CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended ("Exchange Act"). Any statements about our expectations, beliefs, plans, objectives, assumptions, future events or performance are not historical facts and may be forward looking. These forward-looking statements include, but are not limited to, statements about:

These statements are often, but not always, made through the use of words or phrases such as “anticipate,” “estimate,” “plan,” “project,” “continuing,” “ongoing,” “expect,” “believe,” “intend” and similar words or phrases. Accordingly, these statements involve estimates, assumptions and uncertainties that could cause actual results to differ materially from those expressed in them. Discussions containing these forward-looking statements may be found throughout this Annual Report, including the sections entitled “Item 1. Business” in Part I and “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations” in Part II of this Annual Report. These forward-looking statements involve risks and uncertainties, including the risks discussed in the section entitled “Item 1A. Risk Factors” in Part I of this Annual Report that could cause our actual results to differ materially from those in the forward-looking statements. We undertake no obligation to update the forward-looking statements or to reflect events or circumstances after the date of this document, except as required by law. The risks discussed in this Annual Report should be considered in evaluating our prospects and future financial performance.

SUMMARY OF RISK FACTORS

Our business is subject to a number of risks of which you should be aware before making a decision to invest in our common stock, including those described in the section entitled “Item 1A. Risk Factors” in Part I of this Annual Report. These risks include, among others, the following:

PART I

Company Overview

Unless otherwise provided in this Annual Report, references to the “Company,” “we,” “us,” and “our” refer to Puma Biotechnology, Inc., a Delaware corporation formed on April and27, 2007 together with our wholly-owned subsidiaries Puma Biotechnology Ltd and Puma Biotechnology B.V.

We are a biopharmaceutical company with a focus on the developmentthat develops and commercialization ofcommercializes innovative products to enhance cancer care. Our lead product iscare and improve treatment outcomes for patients. We are currently commercializing NERLYNX, an oral version of neratinib, which is a potent irreversible tyrosine kinase inhibitor ("TKI") that blocks signal transduction through the human epidermal growth factor receptors, HER1, HER2 and HER4. In 2017, we obtained approval from the FDA to market, and commenced commercialization of NERLYNX in the United States for the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy. More recently, in February 2020, we received FDA approval to expand the indication for NERLYNX to include its use in combination with capecitabine for the treatment of adultHER2+ breast cancer. Additionally, we recently in-licensed, and are responsible for global development and commercialization of, alisertib. Alisertib is a selective, small-molecule inhibitor of aurora kinase A that is designed to disrupt mitosis leading to apoptosis of rapidly proliferating tumor cells that are dependent on aurora kinase A. Prior to our licensing alisertib from Takeda, alisertib was tested in over 1,300 patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimenswere treated across 22 company-sponsored trials resulting in the metastatic setting. Wea large, well-characterized clinical safety database. Based on information in this database, we believe neratinibalisertib has clinicalpotential application in the treatment of several other cancers as well,range of different cancer types, including other tumor types that over-express or have a mutation in HER2 or epidermal growth factorhormone receptor ("EGFR") such as cervicalpositive breast cancer, triple negative breast cancer, small cell lung cancer or other solid tumors.and head and neck cancer. We intend to pursue development of alisertib initially in small cell lung cancer and hormone receptor positive breast cancer.

The following figure provides an overview of our commercial product and product candidates.

*	EBC: Early breast cancer

**	MBC: Metastic breast cancer

***	HRc+: Hormone receptor positive

Neratinib

Breast cancer is the leading cause of cancer death among women worldwide. Studies show that upworldwide, with approximately 1 million new cases reported each year and more than 400,000 deaths per year. Up to 20% of breast cancer tumors have anshow over-expression of the HER2 protein. Women with breast cancer that over-expresses HER2, referred to as HER2-positive breast cancer, are at greater risk for disease progression and death than women whose tumors do not over-express HER2. Therapeutic strategies such as the use of trastuzumab (marketed as Herceptin ®), pertuzumab (marketed as Perjeta ®) and T-DM1 (marketed as Kadcyla ®), each produced by Genentech, lapatinib (marketed as Tykerb ®) produced by Novartis, fam‐trastuzumab deruxtecan (marketed as Enhertu ®) by Astra Zeneca and Daiichi Sankyo and tucatinib (Tukysa ®) marketed by Seagen, given either alone or in combination with chemotherapy, have been developed to block HER2 in order to improve the treatment of this type of breast cancer. Trastuzumab, pertuzumab, lapatinib, T-DM1, fam‐trastuzumab deruxtecan and tucatinib are all drugs are used as single agents, in combination with other drugs and in combination with chemotherapy to treat patients with HER2-positive breast cancer by binding to the HER2 protein. There are a number of trials ongoing that involveat various combinations of these drugs.stages.

Neratinib is a potent irreversible TKI that blocks signal transduction through the epidermal growth factor receptors, HER1, HER2 and HER4. Based on pre-clinical studies and clinical trials to date, we believe that neratinib may offer an advantage over existing treatments that are used in the treatment of patients with HER2-positive breast cancer, including treatment with trastuzumab, pertuzumab, and T-DM1, fam‐trastuzumab deruxtecan and tucatinib.cancer. We believe that by more potently inhibiting HER2 at a different site and/orand acting via a mechanism different from other agents, neratinib may have therapeutic benefits in breast cancer patients who have been previously treated with these existing treatments, most notably due to its increased selectivity and irreversible inhibition of the HER2 target enzyme.

NERLYNX, the commercial name for neratinib, is currently approved in the United States for two indications: the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy and for use in combination with capecitabine for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in metastatic setting. We also believe neratinib has potential clinical application in the treatment of several other cancers as well, including other tumor types that over-express or have a mutation in HER2 or epidermal growth factor receptor (“EGFR”), such as cervical cancer, lung cancer or other solid tumors.

We currently market NERLYNX in the United States using our direct specialty sales force consisting of approximately 3840 sales specialists. Our sales specialists are supported by an experienced sales leadership team consisting of regional managers and directors, as well as a commercial team of experienced professionals in marketing, access and reimbursement, managed markets, marketing research, commercial operations and sales force planning and management. In 2018,Outside the EC granted marketing authorization for NERLYNX in the European Union ("EU") for the extended adjuvant treatment of adult patients with early stage hormone receptor positive HER2-overexpressed/amplified breast cancer and who are less than one year from the completion of prior adjuvant trastuzumab-based therapy. To facilitate our international activities,United States, we have entered into exclusive sub-license agreements with variousthird parties to pursue regulatory approval, if necessary, and commercialize NERLYNX, if approved. As of December 31, 2022, NERLYNX has received approval for the treatment of certain patients with extended adjuvant or metastatic HER2+ breast cancer in more than 18 countries outside the United States, including the European Union ("EU"), China, Latin America, Australia, Canada, and Hong Kong. We are currently a party to several sub-licenses in various regions outside the United States, including Europe (excluding Russia and Ukraine), Australia, Canada, China, Southeast Asia, Israel, South Korea, and various countries and territories in Central America, South America and Africa.

We have also implemented a managed access program for neratinib.NERLYNX. Managed access programs provide physicians and patients access to medicines when there are limited or no other therapeutic options available. Our managed access program for neratinibNERLYNX enables participation from countries outside the United States where permitted by applicable rules, procedures and regulatory authorities. The program provides access to neratinibNERLYNX for the treatment of early stage HER2-positive breast cancer (extended adjuvant setting), HER2-positive metastatic breast cancer and HER2-mutated solid tumors. In order for patients to qualify for our managed access program they must be unable to participate in any ongoing neratinibNERLYNX clinical trial. Patients in the managed access program are given neratinib and are instructed to take a prophylaxis which consists of high dose loperamide and budesonide, during treatment to manage neratinib-related diarrhea. We have partnered with Caligor Opco LLC, which specializes in early access to medicines, to oversee the managed access program for neratinib.

Alisertib

In additionSeptember 2022, we entered into an exclusive license agreement with a subsidiary of Takeda Pharmaceutical Company Limited (“Takeda”) to commercializing NERLYNXlicense the worldwide research and development and commercial rights to alisertib. Alisertib is an investigational, reversible, ATP-competitive inhibitor that is designed to be highly selective for its approved indications, we are actively conducting the followingAurora Kinase A. Inhibition of Aurora Kinase A leads to disruption of mitotic spindle apparatus assembly, disruption of chromosome segregation, and inhibition of cell proliferation. In clinical trials to evaluatedate, alisertib had shown single agent activity and activity in combination with other cancer drugs in the treatment of many different types of cancers, including hormone receptor positive breast cancer, triple negative breast cancer, small cell lung cancer and head and neck cancer. Alisertib has also shown activity in previous clinical trials in peripheral T cell lymphoma and non Hodgkins lymphoma. Prior to our licensing alisertib from Takeda the drug was tested in over 1,300 patients who were treated across 22 company-sponsored trials resulting in a large well-characterized clinical safety and efficacy of neratinib in various indications:database.

The following chart shows eachWe intend to pursue the development of alisertib in hormone receptor positive breast cancer as well as small cell lung cancer based on the approved indicationsprior clinical data that has been generated. We also plan to evaluate alisertib in biomarker focused populations where it has shown a higher degree of neratinibactivity, such as patients with c-myc amplification and those indications currently under development, togetherRB1 loss/RB1 mutations, as we believe that this may provide a point of differentiation from the other drugs being developed in the treatment of these diseases. We expect to meet with theirthe FDA in the first half of 2023 to discuss our alisertib clinical development stage.

*      EBC: Early breast cancer

**    MBC: Metastatic breast cancer

***  HRC+: Hormone receptor positive

The following table shows the HER2+ Breast Cancer approvals by disease areaExcellence in 2022 in effort to reform dose optimization and country.dose selection procedures used in oncology drug development.

Strategy

Our goal is to become a leading provider of advanced therapies for the treatment of various forms of cancer. The following elements comprise our strategy to achieve this objective:

Neratinib

HER2-Positive Breast Cancer Overview

Breast cancer is the leading cause of cancer death among women worldwide, with approximately 1 million new cases reported each year and more than 400,000 deaths per year. Up to 20% of breast cancer tumors show over-expression of the HER2 protein. Women with breast cancer that over-expresses HER2 are at greater risk for disease recurrence, progression and death than women whose tumors do not over-express HER2. Therapeutic strategies have been developed to block HER2 in order to improve the treatment of this type of breast cancer.

Trastuzumab, pertuzumab, lapatinib, T-DM1, fam‐trastuzumab deruxtecan and tucatinib are all drugs that bind to the HER2 protein and thereby cause the cells to cease reproducing. Today, these drugs are used as single agents, in combination with other drugs and in combination with chemotherapy to treat patients with HER2-positive breast cancer at various stages.

Currently, the only treatment approved by the FDA for the treatment of neoadjuvant (newly diagnosed) HER2-positive breast cancer is the combination of pertuzumab plus trastuzumab and taxane chemotherapy. The FDA-approved treatments for the adjuvant treatment of HER2-positive early stage breast cancer is eitherare the combination of trastuzumab and chemotherapy, the combination of pertuzumab plus trastuzumab and chemotherapy, or Kadcyla, which is approved specifically in patients with HER2-positive early stage breast cancer with residual disease after neoadjuvant treatment. WeIn addition, we are aware of a Phase IIInumerous additional ongoing clinical trial that is comparing trastuzumab plus pertuzumab plus taxane following anthracyclines versus T-DM1 plus pertuzumab following anthracyclines as an adjuvant therapy.trials involving other product candidates used alone or in combination with existing drugs to treat patients with breast cancer. In addition, we are also aware of a Phase III trial in patients with high risk HER2-positive early stage breast cancer with residual disease after neoadjuvant treatment that is testing the combination of Kadcyla plus tucatinib versus Kadcyla alone (the CompassHER2 RD Trial) as well as a Phase III trial in patients with high risk HER2-positive early stage breast cancer with residual disease after neoadjuvant treatment that is testing fam-trastuzumab deruxtecan versus Kadcyla alone (the DESTINY-Breast05 Trial).

We believe that there are approximately 30,000 patients in the United States and 37,000 patients in the EU with early stage HER2-positive breast cancer that get treated with adjuvant treatment. We also believe that there are approximately 6,400 patients in the United States with third-line and 4,700 patients in the United States with fourth-line HER2-positive metastatic breast cancer. The number of patients with third-line or later HER2-positive metastatic breast cancer may decrease in future years as the introduction of new neoadjuvant, adjuvant and extended adjuvant treatments may reduce the number of patients with recurrence of HER2-positive breast cancer and therefore reduce the number of patients with HER2-positive metastatic breast cancer.

We believe that approximately 1% to 12% of all cancer patients have a mutation in HER2 kinase in the United States and that approximately 7% to 9% of all estrogen receptor positive metastatic breast cancer patients who have received prior endocrine treatment have a mutation in HER2 kinase (approximately 8,000 to 10,000 patients in the United States).

Background on Neratinib

Neratinib is a potent irreversible TKI that blocks signal transduction through the epidermal growth factor receptors, HER1, HER2 and HER4. Based on pre-clinical studies and clinical trials to date, we believe that neratinib may offer an advantage over existing treatments that are used in the treatment of patients with HER2-positive breast cancer. We believe that by more potently inhibiting HER2 at a different site and acting via a mechanism different from other agents, neratinib may have therapeutic benefits in patients who have been previously treated with these existing treatments, most notably due to its irreversible inhibition of the HER2 target enzyme.

