws eliminate the right of stockholders to call a special meeting of stockholders, which could make it more difficult for stockholders to effect certain corporate actions. Any of these provisions could also have the effect of delaying or preventing a change in control.

We have broad discretion to use the net proceeds from this offering and our investment of these proceeds pending any such use may not yield a favorable return.

Our management has broad discretion as to how to spend the proceeds from this offering and may spend these proceeds in ways with which our stockholders may not agree. Pending any such uses, we plan to invest the net proceeds of this offering in short-term and long-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders.

You will experience immediate and substantial dilution.

Since the public offering price of the shares of common stock offered pursuant to this prospectus supplement and the accompanying prospectus is higher than the net tangible book value per share of our common stock, you will suffer substantial dilution in the net tangible book value of the common stock you purchase in this offering.

You may experience future dilution as a result of future equity offerings.

In order to raise additional capital, we may in the future offer additional shares of our common stock or other securities convertible into or exchangeable for our common stock at prices that may not be the same as the price

S-7

TABLE OF CONTENTS

per share in this offering. We may sell shares or other securities in any other offering, including under our ATM, at a price per share that is less than the price per share paid by investors in this offering, and investors purchasing shares or other securities in the future could have rights superior to existing stockholders. The price per share at which we sell additional shares of our common stock, or securities convertible or exchangeable into common stock, in future transactions may be higher or lower than the price per share paid by investors in this offering.

Risks related to the COVID-19 pandemic

Major public health issues, and specifically the pandemic caused by COVID-19, could have an adverse impact on our financial condition and results of operations and other aspects of our business.

In December 2019, a novel strain of coronavirus which causes a disease referred to as COVID-19, was first detected in Wuhan, China, and has since spread around the world. On March 11, 2020, the World Health Organization declared that the rapidly spreading COVID-19 outbreak had evolved into a pandemic. In response to the pandemic, many governments around the world are implementing a variety of control measures to reduce the spread of COVID-19, including travel restrictions and bans, instructions to residents to practice social distancing, quarantine advisories, shelter-in-place orders and required closures of non-essential businesses.

The COVID-19 pandemic has negatively impacted the global economy, disrupted global supply chains, and created significant volatility and disruption of financial markets. Although COVID-19 has not had a material adverse effect on our business to date, no assurance can be given that it will not in the future if the situation persists or worsens. The extent to which the COVID-19 pandemic impacts our business and operating results will depend on future developments that are highly uncertain and cannot be accurately predicted, including new information that may emerge concerning the virus and the actions to contain it or treat its impact, the duration, spread and severity of the COVID-19 pandemic, and how quickly and to what extent normal economic and operating conditions can resume if and when the pandemic subsides, among others.

Should the COVID-19 pandemic persist or worsen and government restrictions continue, our business operations could be materially delayed or interrupted. For instance, our ongoing clinical trials may be delayed or compromised; our ability to conduct new clinical trials may be adversely impacted; our supply chain may be disrupted; and health authority review of our regulatory submissions may be delayed. It is unknown how long these disruptions could continue, were they to occur. Any delay in our clinical trials or in regulatory review resulting from such disruptions could materially affect the development and commercialization of our product candidates.

We currently rely on third parties for certain functions or services in support of our clinical trials and key areas of our operations. These third parties include contract research organizations (CROs), medical institutions and clinical investigators, contract manufacturing organizations, suppliers, and external business partners supporting our preparations for commercialization. If these third parties themselves are adversely impacted by restrictions resulting from the COVID-19 outbreak, we will likely experience delays and/or realize additional costs. As a result, our efforts to obtain regulatory approvals for, and to commercialize, our product candidates may be delayed or disrupted.

In addition, as a result of government directives on social distancing and to protect the health of our workforce, we have asked our office-based employees to work remotely and have restricted domestic and international travel indefinitely. Third parties on which we rely may also increase their use of remote working arrangements in response to COVID-19. Our increased reliance on personnel working remotely may negatively impact productivity, including our ability to monitor clinical trials, prepare regulatory applications, and conduct data analysis, or disrupt, delay, or otherwise adversely impact our business. In addition, remote working could increase our cybersecurity risk and make us more susceptible to communication disruptions, any of which could adversely impact our business operations or delay necessary interactions with local and federal regulators, manufacturing sites, research or clinical trial sites and contractors.

Our ability to successfully commercialize any product candidates, if approved, also may be adversely impacted by restrictions and safety measures instituted due to COVID-19. For example, reduced access to healthcare

S-8

TABLE OF CONTENTS

providers and institutions as a result of social distancing protocols may impact or require adjustments to commercialization activities, including, the manner in which our field teams engage with healthcare providers and facilities.

The potential economic impact brought by and the duration of the pandemic may be difficult to assess or predict. However, it has already caused, and is likely to result in further, significant disruption of global financial markets. It is likely that the pandemic will cause an economic slowdown of potentially extended duration, and it is possible that it could cause a global recession. This disruption may reduce our ability to access capital either at all or on favorable terms. In addition, a recession, depression or other sustained adverse market event resulting from the spread of COVID-19 could materially and adversely affect our business and the value of our common stock.

The ultimate impact of the current pandemic, or any other health epidemic, is highly uncertain and subject to change. We do not yet know the full extent of potential delays or impacts on our business, our clinical trials, our research programs, healthcare systems or the global economy as a whole. However, these effects could have a material adverse effect on our business, financial condition and results of operations.

To the extent the COVID-19 pandemic materially adversely affects our business and financial results, it may also have the effect of significantly heightening many of the other risks described in this Risk Factors section and in the section entitled “Risk Factors” in our most recent Quarterly Report on Form 10-Q for the quarter ended September 30, 2020.

The COVID-19 pandemic could have a material adverse effect on our clinical development program if the pandemic and associated government control measures continue.

The ongoing COVID-19 pandemic has presented substantial public health challenges and is impacting the global healthcare system, including the conduct of clinical trials in the U.S. and other parts of the world. As a result of the COVID-19 pandemic, we may encounter delays in our clinical development program. The majority of our clinical trials involve patients with cancer or those receiving ongoing immunosuppressive therapy who may be at higher risk of infection. These patients are thus more likely to be subject to travel restrictions and self-quarantining and may be more likely to withdraw from our clinical trials or unable to complete study assessments. We have made efforts to allow patients currently enrolled in our ongoing clinical trials to continue unimpeded and have continued to allow new patients to enroll in our trials. While we have allowed continued enrollment to our trials, many trial sites have limited enrollment or suspended enrollment entirely in response to the COVID-19 pandemic, which may affect our ability to enroll to our trials and meet our projected timelines.

The UNITY-NHL FL and MZL umbralisib monotherapy cohorts, the UNITY-CLL and the ULTIMATE I and II trials are fully enrolled. However, follow-up is ongoing and data continue to be collected from these studies. These data collection efforts rely on study participants’ ability to contribute such data, often through study specific visits and procedures that can only be conducted in-person. While we anticipate minimal impact from COVID-19 on the previously estimated timelines for these trials, no guarantee can be made that our estimated timelines, or the ultimate outcome from these trials, will not be materially negatively impacted by the COVID-19 pandemic.

Further, we may not be able to complete our clinical trials that we initiated more recently and for which we have not yet completed enrollment in the time frame that we had previously planned. In addition, the pandemic may adversely affect our ability to conduct new trials. Some factors from the COVID-19 outbreak that may delay or otherwise adversely affect our clinical trial programs, as well as adversely impact our business generally, include:

•

delays or difficulties in clinical site initiation, including difficulties in recruiting and retaining clinical sites, impacts on compliance with clinical study protocols, delays enrolling patients in our clinical trials, decreased enrollment in our clinical trials or increased rates of patients withdrawing from our clinical trials following enrollment, in each case, as a result of patients contracting COVID-19, being forced to quarantine, experiencing reluctance to seek medical attention in a healthcare facility setting, or otherwise not being able or willing to complete study assessments, particularly for older patients or others with a higher risk of contracting COVID-19;

S-9

TABLE OF CONTENTS

•

impacts to clinical results, including an increased number of observed adverse events, as a result of participants enrolled in our clinical trials contracting COVID-19;

•

prioritization by healthcare providers, facilities, lawmakers, and regulators of COVID-19-related healthcare needs or, when the pandemic subsides, to address the potential backlog of patients who have deferred medical procedures during the pendency of the pandemic, which may reduce availability of professionals and resources for clinical trials in other disease areas;

•

limitations on travel, including limitations on domestic and international travel, and government-imposed quarantines or restrictions imposed by key third parties that could interrupt key trial activities, such as clinical trial site initiations and monitoring, which could impact the reliability or integrity of subject data and clinical study endpoints;

•

interruption of, or delays in receiving, supplies of our product candidates from our contract manufacturing organizations due to staffing shortages, production slowdowns or stoppages or interruption in global shipping that may affect the transport of clinical trial materials;

•

disruptions and delays caused by potential workplace, laboratory and office closures and an increased reliance on employees working from home across the healthcare system;

•

disruptions in or delays to regulatory reviews, responses, inspections, or other regulatory activities, including review of marketing applications and approvals of protocol changes or amendments to Special Protocol Assessments (SPA), as a result of the spread of COVID-19 affecting the operations of the U.S. Food and Drug Administration (FDA) or other regulatory authorities;

•

changes in local regulations as part of a response to the COVID-19 pandemic which may require us to change the ways in which clinical trials are conducted, which may result in unexpected costs, or to discontinue the clinical trials altogether;

•

refusal of the FDA to accept data from clinical trials in affected geographies outside the United States; and

•

negative effects on the quality, completeness, integrity, interpretability and cost of our clinical study data.

The potential disruptions discussed above and other consequences of the COVID-19 pandemic could result in missed study visits or study procedures in our clinical trials, which could lead to an abundance of protocol deviations that impact the interpretability of the trial results. A significant number of deviations may call into question whether the execution of a clinical trial was consistent with the protocol, which is of particular importance where study designs were agreed to as part of a SPA as in the case of our Phase 3 clinical trial for the combination of ublituximab plus umbralisib for patients with chronic lymphocytic leukemia (UNITY-CLL) and our registration program for ublituximab in relapsing multiple sclerosis (ULTIMATE I and II). In extreme cases, significant deviations from the protocol may be considered a violation of the SPA and result in potential rescindment of the SPA agreement, which could adversely affect our ability to use the results of the impacted study to support a future regulatory application.

We will continue to monitor the potential impact of COVID-19 on our clinical trial program, however, the full extent to which the COVID-19 pandemic may directly or indirectly impact the progress of our current and planned trials will depend on future developments that are highly uncertain and cannot be accurately predicted.

The third parties upon whom we rely for the supply of starting materials, intermediates, active pharmaceutical ingredient (API)/drug substance, drug product, and other materials used in our drug candidates are our sole source of supply, and the loss or disruption of any of these suppliers, including as a result of the COVID-19 pandemic, could significantly harm our business.

The starting materials, intermediates, API/drug substance, and drug product used in many of our drug candidates are currently supplied to us from single-source suppliers. Our ability to successfully develop our drug candidates, supply our drug candidates for clinical trials and to ultimately supply our commercial drugs in quantities sufficient to meet the market demand, depends in part on our ability to obtain starting materials, intermediates, API/drug substance, and drug product for these drugs in accordance with regulatory requirements and in

S-10

TABLE OF CONTENTS

sufficient quantities for clinical testing and commercialization. It is expected that many of our manufacturing partners will be sole source suppliers from single site locations for the foreseeable future. Various raw materials, components, and testing services required for our products may also be single sourced. We are not certain that our single-source suppliers will be able to supply sufficient quantities of their products or on the timelines necessary to meet our needs, either because of the nature of our agreements with those suppliers, our limited experience with those suppliers, our relative importance as a customer to those suppliers, public health emergencies such as the COVID-19 pandemic or natural disasters that may cause those suppliers to stop work for a period of time. If any of our suppliers ceases its operations for any reason or is unable or unwilling to supply starting materials, intermediates, API/drug substance, and drug product in sufficient quantities or on the timelines necessary to meet our needs, it could significantly and adversely affect our business, the supply of our drug candidates and our financial condition. In addition, if our current or future supply of any of our product candidates should fail to meet specifications during its stability program there could be a significant interruption of our supply of drug, which would adversely affect the clinical development and commercialization of the product.

Although COVID-19 has not had a material adverse effect on our supply chain to date, no assurance can be given that it will not in the future if the situation persists or worsens. Umbralisib is manufactured in India, ublituximab is manufactured in South Korea, and TG-1701 is manufactured in China. Each of these countries continues to be, or has been, subject to government-imposed quarantines and travel restrictions due to the COVID-19 pandemic, which, in some cases, have resulted in reduced operations at manufacturing and research locations and time-limited shutdowns. Our contract manufacturers for umbralisib and ublituximab are continuing operations at varying levels of capacity. We are working closely with our contract manufacturer for umbralisib to plan for anticipated commercial supply needs in light of the Prescription Drug User Fee Act (PDUFA) goal date of February 15, 2021 for Marginal Zone Lymphoma (MLZ) and June 15, 2021 for Follicular Lymphoma (FL). We also are working closely with our contract manufacturer for ublituximab to plan for our anticipated commercial supply needs if we are successful in our continued clinical and regulatory development. We believe that we have sufficient inventory of clinical supplies of umbralisib, ublituximab and TG-1701 to support our current clinical program needs through the first quarter 2021. We will continue to monitor the situation very closely with our suppliers in impacted regions.

We continually evaluate our supply chains to identify potential risks and will take steps, as necessary, to identify additional manufacturers and other suppliers for the production of our product candidates. However, establishing additional or replacement suppliers for the API/drug substance and drug product, if required, may not be accomplished quickly or at all and may involve significant expense. If we are able to find a replacement supplier, we would need to evaluate and qualify such replacement supplier and its ability to meet quality and compliance standards. Any change in suppliers or the manufacturing process could require additional regulatory approval and result in operational delays. While we seek to maintain adequate inventory of materials necessary for the production of our drug candidates, any supply interruption or delay, or our inability to identify alternate sources at acceptable prices in a timely manner could impede, delay, limit or prevent our development efforts, which could harm our business, results of operations, financial condition and prospects.

Risks related to our financial position and need for additional capital

We are a biopharmaceutical company with a limited operating history on which investors can base an investment decision. Biopharmaceutical drug development is a highly speculative undertaking and involves a substantial degree of risk. We commenced operations in January 2012. Our operations to date have been limited primarily to organizing and staffing our company, business planning, raising capital, developing our technology, identifying potential drug candidates, undertaking pre-clinical studies and clinical trials, and preparing for commercialization of our lead product candidates. We have never generated any revenue from drug sales. We have not obtained regulatory approvals for any of our drug candidates.

S-11

TABLE OF CONTENTS

We have not yet demonstrated our ability to successfully obtain regulatory approvals, manufacture a commercial scale drug or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful commercialization. Typically, it takes many years to develop one new drug from the time it is discovered to when it is available for treating patients. Consequently, any predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history. We are transitioning 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.

Since inception, we have focused our efforts and financial resources on clinical trials, manufacturing of our drug candidates, and preparing to support a commercial product. To date, we have financed our operations primarily through public offerings of our common stock and a debt financing. Through December 9, 2020, we have received an aggregate of approximately $976 million from such transactions. Approximately $946 million of that amount constitutes the aggregate gross proceeds from the sale of common stock in one or more offerings and through the use of our at the market sales program, or ATM. The remaining $30.0 million is from our term loan facility with Hercules that we secured in February 2019.

Since inception, we have incurred significant operating losses. As of September 30, 2020, we had an accumulated deficit of $892.4 million. Substantially all of our operating losses have resulted from costs incurred in connection with our research and development programs and from general and administrative costs associated with our operations. We expect to continue to incur significant expenses and operating losses for the foreseeable future. Our prior losses, combined with expected future losses, have had and will continue to have an adverse effect on our stockholders’ deficit and working capital. We expect to continue to incur significant research and development expenses in connection with continuing our existing clinical trials and beginning additional clinical trials. In addition, if we obtain regulatory approval for our drug candidates, we will incur significant sales, marketing and outsourced-manufacturing expenses. As a result, we expect to continue to incur significant and increasing operating losses for the foreseeable future. Because of the numerous risks and uncertainties associated with developing pharmaceuticals, we are unable to predict the extent of any future losses or when we will become profitable, if at all. Even if we do become profitable, we may not be able to sustain or increase our profitability on a quarterly or annual basis. Our ability to become profitable depends upon our ability to generate revenue.

To date, we have not generated any significant revenue from our drug candidates, and it is uncertain when and if we will generate any revenue from the sale of our drugs in the future. Our ability to become profitable depends upon our ability to generate significant and sustained revenues. To obtain significant and sustained revenues, we must succeed, either alone or with others, in developing, obtaining regulatory approval for and manufacturing and marketing our product candidates. Accordingly, we do not expect to generate significant and sustained revenue unless and until we obtain marketing approval of, and begin to sell umbralisib, ublituximab and/or one of our other product candidates. Our ability to generate revenue depends on a number of factors, including, but not limited to, our ability to:

•

Successfully complete clinical trials that meet their clinical endpoints;

•

Initiate and successfully complete all safety, pharmacokinetic, biodistribution, and non-clinical studies required to obtain U.S. and foreign marketing approval for our drug candidates;

•

Obtain approval from the FDA and foreign equivalents to market and sell our drug candidates;

•

Establish commercial manufacturing capabilities alone and/or with third parties that are satisfactory to the regulatory authorities, cost effective, and that are capable of providing commercial supply of our drug candidates;

•

Establish a commercial infrastructure to commercialize our drug candidates, if approved, by developing a sales force and/or entering into collaborations with third parties; and

•

Achieve market acceptance of our drug candidates in the medical community and with third-party payors.

If we are unable to generate significant and sustained revenues, we will not become profitable and we will be unable to continue our operations without continued funding.

S-12

TABLE OF CONTENTS

The development of pharmaceuticals is capital-intensive. We are currently advancing our most advanced drug candidates, umbralisib, ublituximab, cosibelimab, TG-1701 and TG-1801 through clinical development. While we may experience short-term decreases in clinical trial expenses as our larger Phase 3 clinical trials complete and before our Phase 1 and 2 programs can advance into Phase 2 and 3, we do expect over time our overall expenses will increase in connection with our ongoing activities, particularly as we continue the research and development of, initiate or continue clinical trials of, seek marketing approval for, and develop an infrastructure to commercialize our drug candidates. In addition, depending on the status of regulatory approval or, if we obtain marketing approval for any of our drug candidates, we expect to incur significant commercialization expenses related to drug sales, marketing, manufacturing and distribution. Moreover, in anticipation of submitting applications for regulatory approvals for umbralisib and ublituximab in chronic lymphocytic leukemia (CLL) and for ublituximab in relapsing multiple sclerosis (MS), we will need to expend substantial resources on manufacturing and biologics license application (BLA) preparation over the next 12 to 18 months, which could exceed any cost savings associated with lower clinical trial expenses during the same period.

While this timing is our current estimate, the amount and timing of our future funding requirements will depend on many factors, including, but not limited to, the following:

•

the progress of our clinical trials, including expenses to support the trials and milestone payments that may become payable under our license agreements;

•

developments relating to the COVID-19 pandemic in the U.S. and around the world;

•

the costs and timing of regulatory approvals;

•

the costs and timing of clinical and commercial manufacturing supply arrangements for each product candidate;

•

the costs of establishing sales or distribution capabilities;

•

the success of the commercialization of our products;

•

our ability to establish and maintain strategic collaborations, including licensing and other arrangements;

•

the costs involved in enforcing or defending patent claims or other intellectual property rights; and

•

the extent to which we in-license or invest in other indications or product candidates.

As a result, significant additional funding will be required. Additional sources of financing to continue our operations in the future might not be available on favorable terms, if at all. If we do not succeed in raising additional funds on acceptable terms, we might be unable to complete planned preclinical studies and clinical trials or obtain approval of any of our product candidates from the FDA or any foreign regulatory authorities. In addition, we could be forced to discontinue product development, reduce or forego sales, marketing and medical educational efforts that are required for a successful launch of umbralisib and/or ublituximab or any of our product candidates and otherwise forego attractive business opportunities. Any additional sources of financing will likely involve the issuance of our equity securities, which would have a dilutive effect to stockholders. Currently, none of our product candidates have been approved by the FDA or any foreign regulatory authority for sale. Therefore, for the foreseeable future, we will have to fund all of our operations and capital expenditures from cash on hand and amounts raised in future offerings or financings. Accordingly, our prospects must be considered in light of the uncertainties, risks, expenses and difficulties frequently encountered by companies in the early stages of operations and the competitive environment in which we operate.

Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to relinquish rights to our technologies or drug candidates and occupy valuable management time and resources.

Until such time, if ever, as we can generate substantial drug revenues, we expect to finance our cash needs through a combination of public and private equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. We do not have any committed external source of funds, other than funds already

S-13

TABLE OF CONTENTS

borrowed under the loan and security agreement that we entered into with Hercules in February 2019 (See Note 7 to our consolidated financial statements for more information). To the extent that we raise additional capital through the sale of common stock or securities convertible or exchangeable into common stock, the ownership interest of our stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that materially adversely affect the rights of our common stockholders. We may also seek funds through collaborations, strategic alliances or licensing arrangements with third parties at a time that is not desirable to us and we may be required to relinquish valuable rights to some intellectual property, future revenue streams, research programs or drug candidates or to grant licenses on terms that may not be favorable to us, any of which may have a material adverse effect on our business, operating results and prospects. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. See our risk factors below under the heading “Risks Related to Our Indebtedness”.

Additionally, fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our ability to develop and commercialize our drug candidates. Dislocations in the financial markets have generally made equity and debt financing more difficult to obtain and may have a material adverse effect on our ability to meet our fundraising needs. We cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all. Moreover, the issuance of additional securities, whether equity or debt, by us, or the possibility of such issuance, may cause the market price of our shares to decline.

All product candidate development timelines and projections in this prospectus are based on the assumption of further financing.

The timelines and projections in this prospectus supplement are predicated upon the assumption that we will raise additional financing in the future to continue the development of our product candidates. In the event we do not successfully raise subsequent financing, our product development activities will necessarily be curtailed commensurate with the magnitude of the shortfall. If our product development activities are slowed or stopped, we would be unable to meet the timelines and projections outlined in this filing. Failure to progress our product candidates as anticipated will have a negative effect on our business, future prospects, and ability to obtain further financing on acceptable terms, if at all, and the value of the enterprise.

Due to limited resources we may fail to capitalize on programs or product candidates that may present a greater commercial opportunity or for which there is a greater likelihood of success.

Because we have limited resources, we may forego or delay pursuit of opportunities with certain programs or product candidates or for indications that later prove to have greater commercial potential. Our estimates regarding the potential market for a product candidate could be inaccurate, and our spending on current and future research and development programs may not yield any commercially viable products. If we do not accurately evaluate the commercial potential for a particular product candidate, we may relinquish valuable rights to that product candidate through strategic collaboration, licensing or other arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate. Alternatively, we may allocate internal resources to a product candidate in a therapeutic area in which it would have been more advantageous to enter into a partnering arrangement.

If any of these events occur, we may be forced to abandon or delay our development efforts with respect to a particular product candidate or fail to develop a potentially successful product candidate, which could have a material adverse effect on our business, financial condition, results of operations and prospects.

Risks related to our indebtedness

Our level of indebtedness and debt service obligations could adversely affect our financial condition, and may make it more difficult for us to fund our operations.

In February 2019, we entered into a Loan and Security Agreement (the “Loan Agreement”), with Hercules Capital, Inc., a Maryland corporation (“Hercules”) (See Note 7 to our consolidated financial statements for more

S-14

TABLE OF CONTENTS

information). Under the Loan Agreement, Hercules will provide access to term loans with an aggregate principal amount of up to $60.0 million (the “Term Loan”). Concurrently with the closing of the Loan Agreement, we borrowed an initial tranche of $30.0 million. In addition, we have incurred short-term liabilities of approximately $19.4 million with a contract manufacturing organization (CMO) for the scale-up, tech-transfer, and long-term supply of one of our drug candidates. This is an expensive and lengthy process and we expect to incur additional obligations associated with these ongoing manufacturing activities over the course of the next 24 months, and potentially longer. To date, this CMO has provided payment terms which we believe are reasonable; however, no assurance can be given that such terms will continue to be available to us in the future. No assurances can be made that the obligations associated with the Loan Agreement and the CMO will not have a material adverse impact on our financial condition.

All obligations under the Loan Agreement are secured by substantially all of our existing property and assets, excluding intellectual property. This indebtedness may create additional financing risk for us, particularly if our business or prevailing financial market conditions are not conducive to paying off or refinancing its outstanding debt obligations at maturity. This indebtedness could also have important negative consequences, including:

•

we will need to repay the indebtedness by making payments of interest and principal, which will reduce the amount of money available to finance our operations, our research and development efforts and other general corporate activities; and

•

our failure to comply with the restrictive covenants in the Loan Agreement could result in an event of default that, if not cured or waived, would accelerate our obligation to repay this indebtedness, and Hercules could seek to enforce its security interest in the assets securing such indebtedness.

To the extent additional debt is added to our current debt levels, the risks described above could increase.

We may not have cash available in an amount sufficient to enable us to make interest or principal payments on our indebtedness when due.

Failure to satisfy our current and future debt obligations under the Loan Agreement, or the breach of any of its covenants, subject to specified cure periods with respect to certain breaches, could result in an event of default and, as a result, Hercules could accelerate all of the amounts due. In the event of an acceleration of amounts due under the Loan Agreement as a result of an event of default, we may not have enough available cash or be able to raise additional funds through equity or debt financings to repay such indebtedness at the time of such acceleration. In that case, we may be required to delay, limit, reduce or terminate our product candidate development or commercialization efforts or grant to others rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves. Hercules could also exercise its rights as collateral agent to take possession and dispose of the collateral securing the Term Loan for its benefit, which collateral includes substantially all of our property other than intellectual property. Our business, financial condition and results of operations could be materially adversely affected as a result of any of these events.

The Loan Agreement imposes operating and other restrictions on the Company. Such restrictions will affect, and in many respects limit or prohibit, our ability and the ability of any future subsidiary to, among other things:

•

dispose of certain assets;

•

change its lines of business;

•

engage in mergers, acquisitions or consolidations;

•

incur additional indebtedness;

•

create liens on assets;

•

pay dividends and make contributions or repurchase our capital stock; and

•

engage in certain transactions with affiliates.

The breach of any of these restrictive covenants could have a material adverse effect on our business and prospects.