In addition, we believe neratinib has clinical application in the treatment of several other cancers as well, including other tumor types that over-express or have a mutation in HER2 or EGFR, such as breast cancer, cervical cancer, lung cancer or other solid tumors.

Our initial focus is on the commercialization and development of the oral formulation of neratinib.

PB272 (neratinib oral)Neratinib—Early Stage Breast Cancer

Extended Adjuvant Breast Cancer

In 2017, the FDA approved NERLYNX formally known as PB272 (neratinib (oral)),(neratinib) for the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy. In 2018, the EC granted marketing authorization for NERLYNX in the EU for the extended adjuvant treatment of adult patients with early stage hormone receptor positive HER2-overexpressed/amplified breast cancer and who are less than one year from the completion of prior adjuvant trastuzumab-based therapy. These approvals were obtained based on the two-year data obtained in our ExteNET trial.

Two-Year ExteNET Data. In July 2014, we announced top line results from our ExteNET trial, a Phase III clinical trial of neratinib for the extended adjuvant treatment of early stage HER2-positive breast cancer. The data from this trial were presented in an oral presentation at the American Society of Clinical Oncology ("ASCO") Annual Meeting in June 2015 and were published online in The Lancet Oncology in February 2016. The ExteNET trial was a double-blind, placebo-controlled, Phase III trial of neratinib versus placebo after adjuvant treatment with Herceptin in women with early stage HER2-positive breast cancer. More specifically, the ExteNET trial enrolled 2,840 patients in 41 countries with early stage HER2-positive breast cancer who had undergone surgery and adjuvant treatment with trastuzumab. After completion of adjuvant treatment with trastuzumab, patients were randomized to receive extended adjuvant treatment with either neratinib or placebo for a period of one year. Patients were then followed for recurrent disease, ductal carcinoma in situ ("DCIS"), or death for a period of two years after randomization in the trial.

The safety results of the study showed that the most frequently observed adverse event for the neratinib-treated patients was diarrhea, with approximately 39.9% of the neratinib-treated patients experiencing grade 3 or higher diarrhea (one patient, 0.1%, had grade 4 diarrhea). Patients who received neratinib in this trial did not receive any prophylaxis with antidiarrheal agents to prevent the neratinib-related diarrhea.

The primary endpoint of the ExteNET trial was invasive disease-free survival ("DFS"). The results of the trial demonstrated that treatment with neratinib resulted in a 33% reduction of risk of invasive disease recurrence or death versus placebo (hazard ratio = 0.67, p = 0.009). The two-year DFS rate for the neratinib arm was 93.9% and the two-year DFS rate for the placebo arm was 91.6%. The secondary endpoint of the trial was disease-free survival including ductal carcinoma in situ ("DFS-DCIS"). The results of the trial demonstrated that treatment with neratinib resulted in a 37% reduction of risk of disease recurrence including DCIS or death versus placebo (hazard ratio = 0.63, p = 0.002). The two-year DFS-DCIS rate for the neratinib arm was 93.9% and the two-year DFS-DCIS rate for the placebo arm was 91.0%.

As an inclusion criteria for the ExteNET trial, patients needed to have tumors that were HER2-positive using local assessment. In addition, as a pre-defined subgroup in the trial, patients had centralized HER2 testing performed on their tumor as well. At the time the two-year data was compiled, centralized HER2 testing had been performed on 1,704 (60%) of the patients in the ExteNET trial and further central testing on available samples was currently ongoing. For the 1,463 patients whose tumors were HER2-positive by central confirmation, the results of the trial demonstrated that treatment with neratinib resulted in a 49% reduction of risk of invasive disease recurrence or death versus placebo (hazard ratio = 0.51, p = 0.002). The two-year DFS rate for the centrally confirmed patients in the neratinib arm was 94.7% and the 2-year DFS rate for the centrally confirmed patients in the placebo arm was 90.6%. For the patients in the trial whose tumors were HER2-positive by central confirmation, the results of the trial demonstrated that treatment with neratinib resulted in a 51% reduction of risk of disease recurrence including DCIS or death versus placebo (hazard ratio = 0.49, p < 0.001). The two-year DFS-DCIS rate for the centrally confirmed patients in the neratinib arm was 94.7% and the two-year DFS rate for centrally confirmed patients in the placebo arm was 90.2%.

For the pre-defined subgroup of patients with hormone receptor positive disease, the results of the trial demonstrated that treatment with neratinib resulted in a 49% reduction of risk of invasive disease recurrence or death versus placebo (hazard ratio = 0.51, p = 0.001). The two-year DFS rate for the neratinib arm was 95.4% and the two-year DFS rate for the placebo arm was 91.2%. For the patients in the trial whose tumors were HER2-positive by central confirmation, the results of the trial demonstrated that treatment with neratinib resulted in a 75% reduction of risk of invasive disease recurrence or death (hazard ratio = 0.25, p < 0.001). The two-year DFS rate for the centrally confirmed patients in the neratinib arm was 97.0% and the two-year DFS rate for centrally confirmed patients in the placebo arm was 88.4%.

Five-Year ExteNET Data. In September 2017, we presented updated data from the ExteNET trial at the European Society of Medical Oncology ("ESMO") 2017 Congress in Madrid, Spain. The data represented a predefined five-year invasive disease-free survival ("iDFS"), analysis as a follow-up to the primary two-year iDFS analysis of the Phase III ExteNet trial. The results of the trial demonstrated that after a median follow up of 5.2 years, treatment with neratinib resulted in a 27% reduction of risk of invasive disease recurrence or death versus placebo (hazard ratio = 0.73, p = 0.008). The five-year iDFS rate for the neratinib arm was 90.2% and the 5-year iDFS rate for the placebo arm was 87.7%. The secondary endpoint of the trial was invasive disease-free survival including ductal carcinoma in situ or iDFS-DCIS.(“iDFS-DCIS”). The results of the trial demonstrated that treatment with neratinib resulted in a 29% reduction of risk of disease recurrence, including DCIS or death versus placebo (hazard ratio = 0.71, p = 0.004). The five-year iDFS-DCIS rate for the neratinib arm was 89.7% and the five-year iDFS-DCIS rate for the placebo arm was 86.8%.

For the pre-defined subgroup of patients with hormone receptor positive disease, the results of the trial demonstrated that treatment with neratinib resulted in a 40% reduction of risk of invasive disease recurrence or death versus placebo (hazard ratio = 0.60, p = 0.002). The five-year iDFS rate for the neratinib arm was 91.2% and the five-year iDFS rate for the placebo arm was 86.8%. For the pre-defined subgroup of patients with hormone receptor negative disease, the results of the trial demonstrated that treatment with neratinib resulted in a hazard ratio of 0.95 (p = 0.762).

The results of the ExteNET trial showed that after two years of follow-up, for patients with hormone receptor positive, HER2-positive early stage breast cancer patients who were treated within one year after the completion of trastuzumab based adjuvant therapy, iDFS was 95.3% in the patients treated with neratinib compared with 90.8% in those receiving placebo (hazard ratio = 0.49; 95% CI: (0.30, 0.78); p=0.002).

The safety results were unchanged from the primary two-year iDFS analysis of the study that showed the most frequently observed adverse event for the neratinib-treated patients was diarrhea, with approximately 39.9% of the neratinib-treated patients experiencing grade 3 or higher diarrhea (one patient, or 0.1%, had grade 4 diarrhea). Patients who received neratinib in this trial did not receive any prophylaxis with antidiarrheal agents to prevent the neratinib-related diarrhea.

In October 2020, we announced that efficacy results of neratinib in HER2-positive, hormone receptor-positive, or HR+, early stage breast cancer, ("eBC") from the Phase III ExteNET trial were published in Clinical Breast Cancer. The manuscript presented data focusing on HR+ patients who initiated treatment within a year of completing an adjuvant trastuzumab containing treatment (HR+ /< 1 yr) and subgroups of clinical interest including patients who did not achieve a pathological complete response (no pCR) after neoadjuvant treatment and therefore were at a high risk of disease recurrence (HR+/ <1 yr, no pCR). In the HR+ /< 1 yr patient population, the absolute 5-year invasive disease-free survival benefit versus placebo was 5.1% (HR=0.58, 95% CI 0.41–0.82) and absolute 8-year overall survival benefit was 2.1%. (HR=0.79, 95% CI 0.55–1.13). The 5-year cumulative incidence of central nervous system (CNS) metastases was 0.7% in the neratinib arm and 2.1% in the placebo arm.

In the HR+/ <1 yr, no pCR subgroup of patients that were at a high risk of disease recurrence the absolute 5-year iDFS benefit in the neratinib arm versus placebo was 7.4% (HR=0.60; 95% CI 0.33–1.07) and the 8- year overall survival benefit was 9.1% (HR=0.47; 95% CI 0.23– 0.92).

NERLYNX is currently in the body of the National Comprehensive Cancer Network ("NCCN") breast cancer guidelines for the treatment of adjuvant HER2-positive Breast Cancer (BINV-L) under the heading Useful in Certain Circumstances, with a recommendation for considering extended adjuvant neratinib for patients with HR-positive, HER2-positive disease with a perceived high risk of recurrence.

CONTROL. In February 2015, we initiated the CONTROL trial which is an international, open-label, Phase II study investigating the use of antidiarrheal prophylaxis or dose escalation in the prevention and reduction of neratinib-associated diarrhea and, more specifically, grade 3 diarrhea. In the CONTROL trial, patients with HER2-positive early stage breast cancer who had completed trastuzumab-based adjuvant therapy received neratinib daily for a period of one year.

In December 2019 and December 2020, interim results from the CONTROL trial were presented at the 2019 CTRC-AACR San Antonio Breast Cancer Symposium, and the 2020 CTRC-AACR San Antonio Breast Cancer Symposium, respectively, and in December 2021, final results from the CONTROL trial were presented at the CTRC-AACR San Antonio Breast Cancer Symposium.

Final results showed the incidence of grade 3 diarrhea for the 137 patients who received the loperamide prophylaxis was 31%, the incidence of grade 3 diarrhea for the 64 patients who received the combination of loperamide plus budesonide was 28%, the incidence of grade 3 diarrhea for the 136 patients who received the combination of loperamide plus colestipol was 21%, the incidence of grade 3 diarrhea for the 104 patients who received colestipol alone with loperamide as needed was 33%, the incidence of grade 3 diarrhea for the 60 patients who used the dose escalation 1 regimen (DE 1) was 13%, and the incidence of grade 3 diarrhea for the 62 patients who used dose escalation regimen 2 (DE 2) was 27%. Further information is provided in Table 1 below:

Table 1: Incidence of Treatment-Emergent Diarrhea

Adoption of neratinib dose escalation at the initiation of treatment, particularly the 2-week DE schedule ("DE1"), most markedly reduced the incidence, severity, and duration of neratinib-associated grade 3 diarrhea in CONTROL compared to other treatment cohorts. Both DE strategies showed a lower incidence of grade 3 diarrhea (DE1 13%; DE2 27%) compared with that observed in the ExteNET trial (historical control: 39.8%). No grade 4 diarrhea was reported in any cohort. The median cumulative duration of grade 3 diarrhea ranged from 2 – 2.5 days across the CONTROL DE study cohorts for the entire 12-month treatment period (compared with 5.0 days for ExteNET). The proportion of patients discontinuing neratinib because of diarrhea was decreased both DE cohorts (DE1 3%; DE2 6%) compared with ExteNET (17%). The adoption of neratinib DE + loperamide PRN during the first 2 weeks of treatment (DE1 cohort) was associated with the lowest rate of grade 3 diarrhea during the trial compared with all other anti-diarrheal strategies investigated in CONTROL. These final findings from the CONTROL study showed improved tolerability of neratinib with all diarrhea prophylaxis strategies and suggest that neratinib DE1 with loperamide PRN may allow patients to stay on treatment longer and receive the full benefit of neratinib therapy.

This study is complete, and the results have been submitted to multiple global Health Authorities to support the addition of a dose escalation regimen to approved package inserts. As of December 31, 2021, label changes to incorporate dose escalation had been approved in the US, Canada and Australia.

Neratinib—PB272 (neratinib, oral)—Metastatic Breast Cancer

OnIn February 25, 2020, the FDA approved our supplemental New Drug Application ("NDA") for the use of neratinib in combination with capecitabine for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting. This approval was based on the results from our NALA trial.

Trials of Neratinib as a Single Agent. In 2009, Pfizer Inc. ("Pfizer") presented data at the CTRC-AACR San Antonio Breast Cancer Symposium from a Phase II trial of neratinib administered as a single agent to patients with HER2-positive metastatic breast cancer. Final results from this trial were published in the Journal of Clinical Oncology in March 2010.

The trial involved a total of 136 patients, 66 of whom had received prior treatment with trastuzumab and 70 of whom had not received prior treatment with trastuzumab. The results of the study showed that neratinib was reasonably well-tolerated among both the pretreated patients and the patients who had not received prior treatment with trastuzumab. Diarrhea was the most common side effect but was manageable with antidiarrheal agents and dose modification. Efficacy results from the trial showed that the objective response rate was 24% for patients who had received prior trastuzumab treatment and 56% for patients with no prior trastuzumab treatment. Furthermore, the median PFSprogression free survival ("PFS") was 22.3 weeks for the patients who had received prior trastuzumab and 39.6 weeks for the patients who had not received prior trastuzumab.

Data from a second Phase II study, in which patients with confirmed HER2-positive metastatic breast cancer who had failed treatment with trastuzumab and taxane chemotherapy were given neratinib in combination with capecitabine, was presented at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium. The results of the study showed that the combination of PB272neratinib and capecitabine had acceptable tolerability. The efficacy results from the trial showed that for the 61 patients in the trial who had not been previously treated with the HER2 targeted anti-cancer drug lapatinib, there was an overall response rate of 64% and a clinical benefit rate of 72%. In addition, for the seven patients in the trial who had previously been treated with lapatinib, there was an overall response rate of 57% and a clinical benefit rate of 71%. The median PFS for patients who had not received prior treatment with lapatinib was 40.3 weeks and the median PFS for the patients who had received prior lapatinib treatment was 35.9 weeks.

NALA. In February 2013, we reached agreement with the FDA under a Special Protocol Assessment ("SPA") for our Phase III clinical trial (PUMA-NER-1301 or the NALA trial) of neratinib in patients with HER2-positive metastatic breast cancer who have failed two or more prior treatments (third-line disease). An SPA is a written agreement between the trial’s sponsor and the FDA regarding the design, endpoints, and plannedplanned statistical analysis of the Phase III trial with respect to the effectiveness of PB272neratinib for the indication to be studied to support a New Drug Application ("NDA").NDA. The European Medicines Agency ("EMA") also provided follow-on Scientific Advice ("SA") consistent with that of the FDA regarding our Phase III trial design and endpoints used for such design to support the submission of an marketing authorization application ("("MAA") in the EU.

Pursuant to the SPA and SA, the Phase III NALA trial was designed as a randomized controlled trial of neratinib plus capecitabine versus Tykerb® (lapatinib) plus capecitabine in patients with third-line HER2-positive metastatic breast cancer. The trial enrolled 621 patients who were randomized (1:1) to receive either neratinib plus capecitabine or lapatinib plus capecitabine. The trial was conducted globally at sites in North America, Europe, Asia-Pacific and South America. The co-primary endpoints of the trial were centrally confirmed PFS and overall survival or OS.(“OS”). An alpha level of 1% was allocated to the PFS and 4% allocated to OS.

In June 2019, we announced that results from the Phase III NALA trial were presented at the ASCO 2019 Annual Meeting in Chicago. For the primary analysis of centrally confirmed PFS, treatment with neratinib plus capecitabine resulted in a statistically significant improvement in centrally confirmed PFS (hazard ratio=0.76, p=0.0059) compared to treatment with lapatinib plus capecitabine. Because the hazard ratio was found to not be constant over time (i.e., the proportional hazard assumption did not hold), the statistical analysis plan for the NALA trial prespecified that a restricted means survival analysis at 24 months would be performed. In this prespecified analysis the mean PFS for the patients treated with neratinib plus capecitabine was 8.8 months and the mean PFS for the patients treated with lapatinib plus capecitabine was 6.6 months.

For the primary analyses of OS, neratinib plus capecitabine resulted in an improvement in OS that, although not statistically significant, trended numerically in favor of the neratinib plus capecitabine arm of the study (hazard ratio = 0.88, p=0.21). The median OS for the patients treated with neratinib plus capecitabine was 21.0 months and the median OS for the patients treated with lapatinib plus capecitabine was 18.7 months. In the prespecified restricted means analysis the mean OS at 48 months for the patients treated with neratinib plus capecitabine was 24.0 months and the mean OS for the patients treated with lapatinib plus capecitabine was 22.2 months.

For the secondary endpoint of time to intervention for symptomatic central nervous system disease (also referred to as brain metastases), the results of the trial showed that treatment with neratinib plus capecitabine led to an improvement over the combination of lapatinib plus capecitabine. The overall cumulative incidence of CNS metastases was 22.8% for the neratinib plus capecitabine arm and 29.2% for the lapatinib plus capecitabine arm (p=0.043). For the secondary endpoint of duration of response, neratinib plus capecitabine treatment resulted in a longer duration of response compared to lapatinib and capecitabine treatment, with a median response of 8.54 months compared to a median response of 5.55 months (HR = 0.495, p = 0.0004).

Treatment-emergent adverse events ("TEAEs") were similar between arms: TEAEs leading to neratinib/lapatinib discontinuation were lower with neratinib (10.9%) than with lapatinib (14.5%). There was a higher rate of grade 3 diarrhea with neratinib plus capecitabine compared to lapatinib plus capecitabine (24.4% vs 12.5%); however, the discontinuations due to diarrhea (neratinib plus capecitabine: 2.6%, lapatinib plus capecitabine: 2.3%) were similar in both arms.

In the NCCN Breast guidelines for HER2 positive unresectable or Stage IV (M1) disease, neratinib + capecitabine is currently listed as a treatment option for the third line and beyond setting (BINV-Q).

Metastatic Breast Cancer with Brain Metastases

Approximately one-half of the patients with HER2-positive metastatic breast cancer develop metastases that spread to their brain. The current antibody-based treatments, including trastuzumab and pertuzumab, do not enter the brain and therefore are not believed to be effective in treating these patients.

Neratinib is currently being tested in a clinical trial in collaboration with Translational Breast Cancer Research Consortium referred to as TBCRC 022. The purpose of this study is to determine how well neratinib works in treating breast cancer that has spread to the brain. In this research study, the investigators are looking to see how well neratinib works to decrease the size of or stabilize breast cancer that has metastasized to the brain.

In June 2017, we presented interim data from the TBCRC 022 at the ASCO 2017 Annual Meeting. The multicenter Phase II clinical trial enrolled patients with HER2-positive metastatic breast cancer who have brain metastases. The trial enrolled three cohorts of patients. Patients in the second cohort (n=5) represent patients who had brain metastases which were amenable to surgery and who were administered neratinib monotherapy prior to and after surgical resection. The third cohort (target enrollment=60) enrolled two sub-groups of patients (prior lapatinib-treated and no prior lapatinib) with progressive brain metastases who were administered neratinib in combination with the chemotherapy drug capecitabine. The oral presentation reflected only the patients in the third cohort of patients without prior lapatinib exposure (cohort 3A, n=37), who all had progressive brain metastases at the time of enrollment and who received the combination of capecitabine plus neratinib.

In cohort 3A, 30% of the patients had received prior craniotomy, 65% of the patients had received prior whole brain radiotherapy, and 35% had received prior stereotactic radiosurgery to the brain. No patients had received prior treatment with lapatinib.

The primary endpoint of the trial was CNS Objective Response Rate according to a composite criteria that included volumetric brain MRI measurements, steroid use, neurological signs and symptoms, and Response Evaluation Criteria in Solid Tumors ("RECIST") evaluation for non-CNS sites. The secondary endpoint of the trial was CNS response by Response Assessment in Neuro-Oncology-Brain Metastases or RANO-BM,(“RANO-BM”), criteria. The efficacy results from the trial showed that 49% of patients experienced a CNS Objective Response by the composite criteria. The results also showed that the CNS response rate using the RANO-BM criteria was 24%. The median time to CNS progression was 5.5 months and the median overall survival was 13.5 months, though 49% of patients remain alive and survival data are immature.

The results for cohort 3A showed that the most frequently observed severe adverse event for the 37 patients evaluable for safety was diarrhea. Patients received antidiarrheal prophylaxis consisting of high dose loperamide, given together with the combination of capecitabine plus neratinib for the first cycle of treatment in order to try to reduce the neratinib-related diarrhea. Among the 37 patients evaluable for safety, 32% of the patients had grade 3 diarrhea and 41% had grade 2 diarrhea.

The TBCRC 022 trial is currently enrollingUpdated results from TBCRC-022 were presented in December 2022 at the 2022 San Antonio Breast Cancer Symposium This presentation outlined updates from three cohorts: 4A – patients in an arm of the study that is administeringwith previously untreated Breast Cancer Brain Metastases (“BCBM”); 4B – patients with BCBM progressing after prior local CNS-directed therapy without prior T-DM1 exposure; and 4C – patients with BCBM progressing after prior local CNS-directed therapy with previous T-DM1 exposure. Patients with measurable HER2-positive BCBM received neratinib 160 mg orally once daily plus T-DM1 3.6 mg/kg intravenously every 21 days in the three parallel-enrolling cohorts. Diarrhea prophylaxis with colestipol and loperamide was required during cycle 1. All enrolled patients underwent a brain MRI plus CT scan of the chest/abdomen/pelvis every six weeks for 18 weeks, followed by every nine weeks thereafter.

The primary endpoint, Response Assessment in Neuro-Oncology-Brain Metastases (“RANO-BM”), was evaluated in each cohort separately. The efficacy results from the trial showed that CNS Objective Response Rate by RANO-BM was 33.3% of patients in cohort 4A, 29.4% in cohort 4B, and 28.6% in cohort 4C. Rates of response + stable disease greater than or equal to 6 months were 50% in cohort 4A, 35.3% in cohort 4B, and 33.3% in cohort 4C.

Intracranial activity was observed for the combination with the drug ado-trastuzumab emtansine (T-DM1, Kadcyla)of neratinib plus T-DM1 in all three cohorts, including in patients with HER2-positive metastatic breast cancer that has metastasizedprior T-DM1 exposure, suggesting a reversal of resistance to T-DM1. Overall, the brain. Data from this trial is expected in 2022.most frequently observed adverse event was diarrhea, grade 2 (32%) and grade 3 (23%).

In April 2018, we announced that NERLYNX has been included as a recommended treatment option in the latest NCCN, Clinical Practice Guidelines in Oncology Central Nervous System Cancers for Breast Cancer patients with brain metastases. The NCCN designated NERLYNX in combination with capecitabine as a category 2B treatment option and NERLYNX in combination with paclitaxel as a category 2B treatment option. Use, as designated for breast cancer patients with brain metastases, is outside the FDA-approved indication for NERLYNX and considered investigational, and we do not market or promote NERLYNX for these uses.

PB272 (neratinib, oral)Neratinib—Other Potential Applications

While we believe neratinib has potential applications in other diseases, such as HER2 Mutation-Positive Solid Tumors, HER2-Mutated, Non-Amplified Breast Cancer and EGFR Exon 18 Mutated Non Small Cell Lung Cancer, we are not currently pursuing additional development in these indications at this time.

Alisertib

Alisertib is an investigational reversible, ATP-competitive inhibitor that is designed to be highly selective for Aurora Kinase A. Inhibition of Aurora Kinase A leads to disruption of mitotic spindle apparatus assembly, disruption of chromosome segregation, and inhibition of cell proliferation. In clinical trials to date, alisertib had shown single agent activity and activity in combination with other cancer drugs in the treatment of many different types of cancers, including hormone receptor positive breast cancer, triple negative breast cancer, small cell lung cancer and head and neck cancer. The drug has also shown activity in previous clinical trials in peripheral T cell lymphoma and non Hodgkins lymphoma. Prior to our licensing alisertib from Takeda the drug was tested in over 1,300 patients who were treated across 22 company sponsored trials resulting in a large well characterized clinical safety database.

We intend to pursue the development of alisertib in hormone receptor positive breast cancer as well as small cell lung cancer based on the prior clinical data that has been generated. We also plan to evaluate alisertib in biomarker focused populations where it has shown a higher degree of activity, such as patients with c-myc amplification and RB1 loss/RB1 mutations, as we believe that this may provide a point of differentiation from the other drugs being developed in the treatment of these diseases. We expect to meet with the FDA in the first half of 2023 to discuss our alisertib clinical development plan. We also plan to discuss with the FDA the FDA’s Project Optimus, an initiative launched by the FDA’s Oncology Center of Excellence in 2022 in effort to reform dose optimization and dose selection procedures used in oncology drug development, in relation to the potential dosing schedule for alisertib.

Alisertib in Small Cell Lung Cancer

Based on the results from the Cancer Genome Atlas Study, we estimate that between 1% and 12% of each solid tumor has a mutation in HER2.

SUMMIT -- Basket Trial for HER2 Mutation-Positive Solid Tumors. In October 2013, we announced that we had initiated a Phase II clinical trial of neratinibthat was published in Lancet Oncology in 2015, alisertib was tested as a single agent in several cohorts of patients with solid tumors that have an activating HER2 mutation, which we refer totumors. These included small cell lung cancer as well as breast cancer. In small cell lung cancer, the SUMMIT basket trial. The Phase II SUMMIT basket trial is an open-label, multicenter, multinational study to evaluatedesign involved the safety and efficacyadministration of PB272 administered dailyalisertib to patients with small cell lung cancer who have solid tumors with activating HER mutations.

In May 2014, we expanded the first cohort from the SUMMIT basket trial. Interim results from this ongoing Phase II trial were presented at the 2017 American Association for Cancer Research Annual Meeting and were published in January 2018 in Nature. All patientshad previously received loperamide (16 mg per day initially) prophylactically for the first cycle of treatment in orderup to reduce the neratinib-related diarrhea. Included in the presentation were data on 141 patients enrolled in the neratinib monotherapy arm of the trial, including 124 patients with HER2 mutations and 17 patients with HER3 mutations. This included patients with 21 unique tumor types, with the most common being breast, lung, bladder and colorectal cancer. There were also 30 distinct HER2 and 12 distinct HER3 mutations observed among these patients, with the most frequent HER2 variants involving S310, L755, A755_G776insYVMA and V777.