S-15

TABLE OF CONTENTS

Risks related to drug development and regulatory approval

We are a development-stage biopharmaceutical company and do not currently have any commercial products that generate revenues or any other sources of revenue. Our pharmaceutical development methods are unproven and may not lead to commercially viable products for a variety of reasons. We have substantially invested all of our efforts and financial resources in the identification and pre-clinical and clinical development of our drug candidates, including ublituximab, umbralisib, cosibelimab, TG-1701 and TG-1801 and building a commercial infrastructure. Our ability to generate drug revenues will depend completely on the successful completion of our current and future Phase 3 and registration-directed clinical trials and commercialization of our drug candidates, which may never occur. Each of our drug candidates will require additional non-clinical or clinical development, regulatory approval in multiple jurisdictions, obtaining manufacturing supply, building of a commercial organization, and substantial investment in marketing efforts before we generate any revenues from drug sales. The success of our most advanced drug candidates and other drug candidates will depend on several factors, including the following:

•

Successful completion of our clinical programs with positive results that support a finding of effectiveness and an acceptable safety profile of our product candidates in the intended populations within the timeframes we have projected;

•

INDs or clinical trial applications, or CTAs, being cleared such that our product candidates can commence clinical trials;

•

Successful initiation and completion of preclinical studies and successful initiation of, enrollment in and completion of clinical trials;

•

Successful preparation of the complete data set from the UNITY-CLL trial for regulatory submission within the timeframe we have projected;

•

Sufficiency of our financial and other resources to complete the necessary preclinical studies and clinical trials;

•

Receipt of regulatory approvals from applicable regulatory authorities for our drug candidates (for example, our NDA submission for our lead product candidate umbralisib which is currently under review with the FDA);

•

Establishing commercially viable arrangements with third-party manufacturers for clinical supply and commercial manufacturing;

•

Obtaining and maintaining patent and trade secret protection or regulatory exclusivity for our drug candidates;

•

Establishing sales and marketing capabilities, whether alone or through a collaboration, to support commercialization of our drug candidates;

•

Acceptance of the drug candidates, if and when approved, by patients, the medical community and third-party payors;

•

Effectively differentiating and competing with other therapies;

•

Establishing appropriate prices for any drug candidates that receive regulatory approval that reflect the value that the drug candidates offer in the indications for which they are approved and adhering to ongoing government program price reporting requirements;

•

Obtaining and maintaining healthcare coverage and adequate reimbursement;

•

Establishing and maintaining an effective healthcare compliance program for a commercial-stage pharmaceutical company to support compliance and mitigate enforcement risk in areas including sales and marketing and advertising and promotion;

S-16

TABLE OF CONTENTS

•

Enforcing and defending intellectual property rights and claims; and

•

Maintaining an acceptable safety profile of the drug candidates following approval.

If we do not achieve one or more of these factors in a timely manner or at all, we could experience significant delays or an inability to successfully commercialize our drug candidates, which would materially harm our business.

If we are unable to develop or receive regulatory approval for or successfully commercialize any of our product candidates, we will not be able to generate product revenues and we may not be able to continue our operations. Even if we are able to develop or receive regulatory approval for or successfully commercialize any of our product candidates, we may not be able to gain market acceptance for our product candidates if healthcare providers and patients do not view the overall safety, tolerability and efficacy profile of our drug candidates favorably.

Because the results of preclinical studies and early clinical trials are not necessarily predictive of future results, any product candidate we advance into clinical trials may not have favorable results in later clinical trials, if any, or receive regulatory approval. Moreover, 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.

Pharmaceutical development has inherent risks. The outcome of preclinical development testing and early clinical trials may not be predictive of the outcome of later clinical trials, and interim results of a clinical trial do not necessarily predict final results. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their drug candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their drug candidates. Once a drug candidate has displayed sufficient preclinical data to warrant clinical investigation, we will be required to demonstrate through adequate and well- controlled clinical trials that our product candidates are effective with a favorable benefit-risk profile for use in populations for their target indications before we can seek regulatory approvals for their commercial sale. Many drug candidates fail in the early stages of clinical development for safety and tolerability issues or for insufficient clinical activity, despite promising pre-clinical results. Accordingly, no assurance can be made that a safe and efficacious dose can be found for these compounds or that they will ever enter into advanced clinical trials alone or in combination with other product candidates. Moreover, success in early clinical trials does not mean that later clinical trials will be successful because product candidates in later-stage clinical trials may fail to demonstrate sufficient safety or efficacy despite having progressed through initial clinical testing. Companies frequently experience significant setbacks in advanced clinical trials, even after earlier clinical trials have shown promising results. There is an extremely high rate of failure of pharmaceutical candidates proceeding through clinical trials.

Individually reported outcomes of patients treated in clinical trials may not be representative of the entire population of treated patients in such studies. For instance, early clinical results seen with ublituximab (TG-1101) in a small number of patients may not be reproduced in expanded or larger clinical trials such as the ULTIMATE I and II trials. Larger scale Phase 3 studies, which are often conducted internationally, are inherently subject to increased operational risks compared to earlier stage studies, including the risk that the results could vary on a region to region, or country to country basis which could materially adversely affect the outcome of the study or the opinion of the validity of the study results by applicable regulatory agencies.

From time to time, we may publicly disclose top-line or preliminary data from our 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. We also make assumptions, estimations, calculations and conclusions as part of our analyses of such data, and we may not have received or had the opportunity to fully and carefully evaluate all data from the particular study or trial. As a result, 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 or preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the topline, interim, or preliminary data we previously published.

S-17

TABLE OF CONTENTS

As a result, top-line and preliminary data should be viewed with caution until the final data are available. Further, 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. For example, time-to-event based endpoints such as duration of response (DOR) and PFS have the potential to change, sometimes drastically, with longer follow-up. In addition, as patients continue on therapy, there can be no assurance given that the final safety data from studies, once fully analyzed, will be consistent with prior safety data presented, will be differentiated from other similar agents in the same class, will support continued development, or will be favorable enough to support regulatory approvals for the indications studied. 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. The information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and regulators or others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure. If the interim, top-line or preliminary data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and commercialize, our product candidates may be harmed, which could harm our business, operating results, prospects or financial condition.

Many of the results reported in our early clinical trials rely on local investigator-assessed efficacy outcomes which may be subject to greater variability or subjectivity than results assessed in a blinded, independent, centrally reviewed manner, often required of later phase, adequate and well-controlled registration-directed clinical trials. If the results from our registration-directed trials are different from the results found in the earlier studies, we may need to terminate or revise our clinical development plan, which could extend the time for conducting our development program and could have a material adverse effect on our business.

Before obtaining marketing approval from regulatory authorities for the sale of any drug candidate, we must complete pre-clinical studies and then conduct extensive clinical trials to demonstrate the safety and efficacy of our drug candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and is uncertain as to outcome. It is impossible to predict when or if our drug candidates will prove effective and safe in humans or will receive regulatory approval or will have a differentiated safety and tolerability profile. A failure of one or more clinical trials can occur at any stage of testing. Accordingly, our ongoing trials and future clinical trials may not be successful. Even if our clinical trials produce positive results, there can be no guarantee that the positive outcomes will be replicated in future studies either within the same indication as previously evaluated or in alternate indications and settings.

Successful completion of our clinical trials is a prerequisite to submitting a New Drug Application (NDA) or a Biologics License Application (BLA) to the U.S. FDA and a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) for each drug candidate and, consequently, the ultimate approval and commercial marketing of our drug candidates. We do not know whether any of our ongoing or future clinical trials for our drug candidates will be completed on schedule, if at all.

Whether or not and how quickly we complete clinical trials depends in part upon the rate at which we are able to engage clinical research/trial sites and, thereafter, the rate of enrollment of patients, and the rate at which we collect, clean, lock and analyze the clinical trial database. Patient enrollment is a function of many factors, including the size of the patient population, the proximity of patients to clinical sites, the eligibility criteria for the study, the existence of competitive clinical trials, and whether existing or new drugs are approved for the indication we are studying. We are aware that other companies are currently conducting or planning clinical trials that seek to enroll patients with the same diseases that we are studying. We may experience numerous unforeseen events,

S-18

TABLE OF CONTENTS

such as the COVID-19 pandemic, that could delay or prevent our ability to complete current clinical trials, initiate new trials, receive marketing approval or commercialize our drug candidates, including:

•

the FDA or other regulatory authorities may require us to submit additional data or impose other requirements before permitting us to initiate a clinical trial;

•

the FDA, other regulatory authorities or institutional review boards (IRBs) or ethics committees (ECs) may not authorize us or our investigators to commence a clinical trial or conduct a clinical trial at a prospective trial site or country; we may experience delays in reaching, or fail to reach, agreement on acceptable terms with prospective trial sites and prospective CROs, the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;

•

clinical trials of our drug candidates may produce negative or inconclusive results, and we may decide, or regulatory authorities may require us, to conduct additional pre-clinical studies or clinical trials or we may decide to abandon drug development programs;

•

the number of patients required for clinical trials of our drug candidates may be larger than we anticipate, and enrollment in these clinical trials may be slower than we anticipate or participants may drop out of these clinical trials or fail to return for post-treatment follow-up at a higher rate than we anticipate;

•

our third-party contractors, including our clinical trial sites, may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all, or may deviate from the clinical trial protocol or drop out of the trial, which may require that we add new clinical trial sites or investigators;

•

we may elect to, or regulatory authorities or IRBs or ECs may require that we or our investigators suspend or terminate clinical research for various reasons, including noncompliance with regulatory requirements or a finding that the participants are being exposed to unacceptable health risks;

•

the cost of clinical trials of our drug candidates may be greater than we anticipate;

•

the supply or quality of our drug candidates or other materials necessary to conduct clinical trials of our drug candidates may be insufficient or inadequate, including, without limitation, as a result of disruptions to our supply chains caused by the COVID-19 pandemic and related work stoppages across the globe;

•

regulatory authorities may revise the requirements for approving our product candidates, or such requirements may not be as we anticipate; and

•

our drug candidates may have undesirable side effects or other unexpected characteristics, causing us or our investigators, regulatory authorities, IRBs or ECs to suspend or terminate the trials, or reports may arise from pre-clinical or clinical testing of other cancer therapies that raise safety or efficacy concerns about our drug candidates.

We also could encounter delays if a clinical trial is suspended or terminated by us, by the IRBs of the institutions in which such trials are being conducted, by the DSMB for such trial or by the FDA or other regulatory authorities. Such regulatory authorities may impose a suspension or termination 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, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. The DSMB for our clinical trials may recommend modification to the study design or closure of the study entirely based on the DSMB’s interpretation of the benefit/risk of the study. While we develop charters that guide the nature of the DSMB meetings, their analysis and interpretation of study data occurs independently from us and is wholly within their control. Even if the DSMB finds no safety concerns and recommends no modifications to the ongoing study, this does not mean the safety profile reported in the study may support a marketing approval or commercial acceptance if marketing approval is granted. 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 drug candidates.

S-19

TABLE OF CONTENTS

Further, the FDA may disagree with our clinical trial design, may have questions about the potential impact of our study design on conclusions that can be drawn from the data, may interpret results differently than we do, and may change its view on the criteria that must be met for approval over time. This could happen even for a protocol that has received a SPA, as is the case for some of our studies. In September 2015, we announced a Phase 3 clinical trial for the combination of ublituximab plus umbralisib for patients with CLL, which is being conducted pursuant to a SPA with the FDA (UNITY-CLL) and in August 2017 we announced SPAs for the ULTIMATE I and II studies evaluating ublituximab in RMS. Many companies that have been granted SPAs have ultimately failed to obtain final approval to market their drugs. Since we are seeking approvals under SPAs for some of our product registration strategies, based on protocol designs negotiated with the FDA, we may be subject to enhanced scrutiny. Further, while changes or amendments to protocols are common during conduct of a clinical trial, protocol changes or amendments to a study that is being conducted under a SPA will have to be reviewed and approved by the FDA to verify that the SPA agreement is still valid. The FDA’s willingness to agree to changes or amendments to a protocol or statistical analysis plan under a SPA agreement is wholly within the FDA’s discretion. Such reviews also provide an opportunity for the FDA to scrutinize any aspect of the study design and conduct, even if previously agreed to under the existing SPA. Failure to reach agreement with the FDA for protocol changes or modifications for any study we conduct under a SPA could have a material negative impact to our ability to execute these studies. Even if the primary endpoint in a Phase 3 clinical trial is achieved, a SPA does not guarantee approval.

Some of our clinical trials may be conducted as open-label studies; meaning that trial participants, investigators, site staff, some employees of our contract research organizations, and our field-level employees (e.g., clinical research associates and monitors), among others, have knowledge of treatment arm assignments on a patient-level, which has the potential to introduce bias into study conduct. Further, even when our clinical trials are double-blind, double-dummy studies, unblinding of treatment arm assignment may occur from time to time, for example, on the occurrence of unexpected safety events which may necessitate understanding of study treatment. While we believe we have put in place adequate firewalls to prevent inappropriate unblinding of study data consistent with standard industry practice for these types of studies, no assurance can be given that issues related to study conduct will not be raised. The FDA may raise issues of safety, study conduct, bias, deviation from the protocol, statistical power, patient completion rates, changes in scientific or medical parameters or internal inconsistencies in the study design or data prior to making its final decision. The FDA may also seek the guidance of an outside advisory committee in evaluating (among other things) clinical data and safety and effectiveness considerations prior to making its final decision.

Negative or inconclusive results from the clinical trials we conduct or unanticipated adverse medical events could cause us to have to repeat or terminate the clinical trials. If we are required to repeat or conduct additional clinical trials or other testing of our drug candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials of our drug candidates or other testing, if the results of these trials or tests are not positive or are only modestly positive or if there are safety concerns, we may:

•

be delayed in obtaining marketing approval for our drug candidates;

•

not obtain marketing approval at all;

•

obtain marketing approval in some countries and not others;

•

obtain approval for indications or patient populations that are not as broad as intended or desired;

•

be subject to post-marketing requirements or post-marketing commitments;

•

be subject to increased pricing pressure; or

•

have the drug removed from the market after obtaining marketing approval.

Our drug development costs will also increase if we experience delays in testing or regulatory approvals. Certain clinical trials are designed to continue until a pre-determined number of events have occurred in the patients enrolled. Trials such as this are subject to delays stemming from patient withdrawal and from lower than expected event rates. Significant clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our drug candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize our drug candidates. Any delays in our pre-clinical or

S-20

TABLE OF CONTENTS

future clinical development programs may harm our business, financial condition and prospects significantly. We may also incur additional costs if enrollment is increased. All of our current Phase 3 and registration-directed clinical trials, such as UNITY-CLL, UNITY-NHL and ULTIMATE I and II enrolled a larger number of patients than our initial projections, adding significant costs to those studies over and above what had been projected.

In addition, principal investigators for our clinical trials may serve as scientific advisors or consultants to us from time to time and receive compensation in connection with such services. If these relationships and any related compensation result in perceived or actual conflicts of interest, the integrity of the data generated at the applicable clinical trial site, or the FDA’s willingness to accept such data, may be jeopardized.

We have and will continue to explore strategies that involve use of the FDA’s accelerated approval pathway. Obtaining accelerated approval for an agent requires demonstration of meaningful benefit over all available therapies for a serious condition and relies on the use of a surrogate endpoint. While we believe we have an understanding of what is considered available therapy today, ultimately the determination of what constitutes available therapy is wholly up to the FDA and is subject to change. No assurance can be given that other agents will not receive full approval prior to our potential receipt of accelerated approval. If that were to occur, no assurance can be given that we would be successful in proving meaningful benefit over those later approved drugs. If we were unable to prove meaningful benefit over any such agents, we would be effectively blocked from receiving accelerated approval. We have submitted an NDA for accelerated approval of umbralisib based on the results from the MZL and FL cohorts from our UNITY-NHL trial. In August 2020, we announced that the FDA accepted the NDA, granting priority review to the MZL indication with a PDUFA target date of February 15, 2021 and standard review to the FL indication with a PDUFA target date of June 15, 2021. No assurance can be given that umbralisib will obtain accelerated approval for either MZL or FL for a variety of reasons, including, without limitation, if we are unable to demonstrate meaningful benefit over a currently approved agent/regimen or any new treatment, if any, that receives full approval prior to our potential receipt of accelerated approval. Previously, we were hopeful to utilize the results from our GENUINE study for accelerated approval but the intervening full approval of a new therapy for the treatment of relapsed/refractory CLL has made that potential application more challenging. In October 2019, we announced that final results from the GENUINE study demonstrated improved progression-free survival for the combination arm compared to ibrutinib alone. Despite this positive outcome, no assurance can be given that a filing based on the GENUINE results will ever be made, or if made would result in a favorable review by regulatory authorities.

Finally, if umbralisib or any of our other drug candidates were ever to receive accelerated approval, we would be required to conduct a post-marketing confirmatory study, which we may not be able to complete, or if completed, may prove unsuccessful. In such instances, the FDA can remove the product from the market or withdraw approval of the indication that received accelerated approval if the product is approved for multiple indications.

Unacceptable or undesirable adverse events caused by any of our product candidates that we take into clinical trials could cause either us, a DSMB, or regulatory authorities to interrupt, delay, modify 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. This, in turn, could prevent us from commercializing the affected product candidate and generating revenues from its sale.

As is the case with all drugs, it is likely that there will be side effects associated with the use of our drug candidates. Results of our trials could reveal a higher than expected and unacceptable severity and prevalence of side effects. In such an event, our trials could be suspended or terminated and the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny approval of our drug candidates for any or all targeted indications. The drug-related side effects could also affect patient recruitment or the ability

S-21

TABLE OF CONTENTS

of enrolled patients to complete the trial or result in potential product liability claims. Any of these occurrences may harm our business, financial condition and prospects significantly.

Many compounds that initially showed promise in early stage testing have later been found to cause side effects that prevented further development of the compound. Further, early clinical trials by their nature utilize a small sample of the potential patient population. With a limited number of patients and limited duration of exposure, rare and severe side effects of our drug candidates may only be uncovered when a significantly larger number of patients are exposed to the drug candidate in Phase 3 or registration-directed trials or when the drug candidate is on the market.

To date, clinical trials using ublituximab and umbralisib have demonstrated a toxicity profile that was deemed acceptable by the investigators performing such studies. Such interpretation may not be shared by future investigators or by the regulatory authorities and in the case of ublituximab and umbralisib, even if deemed acceptable for oncology and/or autoimmune indications, it may not be acceptable for diseases outside the oncology and autoimmune settings, and likewise for any other product candidates we may develop. Additionally, the severity, duration and incidence of adverse events may increase in larger study populations such as the populations found in our on-going Phase 3 and registration-directed trials. Particularly, with respect to umbralisib, although over 1,500 patients have been dosed in umbralisib studies to date, the full adverse effect profile of umbralisib is not known. As additional patients are exposed for longer durations to umbralisib, it is unknown whether greater frequency and/or severity of adverse events are likely to occur. Common toxicities of other drugs in the same class as umbralisib include high levels of liver toxicity, infections and colitis, the latter of which notably has presented with later onset, with incidence increasing with duration of exposure. No assurance can be given that an acceptable safety and tolerability profile for umbralisib will continue to be demonstrated in the future with longer durations of exposure, at the fixed 800mg dose being evaluated in our registration-directed trials and in multiple drug combinations. If any of our product candidates cause unacceptable adverse events in clinical trials, we may not be able to obtain marketing approval and generate revenues from its sale, or even if approved for sale may lack differentiation from competitive products, which could have a material adverse impact on our business and operations.

Additionally, in drug-combination clinical development, there is an inherent risk of drug-drug interactions between combination agents that may affect each component’s individual pharmacologic properties and the overall efficacy and safety of the combination regimen. Both ublituximab and umbralisib are being evaluated in combination with each other, as well as with a variety of other active anti-cancer agents, which may cause unforeseen toxicity, or impact the severity, duration, and incidence of adverse events observed compared to those seen in the single agent studies of these agents. We also intend to explore multiple combination studies involving cosibelimab, TG-1701, and TG-1801. Further, with multi-drug combinations, it is often difficult to interpret or properly assign attribution of an adverse event to any one particular agent, introducing the risk that toxicity caused by a component of a combination regimen could have a material adverse impact on the development of our product candidates. There can be no assurances given that the combination regimens being studied will display tolerability or efficacy suitable to warrant further testing or produce data that is sufficient to obtain marketing approval.

If any of our drug candidates receive marketing approval and we or others later identify undesirable or unacceptable side effects caused by such drug candidates (or any other similar drugs) after such approval, a number of potentially significant negative consequences could result, including:

•

regulatory authorities may withdraw or limit the use (indication) of such drug candidates;

•

regulatory authorities may require the addition of labeling statements, including warnings or boxed warnings, precautions, or contraindications that could diminish the usage of the product or otherwise limit the commercial success of the affected product;

•

we may be required to create a Medication Guide outlining the risks of such side effects for distribution to patients;

S-22

TABLE OF CONTENTS

•

we may be required to change the way such drug candidates are distributed or administered, or to conduct additional clinical trials;

•

regulatory authorities may require a Risk Evaluation and Mitigation Strategy (REMS), a plan to mitigate risks, which could include a Medication Guide, physician communication plans, or elements to assure safe use, such as restricted distribution methods, patient registries and other risk minimization tools;

•

we may be subject to regulatory investigations and government enforcement actions;

•

we may decide to remove such drug candidates from the marketplace;

•

we may not be able to enter into collaboration agreements on acceptable terms and execute on our business model;

•

we could be sued and held liable for injury caused to individuals exposed to or taking our drug candidates; and

•

our reputation may suffer.

Any one or a combination of these events could prevent us from obtaining or maintaining regulatory approval and achieving or maintaining market acceptance of the affected product or could substantially increase the costs and expenses of commercializing the affected product, which in turn could significantly impact our ability to successfully commercialize our drug candidates and generate revenues.

The clinical development, manufacturing, labeling, packaging, storage, record-keeping, advertising, promotion, import, export, marketing and distribution, and pharmacovigilance and adverse event reporting of our product candidates or any future product candidates are subject to extensive regulation by the FDA in the United States and by comparable regulatory authorities worldwide. In the United States, we are not permitted to market a product candidate until we receive approval of a BLA or NDA from the FDA. The process of obtaining a BLA or NDA approval is expensive, often takes many years and can vary substantially based upon the type, complexity and novelty of the products involved. Approval policies or regulations may change, and the FDA has substantial discretion in the pharmaceutical product approval process, including the ability to delay, limit or deny approval of a product candidate for many reasons. In addition, the FDA may require post-marketing clinical trials which also may be costly. The FDA approval for a limited indication with required warning language, such as a boxed warning, could significantly impact our ability to successfully market our product candidates. Finally, the FDA may require adoption of a REMS requiring prescriber training or a post-marketing registry or may restrict the marketing and dissemination of these products. Despite the time and expense invested in the clinical development of product candidates, regulatory approval is never guaranteed. Assuming successful clinical development, we intend to seek product approvals in countries outside of the United States. As a result, we would be subject to regulation by the EMA, as well as the other regulatory agencies in these countries.

Approval procedures vary among countries and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries might differ from that required to obtain FDA approval. Interruptions or delays in the operations of the FDA and foreign regulatory authorities as a result of the COVID-19 pandemic may negatively impact review, inspection, and approval timelines. Regulatory approval in one country does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country may negatively impact the regulatory process in others. As in the United States, the regulatory approval process in Europe and in other countries is lengthy and challenging. The FDA, and any other regulatory body around the world can delay, limit or deny approval of a product candidate for many reasons, including:

•

the FDA or comparable foreign regulatory authorities may disagree with the study design or implementation of our clinical trials;

S-23

TABLE OF CONTENTS

•

we may be unable to demonstrate to the satisfaction of the FDA or comparable foreign regulatory authorities that a product candidate is tolerable and effective for an indication;

•

the FDA may not accept clinical data from trials conducted by individual investigators or in countries where the standard of care is potentially different from that of the United States;

•

the results of clinical trials may not meet the level of statistical significance required by the FDA or comparable foreign regulatory authorities for approval;

•

we may be unable to demonstrate that a product candidate’s clinical and other benefits outweigh its safety risks;

•

the FDA or comparable foreign regulatory authorities may disagree with our interpretation of data from preclinical studies and/or clinical trials;

•

the data collected from clinical trials of our product candidates may not be sufficient to support the submission of a BLA, NDA or other submission or to obtain regulatory approval in the United States or elsewhere;

•

the FDA or comparable foreign regulatory authorities may not approve the manufacturing processes or facilities of third-party manufacturers with which we or our collaborators currently contract for clinical supplies and plan to contract for commercial supplies; or

•

the approval policies or regulations of the FDA or comparable foreign regulatory authorities may significantly change in a manner rendering our clinical data insufficient for approval.

Regulatory approvals for our product candidates may not be obtained without lengthy delays, if at all. Any delay in obtaining, or inability to obtain, applicable regulatory approvals would prevent us from commercializing our product candidates.

A breakthrough therapy designation by the FDA for our drug candidates may not lead to a faster development or regulatory review or approval process, and it does not ensure that our drug candidates will receive marketing approval.

In January 2019, the FDA granted breakthrough therapy designation (also referred to as BTD) to umbralisib for the treatment of adult patients with relapsed or refractory MZL who have received at least one prior treatment including an anti-CD20 monoclonal antibody. We may also seek breakthrough therapy designation for some of our other drug candidates. 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 existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. Our breakthrough therapy designation was based on interim data from the MZL cohort of the UNITY-NHL clinical trial. No assurance can be given that the full results from the MZL cohort of the UNITY-NHL clinical trial will support approval.

For drugs that have been designated as breakthrough therapies, frequent interactions and communication between the FDA and the sponsor can help to identify the most efficient path for clinical development while minimizing the number of patients who may be placed in potentially less effective control regimens. Drugs designated as breakthrough therapies by the FDA are also eligible for priority review. Designation as a breakthrough therapy is wholly within the discretion of the FDA. Accordingly, even if we believe one of our drug candidates meets the criteria for designation as a breakthrough therapy, the FDA may disagree and instead determine not to grant such a designation to the drug candidate. In any event, the receipt of a breakthrough therapy designation for a drug candidate may not result in a faster development process, review or approval compared to drugs 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 drug candidates qualify as breakthrough therapies, the FDA may later decide that the drugs no longer meet the conditions for qualification and rescind the designation.

S-24

TABLE OF CONTENTS

A fast track designation by the FDA may not actually lead to a faster development or regulatory review or approval process.

We may seek fast track designation for some of our drug candidates. For example, in October 2020, the FDA granted fast track designation to the investigation of ublituximab in combination with umbralisib for the treatment of adult patients with CLL. If a drug is intended for the treatment of a serious or life-threatening condition and the drug demonstrates the potential to address unmet medical needs for this condition, the sponsor may apply for fast track designation. The FDA has broad discretion whether or not to grant this designation, so even if we believe a particular drug candidate is eligible for this designation, we cannot be sure that the FDA would decide to grant it. Even if we receive fast track designation for a drug candidate, we may not experience a faster development process, review or approval compared to conventional FDA procedures. The FDA may withdraw fast track designation if it believes that the designation is no longer supported by data from our clinical development program.

We have received orphan drug designation for some of our drug candidates for specified indications, and we may seek additional orphan drug designations for other indications and some of our other drug candidates. However, we may be unsuccessful in obtaining or may be unable to maintain the benefits associated with orphan drug designation, including the potential for market exclusivity.

Ublituximab received orphan drug designation from the FDA for the treatment of MZL (nodal and extranodal) in September 2013, for the treatment of CLL in August 2010, and orphan drug designation by the EMA for the treatment of CLL in November 2009. We also obtained orphan drug designation for umbralisib (as monotherapy) for the treatment of CLL in August 2016, all three types of MZL (nodal, extranodal and splenic) in April 2019, and FL in March 2020. In January 2017, we announced that the FDA granted orphan drug designation covering the combination of ublituximab and umbralisib for the treatment of patients with CLL and DLBCL. As part of our business strategy, we may seek orphan drug designation for our other drug candidates; however, we may be unsuccessful. Regulatory authorities in some jurisdictions, including the United States and the European Union, may designate drugs for relatively small patient populations as orphan drugs. Under the U.S. Orphan Drug Act, the FDA may designate a drug as an orphan drug if it is a drug 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 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 towards clinical trial costs, tax advantages and user-fee waivers.