The interim safety results observed in the SUMMIT study were consistent with that observed previously in metastatic patients with HER2 amplified tumors. With anti-diarrheal prophylaxis and management, diarrhea has not been a treatment-limiting side effect in SUMMIT. The interim safety results of the study showed that the most frequently observed adverse event was diarrhea. For the 141 patients enrolled in the neratinib monotherapy arm with safety data available as of March 10, 2017, 31 patients (22%) reported grade 3 diarrhea. The median duration of grade 3 diarrhea for those patients was two days. Four patients (2.8%) permanently discontinued neratinib due to diarrhea and 21 patients (14.9%) temporarily discontinued neratinib due to diarrhea and then restarted after the diarrhea subsided.

HER2-Mutated, Non-Amplified Breast Cancer

A HER2 mutation in patients with HER2-negative breast cancer was identified as part of a study performed by the Cancer Genome Atlas Network and published in Cancer Discovery in December 2012. We believe this mutation may occur in an estimated 2% of patients with breast cancer. Pre-clinical data from this publication demonstrated that neratinib was active in pre-clinical models of HER2-negative breast cancer that have this HER2 mutation and that neratinib has more anti-cancer activity than either trastuzumab or lapatinib in cells with this mutation. A Phase II trial of neratinib in HER2-negative breast cancer patients who have a HER2 mutation opened for enrollment in December 2012.

In December 2020, we announced that updated interim results from the SUMMIT basket trial in the HER2-mutant, hormone receptor positive breast cancer cohort were presented at the San Antonio Breast Cancer Symposium. In the HER2-mutant, hormone receptor (HR)-positive breast cancer cohort, 51 patients received 240 mg of neratinib daily in combination with trastuzumab and fulvestrant. In this cohort, patients had received a median of four prior lines of therapycytotoxic regimens in the metastatic setting (range 1-10 prior regimens) before entering the trial. 36 patients (70.6%setting. Patients were administered alisertib monotherapy at a dose of 50 mg twice a day (“BID”) had received prior fulvestrant, 35 patients (68.6%) had received prior aromatase inhibitor and 4 patients (7.8%) had received prior tamoxifen. Further, 30 patients (58.8%) received prior cyclin-dependent kinase 4/6-inhibitor (CDK4/6i) therapy. Thirty-five patients (68.6%) had received prior chemotherapy.

The interim efficacy summary of the breast cohort that received neratinib in combination with trastuzumab and fulvestrant showed that for the 37 RECIST efficacy evaluable patients, 17 patients (45.9%) experiencedseven days followed by a confirmed objective response, including one complete response (2.7%) and 16 (43.2%) partial responses, and 20 patients (54.1%) experienced clinical benefit (clinical benefit is defined as confirmed complete response or partial response or stable disease for at least 24 weeks). The median duration of response was 10.9 months and the median progression-free survival was 8.3 months.14-day break. 

In patients with chemotherapy sensitive disease, alisertib resulted in a response rate of 19% and a duration of response of 3.1 months. For the patients with chemotherapy refractory disease or chemotherapy resistant disease, alisertib resulted in a response rate of 25% and a duration of response of 4.3 months. The safety profile observedmain grade 3 or higher adverse events (“AEs”) seen in the trial were neutropenia, anemia, leukopenia and thrombocytopenia.

Alisertib was also tested in a randomized Phase II trial of paclitaxel plus alisertib versus paclitaxel plus placebo in patients treatedwith second line small cell lung cancer, the results of which were published in the Journal of Thoracic Oncology in 2020. In the trial, alisertib was dosed at 40 mg BID for 3 weeks on days 1–3, 8–10, and 15–17 plus paclitaxel (60 mg/m2 intravenously on days 1, 8, and 15) whereas the comparator arm received placebo plus paclitaxel (80 mg/m2 intravenously on days 1, 8, and 15) in 28-day cycles. 

Randomization was stratified by type of relapse after primary treatment, based on the common definition for each type (with sensitive defined as relapsed greater than 90 but less than 180 days after primary treatment and resistant or refractory defined as relapsed less than or equal to 90 days after primary treatment). The protocol was initially written by the sponsor to record relapse type as the time from initial response. The protocol was corrected approximately midway through the trial to correct the stratification definition of relapse type after primary treatment so that relapses were recorded “from last administration of platinum-based chemotherapy,” which is in line with the combinationNCCN treatment guidelines and clinical treatment practice rather than “from initial response.” To maintain balance, the primary end point of neratinib plus trastuzumab plus fulvestrantPFS was analyzed by using the original stratification definition of relapse type. However, a sensitivity analysis which used the corrected stratification definition was also performed. The trial also incorporated an extensive biomarker analysis with a prespecified analysis of c-Myc expression and a [post-hoc] retrospective analysis of genetic alterations in circulating tumor DNA (“ctDNA”) with clinical outcome

The primary endpoint in the SUMMITtrial was PFS. For the intent to treat (“ITT”) population the hazard ratio using the original definition was 0.77 with a p value of 0.113. Using the corrected definition of relapse type, the hazard ratio was 0.71 with a p value of 0.038. For the patients with chemotherapy resistant or refractory relapse the hazard ratio was 0.66 with a p value of 0.037. For the ITT population the OS data showed a hazard ratio of 0.87 with a p value of 0.714 and using the corrected definition the hazard ratio was 0.79 with a p value of 0.209. Higher rates of grade 3 or higher AEs were seen in the alisertib arm for neutropenia, anemia and decreased neutrophil count.

For the patients in the trial who were found to be positive for c-myc expression by immunohistochemistry the hazard ratio in the trial was 0.29 with a median PFS for the paclitaxel plus alisertib arm of 4.64 months and a median PFS for the placebo plus paclitaxel arm of 2.27 months. The trial also incorporated an analysis of patients with alterations in cell cycle genes including cyclin-dependent kinase 6 gene (CDK6), retinoblastoma-like 1 gene (RBL1), retinoblastoma-like 2 gene (RBL2), and retinoblastoma 1 gene (RB1). Of note RB1 mutations were the most frequently mutation with approximately 60% of the patients having RB1 mutations while CDK6, RBL1 and RBL2 mutations were found with very low frequency. For patients with cell cycles mutations (RB1, CDK6, RBL1 and RBL2), the PFS in the paclitaxel plus alisertib arm was 3.68 months while the placebo plus paclitaxel arm was 1.8 months and the hazard ratio was 0.395 with a p value of 0.003. The overall survival in this subgroup of patients was 7.2 months for the alisertib arm and 4.47 months for the placebo arm with a hazard ratio of 0.427 and a p value of 0.00085.

Development plan. In the United States the incidence of small cell lung cancer is approximately 31,000 to 33,000 patients per year with approximately 17,000 to 18,000 deaths per year. There are two biomarkers of interest, c-myc amplifications and RB1 mutations/deletions, that we intend to study with alisertib based on the previous clinical trial results which may provide differentiation from the other drugs in development. According to the published biomarker data from the alisertib clinical trial, approximately 72% of small cell lung cancer patient samples had c-myc amplifications and approximately 60-80% of small cell lung cancer patient samples had RB1 mutations.

Alisertib in Breast Cancer

In the same Phase II trial of alisertib monotherapy that was consistent with that observed previouslypublished in metastaticLancet Oncology in 2015, alisertib was also tested in patients with HER2 amplified tumors. All patients received anti-diarrheal prophylaxis with loperamide alone. The interim safety results of the study showed that the most frequently observed adverse event was diarrhea. For the 51 safety evaluable patients enrolled in this cohort, 20 patients (39.2%) reported grade 3 diarrhea. The median duration of grade 3 diarrhea for those patients was 6 days. No patient permanently discontinued neratinib due to diarrhea.

In December 2021, we announced updated interim results from the SUMMIT basket trial in the HER2-mutant,negative, hormone receptor ("HR")-positive, metastaticpositive breast cancer, cohortHER2 positive breast cancer and triple negative breast cancer. Patients were administered alisertib monotherapy at a separatedose of 50 mg BID for seven days followed by a 14 day break. In the cohort of patients with metastatic tripleHER2 negative, hormone receptor positive breast cancer, treatment with alisertib resulted in a response rate of 23% with a PFS of 7.9 months. The main grade 3/4 AEs seen were neutropenia, leukopenia, stomatitis and fatigue

Alisertib was also tested in a randomized Phase II trial in hormone receptor positive, HER2 negative metastatic breast cancer patients that was presented at the San Antonio Breast Cancer Symposium.Symposium in 2020. In this trial alisertib was dosed at 50 mg BID on days 1-3, 8-10 and 15-17 on a 28 day cycle while fulvestrant was dosed at its approved dose of 500 mg IM on days 1 and 15. The baseline characteristics from the HER2-mutant, HR-positive, metastatic breast cancer cohort, patients who have previously received CDK4/6 inhibitorstrial were previously enrolled inwell balanced although a non-randomized cohort and received 240 mghigher percentage of neratinib per day in combination with fulvestrant and trastuzumab. In the HER2-mutant, TNBC cohort, patients received 240 mg of neratinib per day in combination with trastuzumab. All patients received anti-diarrheal prophylaxis with loperamide alone for the first two treatment cycles.

Following our discussion with the FDA, the SUMMIT trial had been amended to randomize HR-positive, HER2-mutant metastatic breast cancer patients to receive either: (i) the combination of neratinib (N), trastuzumab (T) and fulvestrant (F), (ii) the combination of fulvestrant and trastuzumab, or (iii) fulvestrant alone. Once randomized, patients received either neratinib plus fulvestrant plus trastuzumab, fulvestrant plus trastuzumab, or fulvestrant in 1:1:1 ratio. All patients received anti-diarrheal prophylaxis with loperamide alone for the first two treatment cycles.

In the non-randomized cohort, for the 26 patients with HR-positive, HER2-mutated MBC who had previously received CDK4/6 inhibitors, the efficacy results showed that, as of a cutoff date of September 10, 2021, for the patients who received neratinib plus fulvestrant plus trastuzumab, 12 patients (46.2%) experienced a confirmed objective response, all of which were partial responses, and 15 patients (57.7%) experienced clinical benefit (clinical benefit is defined as confirmed complete response or partial response, or stable disease for at least 24 weeks). The median duration of response was 14.4 months and the median progression-free survival was 8.2 months as of the cutoff date (Table 2).

For the randomized portion of the trial, for the patients with HR-positive, HER2-mutated MBC who had previously received CDK4/6 inhibitors, no patient in either the fulvestrant plus trastuzumab or fulvestrant alone arm experienced a confirmed objective response. In the 7 randomized patients who received the combination of neratinib, trastuzumab and fulvestrant, as of the cutoff date, 2 patients (28.6%) experienced a confirmed objective response, including one complete response (14.3%) and one partial response (14.3%), and 2 patients (28.6%) experienced clinical benefit as of the cutoff date. The median duration of response was not reached and the median progression-free survival was 6.2 months as of the cutoff date (Table 2).

For all 33 patients with HR-positive, HER2-mutated MBC, who had previously received CDK4/6 inhibitors, who received the combination of neratinib plus trastuzumab plus fulvestrant, the efficacy results showed, as of the cutoff date, that 14 patients (42.4%) experienced a confirmed objective response, including one complete response (3.0%) and 13 partial responses (39.4%), and 17 patients (51.5%) experienced clinical benefit. The median duration of response was 14.4 months and the median progression-free survival was 7.0 months as of the cutoff date (Table 2). 

Following review by the Independent Data monitoring committee, the fulvestrant plus trastuzumab and fulvestrant only arms were closed to enrolment and additional patients enrolled to receive the combination of neratinib, trastuzumab and fulvestrant to further evaluate the efficacy of the combination.  Enrolment in this cohort is now complete and no additional patients are being enrolled.

Table 2: Efficacy findings from HR+ MBC patients

We have a history of operatingincurred net losses and areanticipate that we may incur net losses in the future and, therefore, may not profitable and may never become profitable.be able to maintain profitability.

WeAlthough we recorded two thousand dollars of net income for the year ended December 31, 2022, we have otherwise experienced a history of operating losses, with net losses of approximately $29.1 million approximately $60.0 million, and approximately $75.6$60.0 million for the years ended December 31, 2021 2020 and 2019,2020, respectively. As of December 31, 2021,2022, we had an accumulated deficit of approximately $1,366.8approximately $1,366.8  million, outstanding indebtedness of approximately $97.1$98.3 million and cash and cash equivalents and marketable securities of approximately $82.1$81.1 million.

We expect to continue to incur significant expenses and may continue to incur net losses in the foreseeable further. Since inception, we have devoted substantially all of our resources to identifying, acquiring and developing NERLYNX and to its commercialization in the indications for which it has received regulatory approval. In September 2022, we in-licensed the development and global commercialization rights to a new product candidate, alisertib. Biopharmaceutical development is a highly speculative undertaking and involves a substantial degree of risk. WeWhile we experienced modest profitability in 2022, we anticipate that we will continue to incur operating losses for the foreseeable future as we continue our efforts to commercialize NERLYNX in existing indications and to develop NERLYNX for additional indications, continue.and as we commence development efforts for alisertib and any other product candidates we may acquire.

In 2017, the FDA approved NERLYNX for the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy. In February 2020, NERLYNX was also approved by the FDA in combination with capecitabine for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting. In 2018, the EC granted a marketing authorization for NERLYNX in the EU for the extended adjuvant treatment of adult patients with early stage hormone receptor positive HER2-overexpressed/amplified breast cancer and who completed adjuvant trastuzumab-based therapy less than one year from the completion of prior adjuvant trastuzumab-based therapy.ago. Although we have begun to commercialize NERLYNX in the U.S.United States and Europe in these indications, we continue to experience net losses and may never become profitable.losses. Moreover, we are continuing to develop NERLYNX for additional indications.indications and are in the early stages of development for alisertib. The successful development and commercialization of any drugproduct candidate will require us to perform a variety of functions, including:

We are only in the preliminary stages of most of these activities, particularly as they relate to alisertib. We will need to generate significant revenue in order to achieveoffset our expenses and maintain profitability. We may not be able to generate this revenue or achievemaintain profitability in the future. As a result, we expect ourto incur losses to continue for the foreseeable future. Accordingly, we cannot assure you that we will achieve profitability in the futurebe able to maintain or that, if we do become profitable, we will sustainincrease profitability. Our failure to achieve or maintain profitability could negatively impact the value of our common stock.

We are currently a single product company with limited commercial sales experience.

We have invested a significant portion of our efforts and financial resources in the development and commercialization of our lead product, NERLYNX. NERLYNX is the only product for which we currently receive product revenue, and we expect NERLYNX to constitute the vast majority of our product revenue for the foreseeable future. By virtue of being dependent on a single product, we do not have the ability to spread out risk or commercial fluctuations across a portfolio of products. As a result, our success depends almost entirely on the commercial success of NERLYNX. NERLYNX is the first product that we, as an organization, have launched and commercialized, and there is no guarantee that we will be able to do so successfully. There are numerous examples of unsuccessful product launches and failures to meet high expectations of market potential, including by pharmaceutical companies with more experience and resources than we have.

We may not be able to successfully commercialize NERLYNX.

The commercial success of NERLYNX depends on the extent to which patients and physicians accept and adopt NERLYNX. For example, if the expected patient population is smaller than we estimate or if physicians are unwilling to prescribe or patients are unwilling to take or continue to take NERLYNX, due to the related side effects, including diarrhea, or otherwise, the commercial success of NERLYNX will be limited. Thus, significant uncertainty remains regarding the commercial potential of NERLYNX. We believe our ability to effectively increase product revenue from NERLYNX will depend on our ability to, among other things:

We cannot assure you that we will successfully address each of these uncertainties or any others we may face in the commercialization of NERLYNX. In addition, we are dependent on international third-party sub-licensees for the development and commercialization of NERLYNX in several countries outside the United States. The failure of these sub-licensees to meet their contractual, regulatory or other obligations could adversely affect international sales of NERLYNX and hinder our ability to generate revenue. These uncertainties, combined with our limited experience in selling and marketing NERLYNX, make it difficult to evaluate our current business, predict our future prospects and forecast our financial performance.

We may not be able to secure additional financing on favorable terms, or at all, to meet our future capital needs and our failure to obtain additional financing when needed on acceptable terms, or at all, could force us to delay, limit, reduce or terminate our product development or commercialization efforts or other operations.

Our operations have consumed substantial amounts of cash since inception. As we continue to commercialize NERLYNX and as we pursue development of alisertib, our costs and expenses may increase in the future due to, among other things, the cost of a direct sales force and the cost of manufacturing. We will also continue to expend substantial amounts on research and development of our other product candidates, including conducting clinical trials. Our future capital requirements will depend on many factors, including:

While our consolidated financial statements have been prepared on a going concern basis, we expect to continue incurringincur significant losses for the foreseeable future and will continue to remain dependent on our ability to obtain sufficient funding to sustain operations and successfully commercialize NERLYNX. We are party to a Note Purchase Agreement with Athyrium, providing for potential issuance of notes of up to $125.0 million, which mature on July 23, 2026. As of December 31, 2021, we had $100.0 million in principal amounts outstanding.NERLYNX and develop alisertib. While we have been successful in raising financing in the past, there can be no assurance that we will be able to do so in the future. Additional financing may not be available on a timely basis on terms acceptable to us, or at all. We may raise funds in equity or debt financings to access funds for our capital needs. If we raise additional funds through further issuances of equity or convertible debt securities, our existing stockholders could suffer significant dilution in their percentage ownership of our company, and any new equity securities we issue could have rights, preferences and privileges senior to those of holders of our common stock. Any debt financing obtained by us in the future would cause us to incur debt service expenses and could include restrictive covenants relating to our capital raising activities and other financial and operational matters, which may make it more difficult for us to obtain additional capital and pursue business opportunities. If we are unable to obtain adequate financing or financing on terms satisfactory to us when we require it, we may terminate or delay the development of one or more of our product candidates, delay clinical trials necessary to market our products, or delay establishment of sales and marketing capabilities or other activities necessary to commercialize our products. If this were to occur, our ability to continue to grow and support our business and to respond to business challenges could be significantly limited. Furthermore, our ability to obtain funding may be adversely impacted by uncertain market conditions, our success in commercializing neratinib,NERLYNX, unfavorable decisions of regulatory authorities or adverse clinical trial results. The outcome of these matters cannot be predicted at this time.

The terms of our Note Purchase Agreementplace restrictions on our ability to operate our business and on our financial flexibility, and we may be unable to achieve the revenue necessary for us to incur additional borrowings under the Note Purchase Agreement or to satisfy the minimum revenue and cash balance covenants.

We are party to a Note Purchase Agreement with Athyrium Opportunities IV Co-Invest 1 LP (“Athyrium”), providing for potential issuance by us of notes of up to $125.0 million, which mature on July 23, 2026. The terms of our Note Purchase Agreement place restrictions on our ability to operate our business and on our financial flexibility. As of December 31, 2021,2022, the aggregate principal amount outstanding under the notes sold pursuant to the Note Purchase Agreement (collectively, the “Notes”“Athyrium Notes”) was $100.0 million. The Athyrium Notes are secured by collateral which consists of our equity interests in our domestic and foreign subsidiaries (including up to 100% of the issued and outstanding equity interests in each of our domestic subsidiaries directly owned by us or the guarantors of the Athyrium Notes) and substantially all of our property, other than our intellectual property. In addition to voluntary prepayments, we may also be required to make mandatory prepayments under the Athyrium Notes in varying amounts within three (3) business days of the occurrence of certain events, including in the event that we receive proceeds from a voluntary or involuntary disposition and such proceeds are not reinvested in eligible assets within 180 days of the date of such disposition, or in the event that we receive extraordinary receipt cash proceeds and such proceeds are not reinvested in eligible assets within 180 days of the date of such extraordinary receipt. The Note Purchase Agreement includes affirmative and negative covenants applicable to us and our subsidiaries. The affirmative covenants include, but are not limited to, requirements to (i) maintain our legal existence and take all reasonable actions to maintain our rights, privileges and authorizations (including renewal of permits or licenses) necessary to conduct our business and maintain our intellectual property, (ii) deliver certain financial statements, certificates and other information to Athyrium on a regular basis, (iii) maintain adequate insurance coverage with respect to the properties and business and (iv) cause all of our deposit accounts (other than certain “excluded accounts”) to be subject to Deposit Account Control Agreements. The negative covenants include, but are not limited to, restrictions on (i) creating or incurring certain liens on our property, assets or revenues, (ii) making certain investments or incurring additional indebtedness, (iii) engaging in certain business or strategic activities (including transactions with affiliates or insiders) and (iv) paying certain dividends, distributions or other restricted payments. Additionally, pursuant to the Note Purchase Agreement, we must maintain a minimum cash balance in our accounts subject to a Deposit Account Control Agreementdeposit account control agreement and must achieve certain levels of product revenue for any four (4) consecutive fiscal quarter periods. These affirmative and negative covenants may make it difficult for us to operate our business. In addition, we are in the early stages of commercializing NERLYNX, and we cannot assure you that we will be able to achieve the minimum product revenue requirements or minimum cash balance requirements under the Note Purchase Agreement. Our failure to satisfy such requirements, or our direct or indirect breach of certain other covenants, could result in an event of default under the Athyrium Notes. The occurrence and continuation of an event of default could (i) cause interest to accrue at a rate per annum equal to the applicable interest rate under the Note Purchase Agreement plus two percent (2.00%) and (ii) cause accrued and unpaid interest on past due amounts (including interest thereon) to be due and payable in cash on demand. Additionally, upon the occurrence or continuation of an event of default, Athyrium, in its capacity as administrative agent, would have the right to exercise remedies against us, including declaring the unpaid principal amount under the Note (and interest thereon) immediately due and payable, and foreclosure against the property securing the Athyrium Notes (including our cash). Other events of default under the Note Purchase Agreement include, but are not limited to, (i) our failure to pay principal or interest due under the Note Purchase Agreement, (ii) our insolvency or related actions (including an assignment for the benefit of creditors), (iii) the existence of material adverse changes in our business or products, (iv) the occurrence of any default under certain other indebtedness in an amount greater than $750,000 or one or more judgments against us in an amount greater than $750,000 individually or in the aggregate that remains unsatisfied, unvacated or unstayed for a period of ten (10)thirty (30) days after its entry and (v) the delisting of our shares of common stock from the Nasdaq Capital Market.

Risks Related to the Discovery and Development of our Products

We recently in-licensed alisertib, a new product candidate, for which we have assumed all responsibility for global development and commercialization. Our development of alisertib will be expensive, lengthy and unpredictable, and any failure to successfully develop alisertib will have a material adverse effect on our business and financial position.

In September 2022, we in-licensed alisertib, a new product candidate, from Takeda. Pursuant to our exclusive license agreement with Takeda, we are responsible for global development and commercialization of alisertib. Clinical development of alisertib will be expensive, lengthy and unpredictable. Failure or delay can occur at any time during the development process. There are numerous risks associated with our planned development alisertib, including, among others:

Even if we are successful in developing alisertib, we cannot assure you that we will be able to successfully commercialize alisertib. Any delays or failure in our development of alisertib could have material adverse effects on our business, operations and financial condition.

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

From time to time, we may publicly disclose preliminary or topline data from our preclinical studies and clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the topline 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. Preliminary and topline data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. Consequently, preliminary and topline data should be viewed with caution until the final data are available.

From time to time, we may also disclose interim data from our clinical trial. 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. Adverse differences between preliminary or interim data and final data could significantly harm our business prospects. Further, disclosure of interim data by us or by our competitors could result in volatility in the price of our common stock.

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

If the interim, topline, 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.

NERLYNX, alisertib or our other drug candidates may cause undesirable side effects or have other properties when used alone or in combination with other approved products or investigational new drugs 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, as applicable.

Undesirable side effects caused by NERLYNX, alisertib or our other drug candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities. To date, subjects treated with NERLYNX have experienced drug-related side effects including diarrhea. Results of our trials could reveal a high and unacceptable severity and prevalence of these or other 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 product candidates for any or all targeted indications. The drug-related side effects could affect patient recruitment or the ability of enrolled patients to complete clinical trials or result in potential product liability claims. Any of these occurrences may harm our business, financial condition and prospects significantly.

Additionally, if we or others later identify undesirable side effects caused by any approved product, including in combination with other approved products or investigational new drugs, a number of potentially significant negative consequences could result, including:

Any of these events could prevent us from achieving or maintaining market acceptance of NERLYNX or the particular product candidate, if approved, and could significantly harm our business, results of operations and prospects.

NERLYNX is still under clinical development for various additional indications, and we are in the early stages of development of alisertib, and we cannot be certain that we will be successful if we seek regulatory approvals for our drug candidates.

We expect that a substantial portion of our efforts and expenditures over the next few years will be devoted to the development of NERLYNX in various additional indications and the development of alisertib. The research, testing, manufacturing, labeling, approval, sale, marketing and distribution of drug products are and will remain subject to extensive regulation by the FDA and other regulatory authorities in the United States and other countries that each have differing regulations. We cannot predict with any certainty that any NDA or supplemental NDA (or similar foreign applications) seeking to expand the indication for NERLYNX or to market alisertib or our other drug candidates will be approved by the FDA or foreign regulatory authorities. We are not permitted to market NERLYNX for other indications or alisertib or any of our other drug candidates in the United States until we receive approval of an NDA from the FDA or until we receive a MA from the EC in the EU, as applicable, for such indications, or, in any foreign countries, until requisite approval from such countries.

Approval of NERLYNX by the FDA or the EC for any particular indication does not ensure that another foreign jurisdiction will also approve NERLYNX for such indication, nor does it ensure that NERLYNX will be approved by the FDA or the EC for any other indications. Similarly, approval of alisertib by the FDA or the EC would not ensure that another jurisdiction will also approve alisertib. Obtaining approval of an NDA or foreign marketing application is an extensive, lengthy, expensive and inherently uncertain process, and the FDA or a foreign regulator may delay, limit or deny approval of a drug candidate for many reasons, including:

If we do not obtain regulatory approval of NERLYNX for other indications, whether in the United States or in other jurisdictions, we will not be able to market NERLYNX for such indications in those jurisdictions. Similarly, if we do not obtain regulatory approval of alisertib or our other drug candidates in a particular jurisdiction, we will not be able to market such drug candidate in that jurisdiction. Therefore, failure to obtain regulatory approval for NERLYNX for other indications, or regulatory approval of alisertib or our other drug candidates, will limit our commercial revenue.

In addition, FDA and foreign regulatory authorities may change their approval policies and new regulations may be enacted. For instance, the EU pharmaceutical legislation is currently undergoing a complete review process, in the context of the Pharmaceutical Strategy for Europe initiative, launched by the European Commission in November 2020. The European Commission’s proposal for revision of several legislative instruments related to medicinal products (potentially revising the duration of regulatory exclusivity, eligibility for expedited pathways, etc.) is expected during the first quarter of 2023. The proposed revisions, once they are agreed and adopted by the European Parliament and European Council (not expected before the end of 2024 or early 2025) may have a significant impact on the biopharmaceutical industry in the long term.