Generally, if a product with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes FDA or EMA from approving another marketing application for the same drug or biologic for that time period. Even if we obtain orphan drug exclusivity for a drug, that exclusivity may not effectively protect the designated drug from competition because different drugs can be approved for the same condition. Even after an orphan drug is approved, the FDA can subsequently approve another product that meets the definition of a “same drug” under 21 C.F.R. 316.3 for the same condition if the FDA concludes that the later product is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care. In addition, a designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan drug designation. Moreover, orphan drug exclusive marketing rights in the United States may be lost if the FDA exercises its authority to revoke orphan drug designation, which it may do on a variety of grounds, including that the request contained an untrue statement of material fact or omitted material information, or that the drug in fact was not eligible for orphan drug designation. Orphan drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process. While we intend to seek additional orphan drug designation for our other drug candidates, we may never receive such designations. Even if we receive orphan drug designation for any of our drug candidates, there is no guarantee that we will enjoy the benefits of those designations or obtain orphan drug exclusivity.

S-25

TABLE OF CONTENTS

We are conducting clinical trials, and anticipate additional clinical trials, for product candidates at sites outside the United States, and the FDA may not accept data from trials conducted in such locations.

Many of our Phase 3 and registration-directed clinical trials such as UNITY-CLL, UNITY-NHL and ULTIMATE I and II utilize international clinical research sites, including sites in eastern European countries. We work with what we believe are reputable CROs and clinical research sites in conducting our studies internationally. Nevertheless, there can be heightened challenges to monitoring and oversight of global clinical trials and sponsors are subject to the risk that fraud, misconduct, incompetence, unexpected patient variability and other issues affecting the reliability, quality, and outcome of studies. Such problems, if they were to occur, could negatively impact trial results, and depending on the circumstances and scope of concerns could potentially even prevent a trial from being useful or acceptable for regulatory approval. If such events were to occur with respect to any of our trials (and in particular with respect to registration-directed studies), they would have a substantial negative impact on our business.

An approval of one of our product candidates in the United States would not assure approval of that candidate in foreign jurisdictions.

The approval procedures for pharmaceuticals vary among countries and obtaining approval in one jurisdiction does not guarantee approval in another jurisdiction. For example, even if the FDA grants approval of a product candidate, comparable regulatory authorities in foreign jurisdictions may not approve the same product candidate or may require additional evidence for approval. In many countries outside the United States, the product must be approved for reimbursement before it can be marketed. As a general matter, however, the foreign regulatory approval process involves risks similar or identical to the risks associated with the FDA approval discussed above. Therefore, we cannot guarantee that we, or future collaborators, will obtain approvals of our product candidates in any foreign jurisdiction on a timely basis, if at all. Failure to receive approval in certain foreign markets could significantly impact the full market potential of our product candidates. Furthermore, if we obtain regulatory approval for a product candidate in a foreign jurisdiction, we will be subject to the burden of complying with complex regulatory, legal, and other requirements that could be costly and could subject us to additional risks and uncertainties.

We have product candidates still under development and are also preparing for commercial manufacturing activities, and as such clinical and commercial manufacturing site additions, scale-up and process improvements implemented in the production of those product candidates may affect their ultimate activity or function.

Generally, our product candidates are currently manufactured in relatively small batches for use in pre-clinical and clinical studies. Process improvements implemented to date have changed, and process improvements in the future may change, the activity and/or analytical profile of the product candidates, which may affect the safety and efficacy of the products. For instance, the manufacturing process for ublituximab has undergone several process improvements during the clinical trial process which have resulted in analytical differences between the materials. Such process improvements continued during the conduct of Phase 3 and materials from more than one manufacturing process were utilized in the Phase 3 UNITY-CLL trial. While analytical differences exist between those materials, we do not believe the differences will alter the safety or efficacy profile of ublituximab. However, it is possible that additional and/or different adverse events may appear among patients exposed to drug product manufactured under one process compared to the other, or that adverse events may arise with greater frequency, intensity and duration among patients exposed to drug product manufactured under one process compared to the other. Additionally, the efficacy of ublituximab also can be negatively impacted by such process changes. Given the uncertainty of the impact on product specifications, quality and performance, process improvements made during Phase 3 development carry a higher level of risk than those made prior to Phase 3 development. If there are significant differences in product attributes between the two materials, we may need to adjust our statistical analysis plans of the Phase 3 study to confirm that there is no difference in safety or efficacy between product made by each process in order to allow us to utilize data from all enrolled patients, as well as be able to integrate clinical safety and/or efficacy results across studies to support any potential marketing application. There can be no assurance given that such analyses will be successful in demonstrating no clinical differences between these drug products, which could substantially impact the approvability of the combination

S-26

TABLE OF CONTENTS

umbralisib and ublituximab based on the results of the UNITY-CLL study. In such circumstances, that would have a material adverse effect on the Company.

Further, no assurance can be given that the material manufactured from any future optimized processes, if any, for ublituximab or any of our product candidates will perform comparably to the product candidates as manufactured to date which could result in an unexpected safety or efficacy outcome as compared to the data published or presented to date. Similarly, following each round of process improvements, if any, for any of our drug candidates, future clinical trial results conducted with the new material will be subject to uncertainty related to the effects, if any, of those additional process improvements that were made.

In addition, we have engaged a secondary manufacturer for ublituximab to meet our current clinical and future commercial needs and anticipate engaging additional manufacturing sources for umbralisib to meet expanded clinical trial and projected commercial needs. If a secondary manufacturer is not successful in replicating the product or experiences delays, or if regulatory authorities impose unforeseen requirements with respect to product comparability from multiple manufacturing sources, we may experience delays in clinical development. No assurance can be given that any additional manufacturers will be successful or that material manufactured by the additional manufacturers will perform comparably to ublituximab or umbralisib as manufactured to date and used in currently available pre-clinical data and or in clinical trials presented publicly or reported in this or any previous filing, or that the relevant regulatory agencies will agree with our interpretation of comparability.

In addition, as we move closer to commercialization, we are scaling-up production to ensure adequate commercial supply. This is an expensive process and there can be no assurance given that such scale-up will be successful in providing pharmaceutical product that is of sufficient quantity, or of a quality that is consistent with our previously established specifications, or that meets the requirements set by regulatory agencies under which we may seek approval of our product candidates. If scale-up were not to succeed our ability to supply our anticipated market at a reasonable cost of goods would be negatively impacted. In such event, that would have a material adverse effect on the Company. Scale up could also require additional process improvement that might be required to accommodate new and larger equipment utilized in the scaled-up process. If that were to occur and we could not demonstrate to the FDA that the materials were analytically substantially similar, we might be required to run additional clinical testing to demonstrate that they are substantially similar. That would entail a significant delay and significant increase in total cost, all of which would have a material adverse effect on the Company.

Risks related to commercialization

The incidence and prevalence for target patient populations of our drug candidates have not been established with precision. If the market opportunities for our drug candidates are smaller than we estimate or if any approval that we obtain is based on a narrower definition of the patient population, our revenue and ability to achieve profitability will be adversely affected, possibly materially.

The precise incidence and/or prevalence of CLL, relapsed/refractory MZL, relapsed/refractory FL and multiple sclerosis (MS) are unknown. Our projections of both the number of people who are affected by disease within our target indications, as well as the subset of these people who have the potential to benefit from treatment with our product candidates, are based on our beliefs and estimates. Our beliefs are typically based on one on one and group interactions with target physicians, and our estimates have been derived from a variety of sources, including the scientific literature, healthcare utilization databases and market research, and may prove to be incorrect. Further, new studies may change the estimated incidence or prevalence of these diseases.

The total addressable market opportunity for umbralisib and ublituximab for the treatment of patients with CLL, MZL, FL and MS will ultimately depend upon, among other things, the final label indication, approval for sale for these indications, acceptance by the medical community, patient access, drug pricing and reimbursement. The number of patients in major markets, including the number of addressable patients in those markets, may turn out to be lower than expected, patients may not be otherwise amenable to treatment with our drugs, new patients may become increasingly difficult to identify or gain access to, or patients and physicians may choose to utilize competitive products, all of which would adversely affect our results of operations and our business.

S-27

TABLE OF CONTENTS

We operate in a highly competitive segment of the biotechnology and biopharmaceutical market. We face competition from numerous sources, including commercial pharmaceutical and biotechnology enterprises, academic institutions, government agencies, and private and public research institutions. Many of our competitors have significantly greater financial, product development, manufacturing and marketing resources. Large pharmaceutical companies have extensive experience in clinical testing and obtaining regulatory approval for drugs. Additionally, many universities and private and public research institutes are active in cancer research, some in direct competition with us. We may also compete with these organizations to recruit scientists and clinical development personnel. 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 reduced or eliminated if our competitors develop and commercialize drugs that are more effective, have fewer or less severe side effects, are more convenient or are priced or contracted differently than any drugs that we or our collaborators may develop. Our competitors also may obtain FDA or other regulatory approval for their drugs more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we or our collaborators are able to enter the market. The key competitive factors affecting the success of all of our drug candidates, if approved, are likely to be their efficacy, safety, convenience, price, the level of generic competition and the availability of reimbursement from government and other third-party payors.

For the cancer indications for which we are developing our products there are a number of established therapies with which we will compete:

•

For the treatment of CLL, if the combination of umbralisib and ublituximab (U2) is approved, we expect U2 to compete with recently approved drugs such as ibrutinib (AbbVie and Janssen), acalabrutinib (AstraZeneca), venetoclax (AbbVie and Roche), obinutuzumab (Roche), idelalisib (Gilead) and duvelisib (Verastem), and established treatments such as rituximab (Roche), and several generically available chemotherapies. Additionally, there are second generation BTK inhibitors similar to ibrutinib in late-stage clinical testing for CLL that could enter the market in the next 12-36 months. These agents can be used as monotherapy or in combination with one or more of the other agents.

•

For the treatment of MZL, if approved, we expect umbralisib to compete with ibrutinib (AbbVie and Janssen), and the combination of rituximab and lenalidomide (Bristol-Myers Squibb), as well as established treatments such as rituximab (Roche) and several generically available chemotherapies.

•

For the treatment of FL, if approved, we expect umbralisib to compete with recently approved drugs such as obinutuzumab (Roche), idelalisib (Gilead), copanlisib (Bayer), duvelisib (Verastem), tazemetostat (Epizyme), and the combination of rituximab and lenalidomide (Bristol-Myers Squibb), and established treatments such as rituximab (Roche), and several generically available chemotherapies. There are also several PI3K delta inhibitors in earlier stages of development for FL.

•

In addition, a number of pharmaceutical companies are developing antibodies and bispecific antibodies targeting CD20, CD19, CD47 and other B-cell associated targets, chimeric antigen receptor T-cell (CAR-T) immunotherapy, and other B-cell ablative therapy which, if approved, would potentially compete with U2 and umbralisib.

For Multiple Sclerosis for which we are developing ublituximab there are a number of established therapies with which we will compete:

•

If ublituximab is approved, we expect ublituximab will primarily compete against other CD20 targeted agents, while the group of CD20 targeted agents will also compete broadly against a number of already approved MS therapies. Currently, there are two anti-CD20 monoclonal antibodies approved, ocrelizumab (Roche) and ofatumumab (Novartis).

S-28

TABLE OF CONTENTS

Cosibelimab, TG-1701 and TG-1801 if approved will also face competition from drugs on the market and under development in the same therapeutic class as each of those drugs.

New developments, including the development of other pharmaceutical technologies and methods of treating disease, occur in the pharmaceutical and life sciences industries at a rapid pace. These developments may render our product candidates obsolete or noncompetitive. Compared to us, many of our potential competitors have substantially greater:

•

research and development resources, including personnel and technology;

•

regulatory experience;

•

pharmaceutical development, clinical trial and pharmaceutical commercialization experience;

•

experience and expertise in exploitation of intellectual property rights; and

•

capital resources.

We will also face competition from these third parties in recruiting and retaining qualified personnel, establishing clinical trial sites, patient registration for clinical trials, and in identifying and in-licensing new product candidates.

Product liability lawsuits against us could cause us to incur substantial liabilities and could limit commercialization of any drug candidates that we may develop.

We face an inherent risk of product liability exposure related to the testing of our drug candidates in human clinical trials and use of our drug candidates through compassionate use programs in the event we establish such programs, and we will face an even greater risk if we commercially sell any drug candidates that we may develop. If we cannot successfully defend ourselves against claims that our drug candidates caused injuries, we could incur substantial liabilities. Regardless of merit or eventual outcome, liability claims may result in:

•

decreased demand for any drug candidates that we may develop;

•

injury to our reputation and significant negative media attention;

•

withdrawal of clinical trial participants;

•

significant costs to defend the related litigation;

•

substantial monetary awards to trial participants or patients;

•

loss of revenue; and

•

the inability to commercialize any drug candidates that we may develop.

Although we maintain product liability insurance coverage, it may not be adequate to cover all liabilities that we may incur. We anticipate that we will need to increase our insurance coverage if we successfully commercialize any drug candidate. Insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a reasonable cost or in an amount adequate to satisfy any liability that may arise.

Even if our product candidates receive regulatory approval, they may not gain market acceptance among physicians, patients, healthcare payors, and the medical community. The degree of market acceptance of any approved product would depend on a number of factors, including:

•

the timing of our receipt of marketing approvals, the terms of such approvals, and the countries in which such approvals are obtained;

•

the efficacy, safety and tolerability as demonstrated in clinical trials;

•

the timing of market introduction of such a product candidate as well as competitive products;

•

the clinical indications for which the product is approved;

•

acceptance by physicians, major operators of cancer or neurology clinics, and patients of the product as a safe, tolerable and effective treatment;

S-29

TABLE OF CONTENTS

•

the potential and perceived advantages of the product candidate over alternative treatments;

•

the safety and tolerability of the product candidate in a broader patient group;

•

the cost of treatment in relation to alternative treatments;

•

the availability of adequate reimbursement by third party payors and government authorities;

•

changes in regulatory requirements by government authorities for the product candidate;

•

relative convenience and ease of administration;

•

the prevalence and severity of side effects and adverse events;

•

the effectiveness of our sales and marketing efforts; and

•

favorable or unfavorable publicity relating to the product or relating to the Company.

Our ability to successfully launch and secure market acceptance of our late-stage pipeline candidates, umbralisib and ublituximab (if approved), may be impacted by the evolving COVID-19 pandemic, although we are currently unable to predict or quantify any such potential impact with any degree of certainty. As a result of the measures state and local governments have taken to date to control the spread of COVID-19, our office-based employees are working remotely and our preparations for commercialization are happening virtually. The progress of these preparations may be impacted by the increased reliance on work-from-home arrangements for our employees, consultants, vendors, and potential customers. If the spread of COVID-19 and the social distancing measures taken by various governments continue, any commercial launch we may undertake may be hindered by various factors, including challenges in hiring the employees necessary to support commercialization; delays in demand due to impacts on the healthcare system and overall economy; delays in coverage decisions from Medicare and third-party payors; restrictions on our personal interactions with physicians, hospitals, payors, and other customers; interruptions or delays in our commercial supply chain; and increases in the number of uninsured or underinsured patients.

If any product candidate is approved but does not achieve an adequate level of acceptance by physicians, hospitals, healthcare payors and patients, we may not generate sufficient revenue from these products and we may not become or remain profitable, which would have a material adverse effect on our business.

Even if we are able to commercialize any drug candidates, such drugs 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 vary widely from country to country. Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing approval is granted. In some foreign markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain marketing approval for a drug candidate in a particular country, but then be subject to price regulations that delay our commercial launch of the drug candidate, possibly for lengthy time periods, and negatively impact the revenues we are able to generate from the sale of the drug candidate in that country. Adverse pricing limitations may hinder our ability to recoup our investment in one or more drug candidates, even if our drug candidates obtain marketing approval. In addition, if we are successful in receiving FDA approval for ublituximab for the treatment of CLL and MS, we will need to identify and execute a pricing strategy that takes into account the value of the product in each indication independently to realize the product’s full potential in both indications. If we are unable to identify and execute such a strategy, the pricing of ublituximab across indications may not be optimal, which may have a material adverse impact on the sales in one or both of the indications and on our overall business.

Our ability to commercialize any drug candidates successfully also will depend in part on the extent to which coverage and reimbursement for these drug candidates and related treatments will be available from government authorities, private health insurers and other organizations. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for

S-30

TABLE OF CONTENTS

and establish reimbursement levels. A primary trend in the U.S. healthcare industry and elsewhere is cost containment. Government authorities and third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular drugs. Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for drugs Third-party commercial payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies. We cannot be sure that coverage will be available for any drug candidate that we commercialize and, if coverage is available, the level of reimbursement. Even if favorable coverage and reimbursement status is attained for one or more product candidates for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future. Reimbursement may impact the demand for, or the price of, any drug candidate for which we obtain marketing approval. If reimbursement is not available or is available only to limited levels, we may not be able to successfully commercialize any drug candidate for which we obtain marketing approval.

There may be significant delays in obtaining reimbursement for newly approved drugs or new indications, and coverage may be more limited than the purposes for which the drug is approved by the FDA or similar regulatory authorities outside the United States. Moreover, eligibility for reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower-cost drugs and may be incorporated into existing payments for other services. Net prices for drugs 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 from countries where they may be sold at lower prices. Our inability to promptly obtain coverage and profitable payment rates from both government-funded and private payors for any approved drugs that we develop could have a material adverse effect on our operating results, our ability to raise capital needed to commercialize drugs and our overall financial condition.

In the United States, we must offer discounted pricing or rebates on purchases of pharmaceutical products under various federal and state healthcare programs, such as the Medicaid Drug Rebate Program, the 340B drug pricing program and the Medicare Part D Program. We must also report specific prices to government agencies under healthcare programs, such as the Medicaid Drug Rebate Program and Medicare Part B. The calculations necessary to determine the prices reported are complex and the failure to report prices accurately may expose us to penalties.

In both the United States and certain foreign countries, there have been a number of legislative and regulatory changes or proposed changes to the healthcare system, many of which have focused on prescription drug pricing and lowering overall healthcare costs, that could impact our ability to sell our products profitably. We expect prescription drug pricing and other healthcare costs to continue to be subject to intense political and social pressures on a global basis.

In the United States, the President, federal and state legislatures, health agencies and third-party payors continue to focus on containing the cost of healthcare and addressing public concern over access and affordability of prescription drugs. The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010 (collectively, the ACA) was enacted in 2010 and made significant changes to the U.S. healthcare system. ACA changes included expanding healthcare coverage through Medicaid expansion and implementation of the individual health insurance mandate; changing coverage and reimbursement of drug products under government healthcare programs; imposing an annual fee on manufacturers of branded drugs; and expanding government enforcement authority.

We face uncertainties because there have been, and may be additional, federal legislative and administrative efforts to repeal, substantially modify or invalidate some or all of the provisions of the ACA. Such efforts may lead

S-31

TABLE OF CONTENTS

to fewer Americans having more comprehensive health insurance compliant with the ACA, even in the absence of a legislative repeal. For example, the 2017 Tax Cuts and Jobs Act (the “Tax Act”) repealed the penalty for individuals who fail to maintain minimum essential health coverage as required by the ACA, commonly referred to as the individual mandate, effective January 1, 2019.

The ACA has also been subject to judicial challenge. The case Texas v. Azar, which challenges the constitutionality of the ACA, including provisions that are unrelated to healthcare reform but were enacted as part of the ACA, and will be argued before the United States Supreme Court in November 2020 with a decision expected before the summer in 2021. The ongoing litigation challenges the ACA’s individual mandate and raises questions about the entire law’s survival. It is unclear how the ultimate decision in the case or other efforts to repeal, replace, or invalidate the ACA or its implementing regulations, or portions thereof, will affect the ACA, our industry more generally, and the availability of adequate reimbursement for our products if commercialized.

Beyond the ACA, there has been increasing legislative, regulatory and enforcement interest with respect to prescription drug pricing practices. In May 2018, the Trump Administration issued the Blueprint to Lower Drug Prices and Reduce Out-of-Pocket Costs (the “Drug Pricing Blueprint”), a plan to lower prescription drug prices. Under this blueprint for action, the Administration outlined a wide range of high-level proposals to address prescription drug list prices and patient out-of-pocket costs. Since that time, the Administration has taken several regulatory steps with respect to prescription drug pricing. In July 2020, President Trump signed four Executive Orders directing the Department of Health and Human Services (“HHS”) to take several steps to lower costs on prescription drugs, including but not limited to (i) tying the prices paid by the U.S. government (e.g., Medicare) for drugs and biological products to prices paid in other countries; (ii) ensuring that rebates that drug makers pay to pharmacy benefit managers and insurers in the Medicare Part D program get passed directly to patients when they purchase a medication, so long as the change is not projected to increase Federal spending, Medicare beneficiary premiums or patients’ total out-of-pocket costs; and (iii) allowing states, wholesalers and pharmacies to import FDA-approved drugs from Canada and other countries and sell them in the U.S. if the FDA deems them safe. The timing of these Executive Orders is uncertain, as the directives contained therein would require agency rulemaking and implementation. These policy proposals, if implemented, could significantly impact the pharmaceutical industry in the U.S. and adversely affect our ability to generate revenues or commercialize our product candidates in the U.S.

HHS has also taken action to address drug costs. For example, HHS finalized Medicare fee-for-service hospital payment reductions for Part B drugs acquired through the 340B Drug Pricing Program, which remains subject to ongoing legal challenge. HHS also has signaled its intent to continue to pursue reimbursement policy changes for Medicare Part B drugs as a whole that likely would reduce hospital and physician reimbursement for these drugs.

In addition, there continue to be efforts to lower drug prices through increased competition, with policy proposals seeking to facilitate generic and biosimilar approval and marketing authorization. For example, in 2018, the FDA announced the Biosimilar Action Plan and sought input on how the agency can best facilitate greater availability of biosimilar products, including input on whether changes to an approved biologic (e.g., a new indication) would be protected by the remainder of the statutory 12-year exclusivity period (commonly referred to as “umbrella exclusivity”). In the event there is a modification to the biologic exclusivity period or other steps taken to facilitate biosimilar or generic approvals, we could experience biosimilar/generic competition of any products for which we receive FDA approval at an earlier time than currently anticipated.

In addition to the actions taken by the President, HHS, and the FDA, there have been several recent U.S. Congressional inquiries and proposed and enacted legislation designed to bring more transparency to drug pricing, reduce the cost of prescription drugs under Medicare, limit price increases, evaluate the relationship between pricing and manufacturer patient programs, and reform government health care program reimbursement methodologies for prescription drugs. For example, the Bipartisan Budget Act of 2018 (the “BBA”) increased manufacturer point-of-sale discounts off negotiated prices of applicable brand drugs in the Medicare Part D coverage gap from 50% to 70% effective as of January 1, 2019, ultimately increasing the liability for brand drug manufacturers. We expect that health care reform measures that may be adopted in the future, may result in

S-32

TABLE OF CONTENTS

more rigorous coverage criteria and in additional downward pressure on the price that we may receive for any of our product candidates, if approved. Any reduction in reimbursement from Medicare or other government health care programs may result in a similar reduction in payments from private payors.

At the state level, individual states are experiencing significant economic pressure within their state Medicaid programs and responding to public concern over the cost of healthcare. The economic impact of the COVID-19 pandemic has further exacerbated state budgetary pressures. States, including California, Florida, Nevada and Maine, among others, have responded to these pressures with a range of legislative enactments and policy proposals designed to control prescription drug prices by, for example, allowing importation of pharmaceutical products from jurisdictions outside the U.S., imposing price controls on state drug purchases, consolidating state drug purchasing to a single purchaser, and imposing transparency measures around prescription drug prices and marketing costs. These measures, which vary by state, could reduce the ultimate demand for our products, if approved, or put pressure on our product pricing.

In addition, other legislative changes have been adopted that could have an adverse effect upon, and could prevent, our products’ or product candidates’ commercial success. More broadly, the Budget Control Act of 2011, as amended, or the Budget Control Act, includes provisions intended to reduce the federal deficit, including reductions in Medicare payments to providers through 2030 (except May 1, 2020 to December 31, 2020). Any significant spending reductions affecting Medicare, Medicaid or other publicly funded or subsidized health programs, or any significant taxes or fees imposed as part of any broader deficit reduction effort or legislative replacement to the Budget Control Act, or otherwise, could have an adverse impact on our anticipated product revenues.

Furthermore, legislative and regulatory proposals have been made to expand post-approval requirements and restrict sales and promotional activities for drugs. We cannot be sure whether additional legislative changes will be enacted, or whether the FDA regulations, guidance or interpretations will be changed, or what the impact of such changes on the marketing approvals of our product candidates, if any, may be. In addition, increased scrutiny by Congress of the FDA’s approval process may significantly delay or prevent marketing approval, as well as subject us to more stringent product labeling and post-marketing testing and other requirements.

In many international markets, including the European Union, the government regulates prescription drug prices, patient access, and/or reimbursement levels to control the biopharmaceutical budget of their government-sponsored healthcare system. The European Union and some individual countries have announced or implemented measures and may in the future implement new or additional measures, to reduce biopharmaceutical costs to contain the overall level of healthcare expenditures. These measures vary by country and may include, among other things, non-coverage decisions, patient access restrictions, international price referencing, mandatory discounts or rebates, and cross-border sales of prescription drugs. These measures may adversely affect our ability to generate revenues or commercialize our product candidates in certain international markets.

There likely will continue to be pressure on prescription drug prices globally and legislative and regulatory proposals, including at the federal and state levels in the U.S., directed at broadening the availability of health care and containing or lowering the cost of health care products and services. We cannot predict the initiatives that may be adopted in the future. The continuing efforts of the government, health insurance companies, managed care organizations and other payors of health care services to contain or reduce costs of health care may adversely affect, among other things:

•

our ability to generate revenues and achieve or maintain profitability;

•

the demand for any products for which we may obtain regulatory approval;

•

our ability to set a price that we believe is fair for our products;

•

the level of taxes that we are required to pay; and

•

the availability of capital.

In addition, governments may impose price controls, which may adversely affect our future profitability.

S-33

TABLE OF CONTENTS

We 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.

We cannot predict the likelihood, nature or extent of how government regulation that may arise from future legislation or administrative or executive action taken by the U.S. presidential administration may impact our business and industry. In particular, the U.S. President has taken several executive actions, including the issuance of a number of Executive Orders, that could impose significant burdens on, or otherwise materially delay, the FDA’s ability to engage in routine regulatory and oversight activities such as implementing statutes through rulemaking, issuance of guidance, and review and approval of marketing applications. Notably, on January 23, 2017, President Trump ordered a civilian hiring freeze for all executive departments and agencies, including the FDA, which prohibits the FDA from filling employee vacancies or creating new positions. Under the terms of the order, the freeze was to remain in effect until implementation of a plan to be recommended by the Director for the Office of Management and Budget (the “OMB”) in consultation with the Director of the Office of Personnel Management, to reduce the size of the federal workforce through attrition. An under-staffed FDA could result in delays in the FDA’s responsiveness or in its ability to review submissions or applications, issue regulations or guidance or implement or enforce regulatory requirements in a timely fashion or at all. This hiring freeze was lifted later in 2017. Moreover, on January 30, 2017, President Trump issued an Executive Order, applicable to all executive agencies, including the FDA, which requires that for each notice of proposed rulemaking or final regulation to be issued in fiscal year 2017, the agency shall identify at least two existing regulations to be repealed, unless prohibited by law. These requirements are referred to as the two-for-one provisions. This Executive Order includes a budget neutrality provision that requires the total incremental cost of all new regulations in the 2017 fiscal year, including repealed regulations, to be no greater than zero, except in limited circumstances. For fiscal years 2018 and beyond, the Executive Order requires agencies to identify regulations to offset any incremental cost of a new regulation and approximate the total costs or savings associated with each new regulation or repealed regulation. In interim guidance issued by the Office of Information and Regulatory Affairs within OMB on February 2, 2017, the administration indicates that the two-for-one provisions may apply not only to agency regulations, but also to significant agency guidance documents. It is difficult to predict how these requirements will be implemented, and the extent to which they will impact the FDA’s ability to exercise its regulatory authority. If these executive actions impose constraints on the FDA’s ability to engage in oversight and implementation activities in the normal course, our business may be negatively impacted.