We are subject to ongoing obligations and continued regulatory review with regard to NERLYNX, alisertib and any other drug candidates that may receive FDA or foreign regulatory approval, which may result in significant expense. Additionally, NERLYNX, alisertib and our other drug candidates, if approved, could be subject to labeling and other restrictions and market withdrawal and we may be subject to penalties if we fail to comply with regulatory requirements or experience unanticipated problems with our products.

The FDA’s approval of the NDA for NERLYNX and any regulatory approvals that we receive for alisertib or our other drug candidates may also be subject to limitations on the approved indicated uses for which the product may be marketed or to the conditions of approval, or contain requirements for potentially costly post-marketing testing, including Phase IV clinical trials, and surveillance to monitor the safety and efficacy of the drug candidate. In addition, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion and recordkeeping for the product will be subject to extensive and ongoing regulatory requirements. These requirements include submissions of safety and other post-marketing information and reports, registration, as well as continued compliance with cGMPs and similar requirements and GCPs for any clinical trials that we conduct post-approval. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with our third-party manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may result in, among other things:

The FDA’s and foreign regulatory authorities' policies may change, and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our drug candidates. We also cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or outside the United States. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may be subject to enforcement action, which would adversely affect our business, prospects and ability to achieve or sustain profitability.

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

The ability of the FDA and foreign regulatory authorities to review and approve new products can be affected by a variety of factors, including government budget and funding levels, statutory, regulatory, and policy changes, the FDA’s and foreign regulatory authorities' ability to hire and retain key personnel and accept the payment of user fees, and other events that may otherwise affect the FDA’s and foreign regulatory authorities' ability to perform routine functions. Average review times at the FDA and foreign regulatory authorities have fluctuated in recent years as a result. In addition, government funding of other government agencies that fund research and development activities is subject to the political process, which is inherently fluid and unpredictable. Disruptions at the FDA and other agencies, such as the European Medicines Agency ("EMA") following its relocation to Amsterdam and resulting staff changes, may also slow the time necessary for new drugs or modifications to approved drugs to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA, have had to furlough critical FDA employees and stop critical activities.

Separately, in response to the COVID-19 pandemic, the FDA postponed most inspections of domestic and foreign manufacturing facilities at various points. Even though the FDA has since resumed standard inspection operations of domestic facilities where feasible, the FDA has continued to monitor and implement changes to its inspectional activities to ensure the safety of its employees and those of the firms it regulates as it adapts to the evolving COVID-19 pandemic, and any resurgence of the virus or emergence of new variants may lead to further inspectional delays.

Regulatory authorities outside the United States have adopted similar restrictions or other policy measures in response to the COVID-19 pandemic. If a prolonged government shutdown occurs, or if global health concerns continue to prevent the FDA or other regulatory authorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact the ability of the FDA or other regulatory authorities to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

Clinical trials are very expensive, time-consuming and difficult to design and implement.

Although NERLYNX has been approved by the FDA for two limited indications, NERLYNX is still under development for various indications in the United States and in the EU, and alisertib and our other drug candidates are in development, as well, all of which will require extensive clinical testing before we can submit any NDA or similar foreign entities for regulatory approval. We have no prior experience developing alisertib and may face significant difficulties during our development of alisertib or NERLYNX for additional indications. Human clinical trials are very expensive and difficult to design and implement, in part because they are subject to rigorous regulatory requirements. The clinical trial process is also time consuming. We estimate that clinical trials of our other drug candidates will take at least several years to complete. Furthermore, failure can occur at any stage of the trials, and we could encounter problems that cause us to abandon or repeat clinical trials. The results of pre-clinical studies and early clinical trials of our drug candidates may not be predictive of the results of later-stage clinical trials. Drug candidates in later stages of clinical trials may fail to show the desired safety and efficacy traits despite having progressed through pre-clinical studies and initial clinical trials. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier trials. Our future clinical trial results may not be successful.

We do not know whether our future clinical trials will begin on time or enroll patients on time, or whether our ongoing and/or future clinical trials will be completed on schedule or at all. Clinical trials can be delayed for a variety of reasons, including delays related to:

In addition, disruptions caused by the COVID-19 pandemic may increase the likelihood that we encounter such difficulties or delays in initiating, enrolling, conducting or completing our planned and ongoing clinical trials. Further, we, the FDA, foreign regulatory authorities, or an IRB may suspend our clinical trials at any time if it appears that we or our collaborators are failing to conduct a trial in accordance with regulatory requirements, that we are exposing participants to unacceptable health risks, or if the FDA or such other foreign regulator finds deficiencies in our IND or comparable submissions or the conduct of these trials. Therefore, we cannot predict with any certainty the schedule for commencement and completion of future clinical trials. If we experience delays in the commencement or completion of our clinical trials, or if we terminate a clinical trial prior to completion, the commercial prospects of our drug candidates could be harmed, and our ability to generate revenue from the drug candidates may be delayed. In addition, any delays in our clinical trials could increase our costs, slow down the approval process and jeopardize our ability to commence product sales and generate revenue. Any of these occurrences may harm our business, financial condition and results of operations. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval of our drug candidates. 

In addition, the FDA’s and other foreign regulatory authorities’ policies with respect to clinical trials may change and additional government regulations may be enacted. For instance, the regulatory landscape related to clinical trials in the EU recently evolved. The EU CTR which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on January 31, 2022. While the Clinical Trials Directive required a separate CTA to be submitted in each member state, to both the competent national health authority and an independent ethics committee, the CTR introduces a centralized process and only requires the submission of a single application to all member states concerned. The CTR allows sponsors to make a single submission to both the competent authority and an ethics committee in each member state, leading to a single decision per member state. The assessment procedure of the CTA has been harmonized as well, including a joint assessment by all member states concerned, and a separate assessment by each member state with respect to specific requirements related to its own territory, including ethics rules. Each member state’s decision is communicated to the sponsor via the centralized EU portal. Once the CTA is approved, clinical study development may proceed. The CTR foresees a three-year transition period. The extent to which ongoing and new clinical trials will be governed by the CTR varies. Clinical trials for which an application was submitted (i) prior to January 31, 2022 under the Clinical Trials Directive, or (ii) between January 31, 2022 and January 31, 2023 and for which the sponsor has opted for the application of the Clinical Trials Directive remain governed by said Directive until January 31, 2025. After this date, all clinical trials (including those which are ongoing) will become subject to the provisions of the CTR. Compliance with the CTR requirements by us and our third-party service providers, such as CROs, may impact our developments plans.

If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies governing clinical trials, our development plans may be impacted.

Enrollment and retention of patients in clinical trials is an expensive and time-consuming process and could be made more difficult or rendered impossible by multiple factors outside our control.

We may encounter delays in enrolling, or be unable to enroll, a sufficient number of patients to complete any of our clinical trials, and even once enrolled we may be unable to retain a sufficient number of patients to complete any of our trials. Patient enrollment and retention in clinical trials depends on many factors, including the size of the patient population, the nature of the trial protocol, the existing body of safety and efficacy data with respect to the study drug, the number and nature of competing treatments and ongoing clinical trials of competing drugs for the same indication, the proximity of patients to clinical sites and the eligibility criteria for the study. Furthermore, any negative results we may report in clinical trials of any of our drug candidates may make it difficult or impossible to recruit and retain patients in other clinical studies of that same drug candidate. Delays or failures in planned patient enrollment and/or retention may result in increased costs, program delays or both, which could have a harmful effect on our ability to develop our drug candidates or could render further development impossible. In addition, we expect to rely on CROs and clinical trial sites to ensure proper and timely conduct of our future clinical trials and, while we intend to enter into agreements governing their services, we will be limited in our ability to compel their actual performance.

The results of our clinical trials may not support our product candidate claims.

Even if our clinical trials are completed as planned, we cannot be certain that their results will support the safety and effectiveness of our drug candidates for our targeted indications. Success in pre-clinical testing and early clinical trials does not ensure that later clinical trials will be successful, and we cannot be sure that the results of later clinical trials will replicate the results of prior clinical trials and pre-clinical testing. A failure of a clinical trial to meet its predetermined endpoints would likely cause us to abandon a drug candidate and may delay development of other drug candidates.

Moreover, pre-clinical and clinical data are often susceptible to varying interpretations and analyses and many companies that believed their product candidates performed satisfactorily in preclinical studies and clinical trials nonetheless failed to obtain FDA or comparable foreign regulatory authority approval. We cannot guarantee that the FDA or foreign regulatory authorities will interpret trial results as we do, and more trials could be required before we are able to submit applications seeking approval of our product candidates. To the extent that the results of the trials are not satisfactory to the FDA or foreign regulatory authorities for support of a marketing application, we may be required to expend significant resources, which may not be available to us, to conduct additional trials in support of potential approval of our product candidates. Even if regulatory approval is secured for any of our product candidates, the terms of such approval may limit the scope and use of our product candidate, which may also limit its commercial potential. Furthermore, 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, which may lead to the FDA or comparable foreign regulatory authorities delaying, limiting or denying approval of our product candidates. 

Risks Related to Commercialization of our Product Candidates

We have limited experience as a company in marketing or distributing pharmaceutical products. If we are unable to expand our marketing and sales capabilities and successfully commercialize NERLYNX, our business, results of operations and financial condition may be materially adversely affected.

A key part

In the United States, we rely on a direct sales force. NERLYNX is a marketed drug and none of the members of our sales force had ever promoted NERLYNX prior to its commercial launch. There are risks with establishing, growing and maintaining our own sales and marketing capabilities, including:

If we are unable to effectively address these risks, our efforts to commercialize NERLYNX successfully could be harmed, which would negatively impact our ability to generate product revenue.

Additionally, we will need to maintain and further develop our sales force to achieve commercial success, and we will be competing with other pharmaceutical and biotechnology companies to recruit, hire, train and retain marketing and sales personnel. In the event we are unable to continue to develop and effectively maintain our commercial team, including our U.S. sales force, our ability to successfully commercialize NERLYNXour products would be limited, and we would not be able to generate product revenue successfully.

Similarly, if we enter into arrangements with third parties to perform sales, marketing and distribution services, our product revenue or the profitability associated with any product revenue may be lower than if we were to market and sell any products that we develop ourselves. In addition, we may not be successful in entering into arrangements with third parties to sell and market our products or may be unable to do so on terms that are favorable to us. We may 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 products effectively. Moreover, we may be negatively impacted by other factors outside of our control relating to such third parties, including, but not limited to, their inability to comply with regulatory requirements. If we do not establishmaintain sales, marketing and distribution capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our products.

We are exposed to the risks associated with reliance on a direct sales force to commercialize NERLYNX in the United States.

In the United States, we rely on a direct sales force to market NERLYNX. Additionally, for any future products that we successfully develop, we will need to establish or maintain effective sales and marketing capabilities or enter into agreements with third parties to sell or market those products. There are risks with maintaining and growing our own sales and marketing capabilities, including:

If we are unable to effectively address these risks, our efforts to commercialize NERLYNX, or any additional product candidates that we develop, could be harmed, which would negatively impact our ability to generate product revenue.

Outside the United States we rely entirely on third-party sublicenses for the development and commercialization of NERLYNX. For a description of the risks associated with those arrangements see, “—Risks Related to Third Parties—We are dependent on international third-party sub-licensees for the development and commercialization of NERLYNX in several countries outside the United States. The failure of these sub-licensees to meet their contractual, regulatory or other obligations could adversely affect our business.”

Our NERLYNX commercialization efforts may fail to achieve the degree of market acceptance by patients and physicians necessary for commercial success.

NERLYNX was approved by the FDA in 2017. We had total revenue for NERLYNX of $225.1 million, $253.2 million and $228.0 million for the years ended December 31, 2020, 2021 and 2022, respectively. We cannot assure you that the sales of NERLYNX will continue at these levels or grow. We may encounter delays or hurdles related to our sales efforts that affect amount of revenue generated and the timing of such revenue. There is no guarantee that the infrastructure, systems, processes, policies, personnel, relationships and materials we have built to commercialize NERLYNX in the United States will be sufficient for us to achieve success at the levels we expect.

Our NERLYNX commercialization efforts may fail to gain sufficient market acceptance by physicians, patients, third-party payors and others in the medical community. If NERLYNX does not achieve an adequate level of acceptance, we may not generate significant product revenue and we may not maintain profitability. The degree of market acceptance of NERLYNX and will depend on a number of factors, including:

If NERLYNX fails to achieve market acceptance, it could have a material and adverse effect on our business, financial condition, results of operation and prospects.

We depend on a limited number of customers for a significant amount of our total revenue, and if we lose any of our significant customers, our business could be harmed.

The majority of our revenue comes from a limited number of customers. In 2021,2022, two customers individually comprised approximately 31%35% and 22%20%, respectively, of our total product revenue. We expect that revenue from a limited number of customers will continue to account for a large portion of our revenue in the future. The loss by us of any of these customers, or a material reduction in their purchases or their market pricing, could harm our business, results of operations, financial condition and prospects. In addition, if any of these customers were to fail to pay us in a timely manner, it could harm our cash flow.

Outside the United States we rely primarily on third-parties to pursue regulatory approval, if necessary, and to commercialize NERLYNX and they may not commit sufficient time or resources to marketing NERLYNX.