In addition, on October 12, 2017, the President released an Executive Order intended to promote health care choices and competition and on June 24, 2019, the President released an Executive Order intended to improve price transparency and quality transparency. These may push HHS, the FDA, and other relevant agencies to engage in rulemaking that may impact the pharmaceutical industry.

If, in the future, we are unable to establish a commercial operation, including sales and marketing capabilities or enter into agreements with third parties to sell and market our drug candidates, we may not be successful in commercializing our drug candidates if and when they are approved, and we may not be able to generate any revenue.

As we plan for potential FDA approval of our first product, umbralisib, we are making significant investments to build a commercial organization and infrastructure. We are hiring marketing, sales, and medical support personnel in order to build processes and systems to support a commercial launch prior to knowing whether umbralisib will receive FDA approval. It is possible that the FDA approval is unexpectedly delayed, or our product is not approved at all. In either case we will incur delays that may impede or significantly delay our ability to generate revenue and at the same time will incur significant expenses. If this were to occur, it would have a material adverse effect on the Company.

There are risks involved with both establishing our own sales, marketing, and other commercialization capabilities. For example, recruiting and training a sales force are expensive and time-consuming and could delay any drug launch. If the commercial launch of a drug candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely or unnecessarily incurred

S-34

TABLE OF CONTENTS

these commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel.

Factors that may inhibit our efforts to commercialize our drug candidates on our own and generate product revenues include:

•

our inability to recruit and retain adequate numbers of effective sales and marketing personnel;

•

the costs and time associated with the initial and ongoing training of sales and marketing personnel on legal and regulatory compliance matters and with ongoing monitoring of their activities;

•

the inability of sales personnel to obtain access to physicians or to effectively promote any future drugs;

•

the lack of complementary drugs to be offered by sales personnel, which may put us at a competitive disadvantage relative to companies with more extensive product lines;

•

our ability to maintain a healthcare compliance program including effective mechanisms for compliance monitoring; and

•

unforeseen costs and expenses associated with creating a sales and marketing organization.

In the future, we may choose to participate in sales activities with collaborators for some of our drug candidates if and when they are approved. However, there are also risks with entering into these types of arrangements with third parties to perform sales, marketing and distribution services. For example, we may not be able to enter into such arrangements on terms that are favorable to us. Our drug revenues or the profitability of these drug revenues to us are likely to be lower than if we were to market and sell any drug candidates that we develop ourselves. In addition, we likely will have little control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market our drug candidates effectively. If we do not establish sales and marketing capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our drug candidates. Further, our business, results of operations, financial condition and prospects will be materially adversely affected.

Our relationships with customers and third-party payors will be subject to applicable fraud and abuse laws, false claims laws, transparency and disclosure laws, health information and security laws, and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, exclusion from government healthcare programs, contractual damages, reputational harm and diminished profits and future earnings.

Although we do not currently have any drugs on the market, once we begin commercializing our drug candidates, we will be subject to additional extensive healthcare statutory and regulatory requirements and oversight by the federal government and the states and foreign governments in which we conduct our business. Healthcare providers and third-party payors play a primary role in the recommendation and prescription of any drug candidates for which we obtain marketing approval. Our past, current and future relationships, arrangements and interactions with these professionals and entities, as well as with patients and patient advocacy organizations will 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 drug candidates for which we obtain marketing approval. Restrictions under applicable federal and state healthcare laws and regulations include the following:

•

the federal Anti-Kickback Statute prohibits, among other things, persons from knowingly and willfully soliciting, offering, receiving or providing remuneration, directly or indirectly, in cash or in kind, to induce or reward either the referral of an individual for, or the purchase, order or recommendation of, any good or service, for which payment may be made under federal and state healthcare programs such as Medicare and Medicaid. 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;

•

the federal False Claims Act imposes civil penalties, including through civil whistleblower or qui tam actions, against individuals or entities for, among other things, knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent or making a false statement to avoid,

S-35

TABLE OF CONTENTS

decrease or conceal an obligation to pay money to the federal government. In addition, the government may assert that a claim including items and services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the False Claims Act;

•

the federal Health Insurance Portability and Accountability Act of 1996 (or “HIPAA”) imposes criminal and civil liability for executing a scheme to defraud any healthcare benefit program, or knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false 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;

•

the so-called federal “Sunshine Act” under the Affordable Care Act requires manufacturers of drugs, devices, biologics and medical supplies that are reimbursable under Medicare, Medicaid, or the Children’s Health Insurance Program to monitor and report information related to payments and other transfers of value to and the ownership and investment interests of physicians and teaching hospitals (and additional categories of healthcare providers beginning with reports submitted in 2022) to the federal government for redisclosure to the public;

•

HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act of 2009 and its implementing regulations, which also imposes obligations on certain covered entity healthcare providers, health plans, and healthcare clearinghouses as well as their business associates that perform certain services involving the use or disclosure of individually identifiable health information, including mandatory contractual terms, with respect to safeguarding the privacy, security and transmission of individually identifiable health information;

•

federal consumer protection and unfair competition laws, which broadly regulate marketplace activities and activities that potentially harm consumers;

•

the Federal Food, Drug, and Cosmetic Act, which among other things, strictly regulates drug product and medical device marketing, prohibits manufacturers from marketing such products prior to approval or for off-label use and regulates the distribution of samples;

•

federal laws, including the Medicaid Drug Rebate Program, that require pharmaceutical manufacturers to report certain calculated product prices to the government or provide certain discounts or rebates to government authorities or private entities, often as a condition of reimbursement under government healthcare programs;

•

the Drug Supply Chain Security Act, or DSCSA, which imposes obligations on entities in the commercial product supply chain, including manufacturers, to identify and track prescription drugs as they are distributed in the U.S.; and

•

state law equivalents of some of the above federal laws, such as anti-kickback and false claims laws that may apply to items or services reimbursed by any third-party payor, including commercial insurers, state transparency laws, state laws limiting interactions between pharmaceutical manufacturers and members of the healthcare industry, and state laws governing the privacy and security of health information in certain circumstances, many of which differ from each other in significant ways and often are not preempted by federal laws, thus complicating compliance efforts.

Ensuring that our future business arrangements with third parties comply with applicable healthcare laws and regulations will involve substantial costs. It is possible that governmental authorities will conclude that our business practices do not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations, including anticipated activities to be conducted by our sales team, were to be found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, exclusion from government-funded healthcare programs, such as Medicare and Medicaid, qui tam actions brought by individual whistleblowers in the name of the government, and the curtailment or restructuring of our operations.

S-36

TABLE OF CONTENTS

If we violate applicable data privacy and security laws, we may be subject to penalties, including civil and criminal penalties, damages, fines and the curtailment or restructuring of our operations.

We may be subject to privacy and security laws in the various jurisdictions in which we operate, obtain or store personally identifiable information. The legislative and regulatory landscape for privacy and data protection continues to evolve, and there has been an increasing focus on privacy and data protection issues with the potential to affect our business.

Within the United States, various federal and state laws regulate the privacy and security of personal information and so may affect our business operations. For example, at the federal level, our operations may be affected by the data privacy and security provisions of HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act and its implementing regulations. Although we are not currently directly subject to HIPAA, HIPAA affects the ability of healthcare providers and other entities with which we may interact, including clinical trial sites, to disclose patient health information to us.

Numerous other jurisdictions regulate the privacy and security of personally identifiable data. For example, the processing of personal data in the European Economic Area, or the EEA, is subject to the General Data Protection Regulation, or the GDPR, which took effect in May 2018. The GDPR increases obligations with respect to clinical trials conducted in the EEA, such as in relation to the provision of fair processing notices, exercising data subject rights and reporting certain data breaches to regulators and affected individuals, as well as how we document our relationships with third parties that process GDPR-covered personal data on our behalf. The GDPR also increases the scrutiny applied to transfers of personal data from the EEA (including from clinical trial sites in the EEA) to countries that are considered by the European Commission to lack an adequate level of data protection, such as the United States. In July 2020, the Court of Justice of the European Union invalidated the EU-U.S. Privacy Shield framework, one of the mechanisms used to legitimize the transfer of personal data from the EEA to the U.S., which decision may lead to increased scrutiny on data transfers from the EEA to the U.S. generally and increase our costs of compliance with data privacy legislation.

If our operations are found to be in violation of any data privacy and security laws, rules or regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines and the curtailment or restructuring of our operations, which could adversely affect our ability to operate our business and our financial results. Although compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, rules or regulations, we cannot be certain that our program will address all areas of potential exposure and the risks in this area cannot be entirely eliminated, particularly because the requirements and government interpretations of the requirements in this space are constantly evolving. Any action against us for violation of these laws, rules or regulations, even if we successfully defend against it, could cause us to incur significant legal expenses and divert our management’s attention from the operation of our business, as well as damage our business or reputation. Moreover, achieving and sustaining compliance with applicable federal and state privacy, security, fraud and reporting laws may prove costly.

If we fail to adequately understand and comply with the local laws and customs as we expand into new international markets, these operations may incur losses or otherwise adversely affect our business and results of operations.

We expect to operate a portion of our business in certain countries through subsidiaries or through supply, marketing, and distributor arrangements. In those countries where we have limited experience in operating subsidiaries and in reviewing equity investees, we will be subject to additional risks related to complying with a wide variety of national and local laws, including restrictions on the import and export of certain intermediates, drugs, technologies and multiple and possibly overlapping tax laws. In addition, we may face competition in certain countries from companies that may have more experience with operations in such countries or with international operations generally. We may also face difficulties integrating new facilities in different countries into our existing operations, as well as integrating employees hired in different countries into our existing corporate culture. If we do not effectively manage our operations in these subsidiaries and review equity investees effectively, or if we fail to manage our alliances, we may lose money in these countries and it may adversely affect our

S-37

TABLE OF CONTENTS

business and results of our operations. In all interactions with foreign regulatory authorities and other government agencies, we are exposed to liability risks under the Foreign Corrupt Practices Act or similar anti-bribery laws.

Any product for which we obtain marketing approval could be subject to restrictions or withdrawal from the market and we may be subject to penalties if we fail to comply with regulatory requirements or if we experience unanticipated problems with products.

Any regulatory approvals that we receive for our drug candidates may be subject to limitations on the indicated uses for which the drug may be marketed or to conditions of approval that may require potentially costly post-marketing clinical trials or surveillance to monitor safety and efficacy of the drug candidate. In addition, any product for which we obtain marketing approval, along with the manufacturing processes and facilities, post-approval clinical data, labeling, advertising and promotional activities for such product, will be subject to continual requirements of, and review by, the FDA and comparable regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports, registration requirements, current Good Manufacturing Practice (cGMP) requirements relating to quality control, quality assurance and corresponding maintenance of records and documents, and requirements regarding promotional interactions with healthcare professionals.

Failure to comply with these regulatory requirements or later discovery of previously unknown problems with products, manufacturers, or manufacturing processes, may result in actions such as:

•

restrictions on product manufacturing, distribution or use;

•

restrictions on the labeling or marketing of a product;

•

requirements to conduct post-marketing studies or clinical trials;

•

warning letters;

•

withdrawal of the products from the market;

•

refusal to approve pending applications or supplements to approved applications that we or our subsidiaries submit;

•

recalls;

•

suspension or termination of ongoing clinical trials;

•

fines, restitutions, or disgorgement of profits or revenues;

•

refusal to permit the import or export of products;

•

product seizure or detentions;

•

injunctions or the imposition of civil or criminal penalties; and

•

adverse publicity.

Any government investigation of alleged violations of law could require us to expend significant time and resources in response and could generate negative publicity. In addition, the FDA’s regulations, policies or guidance may change and new or additional statutes or government regulations may be enacted that could prevent or delay regulatory approval of our product candidates or further restrict or regulate post-approval activities. We also cannot predict the likelihood, nature, or extent of adverse government regulation that may arise from pending or future legislation or administrative action, either in the United States or abroad.

If we, or our respective suppliers, third-party contractors, clinical investigators or collaborators are slow to adapt, or are unable to adapt, to changes in existing regulatory requirements or adoption of new regulatory requirements or policies, we, our subsidiaries, or our respective collaborators may be subject to the actions listed above, including losing marketing approval for products, resulting in decreased revenue from milestones, product sales or royalties.

S-38

TABLE OF CONTENTS

Risks related to our dependence on third parties

In order to submit an Investigational New Drug application (IND), BLA, or NDA to the FDA and maintain these applications, it is necessary to submit all information on the clinical, non-clinical, chemistry, manufacturing, controls and quality aspects of the product candidate. Clinical trial applications and marketing authorization applications for foreign regulatory bodies have substantially similar requirements. We rely on our third-party contractors and our licensing partners to provide portions of this data. If we are unable to obtain this data, or the data is not sufficient to meet the regulatory requirements, we may experience significant delays in our development programs.

Additionally, we use CROs to assist in the conduct of our current clinical trials and expect to use such services for future clinical trials and we rely upon medical institutions, clinical investigators and contract laboratories to conduct our trials in accordance with our clinical protocols and appropriate regulations. Our current and future CROs, investigators and other third parties play a significant role in the conduct of our trials and the subsequent collection and analysis of data from the clinical trials. There is no guarantee that any CROs, investigators and other third parties will devote adequate time and resources to our clinical trials or perform as contractually required. If any third parties upon whom we rely for administration and conduct of our clinical trials fail to meet expected deadlines, fail to adhere to its clinical protocols or otherwise perform in a substandard manner, our clinical trials may be extended, delayed or terminated, and we may not be able to commercialize our product candidates. In addition to the third parties identified above, we are also heavily reliant on the conduct of our patients enrolled to our studies by our third-party investigators. We rely on our clinical trial sites and investigators to properly identify and screen eligible candidates for our clinical trials, and for them to ensure participants adhere to our clinical protocol requirements. The majority of our clinical trial conduct occurs in the outpatient setting, where patients are expected to continue to adhere to our study protocol specified requirements. The ability of our enrolled patients to properly identify, document, and report adverse events; take protocol specified study drugs at the correct quantity, time, and setting, as applicable; avoid contraindicated medications; and comply with other protocol specified procedures such as returning to the trial site for scheduled laboratory and disease assessments, is wholly out of our control. Deviations from protocol procedures, such as those identified previously, could materially affect the quality of our clinical trial data, and therefore ultimately affect our ability to develop and commercialize our drug candidates. If any of our clinical trial sites terminates for any reason, we may experience the loss of follow-up information on patients enrolled in our ongoing clinical trials unless we are able to transfer the care of those patients to another qualified clinical trial site. If any of our clinical trial sites are required by the FDA or IRB to close down due to data management or patient management or any other issues, we may lose patients. In our MS Phase 2 trial, during routine monitoring and site audits, significant Good Clinical Practice (GCP) violations and other noncompliance issues were identified at one of our US-based large academic sites. The investigator left the institution and shortly thereafter the site terminated their participation in our study before all data could be source document verified. While we do not believe this will have any effect on the overall results of the MS Phase 2 trial, sensitivity analyses excluding data from this site will be performed and no assurance can be given that the results were not affected.

Whether conducted through a CRO or through our internal staff, we are solely responsible for ensuring that each of our clinical trials is conducted in accordance with the applicable protocol, legal and regulatory requirements and scientific standards, and our reliance on CROs will not relieve us of our regulatory responsibilities. For any violations of laws and regulations during the conduct of our clinical trials, we could be subject to warning letters or other enforcement actions that may include civil penalties up to and including criminal prosecution. We and our CROs are required to comply with regulations, including GCP guidelines for conducting, monitoring, recording and reporting the results of clinical trials to ensure that the data and results are scientifically credible and accurate, and that the trial patients are adequately informed of the potential risks of participating in clinical trials and their rights are protected. These regulations are enforced by the FDA, the Competent Authorities of the Member

S-39

TABLE OF CONTENTS

States of the European Economic Area and comparable foreign regulatory authorities for any drug candidates in clinical development. The FDA enforces GCP regulations through periodic inspections of clinical trial sponsors, clinical investigators, CROs, institutional review boards, and non-clinical laboratories. If we, our CROs, our investigators or other third parties fail to comply with applicable GCPs, the clinical data generated in our clinical trials may be deemed unreliable and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that, upon inspection, the FDA will determine that our current or future clinical trials comply with GCPs. In addition, our clinical trials must be conducted with drug candidates produced under cGMP regulations. Our failure or the failure of our CROs or CMOs to comply with these regulations may require us to repeat clinical trials, which would delay the regulatory approval process and could also subject us to enforcement action. We also are required to register most ongoing clinical trials and post the results of completed clinical trials on government-sponsored databases, e.g. ClinicalTrials.gov, within certain timeframes. Failure to do so can result in fines, adverse publicity and civil and criminal sanctions.

Although we intend to design the clinical trials for our drug candidates, CROs play an important role in the conduct of our clinical trials, especially outside of the United States. As a result, many important aspects of our development programs, including their conduct and timing, will be outside of our direct control. Our reliance on third parties to conduct current or future clinical trials will also result in less direct control over the management of data developed through clinical trials than would be the case if we were relying entirely upon our own staff. Communicating with outside parties can also be challenging, potentially leading to mistakes as well as difficulties in coordinating activities. Outside parties may:

•

have staffing difficulties;

•

fail to comply with contractual obligations;

•

experience regulatory compliance issues;

•

undergo changes in priorities or become financially distressed; or

•

form relationships with other entities, some of which may be our competitors.

These factors may materially adversely affect the willingness or ability of third parties to conduct our clinical trials and may subject us to unexpected cost increases that are beyond our control. If the CROs do not perform clinical trials in a satisfactory manner, breach their obligations to us or fail to comply with regulatory requirements, the development, regulatory approval and commercialization of our drug candidates may be delayed, we may not be able to obtain regulatory approval and commercialize our drug candidates, or our development program may be materially and irreversibly harmed. If we are unable to rely on clinical data collected by our CROs, we could be required to repeat, extend the duration of, or increase the size of any clinical trials we conduct, and this could significantly delay commercialization and require significantly greater expenditures.

If any of our relationships with these third-party CROs terminate, we may not be able to enter into arrangements with alternative CROs. If CROs do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols, regulatory requirements or for other reasons, any clinical trials such CROs are associated with may be extended, delayed or terminated, and we may not be able to obtain regulatory approval for or successfully commercialize our drug candidates. As a result, we believe that our financial results and the commercial prospects for our drug candidates in the subject indication would be harmed, our costs could increase and our ability to generate revenue could be delayed.

We contract with third parties for the manufacture of our drug candidates for pre-clinical development and clinical trials, and we expect to continue to do so for commercialization. This reliance on third parties increases the risk that we will not have sufficient quantities of our drug candidates or drugs or such quantities at an acceptable cost or quality, which could delay, prevent or impair our development or commercialization efforts.

We do not currently own or operate, nor do we have any plans to establish in the future, any manufacturing facilities. We rely, and expect to continue to rely, on third parties for the manufacture of our drug candidates for pre-clinical development and clinical testing, as well as for the commercial manufacture of our drugs if any of our

S-40

TABLE OF CONTENTS

drug candidates receive marketing approval. In some circumstances, our licensor has entered into arrangements with contract manufacturers to supply product for our clinical and commercial demand. Our reliance on third parties increases the risk that we will not have sufficient quantities of our drug candidates or drugs or such quantities at an acceptable cost or quality, which could delay, prevent or impair our development or commercialization efforts.

The facilities used by contract manufacturers to manufacture our drug candidates typically undergo inspections by the FDA or a comparable foreign regulatory to verify compliance with applicable cGMP regulations. Such inspections may be conducted after we submit our marketing applications to the FDA or a comparable foreign regulatory authority. We do not control the manufacturing process of, and will be completely dependent on, our contract manufacturers for compliance with cGMPs in connection with the manufacture of our drug candidates. If our contract manufacturers cannot successfully manufacture material that conforms to our specifications and the strict regulatory requirements of the FDA or others and the compliance concerns cannot be resolved, remediated, or otherwise addressed to FDA’s satisfaction in a timely manner during the review of our NDAs or BLAs, it may negatively impact our ability to obtain regulatory approval for our drug candidates or obtain approval within projected timelines. In addition, although we exercise qualification and oversight of our contract manufacturers, we cannot guarantee their ability to maintain compliance with cGMP regulations, including having adequate quality control, quality assurance and qualified personnel. Further, our failure, or the failure of our third-party manufacturers, to comply with applicable regulations could result in sanctions being imposed on us, including clinical holds, fines, injunctions, civil penalties, delays, suspension or withdrawal of approvals, license revocation, seizures or recalls of drug candidates or drugs, operating restrictions and criminal prosecutions, any of which could significantly and adversely affect our business and supplies of our drug candidates.

For certain of our drug candidates, we do not have long-term supply agreements with contract manufacturers. For these drug candidates, we purchase our required drug supply, including the drug product and drug substance on a purchase order basis. We may be unable to establish or maintain agreements with third-party manufacturers for these drug candidates or do so on acceptable terms. No assurance can be given that long-term, scalable manufacturers can be identified or that they can make clinical and commercial supplies of our product candidates that meet the product specifications of previously manufactured batches, or are of a sufficient quality, or at an appropriate scale and cost to make it commercially feasible. If they are unable to do so, it could have a material adverse impact on our business.

Even if we are able to establish and maintain agreements with third-party manufacturers, reliance on third-party manufacturers entails additional risks, including:

•

reliance on the third party for regulatory compliance and quality assurance;

•

the possible breach of the manufacturing or supply agreement by the third party;

•

the possible misappropriation of our proprietary information, including our trade secrets and know-how; and

•

the possible termination or nonrenewal of the agreement by the third party at a time that is costly or inconvenient for us.

Moreover, our current long-term supply agreements contain certain minimum purchases in what are commonly referred to as “take or pay” provisions, and we would expect all future supply agreements to contain such provisions. To the extent our demand does not meet the minimum supply required amounts, we would be forced to pay more than desired. This could create a situation where we are spending more than required and could impact our on-going operations and entail curtailing other important research and development or commercialization efforts, all of which could have a material adverse effect on the Company.

Our drug candidates and any drugs that we may develop may compete with other drug candidates and approved drugs for access to manufacturing facilities. There are a limited number of manufacturers that operate under cGMP regulations and that might be capable of manufacturing for us.

S-41

TABLE OF CONTENTS

Any performance failure on the part of our existing or future manufacturers could delay clinical development or marketing approval. If our current contract manufacturers cannot perform as agreed, we may be required to replace such manufacturers causing additional costs and delays in identifying and qualifying any such replacement.

Our current and anticipated future dependence upon others for the manufacture of our drug candidates or drugs could result in significant delays or gaps in availability of such drug candidates or drugs and may adversely affect our future profit margins and our ability to commercialize any drugs that receive marketing approval on a timely and competitive basis.

We also expect to rely on other third parties to store and distribute drug supplies for our clinical trials and for commercial demand, if and when our product candidates receive approval. Any performance failure on the part of our distributors could delay clinical development or marketing approval of any future product candidates or commercialization of our products, producing additional losses and depriving us of potential product revenue.

In addition, we do not have the capability to package finished products for distribution to hospitals and other customers. Prior to commercial launch, we intend to enter into agreements with one or more alternate packaging and labeling suppliers so that we can ensure proper supply chain management once we are authorized to make commercial sales of our product candidates. If we receive marketing approval from the FDA, we intend to sell pharmaceutical product finished and packaged by such suppliers. We have not yet entered into long-term agreements with our fill/finish suppliers for all of our drug candidates, and we may be unable to enter into such an agreement or do so on commercially reasonable terms, which could have a material adverse impact upon our business.

Because we license our product candidates from third parties and we expect to continue to in-license additional product candidates, if there is any dispute between us and our licensor regarding our rights under a license agreement, our ability to develop and commercialize our product candidates may be adversely affected. Disputes may arise with the third parties from whom we license our product candidates for a variety of reasons, including:

•

the scope of rights granted under the license agreement and other interpretation-related issues;

•

the extent to which our technology and processes infringe on intellectual property of the licensor that is not subject to the license agreement;

•

the sublicensing of patent and other rights under our collaborative development relationships and obligations associated with sublicensing;

•

our diligence obligations under the license agreement and what activities satisfy those diligence obligations;

•

the ownership of inventions and know-how resulting from the joint creation or use of intellectual property by our licensors and us and our partners; and

•

the priority of invention of patented technology.

In addition, the agreements under which we currently license product candidates from third parties are complex, and certain provisions in such agreements may be susceptible to multiple interpretations, or may conflict in such a way that puts us in breach of one or more agreements, which would make us susceptible to lengthy and expensive disputes with one or more of our licensing partners. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, or increase what we believe to be our financial or other obligations under the relevant agreement, either of which could have a material adverse effect on our business, financial condition, results of operations, and prospects. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on commercially acceptable terms, we may be

S-42

TABLE OF CONTENTS

unable to successfully develop and commercialize the affected product candidates, which could have a material adverse effect on our business, financial conditions, results of operations, and prospects.

If conflicts arise between us and our future collaborators or strategic partners, these parties may act in a manner adverse to us and could limit our ability to implement our strategies.

If conflicts arise between our future corporate or academic collaborators or strategic partners and us, the other party may act in a manner adverse to us and could limit our ability to implement our strategies. Future collaborators or strategic partners, may develop, either alone or with others, products in related fields that are competitive with the products or potential products that are the subject of these collaborations. Competing products, either developed by the collaborators or strategic partners or to which the collaborators or strategic partners have rights, may result in the withdrawal of partner support for any future product candidates. Our current or future collaborators or strategic partners may preclude us from entering into collaborations with their competitors, fail to obtain timely regulatory approvals, terminate their agreements with us prematurely, or fail to devote sufficient resources to the development and commercialization of products. Any of these developments could harm any future product development efforts.

We may seek to establish additional collaborations, and, if we are not able to establish them on commercially reasonable terms, we may have to alter our development and commercialization plans.

Our drug development programs and the potential commercialization of our drug candidates will require substantial additional cash to fund expenses. For some of our drug candidates, we may decide to collaborate with additional pharmaceutical and biotechnology companies for the development and potential commercialization of those drug candidates.

We face significant competition in seeking appropriate collaborators. Whether we reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration, and the proposed collaborator’s evaluation of a number of factors. Those factors may include the design or results of our clinical trials, the likelihood of approval by the FDA or similar regulatory authorities outside the United States, the potential market for the subject drug candidate, the costs and complexities of manufacturing and delivering such drug candidate to patients, the potential of competing drugs, the existence of uncertainty with respect to our ownership of technology, which can exist if there is a challenge to such ownership without regard to the merits of the challenge, and industry and market conditions generally. The collaborator may also consider alternative drug candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us for our drug candidate. The terms of any additional collaborations or other arrangements that we may establish may not be favorable to us.

We may be restricted under our collaboration agreements from entering into future agreements on certain terms with potential collaborators. Collaborations are complex and time-consuming to negotiate and document. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators.

We may not be able to negotiate additional collaborations on a timely basis, on acceptable terms, or at all. If we are unable to do so, we may have to curtail the development of the drug candidate for which we are seeking to collaborate, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization or reduce the scope of any sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to increase our expenditures to fund development or commercialization activities on our own, we may need to obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we may not be able to further develop our drug candidates or bring them to market and generate drug revenue.