Outside the United States, we seek to enter into exclusive sub-license agreements with third parties to pursue regulatory approval, if necessary, and commercialize NERLYNX, if approved. As of December 31, 2022, NERLYNX has received approval for the treatment of certain patients with extended adjuvant or metastatic HER2+ breast cancer in more than 18 countries outside the United States, including the European Union (“EU”), Australia, Canada, and Hong Kong. We are currently party to several sub-licenses in various regions outside the United States, including Europe (excluding Russia and Ukraine), Australia, Canada, China, Southeast Asia, Israel, South Korea, and various countries and territories in Central America, South America and Africa. We depend on these third parties for a significant portion of our total revenue. Royalty revenue obtained pursuant to these sub-license agreements was 12% and 5% of total revenue for the years ended December 31, 2022 and 2021, respectively. We have very little control over these third-parties and any of our existing or future licensees may fail to devote the necessary resources and attention to obtain regulatory approval, where needed, and to market and distribute NERLYNX effectively. If these licensees are unsuccessful in receiving regulatory approvals or in commercializing NERLYNX, our business, results of operations and financial condition will be materially adversely affected. Moreover, we intend to seek additional third parties to sub-license NERLYNX in additional geographies, and may pursue a similar strategy for any future product candidates that we develop. We cannot assure you that we will be able to enter these agreements on commercial terms, or at all, and our failure to do so would have an adverse effect on our continued commercialization efforts for NERLYNX or any future product candidates.

Even though the FDA and EC have granted approval of NERLYNX for the extended adjuvant treatment of certain patients with early stage, HER2-positive breast cancer and the FDA has granted approval for NERLYNX for the treatment of certain patients with metastatic HER2-positive breast cancer, the terms of the approvals may limit its commercial potential.

Even though the FDA and EC have granted approval of NERLYNX, the scope and terms of the approvals may limit our ability to commercialize NERLYNX and, therefore, our ability to generate substantial sales revenue. The FDA and EC have both approved NERLYNX for the extended adjuvant treatment of certain adult patients with early stage, HER2-positive breast cancer in patients who are less than one year from the completion of prior adjuvant trastuzumab-based therapy. In connection with the FDA and EC approvals, we have committed to conduct certain post-marketing studies. We have completed the post-marketing commitments related to the FDA approval, and the post-marketing studies related to the EC approval are ongoing. If we fail to comply with all of our post-marketing commitments, or if the results of the post-marketing studies, or any other ongoing clinical studies of NERLYNX, are negative, the FDA or the EC could decide to withdraw its respective approval, add warnings or narrow the approved indication in the product label.

Regulatory approval for any approved product is limited by the FDA and foreign regulatory authorities to those specific indications and conditions for which clinical safety and efficacy have been demonstrated as set forth on the product label. If we market NERLYNXour products for uses beyond such approved indications, we could be subject to enforcement action, which could have a material adverse effect on our business.

The FDA and foreign regulatory authorities strictly regulates marketing, labeling, advertising and promotion of prescription drugs. These regulations include standards and restrictions for direct-to-consumer advertising, industry-sponsored scientific and educational activities, promotional activities involving the internet and off-label promotion. Any regulatory approval that the FDA or foreign regulatory authorities grant is limited to those specific diseases and indications for which a product is deemed to be safe and effective by the FDA and foreign regulatory authorities. For example, the FDA-approved label for NERLYNX is limited to the extended adjuvant treatment of adult patients with early stage, HER2-positive breast cancer following adjuvant trastuzumab-based therapy, and in combination with capecitabine, to the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 based regimens in the metastatic setting. In addition to the FDA or foreign regulatory authorities approval required for new formulations, any new indication for an approved product also requires FDA or foreign regulatory authorities approval. If we are not able to obtain FDA approval for any desired future indications for our drugs and drug candidates, our ability to effectively market and sell our products may be reduced and our business may be adversely affected.

While physicians in the United States and abroadoutside the United States may choose, and are generally permitted, to prescribe drugs for uses that are not described in the product’s labeling and for uses that differ from those tested in clinical trials and approved by the regulatory authorities, our ability to promote the products is narrowly limited to those indications that are specifically approved by the FDA or foreign regulatory authorities. These “off-label” uses are common across medical specialties and may constitute an appropriate treatment for some patients in varied circumstances. For example, in April 2018, we announced that NERLYNX (neratinib) has been included as a recommended treatment option in the latest NCCN Clinical Practice Guidelines in Oncology Central Nervous System Cancers for Breast Cancer patients with brain metastases. The NCCN designated NERLYNX in combination with capecitabine as a category 2A treatment option and NERLYNX in combination with paclitaxel as a category 2B treatment option. Use, as designated for breast cancer patients with brain metastases, is outside the FDA approved indication for NERLYNX and considered investigational, and we do not market or promote NERLYNX for these uses. Regulatory authorities in the United States and abroadoutside the United States generally do not regulate the behavior of physicians in their choice of treatments. Regulatory authorities do, however, restrict communications by pharmaceutical companies on the subject of off-label use. Although recent court decisions in the United States suggest that certain off-label promotional activities may be protected under the First Amendment, the scope of any such protection is unclear. If our promotional activities fail to comply with the FDA’s or foreign regulatory authorities' regulations or guidelines, we may be subject to warnings from, or enforcement action by, these authorities. In addition, our failure to follow FDA or foreign regulatory authorities rules and guidelines relating to promotion and advertising may cause the FDA or foreign regulatory authorities to issue warning letters or untitled letters, bring an enforcement action against us, suspend or withdraw an approved product from the market, require a recall or institute fines or civil fines, or could result in disgorgement of money, operating restrictions, injunctions or criminal prosecution, any of which could harm our reputation and our business.

We may fail to obtain orphan drug designations from the FDA for our product candidates, and even if we obtain such designations, we may be unable to maintain the benefits associated with orphan drug designation, including the potential for market exclusivity.

Regulatory authorities in some jurisdictions, including the U.S., may designate drugs designed to address relatively small patient populations as “orphan drugs.” Under the Orphan Drug Act, the FDA may grant orphan drug designation to a drug intended to treat a rare disease or condition, which is defined as one occurring in a patient population of fewer than 200,000 in the United States, or a patient population greater than 200,000 in the United States, where there is no reasonable expectation that the cost of developing the drug or biologic will be recovered from sales in the United States. In the U.S., orphan designation entitles a party to financial incentives such as opportunities for grant funding for clinical trial costs, tax advantages and user-fee waivers. In addition, if a product candidate that has orphan designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product is entitled to orphan drug exclusivity, which means that the FDA may not approve any other applications, including an NDA, to market the same drug for the same disease or condition for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or where the manufacturer is unable to assure sufficient product quantity.

We may decide to seek Orphan Drug Designations for alisertib. There can be no assurances that we will be able to obtain such designations. Even if we, or any future collaborators, obtain orphan drug designation for a product candidate, we, or they, may not be able to obtain or maintain orphan drug exclusivity for that product candidate. Further, even if we, or any future collaborators, obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different drugs with different active ingredients may be approved for the same disease or condition. Even after an orphan drug is approved, the FDA can subsequently approve the same drug for the same disease or condition if the FDA concludes that the later drug is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care, or the manufacturer of the product with orphan exclusivity is unable to maintain sufficient product quantity. Orphan drug designation neither shortens the development or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

Health care reform measures may hinder or prevent our products’products’ and product candidates’candidates’ commercial success.

The United States and some foreign jurisdictions have enacted or are considering enacting a number of legislative and regulatory proposals to change the healthcare system in ways that could affect our ability to profitably sell our product and product candidates, if and when they are approved. Among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives.

In March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively, the ACA became law in the United States. The ACA substantially changed and will continue to change the way healthcare is financed by both governmental and private insurers and significantly affects the pharmaceutical industry. Among the provisions of the ACA, of greatest importance to the pharmaceutical industry are the following:

Since its enactment, there have been judicial, executive and Congressional challenges to certain aspects of the ACA. On June 17, 2021, the U.S. Supreme Court dismissed the most recent judicial challenge to the ACA brought by several states without specifically ruling on the constitutionality of the ACA. Prior to the Supreme Court’s decision, President Biden issued an Executive Order to initiate a special enrollment period from February 15, 2021 through August 15, 2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The Executive Order also instructed certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the ACA.

In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted. For example, the Budget Control Act of 2011, resulted in aggregateamong other things, led to reductions to Medicare payments toof providers of 2% per fiscal year, which, went into effect on April 1, 2013 and, due to subsequent legislative amendments, will remain in effect through 2030,2031, with the exception of a temporary suspension from May 1, 2020 through July 1, 2022 (with a 1% payment reduction from April 1 to June 30, 2022), unless additional Congressional action is taken. On January 2, 2013, the American Taxpayer Relief Act of 2012, among other things, also reduced Medicare payments to several providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. Recently, there has been heightened governmental scrutiny overMore recently, on March 11, 2021, President Biden signed the mannerAmerican Rescue Plan Act of 2021 into law, which eliminates the statutory Medicaid drug rebate cap, currently set at 100% of a drug’s average manufacturer price, beginning January 1, 2024. 

Most significantly, in which drug manufacturers set prices for their marketed products, which has resultedAugust 2022, President Biden signed the Inflation Reduction Act of 2022, or the IRA, into law. This statute marks the most significant action by Congress with respect to the pharmaceutical industry since adoption of the ACA in several Congressional inquiries and proposed bills designed to, among2010. Among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. For example, the 21st Century Cures Act changes the reimbursement methodology for infusion drugs and biologics furnished through durable medical equipment in an attempt to remedy over- and underpaymentIRA requires manufacturers of certain drugs. We cannot predict alldrugs to engage in price negotiations with Medicare (beginning in 2026), with prices that can be negotiated subject to a cap; imposes rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023); and replaces the Part D coverage gap discount program with a new discounting program (beginning in 2025). The IRA permits the Secretary of the ways in which future federal or state legislative or administrative changes relatingDepartment of Health and Human Services (HHS) to healthcare reformimplement many of these provisions through guidance, as opposed to regulation, for the initial years. For that and other reasons, it is currently unclear how the IRA will affectbe effectuated, and while the impact of the IRA on our business.  business and the pharmaceutical industry cannot yet be fully determined, it is likely to be significant.

The cost of prescription pharmaceuticals in the United States has also been the subject of considerable discussion. There have been several Congressional inquiries, as well as legislative and regulatory initiatives and executive orders designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. MembersMost recently, on August 16, 2022, the Inflation Reduction Act of Congress2022 (“IRA”) was signed into law. Among other things, the IRA requires manufacturers of certain drugs to engage in price negotiations with Medicare (beginning in 2026), with prices that can be negotiated subject to a cap; imposes rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023); and replaces the Biden Administration have indicated they will continue to pursue legislative or administrative measures to control prescription drug costs, althoughPart D coverage gap discount program with a new discounting program (beginning in 2025). The IRA permits the likelihoodSecretary of such measures being adopted remains uncertain. For example, the Build Back Better Act, if enacted, would introduce substantial drug pricing reforms, including the establishment of a drug price negotiation program within the U.S. Department of Health and Human Services (“HHS”) to implement many of these provisions through guidance, as opposed to regulation, for the initial years. For that would require manufacturers to charge a negotiated “maximum fair price” for certain selected drugs or pay an excise tax for noncompliance, and other reasons, it is currently unclear how the establishment of rebate payment requirements on manufacturers of certain drugs payable under Medicare Parts B and D. If the Build Back Better Act is not enacted, similar or other drug pricing proposals could appear in future legislation.IRA will be effectuated. We cannot predict with certainty what impact any federal or state health reforms will have on us, but such changes could impose new or more stringent regulatory requirements on our activities or result in reduced reimbursement for our products, any of which could adversely affect our business, results of operations and financial condition.

Individual states in the United States have also become increasingly active in passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regional healthcare authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescription drug and other healthcare programs.

We anticipate that other healthcare reform measures that may be adopted in the future may result in additional reductions in Medicare and other healthcare funding, more rigorous coverage criteria, new payment methodologies and additional downward pressure on the price that we receive for any approved product, and could seriously harm our business. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability or commercialize our product and product candidates, if approved.

In the EU, similar political, economic and regulatory developments may affect our ability to profitably commercialize NERLYNX and our other product candidates, if approved. In addition to continuing pressure on prices and cost containment measures, legislative developments at the EU or member state level may result in significant additional requirements or obstacles that may increase our operating costs. The delivery of healthcare in the EU, including the establishment and operation of health services and the pricing and reimbursement of medicines, is almost exclusively a matter for national, rather than EU, law and policy. National governments and health service providers have different priorities and approaches to the delivery of health care and the pricing and reimbursement of products in that context. In general, however, the healthcare budgetary constraints in most EU member states have resulted in restrictions on the pricing and reimbursement of medicines by relevant health service providers. Coupled with ever-increasing EU and national regulatory burdens on those wishing to develop and market products, this could restrict or regulate post-approval activities and affect our ability to commercialize NERLYNX and our other product candidates, if approved. In other international markets outside the United States and the EU, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies.

On December 13, 2021, Regulation No 2021/2282 on Health Technology Assessment (“HTA”) amending Directive 2011/24/EU, was adopted. While the Regulation entered into force in January 2022, it will only begin to apply from January 2025 onwards, with preparatory and implementation-related steps to take place in the interim. Once the Regulation becomes applicable, it will have a phased implementation depending on the concerned products. This Regulation intends to boost cooperation among EU member states in assessing health technologies, including new medicinal products, and providing the basis for cooperation at the EU level for joint clinical assessments in these areas. The regulation will permit EU member states to use common HTA tools, methodologies, and procedures across the EU, working together in four main areas, including joint clinical assessment of the innovative health technologies with the most potential impact for patients, joint scientific consultations whereby developers can seek advice from HTA authorities, identification of emerging health technologies to identify promising technologies early, and continuing voluntary cooperation in other areas. Individual EU member states will continue to be responsible for assessing non-clinical (e.g., economic, social, ethical) aspects of health technology, and making decisions on pricing and reimbursement.