Any future collaborations that we enter into may not be successful. The success of our collaboration arrangements will depend heavily on the efforts and activities of our collaborators. Collaborators generally have significant

S-43

TABLE OF CONTENTS

discretion in determining the efforts and resources that they will apply to these collaborations. Disagreements between parties to a collaboration arrangement regarding clinical development and commercialization matters can lead to delays in the development process or commercializing the applicable drug candidate and, in some cases, termination of the collaboration arrangement. These disagreements can be difficult to resolve if neither of the parties has final decision-making authority. Collaborations with pharmaceutical or biotechnology companies and other third parties often are terminated or allowed to expire by the other party. Any termination or expiration of any future collaboration agreement could adversely affect us financially or harm our business reputation.

Risks relating to our intellectual property

Our commercial success in part depends on obtaining and maintaining patent protection and trade secret protection in the United States and other countries with respect to our product candidates or any future product candidate that we may license or acquire, their formulations and uses and the methods we use to manufacture them, as well as successfully defending these patents against third-party challenges. We seek to protect our proprietary and intellectual property position by filing patent applications in the United States and abroad related to our novel technologies and product candidates, and by maintenance of our trade secrets through proper procedures. Because we in-license our drug candidates, we also rely on our licensors to protect the patent and other intellectual property rights necessary for commercialization of our drug candidates.

We will only be able to protect our technologies from unauthorized use by third parties to the extent that valid and enforceable patents or trade secrets cover them in the market they are being used or developed. The degree of patent protection we require to successfully commercialize our drug candidates may be unavailable or severely limited in some cases and may not adequately protect our rights or permit us to gain or keep any competitive advantage. We cannot provide any assurances that any of our patents have, or that any of our pending patent applications that mature into issued patents will include, claims with a scope sufficient to protect any of our drug candidates. In addition, the laws of foreign countries may not protect our rights to the same extent as the laws of the United States.

Furthermore, patents have a limited lifespan. In the United States, the natural expiration of a patent is generally twenty years after it is filed. Various extensions may be available; however, the life of a patent, and the protection it affords, is limited. Given the amount of time required for the development, testing and regulatory review of new drug candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned patent portfolio may not provide us with adequate and continuing patent protection sufficient to exclude others from commercializing drugs similar or identical to our drug candidates, including generic versions of such drugs.

Currently, the composition of matter patent for ublituximab and umbralisib are granted in both the United States and EU, among other countries. A method of use patent covering the combination of ublituximab and umbralisib has also been granted in the United States, European Union, Japan, and several other territories. Additionally, several method of use patents for ublituximab and umbralisib in various indications and settings have also been applied for but have not yet been issued or have been issued in certain territories but not under all jurisdictions in which such applications have been filed. There can be no guarantee that any patents for which an application has already been filed, nor any patents filed in the future, for cosibelimab, TG-1701 and TG-1801 or for our pre-clinical product candidates will be granted in any or all jurisdictions in which they were filed, or that all claims initially included in such patent applications will be allowed in the final patent that is issued. The patent application process is subject to numerous risks and uncertainties, and there can be no assurance that we or our partners will be successful in protecting our product candidates by obtaining and defending patents, or what the scope of an issued patent may ultimately be.

These risks and uncertainties include the following:

S-44

TABLE OF CONTENTS

•

the patent applications that we or our licensors file may not result in any patents being issued;

•

patents that may be issued or in-licensed may be challenged, invalidated, modified, revoked or circumvented, or otherwise may not provide any competitive advantage;

•

as of March 16, 2013, the United States converted from a first to invent to a first to file system. If we do not win the filing race, we will not be entitled to inventive priority;

•

our competitors, many of which have substantially greater resources than we do, and many of which have made significant investments in competing technologies, may seek, or may already have obtained, patents that will limit, interfere with, or eliminate its ability to file new patent applications or make, use, and sell our potential products either in the United States or in international markets;

•

there may be significant pressure on the United States government and other international governmental bodies to limit the scope of patent protection both inside and outside the United States for disease treatments that prove successful as a matter of public policy regarding worldwide health concerns; and

•

countries other than the United States may have less restrictive patent laws than those upheld by United States courts, allowing foreign competitors the ability to exploit these laws to create, develop, and market competing products.

If patents are not issued that protect our product candidates, it could have a material adverse effect on our financial condition and results of operations.

In addition, the patent prosecution process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. Further, with respect to some of the pending patent applications covering our drug candidates, prosecution has yet to commence. Patent prosecution is a lengthy process, during which the scope of the claims initially submitted for examination by the USPTO have been significantly narrowed by the time they issue, if at all. It is also possible that we will fail to identify any patentable aspects of our research and development output and methodology, and, even if we do, an opportunity to obtain patent protection may have passed. Given the uncertain and time-consuming process of filing patent applications and prosecuting them, it is possible that our product(s) or process(es) originally covered by the scope of the patent application may have changed or been modified, leaving our product(s) or process(es) without patent protection. Moreover, in some circumstances, we do not have the right to control the preparation, filing and prosecution of patent applications, or to maintain the patents, covering technology that we license from third parties. Therefore, these patents and applications may not be prosecuted and enforced in a manner consistent with the best interests of our business. If our licensors or we fail to appropriately prosecute and maintain patent protection or trade secret protection for one or more product candidates or any future product candidate we may license or acquire, our ability to develop and commercialize these product candidates may be adversely affected and we may not be able to prevent competitors from making, using and selling competing products. This failure to properly protect the intellectual property rights relating to these product candidates could impair our ability to compete in the market and adversely affect our ability to generate revenues and achieve profitability, which would have a material adverse effect on our financial condition and results of operations. Furthermore, should we enter into other collaborations, including out-licensing or partnerships, we may be required to consult with or cede control to collaborators regarding the prosecution, maintenance and enforcement of licensed patents. Therefore, these patents and applications may not be prosecuted and enforced in a manner consistent with the best interests of our business.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions, and has in recent years been the subject of much litigation. In addition, no consistent policy regarding the breadth of claims allowed in pharmaceutical or biotechnology patents has emerged to date in the United States. The patent situation outside the United States is even more uncertain. The laws of foreign countries may not protect our rights to the same extent as the laws of the United States, and we may fail to seek or obtain patent protection in all major markets. For example, European patent law restricts the patentability of methods of treatment of the human body more than United States law does. Our pending and future patent

S-45

TABLE OF CONTENTS

applications may not result in patents being issued which protect our technology or products, in whole or in part, or which effectively prevent others from commercializing competitive technologies and products. Changes in either the patent laws or interpretation of the patent laws in the United States and other countries may diminish the value of our patents or narrow the scope of our patent protection. For example, the federal courts of the United States have taken an increasingly dim view of the patent eligibility of certain subject matter, such as naturally occurring nucleic acid sequences, amino acid sequences and certain methods of utilizing same, which include their detection in a biological sample and diagnostic conclusions arising from their detection. Such subject matter, which had long been a staple of the biotechnology and biopharmaceutical industry to protect their discoveries, is now considered, with few exceptions, ineligible in the first instance for protection under the patent laws of the United States. Accordingly, we cannot predict the breadth of claims that may be allowed or enforced in our patents or in those licensed from a third-party.

In addition, U.S. patent laws may change, which could prevent or limit us, our subsidiaries, or our licensors from filing patent applications or patent claims to protect products and/or technologies or limit the exclusivity periods that are available to patent holders, as well as affect the validity, enforceability, or scope of issued patents. For example, on September 16, 2011, the Leahy-Smith America Invents Act was signed into law. The Leahy-Smith Act includes a number of significant changes to United States patent law. These include changes to transition from a first-to-invent system to a first-to-file system and to the way issued patents are challenged. The formation of the Patent Trial and Appeal Board now provides a quicker and less expensive process for challenging issued patents.

We may be subject to a third-party pre-issuance submission of prior art to the USPTO, or become involved in opposition, derivation, reexamination, inter parties review, post-grant review or interference proceedings challenging our patent rights or the patent rights of others. The costs of these proceedings could be substantial, and it is possible that our efforts to establish priority of invention would be unsuccessful, resulting in a material adverse effect on our United States patent position. An adverse determination in any such submission, patent office trial, proceeding or litigation could reduce the scope of, render unenforceable, or invalidate, our patent rights, allow third parties to commercialize our technology or products and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize products without infringing third-party patent rights. In addition, if the breadth or strength of protection provided by patents and patent applications for our drug candidates is threatened, it could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

The issuance of a patent does not foreclose challenges to its inventorship, scope, validity or enforceability. Therefore, our owned and licensed patents may be challenged in the courts or patent offices in the United States and abroad. Such challenges may result in loss of exclusivity or in patent claims being narrowed, invalidated or held unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar or identical technology and products, or limit the duration of the patent protection of our technology and products. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such product candidates might expire before or shortly after such product candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with enough rights to exclude others from commercializing products similar or identical to ours.

Even if our patent applications issue as patents, and they are unchallenged, our issued patents and our pending patents, if issued, may not provide us with any meaningful protection or prevent competitors from designing around our patent claims to circumvent our owned or licensed patents by developing similar or alternative technologies or drugs in a non-infringing manner. For example, a third party may develop a competitive drug that provides benefits similar to one or more of our drug candidates but that has a different composition that falls outside the scope of our patent protection. If the patent protection provided by the patents and patent applications we hold or pursue with respect to our drug candidates is not sufficiently broad to impede such competition, our ability to successfully commercialize our drug candidates could be negatively affected, which would harm our business.

In addition, we may in the future be subject to claims by our former employees or consultants asserting an ownership right in our patents or patent applications, as a result of the work they performed on our behalf.

S-46

TABLE OF CONTENTS

Although we have entered into agreements with many of our employees, consultants and advisors and any other third parties who have access to our proprietary know-how, information or technology to assign or grant similar rights to their inventions to us, we cannot be certain that we have executed such agreements with all parties who may have contributed to our intellectual property, nor can we be certain that our agreements with such parties will be upheld in the face of a potential challenge, or that they will not be breached, for which we may not have an adequate remedy. An adverse determination in any such submission or proceeding may result in loss of exclusivity or freedom to operate or in patent claims being narrowed, invalidated or held unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar or identical technology and drugs, without payment to us, or could limit the duration of the patent protection covering our technology and drug candidates. Such challenges may also result in our inability to manufacture or commercialize our drug candidates without infringing third-party patent rights. In addition, if the breadth or strength of protection provided by our patents and patent applications is threatened, it could dissuade companies from collaborating with us to license, develop or commercialize current or future drug candidates.

Patent protection and other intellectual property protection are crucial to the success of our business and prospects, and there is a substantial risk that such protections will prove inadequate.

The USPTO and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. In addition, periodic maintenance fees on issued patents often must be paid to the USPTO and foreign patent agencies over the lifetime of the patent. While an unintentional lapse can in many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which noncompliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction.

Non-compliance events that could result in abandonment or lapse of a patent or patent application include, but are not limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to properly legalize and submit formal documents. If we fail to maintain the patents and patent applications covering our drugs or procedures, we may not be able to stop a competitor from marketing drugs that are the same as or similar to our drug candidates, which would have a material adverse effect on our business.

If we do not obtain patent term extensions under the Hatch-Waxman Amendments and similar foreign legislation extending the terms of our licensed patents and any future patents we may own, our business may be materially harmed.

Depending on the timing, duration, and specifics of any FDA regulatory approval for our drug candidates, one or more of our licensed U.S. patents or future U.S. patents that we may license or own may be eligible for limited patent term restoration under the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent term extension of up to five years as compensation for patent term lost during the FDA regulatory review process. A patent term extension cannot extend the remaining term of a patent beyond 14 years from the date of product approval by the FDA, and only one patent covering the approved product may be extended.

The application for a patent term extension is subject to approval by the USPTO, in conjunction with the FDA. We may not be granted an extension because of, for example, failing to apply within applicable deadlines, failing to apply prior to expiration of relevant patents or otherwise failing to satisfy applicable requirements. Moreover, the applicable time period or the scope of the patent protection afforded could be less than we request. If we are unable to obtain patent term extension or any term of such extension is less than we request, the period during which we will have the right to exclusively market our product will be shortened and our competitors may obtain earlier approval of competing products, and our ability to generate revenues could be materially adversely affected.

S-47

TABLE OF CONTENTS

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

Filing, prosecuting and defending patents on drug candidates throughout the world would be prohibitively expensive. Competitors may use our licensed and owned technologies in jurisdictions where we have not licensed or obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories where we may obtain or license patent protection, but where patent enforcement is not as strong as that in the United States. These products may compete with our products in jurisdictions where we do not have any issued or licensed patents and any future patent claims or other intellectual property rights may not be effective or sufficient to prevent them from so competing.

Moreover, our ability to protect and enforce our intellectual property rights may be adversely affected by unforeseen changes in foreign intellectual property laws. Additionally, laws of some countries outside of the United States and Europe do not afford intellectual property protection to the same extent as the laws of the United States and Europe. Many companies have encountered significant problems in protecting and defending intellectual property rights in certain foreign jurisdictions. The legal systems of some countries, including India, China and other developing countries, do not favor the enforcement of patents and other intellectual property rights. This could make it difficult for us to stop the infringement of our patents or the misappropriation of our other intellectual property rights. For example, many foreign countries have compulsory licensing laws under which a patent owner must grant licenses to third parties. Consequently, we may not be able to prevent third parties from practicing our inventions in certain countries outside the United States and Europe.

Proceedings to enforce our future patent rights, if any, in foreign jurisdictions could result in substantial cost and divert our resources and attention from other aspects of our business. Moreover, such proceedings could put our patents at risk of being invalidated or interpreted narrowly and our patent applications at risk of not issuing and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate, and the damages or other remedies awarded, if any, may not be meaningful. Furthermore, while we intend to protect our intellectual property rights in major markets for our products, we cannot ensure that we will be able to initiate or maintain similar efforts in all jurisdictions in which we may wish to market our products. Accordingly, our efforts to protect our intellectual property rights in such countries may be inadequate.

Our commercial success depends upon our ability and the ability of our collaborators to develop, manufacture, market and sell our drug candidates and use our proprietary technologies without infringing the proprietary rights and intellectual property of third parties. The biotechnology and pharmaceutical industries are characterized by extensive and frequent litigation regarding patents and other intellectual property rights. We may in the future become party to, or threatened with, adversarial proceedings or litigation regarding intellectual property rights with respect to our drug candidates and technology, including interference proceedings before the USPTO.

Our competitors or other third parties may assert infringement claims against us, alleging that our drugs are covered by their patents. Given the vast number of patents in our field of technology, we cannot be certain that we do not infringe existing patents or that we will not infringe patents that may be granted in the future. Numerous United States and foreign issued patents and pending patent applications, which are owned by third parties, exist in the fields in which we are developing products, some of which may be directed at claims that overlap with the subject matter of our intellectual property. In addition, because patent applications can take many years to issue, there may be currently pending applications, unknown to us, which may later result in issued patents that our product candidates or proprietary technologies may infringe. Similarly, there may be issued patents relevant to our product candidates of which we are not aware. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until 18 months after a first filing, or in some cases not at all. Therefore, we cannot know with certainty whether we or our licensors were the first to make the inventions claimed in patents or pending patent applications that we own or licensed, or that we or our licensors were the first to file for patent protection of such inventions.

S-48

TABLE OF CONTENTS

We are aware of certain patents that may pose issues for our commercialization of our drug candidates. If we decide to initiate proceedings to challenge the validity of these patents in the future, we may be unsuccessful, as courts or patent offices in the United States and abroad could uphold the validity of any such patents. If we were to challenge the validity of any issued United States patent in court, we would need to overcome a statutory presumption of validity that attaches to every United States patent. This means that in order to prevail, we would have to present clear and convincing evidence as to the invalidity of the patent’s claims. If we are unable to do so, we may be forced to delay the launch of ublituximab or launch at the risk of litigation for patent infringement, which may have a material adverse effect on our business and results of operations.

If a third-party claims that we or any collaborators of ours infringe their intellectual property rights, we may have to defend litigation or administrative proceedings which may be costly whether we win or lose, and which could result in a substantial diversion of our financial and management resources. If we are found to infringe a third party’s intellectual property rights, we could be required to obtain a license from such third party to continue developing and marketing our drug candidates and technology. However, we may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain such a license, it could be granted on non-exclusive terms, thereby providing our competitors and other third parties access to the same technologies licensed to us. Without such a license, we could be forced, including by court order, to cease developing and commercializing the infringing technology or drug candidates. In addition, we could be found liable for monetary damages, including treble damages and attorneys fees if we are found to have willfully infringed such third-party patent rights. A finding of infringement could prevent us from commercializing our drug candidates or force us to cease some of our business operations, which could materially harm our business.

No assurance can be given that patents issued to third parties do not exist, have not been filed, or could not be filed or issued, which contain claims covering its products, technology or methods that may encompass all or a portion of our products and methods. Given the number of patents issued and patent applications filed in our technical areas or fields, we believe there is a risk that third parties may allege they have patent rights encompassing our products or methods.

Other product candidates that we may in-license or acquire could be subject to similar risks and uncertainties.

We may need to license certain intellectual property from third parties, and such licenses may not be available or may not be available on commercially reasonable terms.

A third party may hold intellectual property, including patent rights that are important or necessary to the development and commercialization of our products. It may be necessary for us to use the patented or proprietary technology of third parties to commercialize our products, in which case we would be required to obtain a license from these third parties, whom may or may not be interested in granting such a license, on commercially reasonable terms, or our business could be harmed, possibly materially. For example, we engage extensively with third parties, including academic institutions, to conduct non-clinical and clinical research on our product candidates. While we seek to ensure all material transfer and service agreements governing this research provide us with favorable terms covering newly generated intellectual property, a general principle under which much of this research with academic institutions is conducted provides third-party ownership of newly generated intellectual property, with an exclusive option available for us to obtain a license to such intellectual property. Through the conduct of this research, it is possible that valuable intellectual property could be developed by a third party, which we will then need to license in order to better develop or commercialize our products. No assurance can be given that we will be able to successfully negotiate such a license on commercially reasonable terms, or at all. Further, should we fail to successfully negotiate a license to such intellectual property, most institutions are then free to license such intellectual property to any other third party, including potentially direct competitors of ours. Should we fail to adequately secure a license to any newly generated intellectual property, our ability to successfully develop or commercialize our products may be hindered, possibly materially.

We may be involved in lawsuits to protect or enforce our patents or the patents of our licensors, which could be expensive, time consuming and unsuccessful.

Competitors may infringe our patents or the patents of our licensors. To counter infringement or unauthorized use, we may be required to file infringement claims, which typically are very expensive, time-consuming and

S-49

TABLE OF CONTENTS

disruptive of day-to-day business operations. Any claims we assert against accused infringers could provoke these parties to assert counterclaims against us alleging invalidity of our or certain of our subsidiaries patents or that we infringe their patents; or provoke those parties to petition the USPTO to institute inter parties review against the asserted patents, which may lead to a finding that all or some of the claims of the patent are invalid. In addition, in an infringement proceeding, a court may decide that a patent of ours or our licensors is not valid or is unenforceable, or may refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation or defense proceedings could put one or more of our pending patents at risk of being invalidated, held unenforceable, or interpreted narrowly.

In patent litigation in the United States, defendant counterclaims challenging the validity, enforceability or scope of asserted patents are commonplace. In addition, third parties may initiate legal proceedings against us to assert such challenges to our intellectual property rights. The outcome of any such proceeding is generally unpredictable. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, including lack of novelty, obviousness or non-enablement. Patents may be unenforceable if someone connected with prosecution of the patent withheld relevant information from the USPTO or made a misleading statement during prosecution. It is possible that prior art of which we and the patent examiner were unaware during prosecution exists, which could render our patents invalid. Moreover, it is also possible that prior art may exist that we are aware of but do not believe is relevant to our current or future patents, but that could nevertheless be determined to render our patents invalid.

Competing drugs may also be sold in other countries in which our patent coverage might not exist or be as strong. If we lose a foreign patent lawsuit, alleging our infringement of a competitor’s patents, we could be prevented from marketing our drugs in one or more foreign countries. Any of these outcomes would have a materially adverse effect on our business.

In addition, 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. Furthermore, adverse results on United States patents may affect related patents in our global portfolio. The adverse result could also put related pending patent applications at risk of not issuing. Additionally, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. 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.

Interference proceedings provoked by third parties or brought by the USPTO may be necessary to determine the priority of inventions with respect to our patents or pending patent applications or those of our collaborators or licensors. An unfavorable outcome could require us to cease using the related technology or to attempt to license rights to it from the prevailing party. The costs of these proceedings could be substantial. As a result, the issuance, scope, validity, enforceability and commercial value of our or any of our respective licensors patent rights are highly uncertain. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms. Litigation or interference proceedings may fail and, even if successful, may result in substantial costs and distract our management and other employees. We may not be able to prevent, alone or with our licensors, misappropriation of our trade secrets or confidential information, particularly in countries where the laws may not protect those rights as fully as in the United States.

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 or misappropriating or from successfully challenging our intellectual property rights. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a material adverse effect on our ability to compete in the marketplace.

S-50

TABLE OF CONTENTS

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

In addition to the protection afforded by patents, we rely upon unpatented trade secret protection, unpatented know-how and continuing technological innovation to develop and maintain our competitive position. With respect to the building of our proprietary compound library, we consider trade secrets and know-how to be our primary intellectual property. We seek to protect our proprietary technology and processes, in part, by entering into confidentiality agreements with our collaborators, scientific advisors, employees and consultants, and invention assignment agreements with our consultants and employees. We may not be able to prevent the unauthorized disclosure or use of our technical know-how or other trade secrets by the parties to these agreements, however, despite the existence generally of confidentiality agreements and other contractual restrictions. Monitoring unauthorized uses and disclosures is difficult, and we do not know whether the steps we have taken to protect our proprietary technologies will be effective. If any of the collaborators, scientific advisors, employees and consultants who are parties to these agreements breaches or violates the terms of any of these agreements, we may not have adequate remedies for any such breach or violation, and we could lose our trade secrets as a result. Enforcing a claim that a third party illegally obtained and is using our trade secrets, like patent litigation, is expensive and time-consuming, and the outcome is unpredictable. In addition, courts outside the United States are sometimes less willing to protect trade secrets.

Our trade secrets could otherwise become known or be independently discovered by our competitors. Competitors could purchase our drug candidates and attempt to replicate some or all of the competitive advantages we derive from our development efforts, willfully infringe our intellectual property rights, design around our protected technology or develop their own competitive technologies that fall outside of our intellectual property rights. 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, or those to whom they communicate it, from using that technology or information to compete with us. If our trade secrets are not adequately protected so as to protect our market against competitors’ drugs, our competitive position could be adversely affected, as could our business.

We may be subject to damages resulting from claims that we or our employees have wrongfully used or disclosed alleged trade secrets of our competitors or are in breach of non-competition or non-solicitation agreements with our competitors.

We could in the future be subject to claims that we or our employees have inadvertently or otherwise used or disclosed alleged trade secrets or other proprietary information of former employers or competitors. Although we try to ensure that our employees and consultants do not use the intellectual property, proprietary information, know-how or trade secrets of others in their work for us, we may in the future be subject to claims that we caused an employee to breach the terms of his or her non-competition or non-solicitation agreement, or that we or these individuals have, inadvertently or otherwise, used or disclosed the alleged trade secrets or other proprietary information of a former employer or competitor. Litigation may be necessary to defend against these claims. Even if we are successful in defending against these claims, litigation could result in substantial costs and could be a distraction to management. If our defenses to these claims fail, in addition to requiring us to pay monetary damages, a court could prohibit us from using technologies or features that are essential to our drug candidates, if such technologies or features are found to incorporate or be derived from the trade secrets or other proprietary information of the former employers. An inability to incorporate such technologies or features would have a material adverse effect on our business and may prevent us from successfully commercializing our drug candidates. In addition, we may lose valuable intellectual property rights or personnel as a result of such claims. Moreover, any such litigation or the threat thereof may adversely affect our ability to hire employees or contract with independent sales representatives. A loss of key personnel or their work product could hamper or prevent our ability to commercialize our drug candidates, which would have an adverse effect on our business, results of operations and financial condition.

S-51

TABLE OF CONTENTS

Risks related to employee matters, managing growth and other risks related to our business

If we fail to attract and keep key management and clinical development personnel, we may be unable to successfully develop or commercialize our product candidates.

We are highly dependent on the research and development, clinical, business development, financial and legal expertise of our senior management team as well as the other principal members of our management, scientific and clinical team. Although we have entered into an employment agreement with our chief executive officer and employment letters with our senior managers, each of our executive officers may terminate their employment with us at any time. We do not maintain key person insurance for any of our executives or other employees. In addition, we rely on consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and development and commercialization strategy. Our consultants and advisors may be employed by employers other than us and may have commitments under consulting or advisory contracts with other entities that may limit their availability to us. If we are unable to continue to attract and retain high quality personnel, our ability to pursue our growth strategy will be limited.

We expect to continue hiring qualified development personnel. Recruiting and retaining qualified scientific, clinical, manufacturing and sales and marketing personnel will be critical to our success. The loss of the services of our chief executive officer or other key employees could impede the achievement of our research, development and commercialization objectives and seriously harm our ability to successfully implement our business strategy. Furthermore, replacing key employees may be difficult and may take an extended period of time because of the limited number of individuals in our industry with the breadth of skills and experience required to successfully develop, gain regulatory approval of and commercialize drugs. Competition to hire from this limited pool is intense, and we may be unable to hire, train, retain or motivate these key personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for similar personnel. Failure to succeed in clinical trials may make it more challenging to recruit and retain qualified medical and scientific personnel. If we are not able to attract and retain the necessary personnel to accomplish our business objectives, we may experience constraints that will impede significantly the achievement of our development objectives, our ability to raise additional capital, and our ability to implement our business strategy.

We will need to develop and expand our business, and we may encounter difficulties in managing this development and expansion, which could disrupt our operations.

As of November 4, 2020, we had 217 full-time employees, and we expect to continue to increase our number of employees and expand the scope of our operations. Our management and medical, commercial, and scientific personnel, systems and facilities currently in place will not be adequate to support our anticipated future growth. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Also, our management may need to divert a disproportionate amount of its attention away from its day-to-day activities and devote a substantial amount of time to managing these development activities. Due to our limited resources, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. This may result in weaknesses in our infrastructure, give rise to operational mistakes, loss of business opportunities, loss of employees and reduced productivity among remaining employees. To accommodate growth, additional physical expansion of our operations in the future may lead to significant costs, including capital expenditures, and may divert financial resources from other projects, such as the development of our drug candidates. If our management is unable to effectively manage our expected development and expansion, our expenses may increase more than expected, our ability to generate or increase our revenue could be reduced and we may not be able to implement our business strategy. Our future financial performance and our ability to commercialize our drug candidates, if approved, and compete effectively will depend, in part, on our ability to effectively manage the future development and expansion of our business.

Additionally, to help manage the expanding needs, we may utilize the services of outside vendors or consultants to perform tasks including clinical trial management, statistics and analysis, regulatory affairs, formulation

S-52

TABLE OF CONTENTS

development, chemistry, manufacturing, controls, and other pharmaceutical development functions. Our growth strategy may also entail expanding our group of contractors or consultants to implement these tasks going forward. Because we rely on a substantial number of consultants, effectively outsourcing many key functions of our business, we will need to be able to effectively manage these consultants to ensure that they successfully carry out their contractual obligations and meet expected deadlines. However, if we are unable to effectively manage our outsourced activities or if the quality or accuracy of the services provided by consultants is compromised for any reason, our clinical trials may be extended, delayed or terminated, and we may not be able to obtain regulatory approval for our product candidates or otherwise advance our business. There can be no assurance that we will be able to manage our existing consultants or find other competent outside contractors and consultants on economically reasonable terms, or at all. If we are not able to effectively expand our organization by hiring new employees and expanding our groups of consultants and contractors, we may be unable to successfully implement the tasks necessary to further develop and commercialize our product candidates and, accordingly, may not achieve our research, development and commercialization goals.

Unfavorable global economic conditions could adversely affect our business, financial condition or results of operations.

Our results of operations could be adversely affected by general conditions in the global economy and in the global financial markets. For example, the COVID-19 pandemic has caused extreme volatility and disruptions in the capital and credit markets. A severe or prolonged economic downturn could result in a variety of risks to our business, including, weakened demand for our drug candidates and our ability to raise additional capital when needed on acceptable terms, if at all. A weak or declining economy could also strain our suppliers, possibly resulting in supply disruption, or cause our customers to delay making payments for our services.

On January 31, 2019 (“Brexit Day”), the United Kingdom formally left the European Union. Although Brexit has already and may continue to adversely affect European and/or worldwide economic or market, political or regulatory conditions and may contribute to instability in the global financial markets, political institutions and regulatory agencies, the resulting immediate changes in foreign currency exchange rates have had a limited overall impact due to natural hedging. The long-term impact of Brexit, including on our business and our industry, will depend on the terms that are negotiated in relation to the United Kingdom’s future relationship with the European Union during the transition period which began on Brexit Day and is currently set to end on December 31, 2020. We are closely monitoring the Brexit developments in order to determine, quantify and proactively address changes as they become clear. Despite the Brexit developments, we do not expect macroeconomic conditions to have a significant impact on our liquidity needs, financial condition or results of operations.

Our internal computer systems, or those of our third-party CROs, CMOs, or other contractors or consultants, may fail or suffer security breaches, which could result in a material disruption of our drug candidates’ development programs.

Despite the implementation of security measures, our internal computer systems and those of our third-party CROs, CMOs, and other contractors and consultants are vulnerable to damage from computer viruses, unauthorized access, cyber-attacks or cyber-intrusions over the Internet, natural disasters, terrorism, war and telecommunication and electrical failures. While we have not experienced any such system failure, accident, or security breach to date, if such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our programs. For example, the loss of clinical trial data for our drug candidates could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. Furthermore, in preparing for potential commercialization of our first drug candidate, we anticipate that our computer systems will increase in magnitude and complexity. Building the systems and infrastructure required for commercialization with appropriate security measures may be time consuming and costly. In addition, there can be no assurance that our efforts will prevent breakdowns or breaches in our systems. To the extent that any disruption or security breach results in a loss of or damage to our data or applications or other data or applications relating to our technology or drug candidates, or inappropriate disclosure of confidential or proprietary information, we could incur financial, legal, business or reputational harm.

S-53

TABLE OF CONTENTS

Our employees, principal investigators, CROs, CMOs and consultants may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements and insider trading, which could have a material adverse effect on our business.

We are exposed to the risk that our employees, principal investigators, CROs, CMOs, and consultants may engage in fraudulent conduct or other illegal activity. Misconduct by these parties could include intentional failures to comply with FDA regulations, provide accurate information to the FDA, comply with manufacturing standards we have established, comply with federal and state healthcare fraud and abuse 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, misconduct, 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 also involve the improper use of information obtained in the course of clinical trials or creating fraudulent data in our pre-clinical studies or clinical trials, which could result in regulatory sanctions and cause serious harm to our reputation. We have adopted a code of ethics applicable to all of our employees, but 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 comply with these laws or regulations. In addition, we are subject to the risk that a person could allege such fraud or other misconduct, even if none occurred. If any such actions are instituted against us, regardless of the outcome, our reputation and our business may suffer. If we are not successful in defending ourselves or asserting our rights, those actions could lead to imposition of civil, criminal and administrative penalties, damages, monetary fines, possible exclusion from participation in Medicare, Medicaid and other federal healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, and curtailment of our operations, any of which could adversely affect our ability to operate our business.

Our third-party manufacturers may use hazardous materials in the production of our product candidates and if so, they must comply with environmental laws and regulations, which can be expensive and restrict how we or they do business.

Manufacturing activities for the production of our product candidates involve the controlled storage, use, and disposal of hazardous materials, including the components of our product candidates, and other hazardous compounds. Our third-party manufacturers and we are subject to federal, state, and local laws and regulations governing the use, manufacture, storage, handling, release, disposal of, and exposure to, these hazardous materials. Violation of these laws and regulations could lead to substantial fines and penalties. Although we believe that our safety procedures, and those of our third-party manufacturers, for handling and disposing of these materials comply with the standards prescribed by these laws and regulations, we cannot eliminate the risk of accidental contamination or injury from these materials. In the event of an accident, state or federal authorities may curtail our use of these materials and interrupt our business operations. In addition, we could become subject to potentially material liabilities relating to the investigation and cleanup of any contamination, whether currently unknown or caused by future releases.

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

We may acquire additional businesses or drugs, form strategic alliances or create joint ventures with third parties that we believe will complement or augment our existing business. If we acquire businesses with promising markets or technologies, we may not be able to realize the benefit of acquiring such businesses if we are unable to successfully integrate them with our existing operations and company culture. We may encounter numerous difficulties in developing, manufacturing and marketing any new drugs resulting from a strategic alliance or acquisition that delay or prevent us from realizing their expected benefits or enhancing our business. We cannot assure you that, following any such acquisition, we will achieve the expected synergies to justify the transaction.

S-54

TABLE OF CONTENTS

We may be subject to adverse legislative or regulatory tax changes that could negatively impact our financial condition.

The rules dealing with U.S. federal, state and local income taxation are constantly under review by persons involved in the legislative process and by the IRS and the U.S. Treasury Department. Changes to tax laws (which changes may have retroactive application) could adversely affect our stockholders or us. In recent years, many such changes have been made and changes are likely to continue to occur in the future. We cannot predict whether, when, in what form, or with what effective dates, tax laws, regulations and rulings may be enacted, promulgated or decided, which could result in an increase in our, or our stockholders, tax liability or require changes in the manner in which we operate in order to minimize increases in our tax liability.

On December 22, 2017, legislation commonly referred to as the Tax Act was signed into law and is generally effective after December 31, 2017. The Tax Act makes significant changes to the United States federal income tax rules for taxation of individuals and business entities. Most of the changes applicable to individuals are temporary and apply only to taxable years beginning after December 31, 2017 and before January 1, 2026. For corporations, the Tax Act reduces the top corporate income tax rate to 21% and repeals the corporate alternative minimum tax, limits the deduction for net interest expense, limits the deduction for net operating losses and eliminates net operating loss carrybacks, modifies or repeals many business deductions and credits, shifts the United States toward a more territorial tax system, and imposes new taxes to combat erosion of the U.S. federal income tax base. The Tax Act makes numerous other large and small changes to the federal income tax rules that may affect potential investors and may directly or indirectly affect us. We continue to examine the impact this tax reform legislation may have on our business. However, the effect of the Tax Act on us, whether adverse or favorable, is uncertain, and may not become evident for some period of time. This document does not discuss such legislation or the manner in which it might affect us or purchasers of our common stock. Prospective investors are urged to consult with their legal and tax advisors with respect to the Tax Act and any other regulatory or administrative developments and proposals, and their potential effects on them based on their unique circumstances.

Risks related to our common stock and being a publicly-traded company

Our stock price is, and we expect it to remain, volatile, which could limit investors ability to sell stock at a profit.

The trading price of our common stock has been and is likely to continue to be highly volatile and subject to wide fluctuations in price in response to various factors, many of which are beyond our control. These factors include:

•

publicity regarding actual or potential clinical results relating to products under development by our competitors or us;

•

delay or failure in initiating, completing or analyzing nonclinical or clinical trials or the unsatisfactory design or results of these trials;

•

achievement or rejection of regulatory approvals by our competitors or us;

•

announcements of technological innovations or new commercial products by our competitors or us;

•

developments concerning proprietary rights, including patents;

•

developments concerning our collaborations;

•

regulatory developments in the United States and foreign countries;

•

economic or other crises and other external factors such as the disruptions in the global economy caused by the COVID-19 pandemic;

•

period-to-period fluctuations in our revenues and other results of operations;

•

changes in financial estimates by securities analysts; and

S-55

TABLE OF CONTENTS

•

sales of our common stock by us.

We will not be able to control many of these factors, and we believe that period-to-period comparisons of our financial results will not necessarily be indicative of our future performance.

Our executive officers, directors, principal stockholders and their affiliates maintain the ability to exercise significant influence over our company and all matters submitted to stockholders for approval.

Our executive officers, directors and stockholders who own more than 5% of our outstanding common stock, together with their affiliates and related persons, beneficially own shares of common stock representing a significant percentage of our capital stock. As a result, if these stockholders were to choose to act together, they would be able to influence our management and affairs and the outcome of matters submitted to our stockholders for approval, including the election of directors and any sale, merger, consolidation, or sale of all or substantially all of our assets. This concentration of voting power could delay or prevent an acquisition of our company on terms that other stockholders may desire. In addition, this concentration of ownership might adversely affect the market price of our common stock by:

•

delaying, deferring or preventing a change of control of us;

•

impeding a merger, consolidation, takeover or other business combination involving us; or

•

discouraging a potential acquirer from making a tender offer or otherwise attempting to obtain control of us.

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

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. In addition, under the Loan Agreement, we are currently restricted from paying cash dividends, and we expect these restrictions to continue in the future. In addition, the terms of any future debt agreements may continue to preclude us from paying dividends. As a result, capital appreciation, if any, of our common stock will be the sole source of gain for our stockholders for the foreseeable future.

Provisions in our amended and restated certificate of incorporation and restated bylaws could have the effect of making it more difficult for a third party to acquire, or of discouraging a third party from attempting to acquire or control us. These factors could limit the price that certain investors might be willing to pay in the future for shares of our common stock. Our amended and restated certificate of incorporation allows us to issue preferred stock without the approval of our stockholders. The issuance of preferred stock could decrease the amount of earnings and assets available for distribution to the holders of our common stock or could adversely affect the rights and powers, including voting rights, of such holders. In certain circumstances, such issuance could have the effect of decreasing the market price of our common stock. Our restated bylaws eliminate the right of stockholders to call a special meeting of stockholders, which could make it more difficult for stockholders to effect certain corporate actions. Any of these provisions could also have the effect of delaying or preventing a change in control.

On July 18, 2014, the Board of Directors declared a distribution of one right for each outstanding share of common stock. The rights may have certain anti-takeover effects. The rights will cause substantial dilution to a person or group that attempts to acquire us on terms not approved by the Board of Directors unless the offer is conditioned on a substantial number of rights being acquired. However, the rights should not interfere with any

S-56

TABLE OF CONTENTS

merger, statutory share exchange or other business combination approved by the Board of Directors since the rights may be terminated by us upon resolution of the Board of Directors. Thus, the rights are intended to encourage persons who may seek to acquire control of the Company to initiate such an acquisition through negotiations with the Board of Directors. However, the effect of the rights may be to discourage a third party from making a partial tender offer or otherwise attempting to obtain a substantial equity position in the equity securities of, or seeking to obtain control of, the Company. To the extent any potential acquirers are deterred by the rights, the rights may have the effect of preserving incumbent management in office.

An active trading market for our common stock may not be sustained, and investors may not be able to resell their shares at or above the price they paid.

Although we have listed our common stock on the Nasdaq Capital Market, an active trading market for our shares may not be sustained. In the absence of an active trading market for our common stock, investors may not be able to sell their common stock at or above the price at which they acquired their shares or at the time that they would like to sell. An inactive trading market may also impair our ability to raise capital to continue to fund operations by selling shares and may impair our ability to acquire other companies or technologies by using our shares as consideration.

If equity research analysts do not publish research or reports about our business or if they publish negative evaluations of or downgrade our common stock, the price of our common stock could decline.

The trading market for our common stock relies in part on the research and reports that equity research analysts publish about us or our business. We do not control these analysts. We may never obtain research coverage by industry or financial analysts. If no or few analysts commence coverage of us, the trading price of our stock would likely decrease. Even if we do obtain analyst coverage, if one or more of the analysts covering our business downgrade their evaluations of our common stock, the price of our common stock could decline. If one or more of these analysts cease to cover our common stock, we could lose visibility in the market for our common stock, which in turn could cause our common stock price to decline.

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

As a public company, we incur significant legal, accounting and other expenses under the Sarbanes-Oxley Act of 2002, as well as rules subsequently implemented by the SEC, and the rules of any stock exchange on which we are listed. These rules impose various requirements on public companies, including requiring establishment and maintenance of effective disclosure and financial controls and appropriate corporate governance practices. Our team has devoted and will continue 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, these rules and regulations make it more difficult and more expensive for us to obtain director and officer liability insurance, and we may be required to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. As a result, it may be more difficult for us to attract and retain qualified persons to serve on our Board of Directors, our Board committees or as executive officers.

The Sarbanes-Oxley Act of 2002 requires, among other things, that we maintain effective internal control over financial reporting and disclosure controls and procedures. As a result, we are required to periodically perform an evaluation of our internal control over financial reporting to allow management to report on the effectiveness of those controls, as required by Section 404 of the Sarbanes-Oxley Act. Additionally, our independent auditors are required to perform a similar evaluation and report on the effectiveness of our internal control over financial reporting. These efforts to comply with Section 404 will require the commitment of significant financial and managerial resources. While we anticipate maintaining the integrity of our internal control over financial reporting and all other aspects of Section 404, we cannot be certain that a material weakness will not be identified when we test the effectiveness of our control systems in the future. If a material weakness is identified, we could be subject to sanctions or investigations by the SEC or other regulatory authorities, which would require additional

S-57

TABLE OF CONTENTS

financial and management resources, costly litigation or a loss of public confidence in our internal control, which could have an adverse effect on the market price of our stock.

Volatility in the price of our common stock may subject us to securities litigation, which could cause us to incur substantial costs and divert management’s attention, financial resources and other company assets.

In the past, securities class action litigation has often been brought against a company following periods of volatility in the market price of its securities. This risk is especially relevant for us because pharmaceutical companies have experienced significant stock price volatility in recent years. Past lawsuits and any future lawsuits to which we may become a party are subject to inherent uncertainties and will likely be expensive and time-consuming to investigate, defend and resolve, and will divert our management’s attention and financial and other resources. The outcome of litigation is necessarily uncertain, and we could be forced to expend significant resources in the defense of these and other suits, and we may not prevail. Any litigation to which we are a party may result in an onerous or unfavorable judgment that may not be reversed upon appeal or in payments of substantial monetary damages or fines, or we may decide to settle this or other lawsuits on similarly unfavorable terms, which could adversely affect our business, financial condition, results of operations or stock price.

Future sales of our common stock, including by us or our directors and executive officers or shares issued upon the exercise of currently outstanding options, could cause our stock price to decline.

A substantial portion of our outstanding common stock can be traded without restriction at any time. In addition, a portion of our outstanding common stock is currently restricted as a result of federal securities laws, but can be sold at any time subject to applicable volume limitations. As such, sales of a substantial number of shares of our common stock in the public market could occur at any time. These sales, or the perception in the market that the holders of a large number of shares intend to sell shares, by us or others, could reduce the market price of our common stock or impair our ability to raise adequate capital through the sale of additional equity securities. In addition, we have a significant number of shares that are subject to outstanding options. The exercise of these options and the subsequent sale of the underlying common stock could cause a further decline in our stock price. These sales also might make it difficult for us to sell equity securities in the future at a time and at a price that we deem appropriate. We cannot predict the number, timing or size of future issuances or the effect, if any, that any future issuances may have on the market price for our common stock.

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

Under Section 382 of the Internal Revenue Code of 1986, as amended, if a corporation undergoes an ownership change (generally defined as a greater than 50% change (by value) in the ownership of its equity over a 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 may be limited. We may have experienced such ownership changes in the past, and we may experience ownership changes in the future as a result of shifts in our stock ownership, some of which are outside our control. As of December 31, 2019, we had federal net operating loss carryforwards of approximately $709.9 million, and our ability to utilize those net operating loss carryforwards could be limited by an ownership change as described above, which could result in increased tax liability to us. In addition, pursuant to the Tax Act, we may not use net operating loss carry-forwards to reduce our taxable income in any year by more than 80%, and we may not carry back any net operating losses to prior years. On March 27, 2020, the “CARES Act” was signed by the U.S. President. Certain provisions of the CARES Act alter the rules regarding net-operating losses for such losses arising in 2018, 2019 and 2020. Such losses may be carried back for five years. Additionally, the CARES Act permits these net operating losses to offset up to 100% of our taxable income if used in 2020 or earlier years. We cannot assure you, however, of our ability to utilize these favorable offset rules within the applicable time period. These rules apply regardless of the occurrence of an ownership change.

S-58

TABLE OF CONTENTS

Capitalization

The following table sets forth our cash and cash equivalents, short-term investment securities, interest receivable and capitalization as of September 30, 2020:

•

on an actual basis; and

•

on an as-adjusted basis to give effect to this offering of common stock.

You should read this information together with our financial statements and the notes to those statements incorporated by reference into this prospectus supplement and the accompanying prospectus.

September 30, 2020 (unaudited) (in thousands)	Actual		As adjusted
Cash and cash equivalents(1)		254,154
Investment securities and interest receivable		—		—
Short-term debt(2)		14,590		14,590
Long-term debt(2)		15,074		15,074
Stockholders’ (deficit) equity:
Common stock, $0.001 par value per share, 150,000,000 shares authorized; 128,959,861 shares issued and 128,918,552 shares outstanding (actual); shares issued and shares outstanding (as adjusted)		129
Additional paid-in capital		1,063,142
Treasury stock, at cost, 41,309 shares		234		234
Accumulated deficit		892,379		892,379
Total stockholders’ (deficit) equity		170,658
Total capitalization		200,799

(1)

Does not include cash from ATM activity from September 30, 2020 through December 11, 2020.

(2)

Reflects principal amount of our term loan facility with Hercules, net of unamortized debt issuance costs, as of September 30, 2020. Our term loan facility provides for up to four separate advances, the first advance of which was drawn on the closing date of the facility, with two additional advances of $10.0 million to be drawn at our option but subject to certain clinical trial milestones, and a fourth advance of $10.0 million available through December 15, 2020 subject to the approval of Hercules’ investment committee (see Note 7 to our consolidated financial statements for more information).

The above table is based on 128,918,552 shares of common stock outstanding as of September 30, 2020, assumes no exercise of the underwriters’ option to purchase additional shares of common stock, and excludes, as of September 30, 2020:

•

2,529,133 shares of common stock issuable upon the exercise of outstanding stock options with a weighted average exercise price of $6.99 per share;

•

17,814 shares of common stock issuable upon the conversion of outstanding notes payable with a weighted average conversion price of $1,125 per share;

•

an aggregate of 5,054,913 shares of common stock reserved for future issuance under our stock option and incentive plans; and

•

147,058 shares of common stock issuable upon the exercise of outstanding warrants with a weighted average exercise price of $4.08 per share.

S-59

TABLE OF CONTENTS

Dilution

Purchasers of the shares offered by this prospectus supplement and the accompanying prospectus will suffer immediate and substantial dilution in the net tangible book value per share of the common stock they purchase. Net tangible book value per share represents the amount of total tangible assets less total liabilities, divided by the number of shares of our common stock outstanding as of September 30, 2020. Our net tangible book value as of September 30, 2020 was approximately $169.9 million, or $1.32 per share of our common stock.

Dilution in net tangible book value per share represents the difference between the amount per share paid by purchasers in this offering and the net tangible book value per share of our common stock immediately after this offering. After giving effect to the sale of shares of our common stock in this offering at a public price of $ per share, and after deducting the underwriting discount and the estimated expenses payable by us, our net tangible book value as of September 30, 2020 would have been approximately $ million, or $ per share of common stock. This represents an immediate increase in net book value of $ per share to our existing stockholders and an immediate dilution in net tangible book value of $ per share to new investors participating in this offering.

The following table illustrates this calculation on a per-share basis:

Public offering price per share			$
Net tangible book value per share as of September 30, 2020	$	1.32
Increase per share attributable to this offering	$
As adjusted net tangible book value per share as of September 30, 2020 after this offering			$
Dilution per share to new investors participating in this offering			$

•

2,529,133 shares of common stock issuable upon the exercise of outstanding stock options with a weighted average exercise price of $6.99 per share;

•

17,814 shares of common stock issuable upon the conversion of outstanding notes payable with a weighted average conversion price of $1,125 per share;

•

an aggregate of 5,054,913 shares of common stock reserved for future issuance under our stock option and incentive plans; and

•

147,058 shares of common stock issuable upon the exercise of outstanding warrants with a weighted average exercise price of $4.08 per share.

If the underwriters exercise in full their option to purchase additional shares of our common stock, the as adjusted net tangible book value after this offering would be $ per share, representing an increase in net tangible book value of $ per share to existing stockholders and immediate dilution in net tangible book value of $ per share to purchasers in this offering.

We may choose to raise additional capital through the sale of equity securities due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that any options or warrants are exercised, new options are issued under our equity incentive plans or we otherwise issue additional shares of common stock or other equity securities in the future at a price less than the public offering price, there will be further dilution to new investors. See “Risk factors—Risks Related to this Offering—You may experience future dilution as a result of future equity offerings.”

S-60

TABLE OF CONTENTS

Use of proceeds

The net proceeds to us from the sale of shares of our common stock will be approximately $ million, or approximately $ million if the underwriters exercise in full their option to purchase additional shares of common stock, in each case, after deducting underwriting discounts and estimated offering expenses payable by us.

We expect to use the net proceeds from this offering:

•

to fund the ongoing development of ublituximab (TG-1101) and umbralisib (TGR-1202);

•

to potentially in-license, acquire, develop and commercialize additional drug candidates; and

•

for general corporate purposes.

The timing and amounts of our actual expenditures will depend on several factors, including the progress of our research and development programs, the results of other pre-clinical and clinical studies and the timing and costs of regulatory approvals. Pending the uses described above, we may invest the net proceeds from this offering in short-term and long-term, investment-grade, interest-bearing securities. Pending application of the net proceeds, we may invest the net proceeds from this offering in short- and intermediate-term, interest-bearing obligations, investment-grade instruments, certificates of deposit or direct or guaranteed obligations of the U.S. government.

S-61

TABLE OF CONTENTS

Dividend policy

We have never declared or paid any cash dividends on our common stock and do not anticipate paying any cash dividends in the foreseeable future. Any future determination to pay dividends will be at the discretion of our Board of Directors.

S-62

TABLE OF CONTENTS

Material U.S. federal income tax consequences to non-U.S. holders

The following is a summary of the material United States federal income tax consequences relating to the acquisition, ownership and disposition of our common stock as of the date hereof. Except where noted, this summary deals only with our common stock that is held as a capital asset (within the meaning of Section 1221 of the Internal Revenue Code of 1986, as amended (the “Code”)) by a “non-U.S. holder” (as defined below).

For purposes of this summary, a “non-U.S. holder” means a beneficial owner of our common stock (other than a partnership or any other entity treated as a partnership for United States federal income tax purposes) that is not for United States federal income tax purposes any of the following:

•

an individual citizen or resident of the United States;

•

a corporation (or any other entity treated as a corporation for United States federal income tax purposes) created or organized in or under the laws of the United States, any state thereof or the District of Columbia;

•

an estate the income of which is subject to United States federal income taxation regardless of its source; or

•

a trust if it (1) is subject to the primary supervision of a court within the United States and one or more United States persons have the authority to control all substantial decisions of the trust or (2) has a valid election in effect under applicable United States Treasury regulations (“Treasury Regulations”) to be treated as a United States person.

You are not a non-U.S. holder if you are a nonresident alien individual present in the United States for 183 days or more in the taxable year of disposition, or if you are a former citizen or former resident of the United States for United States federal income tax purposes. If you are such a person, you should consult your tax adviser regarding the United States federal income tax consequences of the ownership and disposition of our common stock.

This summary is based upon provisions of the Code and Treasury Regulations, administrative rulings and judicial decisions currently in effect, all as of the date hereof and all subject to change at any time, possibly with retroactive effect, or to different interpretation by the Internal Revenue Service (“IRS”). This summary does not address all aspects of United States federal taxes, including the Medicare contribution tax, and does not address any foreign, state, local or other tax considerations that may be relevant to non-U.S. holders in light of their personal circumstances. In addition, this summary does not represent a detailed description of the United States federal income tax consequences applicable to non-U.S. holders that are subject to special treatment under the United States federal income tax laws (including a non-U.S. holder that is a United States expatriate or “controlled foreign corporation”). We cannot provide assurance that a change in law will not alter significantly the tax considerations that we describe in this summary.

If a partnership (or other entity treated as a partnership for U.S. federal income tax purposes) holds our common stock, the tax treatment of a partner will generally depend upon the status of the partner and the activities of the partnership. Non-U.S. holders that are partners of a partnership holding our common stock should consult their tax advisors.

Non-U.S. holders considering the purchase of our common stock should consult their own tax advisors concerning the particular United States federal income and estate tax consequences of the ownership of our common stock, as well as the consequences arising under the laws of any other taxing jurisdiction.

S-63

TABLE OF CONTENTS

Distribution on our common stock

Distributions paid on our common stock will be taxable as dividends to the extent paid out of current or accumulated earnings and profits, as determined under United States federal income tax principles. Dividends paid to a non-U.S. holder of our common stock generally will be subject to United States federal withholding tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty. However, dividends that are effectively connected with the conduct of a trade or business by the non-U.S. holder within the United States (and, if required by an applicable income tax treaty, are attributable to a United States permanent establishment) are not subject to United States federal withholding tax, provided certain certification and disclosure requirements are satisfied. Instead, such dividends are subject to United States federal income tax on a net-income basis in the same manner as if the non-U.S. holder were a “United States person” as defined in Section 7701(a)(30) of the Code. Any such “effectively connected” dividends received by a foreign corporation may, under certain circumstances, be subject to an additional “branch profits tax” at a 30% rate or such lower rate as may be specified by an applicable income tax treaty.

Subject to the discussion below under FATCA, a non-U.S. holder who wishes to claim the benefit of an applicable treaty rate and avoid backup withholding, as discussed below, for dividends will be required (a) to complete IRS Form W-8BEN or W-8BEN-E (or other applicable IRS Form) and certify under penalty of perjury that it is not a “United States person” as defined under the Code and is eligible for treaty benefits or (b) if the common stock is held through certain foreign intermediaries, to satisfy the relevant certification requirements of applicable Treasury Regulations. Special certification and other requirements apply to certain non-U.S. holders that are pass-through entities rather than corporations or individuals.

A non-U.S. holder eligible for a reduced rate of United States withholding tax pursuant to an income tax treaty may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

Gain on disposition of our common stock

Any gain realized on the disposition of our common stock by a non-U.S. holder generally will not be subject to United States federal income tax unless:

•

the gain is effectively connected with a trade or business of the non-U.S. holder in the United States (and, if required by an applicable income tax treaty, is attributable to a United States permanent establishment of the non-U.S. holder);

•

the non-U.S. holder is an individual who is present in the United States for 183 days or more in the taxable year of that disposition, and certain other conditions are met; or

•

we are or have been a “United States real property holding corporation” for United States federal income tax purposes at any time during the shorter of the five-year period ending on the date of the disposition or such non-U.S. holder’s holding period for our common stock and such non-U.S. holder held (at any time during the shorter of the five-year period ending on the date of the disposition or such non-U.S. holder’s holding period) more than 5% of our common stock.

An individual non-U.S. holder described in the first bullet point immediately above will be subject to tax on the net gain derived from the sale under regular graduated United States federal income tax rates. If a non-U.S. holder that is a foreign corporation falls under the first bullet point immediately above, it will be subject to tax on its net gain in the same manner as if it were a “United States person” as defined in the Code and, in addition, may under certain circumstances be subject to a branch profits tax equal to 30% of its effectively connected earnings and profits or at such lower rate as may be specified by an applicable income tax treaty.

Generally, a corporation is a “United States real property holding corporation” if the fair market value of its United States real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business (all as determined for United States federal income tax purposes).

S-64

TABLE OF CONTENTS

We believe we have not been and are not currently a “United States real property holding corporation” for United States federal income tax purposes; however, no assurance can be given that we are not or will not become one in the future. If, however, we are or become a “United States real property holding corporation,” so long as our common stock continues to be regularly traded on an established securities market, only a non-U.S. holder who holds, or held (at any time during the shorter of the five-year period ending on the date of disposition or the non-U.S. holder’s holding period) more than 5% of our common stock will be subject to United States federal income tax on the disposition of the common stock. Non-U.S. holders should consult their own tax advisors about the consequences if we are, or become, a “United States real property holding corporation.”

Information reporting and backup withholding

Information returns are required to be filed with the IRS reporting the amount of dividends paid to each non-U.S. holder and the tax withheld with respect to such dividends, regardless of whether withholding was required. Copies of the information returns reporting such dividends and withholding may also be made available to the tax authorities in the country in which the non-U.S. holder resides, under the provisions of an applicable income tax treaty.

A non-U.S. holder will be subject to backup withholding with respect to dividends paid to it unless it certifies under penalty of perjury that it is a non-U.S. holder (and the payor does not have actual knowledge or reason to know that the non-U.S. holder is a “United States person” as defined in the Code), or it otherwise establishes an exemption.

Information reporting and, depending on the circumstances, backup withholding will apply to the proceeds of a sale or other disposition of our common stock within the United States or conducted through certain United States-related financial intermediaries, unless the non-U.S. holder certifies under penalty of perjury that it is not a “United States person” as defined in the Code (and the payor does not have actual knowledge or reason to know that the non-U.S. holder is a “United States person” as defined in the Code), or it otherwise establishes an exemption.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a non-U.S. holder’s United States federal income tax liability, provided the required information is timely furnished to the IRS.

FATCA

Sections 1471 to 1474 of the Code (such sections, and the Treasury Regulations and administrative guidance issued thereunder, commonly referred to as FATCA) impose a 30% United States withholding tax on certain “withholdable payments” made to a “foreign entity.” “Withholdable payments” include payments of dividends. In general, if a non-U.S. holder is a “foreign financial institution,” the 30% withholding tax will apply to withholdable payments made to it, unless it enters into an agreement with the United States Department of Treasury to collect and provide substantial information regarding its United States account holders, including certain account holders that are foreign entities with United States owners. If it is a “non-financial foreign entity,” FATCA also generally will impose a withholding tax of 30% on withholdable payments made to it unless it provides the withholding agent with a certification that it does not have any “substantial United States owners” or a certification identifying its direct and indirect substantial United States owners. Intergovernmental agreements between the United States and a non-U.S. holder’s resident country may modify the foregoing requirements.

Non-U.S. holders should consult their own tax advisors regarding the impact of FATCA on their ownership and disposition of shares of our common stock and the potential applicability of any intergovernmental agreements.

S-65

TABLE OF CONTENTS

Underwriting

We are offering the shares of common stock described in this prospectus supplement through a number of underwriters. J.P. Morgan Securities LLC , Goldman Sachs & Co. LLC, Evercore Group L.L.C. and Cantor Fitzgerald & Co. are acting as representatives of the underwriters. We have entered into an underwriting agreement with the underwriters. Subject to the terms and conditions of the underwriting agreement, we have agreed to sell to the underwriters, and each underwriter has severally agreed to purchase, at the public offering price less the underwriting discounts and commissions set forth on the cover page of this prospectus supplement, the number of shares of common stock listed next to its name in the following table:

Name			Number of Shares
J.P. Morgan Securities LLC
Goldman Sachs & Co. LLC
Evercore Group L.L.C.
Cantor Fitzgerald & Co.
Total

The underwriters are committed to purchase all the shares of common stock offered by us if they purchase any shares. The underwriting agreement also provides that if an underwriter defaults, the purchase commitments of non-defaulting underwriters may also be increased or the offering may be terminated.

The underwriters propose to offer the shares of common stock directly to the public at the initial public offering price set forth on the cover page of this prospectus supplement and to certain dealers at that price less a concession not in excess of $ per share. Any such dealers may resell shares to certain other brokers or dealers at a discount of up to $ per share from the initial public offering price. After the initial offering of the shares to the public, if all of the shares of common stock are not sold at the initial public offering price, the underwriters may change the offering price and the other selling terms. Sales of any shares made outside of the United States may be made by affiliates of the underwriters.

The underwriters have an option to buy up to additional shares of common stock from us. The underwriters have 30 days from the date of this prospectus supplement to exercise this option to purchase additional shares. If any shares are purchased with this option to purchase additional shares, the underwriters will purchase shares in approximately the same proportion as shown in the table above. If any additional shares of common stock are purchased, the underwriters will offer the additional shares on the same terms as those on which the shares are being offered.

The underwriting fee is equal to the public offering price per share of common stock less the amount paid by the underwriters to us per share of common stock. The underwriting fee is $ per share. The following table shows the per share and total underwriting discounts and commissions to be paid to the underwriters assuming both no exercise and full exercise of the underwriters’ option to purchase additional shares.

Without
option to
purchase
additional shares
exercise

With full
option to
purchase
additional shares
exercise

Per Share

Total

We estimate that the total expenses of this offering, including registration, filing and listing fees, printing fees and legal and accounting expenses, but excluding the underwriting discounts and commissions, will be approximately $ . We have agreed to reimburse the underwriters for certain expenses related to clearance of this offering with the Financial Industry Regulatory Authority, Inc.

S-66

TABLE OF CONTENTS

A prospectus in electronic format may be made available on the web sites maintained by one or more underwriters, or selling group members, if any, participating in the offering. The underwriters may agree to allocate a number of shares to underwriters and selling group members for sale to their online brokerage account holders. Internet distributions will be allocated by the representatives to underwriters and selling group members that may make Internet distributions on the same basis as other allocations.

For a period of 60 days after the date of this prospectus supplement, we have agreed that we will not (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, or submit to, or file with, the SEC a registration statement under the Securities Act relating to, any shares of our common stock or any securities convertible into or exercisable or exchangeable for any shares of our common stock, or publicly disclose the intention to undertake any of the foregoing, (ii) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of any shares of common stock or any such other securities, whether any such transaction described in clauses (i) and (ii) above is to be settled by delivery of shares of common stock or such other securities, in cash or otherwise, in each case without the prior written consent of J.P. Morgan Securities LLC, other than the shares of our common stock to be sold in this offering or (iii) issue and sell shares of our common stock pursuant to our ATM.

The restrictions on our actions, as described above, do not apply to certain transactions, including (i) the issuance of shares of common stock or securities convertible into or exercisable for shares of our common stock pursuant to the conversion or exchange of convertible or exchangeable securities or the exercise of warrants or options (including net exercise) or the settlement of RSUs (including net settlement), in each case outstanding on the date of the underwriting agreement and described in this prospectus supplement; (ii) grants of stock options, stock awards, restricted stock, RSUs, or other equity awards and the issuance of shares of our common stock or securities convertible into or exercisable or exchangeable for shares of our common stock (whether upon the exercise of stock options or otherwise) to our employees, officers, directors, advisors, or consultants pursuant to the terms of an equity compensation plan in effect as of the closing of this offering and described in this prospectus supplement; provided that such recipients enter into a lock-up agreement with the underwriters; or (iii) our filing of any registration statement on Form S-8 relating to securities granted or to be granted pursuant to any plan in effect on the date of the underwriting agreement and described in this prospectus supplement or any assumed benefit plan pursuant to an acquisition or similar strategic transaction.

Our directors and executive officers, and certain of our significant stockholders (such persons, the lock-up parties) have entered into lock-up agreements with the underwriters prior to the commencement of this offering pursuant to which each lock-up party, with limited exceptions, for a period of 45 days after the date of this prospectus supplement (such period, the restricted period), may not (and may not cause any of their direct or indirect affiliates to), without the prior written consent of J.P. Morgan Securities LLC, (i) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend or otherwise transfer or dispose of, directly or indirectly, any shares of our common stock or any securities convertible into or exercisable or exchangeable for our common stock (including, without limitation, common stock or such other securities which may be deemed to be beneficially owned by such lock-up parties in accordance with the rules and regulations of the SEC and securities which may be issued upon exercise of a stock option or warrant (collectively with the common stock, the lock-up securities)), (ii) enter into any hedging, swap or other agreement or transaction that transfers, in whole or in part, any of the economic consequences of ownership of the lock-up securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of lock-up securities, in cash or otherwise, (iii) make any demand for, or exercise any right with respect to, the registration of any lock-up securities, or (iv) publicly disclose the intention to do any of the foregoing. Such persons or entities have further acknowledged that these undertakings preclude them from engaging in any hedging or other transactions or arrangements (including, without limitation, any short sale or the purchase or sale of, or entry into, any put or call option, or combination thereof, forward, swap or any other derivative transaction or instrument, however described or defined) designed or intended, or which could reasonably be expected to lead to or result in, a sale or disposition or transfer (by any person or entity, whether or not a signatory to such agreement) of any economic consequences of ownership, in whole or in part,

S-67

TABLE OF CONTENTS

directly or indirectly, of any lock-up securities, whether any such transaction or arrangement (or instrument provided for thereunder) would be settled by delivery of lock-up securities, in cash or otherwise. According to a Schedule 13G Statement filed on June 10, 2020 by RA Capital Management, L.P., RA Capital Management, L.P. beneficially owns 12,788,457 shares of our common stock, exceeding 10% of our common stock on May 31, 2020. Neither RA Capital Management, L.P. nor any of its affiliates is entering into a lock-up agreement with the underwriters prior to the commencement of this offering.

The restrictions described in the immediately preceding paragraph and contained in the lock-up agreements between the underwriters and the lock-up parties do not apply, subject in certain cases to various conditions, to certain transactions, including (a) transfers of lock-up securities: (i) as bona fide gift or gifts, or for bona fide estate planning purposes, (ii) by will or intestacy, (iii) to any trust for the direct or indirect benefit of the lock-up party or its immediate family member, or if the lock-up party is a trust, to a trustor or beneficiary of the trust or to the estate of a beneficiary of such trust, (iv) to a partnership, limited liability company or other entity of which the lock-up party and its immediate family members are the legal and beneficial owner of all of the outstanding equity securities or similar interests, (v) to a nominee or custodian of a person or entity to whom a disposition or transfer would be permissible under clauses (i) through (iv), (vi) in the case of a corporation, partnership, limited liability company, trust or other business entity, (A) to another corporation, partnership, limited liability company, trust or other business entity that is an affiliate (as defined in Rule 405 promulgated under the Securities Act) of the lock-up party, or to any investment fund or other entity controlling, controlled by, managing or managed by or under common control with the lock-up party or its affiliates or (B) as part of a distribution to members or stockholders of the lock-up party, (vii) by operation of law, (viii) to us from an employee of the Company upon death, disability or termination of employment of such employee, (ix) as part of a sale of lock-up securities acquired in open market transactions after the completion of this offering, (x) to us in connection with the vesting, settlement or exercise of restricted stock units, options, warrants or other rights to purchase shares of our common stock (including, in each case, by way of “net” or “cashless” exercise), including for the payment of exercise price and tax and remittance payments or (xi) pursuant to a bona fide third-party tender offer, merger, consolidation or other similar transaction approved by our Board of Directors and made to all stockholders involving a change in control, provided that if such transaction is not completed, all such lock-up securities would remain subject to the restrictions in the immediately preceding paragraph; (b) exercise of the options, settlement of RSUs or other equity awards, or the exercise of warrants granted pursuant to plans described in in this prospectus supplement; provided that any lock-up securities received upon such exercise, vesting or settlement would be subject to restrictions similar to those in the immediately preceding paragraph; (c) the conversion of outstanding preferred stock, warrants to acquire preferred stock, or convertible securities into shares of our common stock or warrants to acquire shares of our common stock; provided that any common stock or warrant received upon such conversion would be subject to restrictions similar to those in the immediately preceding paragraph; and (d) the establishment by lock-up parties of trading plans pursuant to Rule 10b5-1 under the Exchange Act; provided that such plans do not provide for the transfer of lock-up securities during the restricted period and no filing by any party under the Exchange Act or other public announcement would be required or made voluntarily in connection with such trading plans.

J.P. Morgan Securities LLC, in its sole discretion, may release the securities subject to any of the lock-up agreements with the underwriters described above, in whole or in part at any time.

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act.

Our common stock is listed on the Nasdaq Capital Market under the symbol “TGTX.”

In connection with this offering, the underwriters may engage in stabilizing transactions, which involves making bids for, purchasing and selling shares of common stock in the open market for the purpose of preventing or retarding a decline in the market price of the common stock while this offering is in progress. These stabilizing transactions may include making short sales of common stock, which involves the sale by the underwriters of a greater number of shares of common stock than they are required to purchase in this offering, and purchasing shares of common stock on the open market to cover positions created by short sales. Short sales may be

S-68

TABLE OF CONTENTS

“covered” shorts, which are short positions in an amount not greater than the underwriters’ option to purchase additional shares referred to above, or may be “naked” shorts, which are short positions in excess of that amount. The underwriters may close out any covered short position either by exercising their option to purchase additional shares, in whole or in part, or by purchasing shares in the open market. In making this determination, the underwriters will consider, among other things, the price of shares available for purchase in the open market compared to the price at which the underwriters may purchase shares through the option to purchase additional shares. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of the common stock in the open market that could adversely affect investors who purchase in this offering. To the extent that the underwriters create a naked short position, they will purchase shares in the open market to cover the position.

The underwriters have advised us that, pursuant to Regulation M of the Securities Act, they may also engage in other activities that stabilize, maintain or otherwise affect the price of the common stock, including the imposition of penalty bids. This means that if the representatives of the underwriters purchase common stock in the open market in stabilizing transactions or to cover short sales, the representatives can require the underwriters that sold those shares as part of this offering to repay the underwriting discount received by them.

These activities may have the effect of raising or maintaining the market price of the common stock or preventing or retarding a decline in the market price of the common stock, and, as a result, the price of the common stock may be higher than the price that otherwise might exist in the open market. If the underwriters commence these activities, they may discontinue them at any time. The underwriters may carry out these transactions on the Nasdaq Capital Market, in the over-the-counter market or otherwise.

Other than in the United States, no action has been taken by us or the underwriters that would permit a public offering of the securities offered by this prospectus supplement in any jurisdiction where action for that purpose is required. The securities offered by this prospectus supplement may not be offered or sold, directly or indirectly, nor may this prospectus supplement or any other offering material or advertisements in connection with the offer and sale of any such securities be distributed or published in any jurisdiction, except under circumstances that will result in compliance with the applicable rules and regulations of that jurisdiction. Persons into whose possession this prospectus supplement comes are advised to inform themselves about and to observe any restrictions relating to the offering and the distribution of this prospectus supplement. This prospectus supplement does not constitute an offer to sell or a solicitation of an offer to buy any securities offered by this prospectus supplement in any jurisdiction in which such an offer or a solicitation is unlawful.

Certain of the underwriters and their affiliates have provided in the past to us and our affiliates and may provide from time to time in the future certain commercial banking, financial advisory, investment banking and other services for us and such affiliates in the ordinary course of their business, for which they have received and may continue to receive customary fees and commissions. In addition, from time to time, certain of the underwriters and their affiliates may effect transactions for their own account or the account of customers, and hold on behalf of themselves or their customers, long or short positions in our debt or equity securities or loans, and may do so in the future. Cantor Fitzgerald & Co. is a sales agent under our ATM.

Selling restrictions

Notice to prospective investors in Canada

The shares may be sold only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the shares must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including any amendment thereto) contains a

S-69

TABLE OF CONTENTS

misrepresentation; provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

Notice to prospective investors in the European Economic Area and the United Kingdom

In relation to each Member State of the European Economic Area and the United Kingdom (each a “Relevant State”), no shares have been offered or will be offered pursuant to this offering to the public in that Relevant State prior to the publication of a prospectus in relation to the shares which has been approved by the competent authority in that Relevant State or, where appropriate, approved in another Relevant State and notified to the competent authority in that Relevant State, all in accordance with the Prospectus Regulation, except that offers of shares may be made to the public in that Relevant State at any time under the following exemptions under the Prospectus Regulation:

(a) to any legal entity which is a qualified investor as defined under the Prospectus Regulation;

(b) to fewer than 150 natural or legal persons (other than qualified investors as defined under the Prospectus Regulation), subject to obtaining the prior consent of the underwriters; or

provided that no such offer of shares shall require us or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Regulation or supplement a prospectus pursuant to Article 23 of the Prospectus Regulation and each person who initially acquires any shares or to whom any offer is made will be deemed to have represented, acknowledged and agreed to and with each of the underwriters and the Company that it is a “qualified investor” within the meaning of Article 2(e) of the Prospectus Regulation. In the case of any shares being offered to a financial intermediary as that term is used in the Prospectus Regulation, each such financial intermediary will be deemed to have represented, acknowledged and agreed that the shares acquired by it in the offer have not been acquired on a non-discretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in circumstances which may give rise to an offer of any shares to the public other than their offer or resale in a Relevant State to qualified investors as so defined or in circumstances in which the prior consent of the underwriters have been obtained to each such proposed offer or resale.

For the purposes of this provision, the expression an “offer to the public” in relation to shares in any Relevant State means the communication in any form and by any means of sufficient information on the terms of the offer and any shares to be offered so as to enable an investor to decide to purchase or subscribe for any shares, and the expression “Prospectus Regulation” means Regulation (EU) 2017/1129.

Notice to prospective investors in the United Kingdom

In addition, in the United Kingdom, this document is being distributed only to, and is directed only at, and any offer subsequently made may only be directed at persons who are “qualified investors” (as defined in the Prospectus Regulation) (i) who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”) and/or (ii) who are high net worth companies (or persons to whom it may otherwise be lawfully communicated) falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as relevant persons) or otherwise in circumstances which have not resulted and will not result in an offer to the public of the shares in the United Kingdom within the meaning of the Financial Services and Markets Act 2000.

S-70

TABLE OF CONTENTS

Any person in the United Kingdom that is not a relevant person should not act or rely on the information included in this document or use it as basis for taking any action. In the United Kingdom, any investment or investment activity that this document relates to may be made or taken exclusively by relevant persons.

Notice to prospective investors in Switzerland

The shares may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange (“SIX”) or on any other stock exchange or regulated trading facility in Switzerland. This document does not constitute a prospectus within the meaning of, and has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the shares or the offering may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, the Company, the shares have been or will be filed with or approved by any Swiss regulatory authority. In particular, this document will not be filed with, and the offer of shares will not be supervised by, the Swiss Financial Market Supervisory Authority FINMA (“FINMA”), and the offer of shares has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes (“CISA”). The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of shares.

Notice to prospective investors in Australia

This document:

•

does not constitute a disclosure document or a prospectus under Chapter 6D.2 of the Corporations Act 2001 (Cth) (the “Corporations Act”);

•

has not been, and will not be, lodged with the Australian Securities and Investments Commission (“ASIC”), as a disclosure document for the purposes of the Corporations Act and does not purport to include the information required of a disclosure document for the purposes of the Corporations Act; and

•

may only be provided in Australia to select investors who are able to demonstrate that they fall within one or more of the categories of investors, available under section 708 of the Corporations Act (“Exempt Investors”).

The shares may not be directly or indirectly offered for subscription or purchased or sold, and no invitations to subscribe for or buy the shares may be issued, and no draft or definitive offering memorandum, advertisement or other offering material relating to any shares may be distributed in Australia, except where disclosure to investors is not required under Chapter 6D of the Corporations Act or is otherwise in compliance with all applicable Australian laws and regulations. By submitting an application for the shares, you represent and warrant to us that you are an Exempt Investor.

As any offer of shares under this document will be made without disclosure in Australia under Chapter 6D.2 of the Corporations Act, the offer of those securities for resale in Australia within 12 months may, under section 707 of the Corporations Act, require disclosure to investors under Chapter 6D.2 if none of the exemptions in section 708 applies to that resale. By applying for the shares you undertake to us that you will not, for a period of 12 months from the date of issue of the shares, offer, transfer, assign or otherwise alienate those shares to investors in Australia except in circumstances where disclosure to investors is not required under Chapter 6D.2 of the Corporations Act or where a compliant disclosure document is prepared and lodged with ASIC.

Notice to prospective investors in Hong Kong

The shares have not been offered or sold and will not be offered or sold in Hong Kong, by means of any document, other than (a) to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571 of the Laws of Hong Kong) (the “SFO”) of Hong Kong and any rules made thereunder; or (b) in other circumstances which

S-71

TABLE OF CONTENTS

do not result in the document being a “prospectus” as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32) of Hong Kong) (the “CO”) or which do not constitute an offer to the public within the meaning of the CO. No advertisement, invitation or document relating to the shares has been or may be issued or has been or may be in the possession of any person for the purposes of issue, whether in Hong Kong or elsewhere, which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the SFO and any rules made thereunder.

Notice to prospective investors in Japan

The shares have not been and will not be registered pursuant to Article 4, Paragraph 1 of the Financial Instruments and Exchange Act. Accordingly, none of the shares nor any interest therein may be offered or sold, directly or indirectly, in Japan or to, or for the benefit of, any “resident” of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to or for the benefit of a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the Financial Instruments and Exchange Act and any other applicable laws, regulations and ministerial guidelines of Japan in effect at the relevant time.

Notice to prospective investors in Singapore

The underwriters have has acknowledged that this prospectus supplement has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, the underwriters have represented and agreed that they have not offered or sold any shares or caused the shares to be made the subject of an invitation for subscription or purchase and will not offer or sell any shares or cause the shares to be made the subject of an invitation for subscription or purchase, and have not circulated or distributed, nor will they circulate or distribute, this prospectus supplement or any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares, whether directly or indirectly, to any person in Singapore other than:

(a)

to an institutional investor (as defined in Section 4A of the Securities and Futures Act (Chapter 289) of Singapore, as modified or amended from time to time (the “SFA”)) pursuant to Section 274 of the SFA;

(b)

to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275 of the SFA; or

(c)

otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

(a)

a corporation (which is not an accredited investor (as defined in Section 4A of the SFA)) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or

(b)

a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary of the trust is an individual who is an accredited investor,

securities or securities-based derivatives contracts (each term as defined in Section 2(1) of the SFA) of that corporation or the beneficiaries’ rights and interest (howsoever described) in that trust shall not be transferred within six months after that corporation or that trust has acquired the shares pursuant to an offer made under Section 275 of the SFA except:

(i)

to an institutional investor or to a relevant person, or to any person arising from an offer referred to in Section 275(1A) or Section 276(4)(i)(B) of the SFA;

S-72

TABLE OF CONTENTS

(ii)

where no consideration is or will be given for the transfer;

(iii)

where the transfer is by operation of law;

(iv)

as specified in Section 276(7) of the SFA; or

(v)

as specified in Regulation 37A of the Securities and Futures (Offers of Investments) (Securities and Securities-based Derivatives Contracts) Regulations 2018.

Singapore SFA Product Classification—In connection with Section 309B of the SFA and the CMP Regulations 2018, unless otherwise specified before an offer of the shares, the Company has determined, and hereby notifies all relevant persons (as defined in Section 309A(1) of the SFA), that the shares are “prescribed capital markets products” (as defined in the CMP Regulations 2018) and Excluded Investment Products (as defined in MAS Notice SFA 04-N12: Notice on the Sale of Investment Products and MAS Notice FAA-N16: Notice on Recommendations on Investment Products).

Notice to prospective investors in Israel

This document does not constitute a prospectus under the Israeli Securities Law, 5728-1968, and has not been filed with or approved by the Israel Securities Authority. In Israel, this prospectus is being distributed only to, and is directed only at, qualified investors listed in the first addendum, or the Addendum, to the Israeli Securities Law. Qualified investors may be required to submit written confirmation that they fall within the scope of the Addendum. In addition, we may distribute and direct this document in Israel, at our sole discretion, to investors who are not considered qualified investors; provided that the number of such investors in Israel shall be no greater than 35 in any 12-month period.

Notice to prospective investors in the Dubai International Financial Centre (“DIFC”)

This document relates to an Exempt Offer in accordance with the Markets Rules 2012 of the Dubai Financial Services Authority (“DFSA”). This document is intended for distribution only to persons of a type specified in the Markets Rules 2012 of the DFSA. It must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus supplement nor taken steps to verify the information set forth herein and has no responsibility for this document. The securities to which this document relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the securities offered should conduct their own due diligence on the securities. If you do not understand the contents of this document you should consult an authorized financial advisor.

In relation to its use in the DIFC, this document is strictly private and confidential and is being distributed to a limited number of investors and must not be provided to any person other than the original recipient, and may not be reproduced or used for any other purpose. The interests in the securities may not be offered or sold directly or indirectly to the public in the DIFC.

Notice to prospective investors in the United Arab Emirates

The shares have not been, and are not being, publicly offered, sold, promoted or advertised in the United Arab Emirates (including the DIFC) other than in compliance with the laws of the United Arab Emirates (and the DIFC) governing the issue, offering and sale of securities. Further, this prospectus supplement does not constitute a public offer of securities in the United Arab Emirates (including the DIFC) and is not intended to be a public offer. This prospectus supplement has not been approved by or filed with the Central Bank of the United Arab Emirates, the Securities and Commodities Authority or the DFSA.

Notice to prospective investors in Bermuda

Shares may be offered or sold in Bermuda only in compliance with the provisions of the Investment Business Act of 2003 of Bermuda which regulates the sale of securities in Bermuda. Additionally, non-Bermudian persons

S-73

TABLE OF CONTENTS

(including companies) may not carry on or engage in any trade or business in Bermuda unless such persons are permitted to do so under applicable Bermuda legislation.

Notice to prospective investors in the British Virgin Islands

The shares are not being, and may not be offered to the public or to any person in the British Virgin Islands for purchase or subscription by or on behalf of the Company. The shares may be offered to companies incorporated under the BVI Business Companies Act, 2004 (British Virgin Islands) (“BVI Companies”), but only where the offer will be made to, and received by, the relevant BVI Company entirely outside of the British Virgin Islands.

Notice to prospective investors in China

This prospectus supplement will not be circulated or distributed in the PRC and the shares will not be offered or sold, and will not be offered or sold to any person for re-offering or resale directly or indirectly to any residents of the PRC except pursuant to any applicable laws and regulations of the PRC. Neither this prospectus supplement nor any advertisement or other offering material may be distributed or published in the PRC, except under circumstances that will result in compliance with applicable laws and regulations.

Notice to prospective investors in Taiwan

The shares have not been and will not be registered with the Financial Supervisory Commission of Taiwan pursuant to relevant securities laws and regulations and may not be sold, issued or offered within Taiwan through a public offering or in circumstances which constitutes an offer within the meaning of the Securities and Exchange Act of Taiwan that requires a registration or approval of the Financial Supervisory Commission of Taiwan. No person or entity in Taiwan has been authorized to offer, sell, give advice regarding or otherwise intermediate the offering and sale of the shares in Taiwan.

S-74

TABLE OF CONTENTS

Legal matters

Alston & Bird LLP, New York, New York has passed upon certain legal matters regarding the shares offered by this prospectus supplement. The underwriters are being represented in connection with this offering by Cravath, Swaine & Moore LLP, New York, New York.

Experts

The consolidated financial statements incorporated by reference herein and included in the TG Therapeutics, Inc. and subsidiaries Annual Report on Form 10-K for the year ended December 31, 2019 as well as the effectiveness of the TG Therapeutics, Inc. and subsidiaries internal control over financial reporting have been audited by CohnReznick LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

Where you can find more information

We file reports with the SEC on an annual basis using Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K. The SEC maintains a website that contains annual, quarterly, and current reports, proxy statements, and other information that issuers (including us) file electronically with the SEC. The SEC’s website address is http://www.sec.gov. You can also obtain copies of materials we file with the SEC from our website found at www.tgtherapeutics.com. Our stock is quoted on the Nasdaq Capital Market under the symbol “TGTX.”

Incorporation of certain information by reference

The SEC allows us to “incorporate by reference” the information we file with them which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus supplement and accompanying prospectus. The information incorporated by reference is considered to be part of this prospectus supplement and accompanying prospectus, and later information that we file with the SEC will automatically update and supersede this information. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act between the date of this prospectus supplement and the termination of the offering (other than, unless otherwise specifically indicated, current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items):

•

Our Annual Report on Form 10-K for the year ended December 31, 2019;

•

Our Proxy Statement on Schedule 14A filed with the SEC on April 29, 2020 (excluding any portions that were not incorporated by reference into Part III of our Annual Report on Form 10-K for the year ended December 31, 2019);

•

Our Quarterly Reports on Form 10-Q for the quarters ended each of March 31, 2020, June 30, 2020 and September 30, 2020; and

•

Our Current Reports on Form 8-K filed with the SEC on March 20, 2020, April 30, 2020, May 5, 2020, May 18, 2020, June 24, 2020, November 5, 2020, November 9, 2020 (relating to Item 8.01 and the corresponding Item 9.01), December 8, 2020 and December 10, 2020.

We will provide to each person, including any beneficial owner, to whom a copy of this prospectus supplement and the accompanying prospectus is delivered, a copy of any or all of the information that we have incorporated by reference into this prospectus supplement and the accompanying prospectus, but not delivered with this prospectus supplement and the accompanying prospectus (see Item 12(c)(1)(i) of Form S-3). We will provide this information upon written or oral request at no cost to the requester. You may request this information by contacting our corporate headquarters at the following address: 2 Gansevoort Street, 9th Floor, New York, New York 10014, Attn: Chief Financial Officer, or by calling (212) 554-4484.

S-75

TABLE OF CONTENTS

PROSPECTUS

Common Stock

Preferred Stock

Warrants

Debt Securities

Units

The following are types of securities that we may offer, issue and sell from time to time, together or separately:

•

shares of our common stock;

•

shares of our preferred stock;

•

warrants;

•

debt securities; and

•

units consisting of any combination of our common stock, preferred stock, warrants or debt securities.

We may offer our securities in one or more offerings in amounts, at prices, and on terms determined at the time of the offering. We may sell our securities through agents we select or through underwriters and dealers we select. If we use agents, underwriters or dealers, we will name them and describe their compensation in a prospectus or prospectus supplement.

This prospectus provides a general description of the securities we may offer. Each time we sell securities, we will provide specific terms of the securities offered in a supplement to this prospectus. The prospectus supplement may also add, update or change information contained in this prospectus. You should read this prospectus and the applicable prospectus supplement carefully before you invest in any securities. This prospectus may not be used to consummate a sale of securities unless accompanied by the applicable prospectus supplement.

Our common stock is traded on the Nasdaq Capital Market under the symbol “TGTX.” On September 4, 2019, the per share closing price of our common stock as reported on the Nasdaq Capital Market was $6.17 per share.

Investing in our securities involves certain risks. See “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2018, as well as our Quarterly Reports on Form 10-Q for the periods ended March 31, 2019 and June 30, 2019, which have been filed with the SEC and are incorporated by reference into this prospectus. You should read the entire prospectus carefully before you make your investment decision.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is September 5, 2019.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of an automatic “shelf registration” statement on Form S-3 that we filed with the Securities and Exchange Commission (“Commission” or “SEC”), as a “well-known seasoned issuer” as defined in Rule 405 under the Securities Act of 1933, as amended (the “Securities Act”). Under this shelf process, we may sell any combination of the securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities we may offer. We will provide the terms of these securities in supplements to this prospectus. The prospectus supplement may also add, update, or change information contained in this prospectus. We urge you to read both this prospectus and any prospectus supplement together with additional information described under the heading “Where You Can Find More Information” on page 13.

You should rely only on the information contained or incorporated by reference in this prospectus and any prospectus or prospectus supplement. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We will not make an offer to sell securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus, as well as information we previously filed with the SEC and have incorporated by reference, is accurate as of the date on the front cover of this prospectus only, or when such document was filed with the SEC. Our business, financial condition, results of operations and prospects may have changed since the relevant date.

We will not use this prospectus to offer and sell securities unless it is accompanied by a prospectus or prospectus supplement that more fully describes the terms of the offering.

When used in this prospectus, the terms “company,” “TGTX,” “issuer,” “we,” “our,” and “us” may refer to TG Therapeutics, Inc. and our consolidated subsidiaries, unless otherwise specified.

TG THERAPEUTICS, INC.

We are a biopharmaceutical company dedicated to developing and delivering medicines for patients with B-cell mediated diseases, including Chronic Lymphocytic Leukemia (CLL), non-Hodgkin Lymphoma (NHL) and Multiple Sclerosis (MS). We have developed a robust B-cell directed research and development (R&D) platform for identification of key B-cell pathways of interest and rapid clinical testing. Currently, we have five B-cell targeted drug candidates in clinical development, with the lead two therapies, ublituximab (TG-1101) and umbralisib (TGR-1202), in pivotal trials for CLL and NHL, with ublituximab also in pivotal trials for MS. Ublituximab is a novel anti-CD20 monoclonal antibody (mAb) that has been glycoengineered for enhanced potency over first generation antibodies. Umbralisib is an oral, once daily inhibitor of PI3K delta. Umbralisib also uniquely inhibits CK1-epsilon, which may allow it to overcome certain tolerability issues associated with first generation PI3K delta inhibitors. When used together in combination therapy, ublituximab and umbralisib are referred to as “U2”. Additionally, we have recently brought into Phase 1 clinical development TG-1501, an anti-PD-L1 monoclonal antibody, TG-1701, a covalently-bound Bruton’s Tyrosine Kinase (BTK) inhibitor, and TG-1801, an anti-CD47/CD19 bispecific antibody.

Our principal executive offices are located at 2 Gansevoort Street, 9th Floor, New York, New York 10014, and our telephone number is 212-554-4484. We maintain a website on the Internet at www.tgtherapeutics.com and our e-mail address is info@tgtxinc.com. Our Internet website, and the information contained on it, are not to be considered part of this prospectus.

TABLE OF CONTENTS

RISK FACTORS

Investing in our securities involves risks. You should carefully consider any specific risks discussed or incorporated by reference in the applicable prospectus supplement, together with all other information contained in the prospectus supplement or incorporated by reference in this prospectus. You should also consider the risks, uncertainties and assumptions discussed under the caption “Risk Factors” included in our Annual Report on Form 10-K for the year ended December 31, 2018, as well as our Quarterly Reports on Form 10-Q for the periods ended March 31, 2019 and June 30, 2019, which have been filed with the SEC and are incorporated by reference in this prospectus, and which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future.

TABLE OF CONTENTS

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, any prospectus supplement, the documents incorporated by reference herein and therein, other public filings and oral and written statements by us and our management, may include statements that constitute “forward-looking statements” within the meaning of the United States securities laws. These statements are based on the beliefs and assumptions of our management and on information available to us at the time such statements are made. Forward-looking statements include information concerning possible or assumed future results of our operations, expenses, earnings, liquidity, cash flows and capital expenditures, industry or market conditions, assets under management, acquisitions and divestitures, debt levels and our ability to obtain additional financing or make payments, regulatory developments, demand for and pricing of our products, the prospects for certain legal contingencies, and other aspects of our business or general economic conditions. In addition, when used in this prospectus, the documents incorporated by reference herein or such other documents or statements, words such as “believes,” “expects,” “anticipates,” “intends,” “plans,” “estimates,” “projects,” “forecasts,” and future or conditional verbs such as “will,” “may,” “could,” “should,” and “would,” and any other statement that necessarily depends on future events, are intended to identify forward-looking statements.

Forward-looking statements are not guarantees of performance. They involve risks, uncertainties and assumptions. Although we make such statements based on assumptions that we believe to be reasonable, there can be no assurance that actual results will not differ materially from our expectations. We caution investors not to rely unduly on any forward-looking statements.

The factors described in this prospectus, incorporated by reference into this prospectus or contained in our other filings with the Commission, among others, could cause our results to differ materially from any results described in any forward-looking statements.

For more discussion of the risks affecting us, please refer to the section above entitled “Risk Factors.”

You should consider the areas of risk described above in connection with any forward-looking statements that may be made by us and our businesses generally. We expressly disclaim any obligation to update any of the information in this or any other public filing if any forward-looking statement later turns out to be inaccurate, whether as a result of new information, future events or otherwise. For all forward-looking statements, we claim the “safe harbor” provided by Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”).

TABLE OF CONTENTS

USE OF PROCEEDS

Unless otherwise specified in connection with a particular offering of securities, the net proceeds from the sale of the securities offered by this prospectus will be used for general corporate purposes.

TABLE OF CONTENTS

DESCRIPTION OF COMMON STOCK

The following summary of the terms of our common stock may not be complete and is subject to, and qualified in its entirety by reference to, the terms and provisions of our amended and restated certificate of incorporation and our restated bylaws. You should refer to, and read this summary together with, our amended and restated certificate of incorporation and restated bylaws to review all of the terms of our common stock that may be important to you.

Common Stock

Under our certificate of incorporation, we are authorized to issue a total of 150,000,000 shares of common stock, par value $0.001 per share. As of August 23, 2019, we had 94,884,218 shares issued and 94,842,909 shares outstanding of our common stock. As of August 23, 2019, we have approximately 242 holders of record. All outstanding shares of our common stock are fully paid and nonassessable. Our common stock is listed on the Nasdaq Capital Market under the symbol “TGTX.”

Dividends

Subject to the dividend rights of the holders of any outstanding series of preferred stock, holders of our common stock are entitled to receive ratably such dividends and other distributions of cash or any other right or property as may be declared by our board of directors out of our assets or funds legally available for such dividends or distributions.

Voting Rights

The holders of our common stock are entitled to one vote for each share of common stock owned by that stockholder on every matter properly submitted to the stockholders for their vote. Stockholders are not entitled to vote cumulatively for the election of directors.

Liquidation and Dissolution

In the event of any voluntary or involuntary liquidation, dissolution or winding up of our affairs, holders of common stock would be entitled to share ratably in our assets that are legally available for distribution to stockholders after payment of liabilities. If we have any preferred stock outstanding at such time, holders of the preferred stock may be entitled to distributions and/or liquidation preferences. In either such case, we must pay the applicable distribution to the holders of our preferred stock (if any) before we may pay distributions to the holders of common stock.

Other

Holders of our common stock have no conversion, redemption, preemptive, subscription or similar rights.

Transfer Agent

American Stock Transfer and Trust Company serves as the transfer agent and registrar for all of our common stock.

Preferred Stock

Under the terms of our restated certificate of incorporation, our board of directors is authorized to issue up to 10,000,000 shares of preferred stock, par value $0.001 per share. Our board of directors may issues shares of preferred stock in one or more series without stockholder approval, and has the discretion to determine the rights, preferences, privileges and restrictions, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences, of each series of preferred stock. We may amend from time to time our restated certificate of incorporation to increase the number of authorized shares of preferred stock. Any such amendment would require the approval of the holders of a majority of the voting power of the shares entitled to vote thereon. As of the date of this prospectus, we have 10,000,000 shares of preferred shares authorized, but no shares of preferred stock outstanding.

TABLE OF CONTENTS

It is not possible to state the actual effect of the issuance of any shares of preferred stock upon the rights of the holders of common stock until the board of directors determines the specific rights of the holders of preferred stock. However, effects of the issuance of preferred stock include restricting dividends on common stock, diluting the voting power of common stock, impairing the liquidation rights of common stock, and making it more difficult for a third party to acquire us, which could have the effect of discouraging a third party from acquiring, or deterring a third party from paying a premium to acquire, a majority of our outstanding voting stock.

The particular terms of any series of preferred stock being offered by us will be described in the prospectus supplement relating to that series of preferred stock. Those terms may include:

•

the title and liquidation preference per share of the preferred stock and the number of shares offered;

•

the purchase price of the preferred stock;

•

the dividend rate (or method of calculation);

•

the dates on which dividends will be paid and the date from which dividends will begin to accumulate;

•

any redemption or sinking fund provisions of the preferred stock;

•

any listing of the preferred stock on any securities exchange or market;

•

any conversion provisions of the preferred stock;

•

the voting rights, if any, of the preferred stock; and

•

any additional dividend, liquidation, redemption, sinking fund and other rights, preferences, privileges, limitations and restrictions of the preferred stock.

The preferred stock will, when issued, be fully paid and non-assessable.

TABLE OF CONTENTS

DESCRIPTION OF WARRANTS

We may issue warrants to purchase shares of our common stock and/or preferred stock in one or more series together with other securities or separately, as described in each applicable prospectus supplement.

The prospectus supplement relating to any warrants we offer will include specific terms relating to the offering. These terms will include some or all of the following:

•

the title of the warrants;

•

the aggregate number of warrants offered;

•

the designation, number and terms of the shares of common stock purchasable upon exercise of the warrants and procedures by which those numbers may be adjusted;

•

the exercise price of the warrants;

•

the dates or periods during which the warrants are exercisable;

•

the designation and terms of any securities with which the warrants are issued;

•

if the warrants are issued as a unit with another security, the date on and after which the warrants and the other security will be separately transferable;

•

if the exercise price is not payable in U.S. dollars, the foreign currency, currency unit or composite currency in which the exercise price is denominated;

•

any minimum or maximum amount of warrants that may be exercised at any one time;

•

any terms relating to the modification of the warrants;

•

any terms, procedures and limitations relating to the transferability, exchange or exercise of the warrants; and

•

any other specific terms of the warrants.

TABLE OF CONTENTS

DESCRIPTION OF DEBT SECURITIES

We may offer debt securities which may be senior, subordinated or junior subordinated and may be convertible. Unless otherwise specified in the applicable prospectus supplement, our debt securities will be issued in one or more series under an indenture to be entered into between us and a trustee. We will issue the debt securities offered by this prospectus and any accompanying prospectus supplement under an indenture to be entered into between us and the trustee identified in the applicable prospectus supplement. The terms of the debt securities will include those stated in the indenture and those made part of the indenture by reference to the Trust Indenture Act of 1939, as in effect on the date of the indenture. We have filed a copy of the form of indenture as an exhibit to the registration statement in which this prospectus is included. The indenture will be subject to and governed by the terms of the Trust Indenture Act of 1939.

The following description briefly sets forth certain general terms and provisions of the debt securities that we may offer. The particular terms of the debt securities offered by any prospectus supplement and the extent, if any, to which these general provisions may apply to the debt securities, will be described in the related prospectus supplement. Accordingly, for a description of the terms of a particular issue of debt securities, reference must be made to both the related prospectus supplement and to the following description.

Debt Securities

The aggregate principal amount of debt securities that may be issued under the indenture is unlimited. The debt securities may be issued in one or more series as may be authorized from time to time pursuant to a supplemental indenture entered into between us and the trustee or an order delivered by us to the trustee. For each series of debt securities we offer, a prospectus supplement accompanying this prospectus will describe the following terms and conditions of the series of debt securities that we are offering, to the extent applicable:

•

title and aggregate principal amount;

•

whether the debt securities will be senior, subordinated or junior subordinated;

•

applicable subordination provisions, if any;

•

provisions regarding whether the debt securities will be convertible or exchangeable into other securities or property of the Company or any other person;

•

percentage or percentages of principal amount at which the debt securities will be issued;

•

maturity date(s);

•

interest rate(s) or the method for determining the interest rate(s);

•

whether interest on the debt securities will be payable in cash or additional debt securities of the same series;

•

dates on which interest will accrue or the method for determining dates on which interest will accrue and dates on which interest will be payable;

•

whether the amount of payment of principal of, premium, if any, or interest on the debt securities may be determined with reference to an index, formula or other method;

•

redemption, repurchase or early repayment provisions, including our obligation or right to redeem, purchase or repay debt securities under a sinking fund, amortization or analogous provision;

•

if other than the debt securities’ principal amount, the portion of the principal amount of the debt securities that will be payable upon declaration of acceleration of the maturity;

•

authorized denominations;

•

form;

•

amount of discount or premium, if any, with which the debt securities will be issued, including whether the debt securities will be issued as “original issue discount” securities;

TABLE OF CONTENTS

•

the place or places where the principal of, premium, if any, and interest on the debt securities will be payable;

•

where the debt securities may be presented for registration of transfer, exchange or conversion;

•

the place or places where notices and demands to or upon the Company in respect of the debt securities may be made;

•

whether the debt securities will be issued in whole or in part in the form of one or more global securities;

•

if the debt securities will be issued in whole or in part in the form of a book-entry security, the depository or its nominee with respect to the debt securities and the circumstances under which the book-entry security may be registered for transfer or exchange or authenticated and delivered in the name of a person other than the depository or its nominee;

•

whether a temporary security is to be issued with respect to such series and whether any interest payable prior to the issuance of definitive securities of the series will be credited to the account of the persons entitled thereto;

•

the terms upon which beneficial interests in a temporary global security may be exchanged in whole or in part for beneficial interests in a definitive global security or for individual definitive securities;

•

the guarantors, if any, of the debt securities, and the extent of the guarantees and any additions or changes to permit or facilitate guarantees of such debt securities;

•

any covenants applicable to the particular debt securities being issued;

•

any defaults and events of default applicable to the debt securities, including the remedies available in connection therewith;

•

currency, currencies or currency units in which the purchase price for, the principal of and any premium and any interest on, such debt securities will be payable;

•

time period within which, the manner in which and the terms and conditions upon which the Company or the purchaser of the debt securities can select the payment currency;

•

securities exchange(s) on which the debt securities will be listed, if any;

•

whether any underwriter(s) will act as market maker(s) for the debt securities;

•

extent to which a secondary market for the debt securities is expected to develop;

•

provisions relating to defeasance;

•

provisions relating to satisfaction and discharge of the indenture;

•

any restrictions or conditions on the transferability of the debt securities;

•

provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;

•

any addition or change in the provisions related to compensation and reimbursement of the trustee;

•

provisions, if any, granting special rights to holders upon the occurrence of specified events;

•

whether the debt securities will be secured or unsecured, and, if secured, the terms upon which the debt securities will be secured and any other additions or changes relating to such security; and

•

any other terms of the debt securities that are not inconsistent with the provisions of the Trust Indenture Act (but may modify, amend, supplement or delete any of the terms of the indenture with respect to such series of debt securities).

General

One or more series of debt securities may be sold as “original issue discount” securities. These debt securities would be sold at a substantial discount below their stated principal amount, bearing no interest or

TABLE OF CONTENTS

interest at a rate which at the time of issuance is below market rates. One or more series of debt securities may be variable rate debt securities that may be exchanged for fixed rate debt securities.

United States federal income tax consequences and special considerations, if any, applicable to any such series will be described in the applicable prospectus supplement.

Debt securities may be issued where the amount of principal and/or interest payable is determined by reference to one or more currency exchange rates, commodity prices, equity indices or other factors. Holders of such debt securities may receive a principal amount or a payment of interest that is greater than or less than the amount of principal or interest otherwise payable on such dates, depending upon the value of the applicable currencies, commodities, equity indices or other factors. Information as to the methods for determining the amount of principal or interest, if any, payable on any date, the currencies, commodities, equity indices or other factors to which the amount payable on such date is linked and certain additional United States federal income tax considerations will be set forth in the applicable prospectus supplement.

The term “debt securities” includes debt securities denominated in U.S. dollars or, if specified in the applicable prospectus supplement, in any other freely transferable currency or units based on or relating to foreign currencies.

We expect most debt securities to be issued in fully registered form without coupons and in denominations of $2,000 and any integral multiples thereof. Subject to the limitations provided in the indenture and in the prospectus supplement, debt securities that are issued in registered form may be transferred or exchanged at the principal corporate trust office of the trustee, without the payment of any service charge, other than any tax or other governmental charge payable in connection therewith.

Global Securities

The debt securities of a series may be issued in whole or in part in the form of one or more global securities that will be deposited with, or on behalf of, a depositary identified in the prospectus supplement. Global securities will be issued in registered form and in either temporary or definitive form. Unless and until it is exchanged in whole or in part for the individual debt securities, a global security may not be transferred except as a whole by the depositary for such global security to a nominee of such depositary or by a nominee of such depositary to such depositary or another nominee of such depositary or by such depositary or any such nominee to a successor of such depositary or a nominee of such successor. The specific terms of the depositary arrangement with respect to any debt securities of a series and the rights of and limitations upon owners of beneficial interests in a global security will be described in the applicable prospectus supplement.

Governing Law

The indenture and the debt securities shall be construed in accordance with and governed by the laws of the State of New York.

TABLE OF CONTENTS

DESCRIPTION OF UNITS

We may issue, in one more series, units comprised of shares of our common stock or preferred stock, warrants to purchase common stock or preferred stock, debt securities or any combination of those securities. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

We may evidence units by unit certificates that we issue under a separate agreement. We may issue the units under a unit agreement between us and one or more unit agents. If we elect to enter into a unit agreement with a unit agent, the unit agent will act solely as our agent in connection with the units and will not assume any obligation or relationship of agency or trust for or with any registered holders of units or beneficial owners of units. We will indicate the name and address and other information regarding the unit agent in the applicable prospectus supplement relating to a particular series of units if we elect to use a unit agent.

We will describe in the applicable prospectus supplement the terms of the series of units being offered, including:

•

the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

•

any provisions of the governing unit agreement that differ from those described herein; and

•

any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units.

The other provisions regarding our common stock, preferred stock, warrants and debt securities as described in this section will apply to each unit to the extent such unit consists of shares of our common stock, preferred stock, warrants and/or debt securities.

TABLE OF CONTENTS

PLAN OF DISTRIBUTION

We may sell the securities covered in this prospectus in any of three ways (or in any combination):

•

through underwriters or dealers;

•

directly to a limited number of purchasers or to a single purchaser; or

•

through agents.

Each time that we use this prospectus to sell securities, we will also provide a prospectus supplement that contains the specific terms of the offering. The prospectus supplement will set forth the terms of the offering of the securities, including:

•

the name or names of any underwriters, dealers or agents and the amounts of any securities underwritten or purchased by each of them; and

•

the public offering price and the proceeds to us and any discounts, commissions or concessions allowed or reallowed or paid to dealers.

Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

If underwriters are used in the sale of any securities, the securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The securities may be either offered to the public through underwriting syndicates represented by managing underwriters, or directly by underwriters. Generally, the underwriters’ obligations to purchase the securities will be subject to certain conditions precedent. The underwriters will be obligated to purchase all of the securities if they purchase any of securities.

We may sell the securities through agents from time to time. The prospectus supplement will name any agent involved in the offer or sale of the securities and any commissions we pay to them. Generally, any agent will be acting on a best efforts basis for the period of its appointment.

We may authorize underwriters, dealers or agents to solicit offers by certain purchasers to purchase the securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. The contracts will be subject only to those conditions set forth in the prospectus supplement, and the prospectus supplement will set forth any commissions we pay for solicitation of these contracts.

Agents and underwriters may be entitled to indemnification by us against certain civil liabilities, including liabilities under the Securities Act of 1933, as amended, or to contribution with respect to payments which the agents or underwriters may be required to make in respect thereof. Agents and underwriters may be customers of, engage in transactions with, or perform services for us in the ordinary course of business.

We may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of securities, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of securities. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement.

In compliance with the guidelines of the Financial Services Regulatory Authority, Inc., or FINRA, the maximum compensation to be received by a FINRA member or independent broker-dealer may not exceed 8% of the offering proceeds. It is anticipated that the maximum compensation to be received in any particular offering of securities will be less than this amount.

TABLE OF CONTENTS

WHERE YOU CAN FIND MORE INFORMATION

We file reports with the SEC on an annual basis using Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K. You may read and copy any such reports and amendments thereto at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549 on official business days during the hours of 10:00 a.m. to 3:00 p.m. Please call the SEC at 1-800-SEC-0330 for information on the Public Reference Room. Additionally, the SEC maintains a website that contains annual, quarterly, and current reports, proxy statements, and other information that issuers (including us) file electronically with the SEC. The SEC’s website address is http://www.sec.gov. You can also obtain copies of materials we file with the SEC from our Internet website found at www.tgtherapeutics.com. Our stock is quoted on the Nasdaq Capital Market under the symbol “TGTX.”

TABLE OF CONTENTS

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information we file with the SEC. This means that we can disclose important information to you by referring you to those documents without restating that information in this document. The information incorporated by reference into this prospectus is considered to be part of this prospectus, and information we file with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, after the date of this prospectus, will automatically update and supersede the information contained in this prospectus and documents listed below. We incorporate by reference into this prospectus the documents listed below, except to the extent information in those documents differs from information contained in this prospectus, and any future filings made by us with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including exhibits:

(a)

Our Annual Report on Form 10-K for the year ended December 31, 2018;

(b)

Our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2019 and June 30, 2019;

(c)

Our Current Reports on Form 8-K filed with the SEC on March 5, 2019, April 1, 2019, May 8, 2019, and June 13, 2019 (excluding any information pursuant to Item 2.02 or Item 9.01);

(d)

Our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 30, 2019; and

(e)

The description of our common stock contained in our registration statement on Form 8-A filed with the SEC on May 28, 2013 (File No. 001-32639).

We will provide to each person, including any beneficial owner, to whom a copy of this prospectus is delivered, a copy of any or all of the information that we have incorporated by reference into this prospectus. We will provide this information upon written or oral request at no cost to the requester. You may request this information by contacting our corporate headquarters at the following address: 2 Gansevoort Street, 9th Floor, New York, New York 10014, Attn: Chief Financial Officer, or by calling (212) 554-4484.

TABLE OF CONTENTS

LEGAL MATTERS

The legality and validity of the securities offered from time to time under this prospectus will be passed upon by Alston & Bird LLP, New York, New York.

EXPERTS

The consolidated financial statements incorporated by reference herein and included in the TG Therapeutics, Inc. and subsidiaries Annual Report on Form 10-K for the year ended December 31, 2018 as well as the effectiveness of the TG Therapeutics, Inc. and subsidiaries internal control over financial reporting have been audited by CohnReznick LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such consolidated financial statements have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

TABLE OF CONTENTS

TG Therapeutics, Inc.

Common Stock

Preferred Stock

Warrants

Debt Securities

Units

PROSPECTUS

September 5, 2019

TABLE OF CONTENTS

$200,000,000

TG Therapeutics, Inc.

Common Stock

PROSPECTUS SUPPLEMENT

Joint Book-Running Managers

J.P. Morgan Goldman Sachs & Co. LLC Evercore ISI Cantor

December , 2020

TG Therapeutics (TGTX) 424B5Prospectus supplement for primary offering