We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad.outside the United States. If we or our collaborators are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we or our collaborators are not able to maintain regulatory compliance, NERLYNX or any future approved product may lose any regulatory approval that may have been obtained and we may not achieve or sustain profitability.

Failure to obtain or maintain adequate coverage and reimbursement for our products or product candidates, if approved, could limit our ability to market those products and decrease our ability to generate revenue.

Successful commercial sales of any approved products will depend on the availability of adequate coverage and reimbursement from government health administration authorities, private health insurers and other third-party payors. Each third-party payor separately decides which products it will cover and establishes the reimbursement level, and there is no guarantee that any of our approved products or product candidates that may be approved for marketing by regulatory authorities will receive adequate coverage or reimbursement levels. Obtaining and maintaining coverage approval for a product is time-consuming, costly and may be difficult. We may be required to conduct expensive pharmacoeconomic studies to justify coverage and reimbursement or the level of coverage and reimbursement relative to other therapies. If coverage and adequate reimbursement are not available or limited, we may not be able to successfully commercialize any product or product candidate for which we obtain marketing approval. Government authorities and third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. 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 and biologics. Even if we obtain coverage for a given product, the resulting reimbursement rates may be inadequate and may affect the demand for, or the price of, any product candidate for which we obtain marketing approval.

We expect to experience pricing pressures in connection with the sale of our current or future commercial products, due to the trend toward managed healthcare, the increasing influence of health maintenance organizations and additional legislative proposals. There may be additional pressure by payors and healthcare providers to use generic drugs that contain the active ingredients found in neratinib or any other drug candidates that we may develop. If we fail to successfully secure and maintain adequate coverage and reimbursement for our products or are significantly delayed in doing so, we will have difficulty achieving market acceptance of our products and expected revenue and profitability which would have a material adverse effect on our business, results of operations and financial condition.

We are subject to federal, state and foreignhealthcare fraud and abuse laws, false claims laws and physician payment transparency laws. Failure to comply with these laws may subject us to substantial penalties.

We do not and will not control referrals of healthcare services or bill directly to Medicare, Medicaid or other third-party payors. However, federal, state and foreign healthcare laws and regulations pertaining to fraud and abuse and physician payment transparency laws and regulations apply to us depending on programs we operate and have been asserted by the government and others to apply to companies like us, and our arrangements with healthcare providers, customers and other entities, including our marketing practices, educational programs and pricing policies. These laws include:

Because of the breadth of these laws and the narrowness of the statutory exceptions and safe harbors available under such laws, it is possible that some of our business activities, including our relationships with physicians and other healthcare providers, some of whom recommend, purchase and/or prescribe our products, and the manner in which we promote our products, could be subject to challenge under one or more of such laws.

We are also exposed to the risk that our employees, independent contractors, principal investigators, consultants, vendors, distributors and agents may engage in fraudulent or other illegal activity. While we have policies and procedures in place prohibiting such activity, misconduct by these parties could include, among other infractions or violations, intentional, reckless and/or negligent conduct or unauthorized activity that violates FDA or foreign regulatory authority requirements, including those laws that require the reporting of true, complete and accurate information to the FDA or foreign regulatory authorities, manufacturing standards, federal and state healthcare fraud and abuse laws and regulations, laws that require the true, complete and accurate reporting of financial information or data or other commercial or regulatory laws or requirements. It is not always possible to identify and deter misconduct by our employees and other third parties, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws or regulations.

If our operations are found to violate any of the laws described above or any other laws and regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines, disgorgement, the curtailment or restructuring of our operations, the exclusion from participation in federal and state healthcare programs and imprisonment of officers involved, any of which could adversely affect our ability to market our current and any future products, once approved, and materially adversely affect our business, results of operations and financial condition. Any action against us for violation of these laws, 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.

If we fail to comply with our reporting and payment obligations under the Medicaid Drug Rebate Program or other governmental pricing programs in the United States, we could be subject to additional reimbursement requirements, penalties, sanctions and fines, which could have a material adverse effect on our business, results of operations and financial condition.

We participate in the Medicaid Drug Rebate Program ("MDRP") and other federal and state government pricing programs in the United States, and we may participate in additional government pricing programs in the future. These programs generally require us to pay rebates or otherwise provide discounts to government payors in connection with drugs, including NERLYNX, that are dispensed to beneficiaries of these programs. As a condition of having federal funds being made available for our covered outpatient drugs under Medicaid and Medicare Part B, we have enrolled in the MDRP, which requires us to pay a rebate to state Medicaid programs for each unit of our covered outpatient drugs dispensed to a Medicaid beneficiary and paid for by a state Medicaid program. Medicaid drug rebates are based on pricing data that we must report on a monthly and quarterly basis to the U.S. Centers for Medicare & Medicaid Services (“CMS”), the federal agency that administers the MDRP and Medicare programs. For the MDRP, these data include the average manufacturer price (“AMP”) for each drug and, in the case of our innovator products, the best price (“BP”).price. If we become aware that our MDRP price reporting submission for a prior period was incorrect or has changed as a result of recalculation of the pricing data, we must resubmit the corrected data for up to three years after those data originally were due. In addition, there is increased focus by the Office of Inspector General within the U.S. Department of Health and Human Services on the methodologies used by manufacturers to calculate AMP, and BP, to assess manufacturer compliance with MDRP reporting requirements. If we fail to provide information timely or are found to have knowingly submitted false information to the government, we may be subject to civil monetary penalties and other sanctions, including termination from the MDRP, which would result in payment not being available for our covered outpatient drugs under Medicaid or, if applicable, Medicare Part B. Failure to make necessary disclosures and/or to identify overpayments could result in allegations against us under the Federal False Claims Act and other laws and regulations. 

Federal law requires that a manufacturer that participates in the MDRP also participate in the Public Health Service’s 340B drug pricing program (the “340B program”) in order for federal funds to be available for the manufacturer’s drugs under Medicaid and Medicare Part B. We participate in the 340B program, which is administered by the Health Resources and Services Administration (“HRSA”), and requires us to charge statutorily defined covered entities no more than the 340B “ceiling price” for our covered outpatient drugs used in an outpatient setting. These 340B covered entities include a variety of community health clinics and other entities that receive health services grants from the Public Health Service, as well as hospitals that serve a disproportionate share of low-income patients. The 340B ceiling price is calculated using a statutory formula, which is based on the AMP and rebate amount for the covered outpatient drug as calculated under the MDRP. In general, products subject to Medicaid price reporting and rebate liability are also subject to the 340B ceiling price calculation and discount requirement. We must report 340B ceiling prices to HRSA on a quarterly basis, and HRSA publishes them to 340B covered entities. HRSA has finalized regulations regarding the calculation of the 340B ceiling price and the imposition of civil monetary penalties on manufacturers that knowingly and intentionally overcharge covered entities for 340B-eligible drugs. HRSA has also finalized an administrative dispute resolution process through which 340B covered entities may pursue claims against participating manufacturers for overcharges, and through which manufacturers may pursue claims against 340B covered entities for engaging in unlawful diversion or duplicate discounting of 340B drugs. In addition, legislation may be introduced that, if passed, would further expand the 340B program, such as adding further covered entities or requiring participating manufacturers to agree to provide 340B discounted pricing on drugs used in an inpatient setting.  

In order to be eligible to have drug products paid for with federal funds under Medicaid and Medicare Part B and purchased by certain federal agencies and grantees, we also must participate in the U.S. Department of Veterans Affairs (“VA”) Federal Supply Schedule (“FSS”) pricing program. Under the VA/FSS program, we must report the Non-Federal Average Manufacturer Price (“Non-FAMP”) for our covered drugs to the VA and charge certain federal agencies no more than the Federal Ceiling Price, which is calculated based on Non-FAMP using a statutory formula. These four agencies are the VA, the U.S. Department of Defense, the U.S. Coast Guard, and the U.S. Public Health Service (including the Indian Health Service). We must also pay rebates on products purchased by military personnel and dependents through the TRICARE retail pharmacy program. If we fail to provide timely information or are found to have knowingly submitted false information, we may be subject to civil monetary penalties. 

Individual states continue to consider and have enacted legislation to limit the growth of healthcare costs, including the cost of prescription drugs and combination products. A number of states have either implemented or are considering implementation of drug price transparency legislation that may prevent or limit our ability to take price increases at certain rates or frequencies. Requirements under such laws include advance notice of planned price increases, reporting price increase amounts and factors considered in taking such increases, wholesale acquisition cost information disclosure to prescribers, purchasers, and state agencies, and new product notice and reporting. Such legislation could limit the price or payment for certain drugs, and a number of states are authorized to impose civil monetary penalties or pursue other enforcement mechanisms against manufacturers who fail to comply with drug price transparency requirements, including the untimely, inaccurate, or incomplete reporting of drug pricing information. If we are found to have violated state law requirements, we may become subject to penalties or other enforcement mechanisms, which could have a material adverse effect on our business. 

Pricing and rebate calculations are complex, vary among products and programs, and are often subject to interpretation by us, governmental or regulatory agencies, and the courts. The terms, scope and complexity of these government pricing programs change frequently, as do interpretations of applicable requirements for pricing and rebate calculations. Responding to current and future changes may increase our costs and the complexity of compliance will be time consuming. Any required refunds to the U.S. government or responding to a government investigation or enforcement action would be expensive and time consuming and could have a material adverse effect on our business, results of operations and financial condition. Price recalculations under the MDRP also may affect the ceiling price at which we are required to offer products under the 340B program. Pursuant to the IRA, the AMP figures we report to the MDRP will also be used to compute rebates under Medicare Part D triggered by price increases that outpace inflation. Civil monetary penalties can be applied if we are found to have knowingly submitted any false price or product information to the government, if we fail to submit the required price data on a timely basis, or if we are found to have charged 340B covered entities more than the statutorily mandated ceiling price. In the event that CMS were to terminate our Medicaid rebate agreement, no federal payments would be available under Medicaid or Medicare for our covered outpatient drugs. We cannot assure you that our submissions will not be found to be incomplete or incorrect.

Risks Related to the Discovery and Development of our Products

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

From time to time, we may publicly disclose preliminary or topline data from our preclinical studies and clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the topline 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. Preliminary and topline data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. Consequently, preliminary and topline data should be viewed with caution until the final data are available.

From time to time, we may also disclose interim data from our clinical trial. 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. Adverse differences between preliminary or interim data and final data could significantly harm our business prospects. Further, disclosure of interim data by us or by our competitors could result in volatility in the price of our common stock.

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

If the interim, topline, 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.

NERLYNX or our other drug candidates may cause undesirable side effects or have other properties when used alone or in combination with other approved products or investigational new drugs 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, as applicable.

Undesirable side effects caused by NERLYNX or our other drug candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign authorities. To date, subjects treated with NERLYNX have experienced drug-related side effects including diarrhea. Results of our trials could reveal a high and unacceptable severity and prevalence of these or other 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 product candidates for any or all targeted indications. The drug-related side effects could affect patient recruitment or the ability of enrolled patients to complete clinical trials or result in potential product liability claims. Any of these occurrences may harm our business, financial condition and prospects significantly.

Additionally, if we or others later identify undesirable side effects caused by any approved product, including in combination with other approved products or investigational new drugs, a number of potentially significant negative consequences could result, including:

Any of these events could prevent us from achieving or maintaining market acceptance of NERLYNX or the particular product candidate, if approved, and could significantly harm our business, results of operations and prospects.

NERLYNX is still under clinical development for various additional indications, and we cannot be certain that NERLYNX will receive regulatory approval for any other indication for which we may seek approval.

The FDA and the EC have both approved NERLYNX for the extended adjuvant treatment of adult patients with early stage hormone receptor positive HER2-overexpressed/amplified breast cancer and who are less than one year from the completion of prior adjuvant trastuzumab-based therapy. In February 2020, the FDA also approved NERLYNX in combination with capecitabine, for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2 based regimens in the metastatic setting. We expect that a substantial portion of our efforts and expenditures over the next few years will be devoted to the development of NERLYNX in various additional indications. Accordingly, our business currently depends heavily on the successful development and regulatory approval of NERLYNX for additional indications. The research, testing, manufacturing, labeling, approval, sale, marketing and distribution of drug products are and will remain subject to extensive regulation by the FDA and other regulatory authorities in the United States and other countries that each have differing regulations. We are not permitted to market NERLYNX for other indications or any of our other drug candidates in the United States until we receive approval of an NDA from the FDA or in the EU until we receive approval from the EC, as applicable, for such indications, or, in any foreign countries, until requisite approval from such countries.

Approval of NERLYNX by the FDA or the EC for any particular indication does not ensure that a foreign jurisdiction will also approve NERLYNX for such indication, nor does it ensure that NERLYNX will be approved by the FDA or the EC for any other indications. Obtaining approval of an NDA or foreign marketing application is an extensive, lengthy, expensive and inherently uncertain process, and the FDA or a foreign regulator may delay, limit or deny approval of a drug candidate for many reasons, including: