UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 20172020

or

For the transition period from to

Commission File Number: 001-35703

PUMA BIOTECHNOLOGY, INC.

(Exact name of registrant as specified in its charter)

10880 Wilshire Boulevard, Suite 2150

Los Angeles, CA 90024

(424) 248-6500

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

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

Securities registered pursuant to Section 12(g) of the Act: None

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

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

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

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

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

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

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

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

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

The aggregate market value of voting stock held by non-affiliates of the registrant was $2,481,469,190approximately $413.3 million as of June 30, 2017,2020, based upon the closing price of $87.40$10.43 per share of the registrant’s common stock on the NASDAQ Global Select Market on Friday, June 30, 2017,2020, the last business day of the registrant’s most recently completed second fiscal quarter. Shares of common stock held by each executive officer, director and holder of 10% or more of the outstanding common stock have been excluded in that such persons may be deemed to be affiliates. This determination of affiliate status is not necessarily a conclusive determination for other purposes. As of February 20, 2018,18, 2021, there were 37,719,72440,258,460 shares of the registrant’s common stock outstanding.

Documents Incorporated by Reference:

Portions of the Proxy Statement for the registrant’s 20182021 Annual Meeting of Stockholders, or the 20182021 Proxy Statement, are incorporated by reference into Part III of the Form 10-K to the extent stated herein.

TABLE OF CONTENTS

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, or the 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.document, except as required by law. The risks discussed in this Annual Report should be considered in evaluating our prospects and future financial performance.

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PARTSUMMARY 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:

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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 27, 2007 and formerly known as Innovative Acquisitions Corp., together with itsour wholly-owned subsidiary,subsidiaries, Puma Biotechnology Ltd.,Ltd and all references to “Former Puma” refer to Puma Biotechnology Inc., a privately-held Delaware corporation formed on September 15, 2010, that merged with and into us in October 2011. We refer to this transaction as the “Merger.”B.V.

We are a biopharmaceutical company with a focus on the development and commercialization of innovative products to enhance cancer care. We in-license the global development and commercialization rights to three drug candidates – PB272 (neratinib, oral), PB272 (neratinib, intravenous) and PB357. NeratinibOur lead product is NERLYNX, an oral version of neratinib, which is a potent irreversible tyrosine kinase inhibitor, or TKI, that blocks signal transduction through the human epidermal growth factor receptors, HER1, HER2 and HER4. Currently,In 2017, we are primarily focused onobtained approval from the U.S. commercialization of NERLYNX (neratinib), our first U.S.United States Food and Drug Administration, or FDA, approved product,to market, and oncommenced commercialization of NERLYNX in the further developmentUnited 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 oral version of neratinibindication for additional indicationsNERLYNX to include its use in combination with capecitabine for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer.cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting. We believe neratinib has clinical application in the treatment of several other cancers as well, including non-small cell lung cancer and other tumor types that over-express or have a mutation in HER2. Until recently, we have focused our efforts and resources primarily on obtaining regulatory approval for NERLYNX (neratinib) and on acquiring and developing our pharmaceutical technologies, raising capital and recruiting personnel.

On July 17, 2017, we received regulatory approval of our first product, NERLYNX (neratinib), formally knownHER2 or epidermal growth factor receptor, or EGFR, such as PB 2727 (neratinib (oral)), for the extended adjuvant treatment of adult patients with early state HER2-overexpressed/amplified breastcervical cancer, following adjuvant trastuzumab-based therapy from the FDA.  After receiving FDA approval, we commenced commercialization of NERLYNX in the United States using a direct sales force.

Before we can market neratinib in countries outside the United States, we must receive regulatory approval from the appropriate government entities in those countries.  We filed a Marketing Authorization Application,lung cancer or MAA, with the European Medicines Agency, or EMA, in July 2016.  We recently announced that the EMA’s Committee for Medicinal Products for Human Use, or CHMP, adopted a negative opinion and recommend refusal of our MAA for neratinib for the extended adjuvant treatment of early stage HER2-positive breast cancer.  We have 15 days from the date of acknowledgement of receipt of the final opinion package to request a re-examination, and we intend to submit the request within the prescribed timeline. We recently entered into exclusive license agreements with Specialised Therapeutics Asia Pte Ltd., or STA, Medison Pharma Ltd., or Medison, and CANbridgepharma Limited, or CANbridge, to pursue regulatory approval and commercialize NERLYNX, if approved, in South East Asia, Israel and greater China, respectively.  We plan to continue to pursue commercialization of NERLYNX in other countries outside the United States, if approved, and will evaluate various commercialization options in those countries, including developing a direct sales force, contracting with third parties to provide sales and marketing capabilities, or some combination of these two options.  We expect that our expenses will continue to increase as we continue commercialization efforts.solid tumors.

Breast cancer is the leading cause of cancer death among women worldwide. Studies show that approximatelyup to 20% to 25% of breast cancer tumors have an 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)Herceptin ®), pertuzumab (marketed as Perjeta)Perjeta ®) and T-DM1 (marketed as Kadcyla)Kadcyla ®), each produced by Genentech, and lapatinib (marketed as Tykerb)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 improve the treatment of this type of breast cancer by binding to the HER2 protein. There are a number of trials ongoing that involve various combinations of these drugs (for example, Perjeta). drugs.

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. We believe that by more potently inhibiting HER2 at a different site and usingand/or acting via a mechanism different mechanism than thesefrom other drugs.

Separately, in February 2013, we reached agreement with the FDA under a Special Protocol Assessment, or SPA for a planned Phase III clinical trial of PB272agents, neratinib may have therapeutic benefits in patients with HER2-positive metastatic breast cancer who have failed two or more priorbeen previously treated with these existing treatments, (third-line disease). The EMA has provided follow-on scientific advice, or SA, consistent with thatmost notably due to its increased selectivity and irreversible inhibition of the FDA regardingHER2 target enzyme.

We currently market NERLYNX in the United States using our ability to usedirect specialty sales force consisting of approximately 68 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, the trial to support regulatory approvalEuropean Commission, or EC, granted marketing authorization for NERLYNX in the European Union.Union 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, we have entered into exclusive sub-license agreements with various parties to pursue regulatory approval, if necessary, and commercialize NERLYNX, if approved. We referare currently party to this trial as PUMA-NER-1301. 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 and South America.

We initiated this trial in June 2013.   We expect to report the top line data from this trial in 2018.

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Additionally, in December 2016, we initiatedhave also implemented a managed access program for neratinib. 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 neratinib enables participation from countries outside the United States including European Union member states, where permitted by applicable rules, procedures and regulatory authorities. The program will provideprovides access to neratinib 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 neratinib clinical trial. Patients in the managed access program will beare given neratinib and will beare instructed to take a prophylaxis which consists of high dose loperamide and budesonide, during treatment to manage neratinib-related diarrhea, which we expect will consist of high dose loperamide and budesonide.diarrhea. We have partnered with Caligor Opco LLC, which specializes in early access to medicines, to implement and oversee the managed access program for neratinib.

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In addition to continuing to follow the patients from the ExteNET trial and continuing the PUMA-NER-1301 trial,commercializing NERLYNX for its approved indications, we are actively conducting the following trials to evaluate the safety and efficacy of neratinib in various indications:

We license the commercial rights to our current drug candidates from Pfizer, Inc., Pfizer or the Licensor, which had previously been responsible for the clinical trials regarding neratinib.  Going forward, we expect to augment our product pipeline by acquiring, through license or otherwise, additional drug candidates for research and development, and potential commercialization.  In evaluating potential drug candidates, we employ disciplined decision criteria that favor drug candidates that have undergone at least some clinical study. Our decision to acquire a drug candidate will also depend on our evaluation of the scientific merits of the underlying technology, the costs of the transaction and other economic terms of any proposed license, the amount of capital that we anticipate will be required to develop the drug candidate and the economic potential of the drug candidate if approved for commercialization.  We believe this strategy minimizes our clinical development risk and allows us to accelerate the development and potential commercialization of current and future drug candidates.

Strategy

Our primary objective is to build neratinib into a significant oncology franchise as a single agent, and potentially in combination with other therapies. The following elements comprise theour strategy to achieve this objective:

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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. ApproximatelyUp to 20% to 25% 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 T-DM1tucatinib 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 therapytreatments for the adjuvant treatment of HER2-positive early stage breast cancer is either the combination of trastuzumab and chemotherapy.   In addition,chemotherapy, the combination of pertuzumab plus trastuzumab and chemotherapy, was recentlyor Kadcyla, which is approved as adjuvant treatment ofspecifically in patients with HER2-positive early stage breast cancer at high risk of recurrence based on the results of the APHINITY trial.with residual disease after neoadjuvant treatment. We are also aware of the KAITLINa Phase III clinical trial whichthat is comparing trastuzumab plus pertuzumab plus taxane following anthracyclines versus T-DM1 plus pertuzumab following anthracyclines as an adjuvant therapy.

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Trastuzumab and pertuzumab given in combination with taxane chemotherapy is the current first-line standard In addition, we are also aware of care for HER2-positive metastatic breast cancer.  Lapatinib (Tykerb), given in combination with the chemotherapy drug capecitabine, is also FDA-approved for the treatment of patients who have failed prior treatments. In a Phase II clinical trial, lapatinib demonstrated a median progression free survival of 8 to 9 weeks and a response rate of 5 – 7%.  In a Phase III clinical trial in patients with high risk HER2-positive metastaticearly stage breast cancer who receivedwith residual disease after neoadjuvant treatment that is testing the combination of lapatinibKadcyla plus capecitabine demonstratedtucatinib versus Kadcyla alone (the CompassHER2 RD Trial) as well as a median progression free survival of 27.1 weeks and a response rate of 23.7%.  In the Phase III EMILIA trial the combination of lapatinib plus capecitabine demonstrated a median progression free survival of 25.6 weeks and a response rate of 30.8%.  T-DM1 is approved by the FDA for the treatment of patients with HER2-positive metastatic breast cancer who previously received first line trastuzumab-based therapy.  Unfortunately, the disease eventually progresses for most patients with HER2-positive breast cancer while on these treatments. For these reasons, there is a need for alternatives to block HER2 signaling in patients who fail treatment with prior HER2 directed treatments. Neratinib is an orally active small molecule that inhibits HER2 at a different site and uses a different mechanism than trastuzumab. As a result, we believe that neratinib may have utility in patients with high risk HER2-positive metastaticearly stage breast cancer who have failedwith residual disease after neoadjuvant treatment with trastuzumab.that is testing fam-trastuzumab deruxtecan versus Kadcyla alone (the DESTINY-Breast05 Trial).

We believe that there are approximately 36,00030,000 patients in the United States and 34,00037,000 patients in the European Union, or the EU with newly diagnosedearly stage HER2-positive breast cancer.  Based on our internal estimates, we believecancer that the worldwide Herceptinget treated with adjuvant revenue was approximately $4.5 to $5.0 billion in 2015.treatment. We also believe that there are between 5,000 and 6,000approximately 6,400 patients in the United States with third-line or laterand 4,700 patients in the United States with fourth line HER2-positive metastatic breast cancer. The number of patients with third linethird-line or later HER2 positiveHER2-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 positiveHER2-positive breast cancer and therefore reduce the number of patients with HER2 positiveHER2-positive metastatic breast cancer.  In 2013, worldwide sales of Tykerb for this indication were approximately $325 million.  

We believe that approximately 2%1% to 12% of all newly diagnosed breast cancer patients have mutation in HER2 kinase (approximately 4,000 to 5,000 patients in the United States)States and that approximately 4 – 5%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). We believe that this mutation occurs mostly in patients with hormone receptor-positive disease.

Product Development Pipeline

The following chart shows each of our current drug candidates and their clinical development stage.  

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Neratinib

Neratinib is a potent irreversible tyrosine kinase inhibitor, or 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 metastatic breast cancer who have failed prior treatments, including treatment with trastuzumab, pertuzumab, and T-DM1. Currently, the treatment of metastatic breast cancer patients involves treatment with these agents either alone or in combination with chemotherapy.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 failedbeen previously treated with these existing treatments, most notably due to its increased selectivity and 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 non-small cell lung cancer and other tumor types that over-express or have a mutation in HER2.  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.  We are also evaluating for potential development an intravenous formulation of neratinib and PB357, a back-up compound to neratinib.

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PB272 (neratinib oral)—Early Stage Breast Cancer

Extended Adjuvant Breast Cancer

In 2017, the FDA approved NERLYNX, formally known as PB272 (neratinib (oral)), 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 European Union 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 theour ExteNET trial, a Phase III clinical trial of neratinib for the extended adjuvant treatment of early stage HER2-positive breast cancer (ExteNET Trial).cancer. The data from this trial waswere presented in an oral presentation at the American Society of Clinical Oncology, (ASCO) 2015or ASCO, Annual Meeting in June 2015 and waswere published online in The Lancet Oncology in February 2016. The ExteNET trial iswas 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 (1(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. Puma’s previously reported clinical data from several trials have demonstrated that the use of high dose prophylactic loperamide may greatly reduce the rate of grade 3 diarrhea with neratinib, with grade 3 diarrhea rates ranging from 0-17% in studies in which high dose loperamide prophylaxis was used.  We are currently conducting an international, open-label, Phase II study investigating the use of antidiarrheal prophylaxis with loperamide alone or with other agents in the prevention and reduction of neratinib-associated diarrhea and, more specifically, grade 3 diarrhea.  The interim results of this trial (data cut-off of November 2016) showed that the incidence of grade 3 diarrhea for the total 135 patients who received the loperamide prophylaxis was 28.1% and that the incidence of grade 3 diarrhea was 15.0% for the 40 patients who received the combination of loperamide plus budesonide.   In all of its current ongoing studies Puma is instituting the use of antidiarrheal prophylaxis for the first cycle of treatment in order to continue to reduce the neratinib-related diarrhea.  See “–Safety Database” for additional information.

The primary endpoint of the ExteNET trial was invasive disease-free survival, (DFS).or 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 2-yeartwo-year DFS rate for the neratinib arm was 93.9% and the 2-yeartwo-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).or 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 2-yeartwo-year DFS-DCIS rate for the neratinib arm was 93.9% and the 2-yeartwo-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 2-yeartwo-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 2-yeartwo-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 2-yeartwo-year DFS-DCIS rate for the centrally confirmed patients in the neratinib arm was 94.7% and the 2-yeartwo-year DFS rate for centrally confirmed patients in the placebo arm was 90.2%.

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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 2-yeartwo-year DFS rate for the neratinib arm was 95.4% and the 2-yeartwo-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 2-yeartwo-year DFS rate for the centrally confirmed patients in the neratinib arm was 97.0% and the 2-yeartwo-year DFS rate for centrally confirmed patients in the placebo arm was 88.4%.

Based on the results from the ExteNET trial, in June and July 2016, we submitted an MAA with the EMA and filed an NDA with the FDA, respectively, for regulatory approval of neratinib in the extended adjuvant setting.7

Five-Year ExteNET Data.  In September 2017, we presented updated data from the ExteNET trial at the European Society of Medical Oncology, (ESMO)or ESMO, 2017 Congress in Madrid, Spain. The data represented a predefined 5-yearfive-year invasive disease freedisease-free survival, (iDFS)or iDFS, analysis as a follow-up to the primary 2-yeartwo-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 5-yearfive-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 freedisease-free survival including ductal carcinoma in situ, (iDFS-DCIS).or 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 5-yearfive-year iDFS-DCIS rate for the neratinib arm was 89.7% and the 5-yearfive-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 5-yearfive-year iDFS rate for the neratinib arm was 91.2% and the 5-yearfive-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 2-yeartwo-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 (1(one patient, (0.1%)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.

NeoadjuvantIn October 2020, we announced that efficacy results of neratinib in HER2-positive, hormone receptor-positive, or HR+, early stage breast cancer, or 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).

AtCONTROL. In February 2015, we initiated the 2010CONTROL 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 Sant Antonio Breast Cancer Symposium, respectively.

The interim results of the Neoadjuvant Lapatinib and/or Trastuzumab Treatment Optimisation Study, or the Neo-ALTTO study, were presented. In this trial patients with HER2-positive breast cancer were randomized to receive either the combination of paclitaxel plus trastuzumab, the combination of paclitaxel plus lapatinib or the combination of paclitaxel plus trastuzumab plus lapatinib,presented in December 2019 and December 2020 showed that as a neoadjuvant (preoperative) therapy. The results of the trial demonstrated thatcutoff date, 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 paclitaxelloperamide plus trastuzumab demonstrated a pathological complete response rate, or pCR,budesonide was 28%, the incidence of 27.6% ingrade 3 diarrhea for the breast and lymph nodes, the patients who received paclitaxel plus lapatinib had a pCR of 20.0% and the136 patients who received the combination of paclitaxelloperamide plus trastuzumab plus lapatinib had a pCRcolestipol was 21%, the incidence of 46.8%.

Also atgrade 3 diarrhea for the 2010 CTRC-AACR San Antonio Breast Cancer Symposium, the results of the Neo-Sphere study were presented. In this trial, patients with HER2-positive breast cancer were randomized to receive either the combination of docetaxel plus trastuzumab, the combination of docetaxel plus pertuzumab, the combination of trastuzumab plus pertuzumab or the combination of docetaxel plus trastuzumab plus pertuzumab, as a neoadjuvant (preoperative) therapy. The results of the trial demonstrated that the104 patients who received colestipol alone with loperamide as needed was 32%, and the combinationincidence of docetaxel plus trastuzumab had a pCR of 21.5%ingrade 3 diarrhea for the breast and lymph nodes, the60 patients who received docetaxel plus pertuzumab had a pCR of 17.7%,used the patients who received pertuzumab plus trastuzumab had a pCR of 11.2% and the patients who received the combination of docetaxel plus trastuzumab plus pertuzumab had a pCR of 39.3%.

I-SPY 2 TRIAL. In 2010, the Foundation for the National Institutes of Health initiated the I-SPY 2 TRIAL (Investigation of Serial Studies to Predict Your Therapeutic Response with Imaging And moLecular Analysis 2)dose escalation was 13%. The I-SPY 2 TRIALFurther information is a randomized Phase II clinical trial for women with newly diagnosed Stage 2 or higher (tumor size at least 2.5 cm) breast cancer that addresses whether adding investigational drugs to standard chemotherapyprovided in the neoadjuvant setting is better than standard chemotherapy. The primary endpoint was pCR in the breast and the lymph nodes at the time of surgery. The goal of the trial was to match investigational regimens with patient subsets on the basis of molecular characteristics, referred to as biomarker signatures, that benefit from the regimen.  

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The I-SPY 2 TRIAL involved an adaptive trial design based on Bayesian predictive probability that a regimen will be shown to be statistically superior to standard therapy in an equally randomized 300-patient confirmatory trial. Regimens that have a high Bayesian predictive probability of showing superiority in at least one of 10 predefined signatures graduate from the trial. Regimens are dropped for futility if they show a low predictive probability of showing superiority over standard therapy in all 10 signatures. A maximum total of 120 patients can be assigned to each experimental regimen. A regimen can graduate early and at any time after having 60 patients assigned to it.

In April 2014, we announced the results for the neratinib-containing regimen of the I-SPY 2 TRIAL.  The neratinib-containing regimen (neratinib plus paclitaxel followed by doxorubicin and cyclophosphamide) graduated from the I-SPY 2 TRIAL based on having a high probability of success in Phase III with a signature of HER2 positive/HR negative. In this group, treatment with the neratinib-containing regimen resulted in an estimated pCR rate of 55.6% compared to the control arm (standard neoadjuvant chemotherapy: paclitaxel in combination with trastuzumab followed by doxorubicin and cyclophosphamide), which had an estimated pCR rate of 32.6%. The Bayesian probability of superiority for the neratinib-containing regimen (compared to standard therapy) is 94.9%, which is analogous to a p-value of 0.051. In addition, the Bayesian predictive probability of showing statistical superiority in a 300-patient Phase III randomized trial of paclitaxel plus neratinib versus paclitaxel plus trastuzumab, both followed by doxorubicin/cyclophosphamide, is 79.1%.

For the 65 patients in the trial who were HER2 positive (including those who were either hormone receptor positive or negative), treatment with the neratinib-containing regimen resulted in an estimated pCR rate of 39.4% compared to the control arm, which demonstrated an estimated pCR rate of 22.8%. The Bayesian probability of superiority for the neratinib-containing regimen is 95.4%, which is analogous to a p-value of 0.046. In addition, the Bayesian predictive probability of showing statistical superiority in a 300-patient Phase III randomized trial of paclitaxel plus neratinib versus paclitaxel plus trastuzumab is 72.7%.

Patients in the I-SPY 2 TRIAL were screened using the MammaPrint 70-gene signature test to determine if they had a heightened risk of breast cancer recurrence. The median MammaPrint score from the patients in the previous I-SPYTable 1 TRIAL who fit the eligibility criteria for I-SPY 2 was used as a predefined stratification factor for the I-SPY 2 TRIAL. Patients in I-SPY 2 were stratified as either MammaPrint High (below the median from I-SPY 1) or MammaPrint Ultra High (above the median from I-SPY 1). For the 41 neratinib treated patients in the trial who were MammaPrint Ultra High (80.5% of whom were HER2 negative), treatment with the neratinib-containing regimen resulted in an estimated pCR rate of 47.5% compared to the control arm, which demonstrated an estimated pCR rate of 29.4%. The Bayesian probability of superiority for the neratinib-containing regimen is 93.3%, which is analogous to a p-value of 0.067. In addition, the Bayesian predictive probability of showing statistical superiority in a 300-patient Phase III randomized trial of paclitaxel plus neratinib versus paclitaxel alone for HER2-negative patients, or in combination with trastuzumab for the HER2-positive patients, is 71.8%.

The results of the I-SPY2 TRIAL with neratinib were published in The New England Journal of Medicine in July 2016.

FB-7 Trial.  In 2010, Pfizer, in collaboration with the National Surgical Adjuvant Breast and Bowel Project, or NSABP, a clinical trials cooperative group supported by the National Cancer Institute, or NCI, initiated the FB-7 study to investigate the use of neratinib as a neoadjuvant therapy for newly diagnosed HER2-positive breast cancer. In this trial, a total of 126 patients are randomized to receive neratinib plus the chemotherapy drug paclitaxel or trastuzumab plus paclitaxel prior to having surgery to remove their tumors. The purpose of this study is to test whether adding neratinib to paclitaxel chemotherapy is better than trastuzumab plus paclitaxel chemotherapy before having surgery. This trial was modified in 2012 to include a third treatment arm where patients will receive the combination of neratinib plus trastuzumab plus paclitaxel prior to having surgery to remove their tumors.

Data from this trial were presented at the 2015 CTRC-AACR San Antonio Breast Cancer Symposium.  Patients were randomly assigned to trastuzumab (T) or neratinib (N) or the combination (T+N) with weekly paclitaxel (P) followed by standard doxorubicin and cyclophosphamide chemotherapy (AC) administered prior to surgery.  126 U.S., Canadian, and European patients were randomly assigned to Arm 1 (T+P followed by AC), Arm 2 (N+P followed by AC) or Arm 3 (T+N+P followed by AC).  The primary endpoint of the trial was pathological complete response rate (pCR) in the breast and lymph nodes.  Tumor tissue was collected on patients at the time of diagnosis. This tissue will be analyzed for several biomarkers including AKT, cMET, EGFR, ESR-alpha, HER2, HER3, HER4, p95 HER2 and PI3K and intrinsic subtypes. A key secondary endpoint of this trial is the molecular and genetic correlates of response for each of these biomarkers.

For the intent-to-treat patient population (hormone receptor positive (HR+) and hormone receptor negative (HR-)), the pCR rate for Arm 1 was 38.1%, for Arm 2 was 33.3% and for Arm 3 was 50.0%. For the HR+ patients, the pCR rate for Arm 1 was 29.6%, for Arm 2 was 27.6% and for Arm 3 was 30.4%. For the HR- patients, the pCR rate for Arm 1 was 57.1%, for Arm 2 was 46.2% and for Arm 3 was 73.7%.

below:

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TheTable 1:  Incidence of Treatment-Emergent Diarrhea

Safety Database. Our safety database includes over 3,000 patients who have been treated with neratinib. To date, the most frequently observed severesignificant grade 3 or higher adverse event associated with neratinib has been diarrhea, which occurs in approximately 30% to 40% of patients receiving the drug. Historically, once diarrhea occurred, patients were treated with loperamide and/or a reduction in the two neratinib treated armsdose of the trial (Arm 2 and Arm 3) was diarrhea. In the first 19 patients treated in Arm 2 of the trial, high dose loperamide (16 mg per day initially) as primary prophylaxis was not given to prevent the neratinib-related diarrhea. In this subset of patients the grade 3 diarrhea rate was 42% (8/19). In the next 10 patients treated in Arm 2 and the first 20 patients treated in Arm 3, high dose primary prophylaxis (16 mg per day initially) with loperamide was given during the initial two weeks of the first cycle of treatment. Using two weeks of intensive loperamide prophylactically, the grade 3 diarrhea rate in Arm 2 was 30% (3/10) and the grade 3 diarrhea rate in Arm 3 was 35% (7/20). In the next 13 patients in Arm 2 and 22 patients in Arm 3, high dose prophylaxis (16 mg per day initially) was given for the entire first cycle of treatment (4 weeks). The grade 3 diarrhea rate was 15% (2/13) in Arm 2 and 23% (5/22) in Arm 3.

In December 2016, a biomarker analysis of the FB-7 trial was presented at the 2016 CTRC-AACR San Antonio Breast Cancer Symposium .  Pre-treatment core biopsy samples (n=59) and post treatment surgical samples (n=17) were obtained from a subset of patients treated in the FB-7 trial. pCR data were available for 51 patients from the biomarker cohort. After excluding low tumor content non-evaluable samples, correlative biomarker analysis was performed in 42 patients.

Expression levels and the activation status of EGFR/HER2 signaling proteins were investigated. The results of the phosphorylated HER2 (phosphoHER2) showed that median levels of phosphoHER2 were higher in the patients who achieved a pCR with neratinib (n=7) than in the patients who did not achieve a pCR who received either trastuzumab (n=8, p=0.07) or the combination of trastuzumab plus neratinib (n=4, p=0.035). There was not a significant difference in the median levels of phosphoHER2 in the patients who achieved a pCR with neratinib (n=7), trastuzumab (n=8, p=0.16) or the combination of trastuzumab plus neratinib (n=4, p=0.10).

The truncated form of HER2 known as p95HER2 was measured by the proprietary assay of Pierian Bioscience. p95HER2 represents a truncated form of the HER2 receptor that lacks the extracellular trastuzumab binding domain. It is believed to represent a mechanism of trastuzumab resistance. Median p95HER2 levels were higher in samples from patients who achieved a pCR with neratinib than in the patients who did not achieve a pCR and who received either trastuzumab (p=0.027) or the combination of trastuzumab plus neratinib (p=0.009). There was not a significant difference in the median levels of p95HER2 in the patients who achieved a pCR with neratinib (n=7), trastuzumab (n=8, p=0.16) or the combination of trastuzumab plus neratinib (n=4, p=0.35).

The MammaPrint assay was performed on 59 samples to determine if there was any imbalance between arms. This assay is a genomic test that analyzes the activity of 70 genes and then calculates a recurrence score that is either low risk or high risk. The results of the MammaPrint showed that the patients in all three arms of the FB-7 trial were balanced with the median MammaPrint risk score being similar across arms. There were only three patients with a MammaPrint low score.neratinib.

PB272 (neratinib, oral)—Metastatic Breast Cancer

On February 25, 2020, the FDA approved our supplemental New Drug Application, or sNDA, 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., or 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 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.

Trials of Neratinib in Combination with Other Anti-Cancer Drugs. In November 2014, we announced top line results from a Phase II clinical trial of neratinib for the treatment of first-line HER2-positive locally recurrent or metastatic breast cancer (NEfERTT trial). Data from this trial was presented at the American Society of Clinical Oncology (ASCO) 2015 Annual Meeting in June 2015.  The NEfERTT trial was a randomized, two-arm Phase II trial of neratinib plus the anticancer drug paclitaxel versus trastuzumab (Herceptin) plus paclitaxel as a first-line treatment for HER2-positive locally recurrent or metastatic breast cancer.  The trial enrolled 479 patients in 33 countries with locally recurrent or metastatic breast cancer who had not received prior anticancer therapy for locally recurrent or metastatic disease. Patients were randomized to receive first-line treatment with either paclitaxel plus neratinib or paclitaxel plus trastuzumab. The primary endpoint of the trial was progression free survival. The secondary endpoints of the study included objective response rate and the incidence of central nervous system (CNS) metastases, including brain metastases.

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The results of the trial demonstrated that the progression free survival for the patients who received the combination of paclitaxel plus neratinib was 12.9 months and the progression free survival for the patients who received the combination of paclitaxel plus trastuzumab was 12.9 months (p=0.777). The objective response rate in the trial for the patients who received the combination of paclitaxel plus neratinib was 74.8% and the objective response rate for the patients who received the combination of paclitaxel plus trastuzumab was 77.6% (p=0.522).  With respect to the incidence of central nervous system metastases (e.g., brain metastases), treatment with the combination of paclitaxel plus neratinib resulted in a 52% reduction in the incidence of CNS metastases compared to the incidence of CNS metastases in patients who received the combination of paclitaxel plus trastuzumab. Symptomatic or progressive CNS recurrences occurred in 20 patients (8.3%) in the neratinib-paclitaxel group and 41 patients (17.3%) in the trastuzumab-paclitaxel group (relative risk 0.48, p=0.002). The estimated Kaplan-Meier 2-year incidence of CNS recurrences was 16.3% in the neratinib-paclitaxel group and 31.2% in the trastuzumab-paclitaxel group (hazard ratio 0.45, p=0.004). These results reflect a statistically significant difference between the two treatment arms.  We believe that this represents the first randomized trial with a HER2 targeted agent that has shown a statistically significant reduction in the incidence of CNS metastases.  The Phase II trial results were published online in the JAMA Oncology in April 2016.

Pfizer presented data from a Phase II trial at the 2010 CTRC-AACR San Antonio Breast Cancer Symposium, which evaluated the safety and efficacy of neratinib when given in combination with the anti-cancer drug vinorelbine in patients with HER2-positive metastatic breast cancer. In the 56 patients who had not been previously treated with the anti-HER2 therapy lapatinib, treatment with the combination of vinorelbine plus neratinib resulted in an overall response rate of 57% and PFS was 44.1 weeks. For those patients who had received prior treatment with lapatinib, the overall response rate was 50%. The combination of vinorelbine and neratinib was generally well tolerated.

Data from a thirdsecond 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 PB272 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.

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NALA.In February 2013, we reached agreement with the FDA under ana Special Protocol Assessment, or SPA, for our planned 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). TheAn SPA is a written agreement between us, as the trial’s sponsor and the FDA regarding the design, endpoints, and planned statistical analysis of the Phase III trial with respect to the effectiveness of PB272 for the indication to be studied to support ana New Drug Application, or NDA. The EMA has also provided follow-on Scientific Advice, or SA, consistent with that of the FDA regarding our Phase III trial design and endpoints to be used and ability offor such design to support the submission of an MAA in the EU.

Pursuant to the SPA and SA, the Phase III NALA trial iswas designed as a randomized studycontrolled trial of neratinib plus capecitabine versus lapatinibTykerb® (lapatinib) plus capecitabine in patients with third-line HER2-positive metastatic breast cancer. The trial is expected to enroll approximately 600enrolled 621 patients who will bewere randomized (1:1) to receive either PB272neratinib plus capecitabine or lapatinib plus capecitabine. The trial will bewas conducted globally at approximately 250 sites in North America, Europe, Asia-Pacific and Asia-Pacific.South America. The agreed upon co-primary endpoints of the trial arewere centrally confirmed PFS and overall survival. Our plan issurvival, or OS. An alpha level of 1% was allocated to use the PFS dataand 4% allocated to OS.

In June 2019, we announced that results from the trial as the basis for submission of an NDA, and its foreign equivalents for Accelerated/Conditional Approval for PB272 from the regulatory agencies. We commenced patient enrollment in this Phase III NALA trial in the second quarter of 2013.   We expect to report the top line data from this trial in 2018.

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In 2010, Pfizer also initiated a Phase I/II trial of neratinib in combination with the anti-cancer drug temsirolimus, or Torisel, in patients with HER2-positive metastatic breast cancer who have failed multiple prior treatments. The trial was conducted as a Phase I/II trial of PB272 given in combination with the anticancer drug temsirolimus in patients with HER2-positive metastatic breast cancer. The Phase I portion of the trial, which was reported previously, determined that the maximum tolerated dose was 240 mg of neratinib daily with 8 mg of temsirolimus weekly and the dose limiting toxicity was diarrhea. The interim Phase II data waswere presented at the 2014 CTRC-AACR San Antonio Breast Cancer Symposium.  The Phase II portionASCO 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 conducted in two cohorts. The first cohort,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 the Maximum Tolerated Dose (MTD) cohort, received 240 mg of neratinib daily with 8 mg of temsirolimus weekly. This cohort of patients received low dose loperamide (4 mg per day) prophylactically in order to reduce the neratinib-related diarrhea. The second cohort of patients, referred to as the Dose Escalation cohort (DE cohort)brain metastases), received 240 mg of neratinib daily and initially received 8 mg of temsirolimus weekly. This cohort of patients received high dose loperamide (16 mg per day initially) prophylactically in order to reduce the neratinib-related diarrhea. If patients in the DE cohort had no tolerability issues with the combination of neratinib and temsirolimus given at 8 mg per week during the first cycle of treatment, patients in this DE cohort were allowed to dose escalate the temsirolimus to 15 mg per week for the remainder of the study. Patients in both cohorts in the study received a median of 3 prior regimens in the metastatic setting (range 1-8 prior regimens) before entering the trial. The 37 patients in the MTD cohort were enrolled at 3 centers in the United States and the 45 patients in the DE cohort were enrolled at 8 centers in the United States, Europe and Asia.  The interim safety results of the study showed that the most frequently observed adverse event for the patients who received the combination of neratinib plus temsirolimus was diarrhea. For the 37 patients in the MTD cohort, who received low dose loperamide prophylactically, 12 patients (32%) experienced grade 3 diarrhea. For the 41 patients in the DE cohort, who received high dose loperamide prophylactically and were allowed to dose escalate the temsirolimus dose, 7 patients (17%) reported grade 3 diarrhea. 4 (57%) of the 7 patients in the DE cohort who experienced grade 3 diarrhea were not compliant with the high dose loperamide prophylaxis. There were 4 patients in the DE cohort who did not yet have safety data reported and are therefore not included in the safety population. For the patients in the DE cohort, thus far 47% of the patients have been able to dose escalate  temsirolimus from 8 mg per week to 15 mg per week.  The interim efficacy results from 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 37 patients inneratinib plus capecitabine arm and 29.2% for the MTD cohort, 11 patients (30%) experienced a partial response (PR)lapatinib plus capecitabine arm (p=0.043). The medianFor the secondary endpoint of duration of response, for this cohortneratinib plus capecitabine treatment resulted in a longer duration of patientsresponse 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 3.0 months anda higher rate of grade 3 diarrhea with neratinib plus capecitabine compared to lapatinib plus capecitabine (24.4% vs 12.5%); however, the median progression-free survival was 4.8 months.  For the 37 evaluable patientsdiscontinuations due to diarrhea (neratinib plus capecitabine: 2.6%, lapatinib plus capecitabine: 2.3%) were similar in the DE cohort, the efficacy results from the trial demonstrated that 11 patients (30%) experienced a PR.both arms.

Metastatic Breast Cancer with Brain Metastases

Approximately one-thirdone-half of the patients with HER2-positive metastatic breast cancer develop metastases that spread to their brain. The current antibody-based treatments, including trastuzumab pertuzumab and T-DM1,pertuzumab, do not enter the brain and therefore are not believed to be effective in treating these patients. In

Neratinib is currently being tested in a Phase IIclinical trial in collaboration with lapatinib givenTranslational Breast Cancer Research Consortium (TBCRC) referred to as a single agent, lapatinib demonstrated a 6% objective response rateTBCRC 022. The purpose of this study is to determine how well neratinib works in the patients with HER2-positive metastatic breast cancer whose disease spread to their brain. In January 2012, a Phase II trial of neratinib as a single agent and in combination with the anticancer drug capecitabine in patients with HER2-positive metastatictreating breast cancer that has spread to theirthe 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 was initiated in conjunction with the Dana Farber Translational Breast Cancer Research Consortium. In June 2014, at the ASCO 2014 Annual Meeting, results from the first cohort (n=40) who were administered neratinib monotherapy was presented. The efficacy results from the first cohort of the trial showed that for the 40 evaluable patients, 3 (7.5%) patients experienced a PR, 4 (10%) patients experienced prolonged stable disease (SD) for greater than or equal to 6 months and 12 (30%) patients experienced SD for less than 6 months. The median progression-free survival of the 40 evaluable patients was seen to be 1.9 months and the median overall survival was seen to be 8.7 months.

In June 2017, we presented additionalinterim data from this trialthe 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 metasteses. 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. Results from the second cohort and cohort 3B (prior lapatinib-treated) will be presented at a forthcoming medical meeting.

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

The primary endpoint of the trial was central nervous system (CNS)CNS Objective Response Rate according to a composite criteria that included volumetric brain MRI measurements, steroid use, neurological signs and symptoms, and RECISTResponse 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, (RANO-BM) Criteria.or 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.

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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.

Safety Database. Our safety database includes over 3,000The TBCRC 022 trial is currently enrolling patients who have been treated with neratinib. To date,in an arm of the most significant grade 3 or higher adverse event associated withstudy that is administering neratinib has been diarrhea, which occurs in approximately 30% of patients receiving the drug. Historically, once diarrhea occurred, patients were treated with loperamide and/or a reduction in the dose of neratinib. We have evaluated a prophylactic protocol pursuant to which a high dose of loperamide, approximately 16 mg, is given togethercombination with the initial dose of neratinib and then tapered down during the first cycle of treatment.  We plan to continue evaluating this protocol as the preliminary data has suggested that this prophylactic regimen significantly reduces the incidence of diarrhea with neratinib.

In February 2015, Puma initiated a Phase II open-label trial of neratinib monotherapy for one yeardrug ado-trastuzumab emtansine (T-DM1, Kadcyla) in 120 patients with early HER2-positive breast cancer who have completed one year of adjuvant trastuzumab, or the CONTROL trial.  The CONTROL trial is an international, open-label, Phase II study investigating the use of loperamide prophylaxis with or without other agents in the reduction of neratinib-associated diarrhea that has a primary endpoint of the incidence of grade 3 diarrhea.  In the CONTROL trial, patients with HER2-positive early stagemetastatic breast cancer who had completed trastuzumab-based adjuvant therapy received neratinib dailythat has metastasized to the brain. Data from this trial are expected in the second half of 2021.

In April 2018, we announced that NERLYNX has been included as a recommended treatment option in the latest National Comprehensive Cancer Network, or 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 period of one year. The trial initially tested high dose loperamide prophylaxis givencategory 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 first 2 cycles (56 days) of treatment (12 mg on days 1-14, 8 mg on days 15-56FDA-approved indication for NERLYNX and as needed thereafter).  In the original protocol, 4 mg loperamide is self-administered with the first dose of neratinib, followed by 2 mg loperamide every 4 hours for the first 3 days, reducing to 2 mg loperamide every 6 to 8 hours through the first 2 cycles of therapy.  With Amendment 1 of the protocol, the loperamide dosing schedule was modified to simplify the regimen.  Following Amendment 1 of the protocol, 4 mg loperamide is self-administered with the first dose of neratinib, followed by 4 mg loperamide three times a day for 2 weeks, followed by 4 mg loperamide twice daily through the first 2 cycles of therapy.  After two cycles, patientsconsidered investigational, and we do not take loperamide prophylactically but take it as needed throughout the remainder of the treatment duration if diarrhea occurs.

In December 2017, interim results from the CONTROL trial were presented at the 2017 CTRC-AACR San Antonio Breast Cancer Symposium.  The CONTROL trial was then expanded to include two additional cohorts. One cohort received the combination of loperamide and budesonide and the other cohort received the combination of loperamide plus colestipol. Budesonide is a locally acting corticosteroid that the Company believes targets the inflammation identified in a preclinical model of neratinib-induced diarrhea and colestipol is a bile acid sequestrant that the Company believes targets potential bile acid malabsorption that could result from such inflammation.  

The interim analysis of the trial presented in the poster included a total of 137 patients who received neratinib plus loperamide prophylaxis, 64 patients who received neratinib plus loperamide prophylaxismarket or promote NERLYNX for 2 cycles and budesonide for 1 cycle, and 120 patients who received neratinib plus loperamide prophylaxis for 1 cycle and colestipol for 1 cycle.  The results of the trial showed that the incidence of grade 3 diarrhea for the 137 patients who received the loperamide prophylaxis was 30.7%. For the 137 patients who received the loperamide prophylaxis, the median number of grade 3 diarrhea episodes per patient was 1 and the median cumulative duration of grade 3 diarrhea was 3 days. For the 137 patients who received loperamide prophylaxis, 20.4% discontinued neratinib due to diarrhea.  For the 64 patients who received the combination of loperamide plus budesonide, the results of the trial showed that the incidence of grade 3 diarrhea was 26.6%. The median number of grade 3 diarrhea episodes per patient was 1 and the median cumulative duration of grade 3 diarrhea was 2 days. For the 64 patients who received loperamide plus budesonide prophylaxis, 10.9% discontinued neratinib due to diarrhea.these uses.

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For the 120 patients who received the combination of loperamide plus colestipol, the results of the trial showed that the incidence of grade 3 diarrhea was 10.8%. The median number of grade 3 diarrhea episodes per patient was 1 and the median cumulative duration of grade 3 diarrhea was 3 days. For the 120 patients who received loperamide plus colestipol prophylaxis, 1.7% discontinued neratinib due to diarrhea. Further information is provided in Table 1 below:

Table 1:  Characteristics of Treatment-Emergent Diarrhea

PB272 (neratinib, oral)—Other Potential Applications

Non-Small Cell Lung Cancer (NSCLC)

Approximately 2% to 4% of patients with NSCLC have a HER2 mutation in the kinase domain. This mutation is believed to narrow the ATP binding cleft, which results in increased tyrosine kinase activity. The mutation is also believed to result in increased PI3K activity and mTOR activation. Published data suggests that patients with HER2-mutated non-small cell lung cancer do not respond to platinum chemotherapy and do not respond to epidermal growth factor receptor inhibitors.

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In September 2014, we reported initial data from the ongoing, open label Phase II clinical trial of PB272 (neratinib) for the treatment of patients with NSCLC with HER2 mutations as a late-breaking oral presentation at the ESMO 2014 Congress. In the trial, patients with confirmed Stage IIIB or Stage IV NSCLC with documented somatic HER2 mutations were randomized to receive either oral neratinib monotherapy at a dose of 240 mg per day or the combination of oral neratinib (at a dose of 240 mg daily) with intravenous temsirolimus administered at a dose of 8 mg per week. In order to attempt to reduce the neratinib-related diarrhea, high-dose loperamide prophylaxis (Imodium) was given to all patients in both arms of the study beginning on day 1 of neratinib dosing. The data presented in the oral presentation involved a total of 27 patients who completed the first stage of the trial; 13 of these patients received neratinib monotherapy and 14 of these patients received the combination of neratinib plus temsirolimus.  The results of the study showed that the combination of PB272 and temsirolimus had acceptable tolerability. Historically the most frequently seen adverse event associated with neratinib has been diarrhea. In the previous Phase I trial of neratinib plus temsirolimus (published in the Journal of Clinical Oncology in 2014) the diarrhea with neratinib was seen to be dose dependent and its incidence increased with increasing neratinib dosage. In that Phase I trial, grade 3 or higher diarrhea was seen in approximately 30% of the patients treated with doses of neratinib that were 200 mg or higher. In the Phase II study, all patients received high-dose loperamide in order to attempt to prevent or reduce the neratinib-related diarrhea. For the 13 patients enrolled in the neratinib monotherapy arm, 1 patient (8%) experienced grade 3 diarrhea, and for the 14 patients enrolled in the combination of neratinib plus temsirolimus arm, 2 patients (14%) experienced grade 3 diarrhea. There were no grade 4 diarrhea events seen in the trial. For the 3 patients in the study (1 in the monotherapy arm, 2 in the combination arm) who experienced grade 3 diarrhea, 2 of the 3 patients were not compliant with the loperamide prophylaxis regimen and were not taking loperamide at the onset of grade 3 diarrhea.

The efficacy results from the trial showed that for the 13 patients in the trial who received neratinib monotherapy, no patient experienced a partial response, 7 patients (54%) achieved stable disease and 4 patients (31%) achieved clinical benefit (defined as a partial response or stable disease for 12 or more weeks). For the 14 patients who received the combination of neratinib plus temsirolimus, 3 patients (21%) experienced a partial response, 11 patients (79%) experienced stable disease and 9 patients (64%) achieved clinical benefit. The median PFS of the neratinib monotherapy arm was 2.9 months and the median PFS of the arm that received neratinib plus temsirolimus was 4.0 months. Patients continue to be enrolled in the arm of the trial that is receiving the combination of neratinib plus temsirolimus.

HER2 Mutation-Positive Solid Tumors

Based on the results from the Cancer Genome Atlas Study, we estimate that between 2%1% and 11%12% of each solid tumor has a mutation in HER2. In the United States, this includes new diagnoses of an estimated 7,000 – 7,500 patients with bladder cancer; 4,000 – 4,500 patients with colorectal cancer; 1,500 – 2,000 patients with glioblastoma; 1,000 patients with melanoma; 4,000 – 5,000 patients with prostate cancer; 1,000 patients with stomach cancer; and 1,000 – 2,000 patients with uterine cancer.

SUMMIT -- Basket Trial for HER2 Mutation-Positive Solid Tumors. In October 2013, we announced that we had initiated a Phase II clinical trial of neratinib as a single agent in patients with solid tumors that have an activating HER2 mutation, (SUMMITwhich we refer to as the SUMMIT basket trial).trial. The Phase II SUMMIT basket trial is an open-label, multicenter, multinational study to evaluate the safety and efficacy of PB272 administered daily to patients who have solid tumors with activating HER2 or HER3 mutations. The study initially included six cohorts (baskets) of patients, each of which will include one of the following cancers: (i) bladder/urinary tract cancer; (ii) colorectal cancer; (iii) endometrial cancer; (iv) gastric/esophageal cancer; (v) ovarian cancer; and (vi) all other solid tumors (including prostate, melanoma and pancreatic cancer). Each basket will initially consist of seven patients. If a certain predetermined objective response rate is seen in the initial cohort of seven patients, the basket will be expanded to include a larger number of patients.

In May 2014, we announced that we expanded the first cohort from the SUMMIT basket trial. The cohort that has been expanded includes patients with metastatic breast cancer that is not HER2 amplified or overexpressed (HER2 negative) and has a HER2 mutation. In April 2015, we announced that we expanded the cohort from the Phase II clinical trial of PB272 in patients with metastatic NSCLC that is not HER2 amplified or overexpressed (HER2 negative) and has a HER2 mutation. In December 2015, we announced that we expanded the cohort that includes patients with metastatic biliary duct (bile duct) cancer that is not HER2 amplified or overexpressed (HER2 negative) and has a HER2 mutation. In January 2017, we announced that we expanded the fourth cohort that includes patients with metastatic cervical cancer and whose tumors have a HER2 mutation.  The cervical cancer patients initially entered the study in the “other solid tumors with a HER2 mutation” cohort and, due to the preliminary activity seen in the trial, we expanded a separate cervical cancer cohort pursuant to the protocol for the trial. The expanded HER2-mutant cervical cancer cohort will now enroll a total of 18 patients.

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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.

As stated above, 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 (AACR) during the plenary session of the meeting.and were published in January 2018 in Nature. All patients received loperamide (16 mg per day initially) prophylactically for the first cycle of treatment in order 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.

In the HER2-mutant cohort, clinical responses were observed in tumors with S310, L755, V777, P780_Y781insGSP and A775_G776insYVMA mutations. When stratified by tumor type, responses were observed in patients with breast, cervical, biliary, salivary and non-small-cell lung cancers, which led to cohort expansions in these tumor types. No activity was observed in the HER3-mutant cohort. A more detailed presentation of the data is presented in Table 1 below

The neratinibinterim safety profileresults observed in the SUMMIT study iswere consistent with that observed previously in metastatic patients with HER2 amplified tumors. With anti-diarrheal prophylaxis and management, diarrhea washas 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 2two days. 4Four 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.

PB272 (neratinib, intravenous)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 also plan to developbelieve this mutation may occur in an estimated

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2% of patients with breast cancer. Pre-clinical data from this publication demonstrated that neratinib as an intravenously administered agent. The intravenous versionwas active in pre-clinical models of HER2-negative breast cancer that have this HER2 mutation and that neratinib resultedhas more anti-cancer activity than either trastuzumab or lapatinib in higher exposure levelscells 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 therapy in the metastatic setting (range 1-10 prior regimens) before entering the trial. 36 patients (70.6%)  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%) experienced 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.

The safety profile observed in patients treated with the combination of neratinib plus trastuzumab plus fulvestrant in the SUMMIT study was consistent with that observed previously in metastatic 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.

Table 1: HER2-Mutant, HR-Positive Metastatic Breast Cancer

Phase II SUMMIT Trial Interim Efficacy Results Summary as of October 16, 2020

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EGFR Exon 18 Mutated Non Small Cell Lung Cancer

Exon 18 mutations comprise approximately 5% of the EGFR mutations detected in lung cancer. Pre-clinical data have demonstrated that neratinib was active in pre-clinical models. We believe this may resultmodels of EGFR exon 18 mutated lung cancer and neratinib was previously shown to be active in higher blood levelstreating patients with exon 18 mutated lung cancer in a Phase II trial that was published in the Journal of Clinical Oncology in 2010.

In November 2020, we announced interim results from the ongoing SUMMIT trial of neratinib in the cohort of metastatic non-small cell lung cancer, or NSCLC, patients with EGFR exon 18 mutations who have been previously treated with an EGFR targeted TKI. In the EGFR exon 18 mutation cohort, patients with lung cancer with single or complex EGFR exon 18 mutations, who were EGFR TKI naïve or were previously exposed to EGFR TKI, were enrolled into this study and may translate into enhanced efficacy. We are evaluating the intravenous formulationreceived 240 mg of neratinib daily as a single agent. 

In this cohort of 11, patients had received a median of two prior lines of therapy in the metastatic setting (range 1-3 prior regimens) before entering the trial. Ten patients had been previously treated with an EGFR targeted TKI (gefitinib, erlotinib, osimertinib and/or afatinib). 

The interim efficacy results from the trial showed that for the 10 evaluable patients who had been treated with a prior EGFR TKI, six patients (60%) experienced a partial response, which included four patients (40%) with a confirmed partial response. Eight patients (80%) experienced clinical benefit (clinical benefit is defined as confirmed complete response or partial response or stable disease for at least 16 weeks). The median duration of response was 7.5 months and considering options relativethe median progression free survival was 9.1 months. The success criteria for both the first stage and the second stage of the Simon’s 2-stage design were met and enrollment in the second stage of this cohort continues.

The safety profile observed in the subgroup of patients with EGFR exon 18 mutated NSCLC showed that for the 11 patients who received neratinib in the trial, there were no reports of grade 3 or higher diarrhea. Four patients (36%) reported grade 1 and one patient (9%) reported grade 2 diarrhea. No patients required a dose hold, dose reduction, hospitalization or permanently discontinued neratinib due to its development.

PB357

PB357 is an orally administered agent that is an irreversible TKI that blocks signal transduction through the epidermal growth factor receptors, HER1, HER2 and HER4. PB357 is structurally similar to PB272. Pfizer completed single-dose Phase I trials of PB357. We are evaluating PB357 and considering options relative to its development.  diarrhea.

Clinical Testing of Our Products in Development

Each of our products in development, and likely all future drug candidates we in-license, will require extensive pre-clinical and clinical testing to determine the safety and efficacy of the product applications prior to seeking and obtaining regulatory approval. This process is expensive and time consuming. In completing these trials, we are dependent upon third-party consultants, consisting mainly of investigators and collaborators, who will conduct such trials.

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We and our third-party consultants conduct pre-clinical testing in accordance with Good Laboratory Practices, or GLP, and clinical testing in accordance with Good Clinical Practice standards, or GCP, which are international ethical and scientific quality standards utilized for pre-clinical and clinical testing, respectively. GCP is the standard for the design, conduct, performance, monitoring, auditing, recording, analysis and reporting of clinical trials and the FDA requires compliance with GCP regulations in the conduct of clinical trials. Additionally, our pre-clinical and clinical testing completed in the EU is conducted in accordance with applicable EU standards, such as the EU Clinical Trials Directive (Directive 2001/20/EC of April 4, 2001), or the EU Clinical Trials Directive, and the national laws of the 28 member states of the EU, or Member States, implementing its provisions.

We have entered into, and may enter into in the future, master service agreements with clinical research organizations, or CROs, with respect to initiating, managing and conducting the clinical trials of our products. These contracts contain standard terms for the type of services provided that contain cancellation clauses requiring between 30 and 45 days written notice and that obligate us to pay for any services previously rendered with prepaid, unused funds being returned to us. 

Competition

The development and commercialization of new products to treat cancer is highly competitive, and we face considerable competition from major pharmaceutical, biotechnology and specialty cancer companies. As a result, there are and will likely continue to be extensive research and substantial financial resources invested in the discovery and development of new cancer products. Our competitors include, but are not limited to, Genentech, Novartis, Roche, Boehringer Ingelheim, Takeda, Daiichi Sankyo and Seattle Genetics.Seagen. None of these companies are developing their drugs for the extended adjuvant treatment of early stage HER2-positive breast cancer that has been previously treated with a trastuzumab-containing regimen. All of these competitors are developing their drugs for the treatment of early stage and/or metastatic HER2-positive breast cancer.cancer and/or for cancers that have a HER2 mutation. We are an early commercial stage company with a limited history of operations, sales, marketing and commercial manufacturing. Many of our competitors have substantially more financial and technical resources than we do. In addition, many of our competitors have more experience than we have in pre-clinical and clinical development, manufacturing, regulatory and global commercialization. We are

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also competing with academic institutions, governmental agencies and private organizations that are conducting research in the field of cancer.

We anticipate that we will face intense competition if we are able to commercialize additional product candidates. We expect that our products under development and in clinical trials will address major markets within the cancer sector. Our competition will be determined in part by the potential indications for which drugs are developed and ultimately approved by regulatory authorities. Additionally, the timing of market introduction of some of our potential products or of competitors’ products may be an important competitive factor. Accordingly, the speed with which we can develop products, complete pre-clinical testing, clinical trials and approval processes, and supply commercial quantities to market are expected to be important competitive factors. We expect that competition among products approved for sale will be based on various factors, including product efficacy, safety, reliability, availability, price, reimbursement and patent position.

Sales and Marketing

During 2017, in connection with FDA approval of NERLYNX, we hiredWe currently have a U.S. direct specialty sales force of approximately 8568 sales specialists who are focused on promoting NERLYNX to oncologists. This sales force is supported by an experienced sales leadership team comprisedconsisting of regional sales managers and our experienceddirectors, as well as a commercial team comprised of experienced professionals in marketing, access and reimbursement, managed markets, marketing research, commercial operations, and sales force planning and management. In addition, our commercial infrastructure includes capabilities in manufacturing, medical affairs, quality control, and compliance.

We launched NERLYNX in the United States in July 2017, and our focus is to establish NERLYNX as the first choice for 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 European Union 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. We plan to continue to pursue commercialization of NERLYNX in Europe and other marketscountries outside of the United States, where approved. To facilitate our international activities, we have entered into exclusive sub-license agreements with various parties to pursue regulatory approval, if necessary, and commercialize NERLYNX, if approved. We are currently party to several sub-licenses in which NERLYNX may be approved, if any,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 and South America. As we may chooseexpand into additional territories we will continue to evaluate whether we seek to commercialize NERLYNX independentlyin those territories directly or by establishing one or more strategic alliances such as the ones we have established for commercializing NERLYNX in South East Asia, beginning with Australia, Singapore, Malaysia, Brunei and New Zealand, Israel and in greater China, including mainland China, Taiwan, Hong Kong and Macau.through additional sub-licenses.

Intellectual Property and License Agreements

We hold a worldwide exclusive license under our license agreement with Pfizer to four21 granted U.S. patents and ninefour pending U.S. patent applications, as well as foreign counterparts thereof, and other patent applications and patents claiming priority therefrom.therefrom to develop and commercialize certain compounds, including neratinib.

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In the United States, we have a license to an issued patent, which currently will expire in 2025, for the composition of matter of neratinib, our lead compound. We have a license to an issued U.S. patent covering a family of compounds including neratinib, as well as equivalent patents in the EU and Japan, that currently expire in 2019. We also have a license to an issued U.S. patent for the use of neratinib in the treatment of breast cancer, which currently expires in 2025, and an issued patent for the use of neratinib in the extended adjuvant treatment of early stage HER2 positiveHER2-positive breast cancer that has previously been treated with a trastuzumab containing regimen that expires in 2030,. two issued patents for the use of neratinib in combination with capecitabine the later of which expires in 2031 and two issued patents for the formulation of NERLYNX that expire in 2030, one issued patent for the preparation of the polymorphic forms of neratinib, and three issued patents for the use of the polymorphic forms of neratinib in the treatment of breast cancer. In jurisdictions which permit such, we will seek patent term extensions where possible for certain of our patents.patents (discussed further below, including in “Government Regulation”). We plan to pursue additional patents in and outside the United States from the four pending U.S. patent applications noted above and the 77 pending foreign patent applications, respectively, covering neratinib composition, formulations, and combinations and uses thereof, and additional therapeutic uses and polymorphs of neratinib from these existing applications.neratinib. In addition, we will pursue patent protection for any new discoveries or inventions made in the course of our development of neratinib.

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In the United States, marketing approval for neratinib was obtained on July 17, 2017, which provided five years of regulatory exclusivity. Marketing approval in the United States for neratinib in combination with capecitabine was obtained on February 25, 2020, which provided three years of regulatory exclusivity. Requests for patent term extension under the Hatch-Waxman Act have been filed for two patents in the United States: U.S. Patent No. 7,399,865 and U.S. Patent No. 9,211,291. We elected to apply patent term extension to U.S. Patent No. 7,399,865. The U.S. Patent and Trademark Office, or USPTO, has determined that U.S. Patent No. 7,399,865 is eligible for five years of patent term extension. Once extended, U.S. Patent No. 7,399,865 will expire December 29, 2030. See “Government Regulation” below. If we obtain marketing approval in the United States for new uses or combinations therapies for neratinib, we may be eligible for additional periods of regulatory exclusivity, such as three-year market exclusivity covering the new use. If we obtain marketing approval for neratinib or other drug candidates in the United States or in certain jurisdictions outside the United States, we may be eligible for regulatory protection, such as, five years of new chemical entity exclusivity and, as mentioned below, up to five years of patent term extension potentially available in the United States under the Hatch-Waxman Amendments. In addition, eight to eleven years of data and marketing exclusivity potentially are available for new drugs in the European Union; up to five years of patent extension are potentially available in Europe (Supplemental Protection Certificate), and eight years of data exclusivity are potentially available in Japan. In Europe, marketing approval for neratinib was obtained on August 31, 2018, which provided 10 years of regulatory exclusivity. Between 2019 and 2020, marketing approval for neratinib was obtained in Argentina, Brunei, Canada, Chile, China, Ecuador, Hong Kong, Israel, Malaysia, Singapore and Taiwan. Where available and eligible, regulatory or data exclusivity has been obtained, or is currently being pursued in these jurisdictions outside the United States and Europe. Patent term extension or supplemental protection certificate are being, or will be, pursued in jurisdictions where available and eligible, including Chile, Europe and Taiwan. Current market approved jurisdictions where patent term extensions or supplemental protection certificates are not available, not eligible, or not pursued, include Argentina, Brunei, Canada, China, Ecuador, Hong Kong, Israel, Malaysia and Singapore. There can be no assurance that we will qualify for any such regulatory exclusivity, or that any such exclusivity will prevent competitors from seeking approval solely on the basis of their own studies. See “Government Regulation” below.

The intellectual property portfolio that was licensed from Pfizer in 2011 when we licensed neratinib included issued patents in a number of countries, including in Europe (EP 1848414), as well as pending patent applications in several countries, including the United States,(EP1848414) relating to methods of treating gefitinib-and/or erlotinib-resistant cancer by administering an irreversible epidermal growth factor receptor inhibitor. More specifically,In addition, in March 2020, we obtained issuance of U.S. Patent No. 10,603,314 containing claims for methods of treating gefitinib-and/or erlotinib-resistant non-small cell lung cancer (NSCLC) cancer and U.S. Patent No. 10,596,162 containing claims for methods of treating gefitinib-and/or erlotinib-resistant NSCLC having a T790M mutation in EGFR. Regarding Europe, the EP1848414 patent that was issued in Europe in April 2011 included specific claims that included a pharmaceutical composition for use in treating cancer in a subject with a cancer having a mutation in epidermal growth factor receptor with a T790M mutation. On November 28, 2011, Boehringer Ingelheim International GmbH filed an opposition to this patent asking for this patent to be revoked. The Oral Proceedingsproceedings were held before the Opposition Division of the European Patent Office were held in Munich, Germany on February 4, 2014. The decision of the European Patent OfficeOpposition Division was to uphold the granted claims of the European patent that relate to the T790M mutation without any modification. This included specific claims that include claims for the pharmaceutical composition comprising an irreversible epidermal growth factor receptor inhibitor for use in treating cancer in a subject having a T790M mutation, and claims for the pharmaceutical composition for use in the treatment of numerous cancers, including lung cancer and non-small cell lung cancer. InBoth parties appealed that decision in 2017. At a final hearing, on December 20, 2020, the Board of Appeals announced its decision, concluding that the opposition was inadmissible and reversing the European Opposition Division decision issued in 2014, thereby upholding the EP Patent 1848414 as originally granted.

An Opposition was filed by Hexal AG, or Hexal, on August 3, 2016 against European Patent No. EP2416774 which was licensed from Pfizer in 2011, and which claims neratinib for use in a method for treating HER-2/neu overexpressed/amplified cancer and improving IDFS, wherein the method comprises delivering neratinib therapy to HER-2/neu overexpressed/amplified cancer patients following the completion of at least one year of trastuzumab adjuvant therapy, and wherein the neratinib therapy comprises treating the cancer patients with neratinib for at least twelve months. An oral hearing was held December 8, 2017, wherein the patent was maintained as granted. Hexal then appealed, which appeal is pending.

On October 4, 2017, Hexal also filed an Opposition to European Patent No. EP2326329 which was licensed from Pfizer in 2011, and which claims a combination of neratinib and pharmaceutically acceptable salts thereof with capecitabine for use in a method of treating an Erb-2 positive metastatic breast cancer. An oral hearing was held on February 13, 2019, wherein the patent was maintained as granted. Hexal then appealed, which appeal is pending.

On May 21, 2020, Hexal also filed an Opposition to European Patent No. EP2498756, which was licensed from Pfizer in 2011, and which claims, inter alia, tablet formulations of neratinib maleate comprising intragranular and extragranular components. Oral hearings have not yet been scheduled, and briefings exchange between the parties are still in progress.

An Opposition was filed by Generics (UK) Ltd., or Generics, on September 3, 2015 we were advisedagainst European Patent No. EP2656844, which was licensed from Pfizer in 2011, and which claims, inter alia, a pharmaceutical pack containing 50 to 300 mg of neratinib and pharmaceutically acceptable salts thereof and vinorelbine for use in a method of treating a neoplasm. An oral hearing was held July 3, 2017, wherein the patent was maintained as granted. Generics then appealed. The appeal was dismissed by the Board of Appeal of the issuanceEuropean Patent Office on August 11, 2020, and the EP2656844 patent was upheld as originally granted.

Unipharm filed a pre-grant opposition to Israeli Patent Application No. IL210616 on January 31, 2016. This application was licensed from Pfizer in 2011. An oral hearing was held in Jerusalem before the Israeli Patent Office on January 22, 2018. The patent was granted by the United StatesIsraeli Patent and Trademark Office upon filing of amendments to the claims. No opposition to the patent has been filed within the

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allowed opposition period. The granted claims are directed to use of a Noticecombination of Allowanceneratinib and capecitabine in the manufacture of a medicament for U.S. Patent Application 11/883,474 titled “Method for Treating Gefitinib Resistant Cancer.”treating a neoplasm.

Our goal is to obtain, maintain and enforce patent protection for our products, formulations, processes, methods and other proprietary technologies, preserve our trade secrets, and operate without infringing on the proprietary rights of other parties, both in the United States and in other countries. Our policy is to actively seek to obtain, where appropriate, the broadest intellectual property protection possible for our current product candidates and any future product candidates, proprietary information and proprietary technology through a combination of contractual arrangements and patents, both in the United States and abroad. However, even patent protection may not always provide us with complete protection against competitors who seek to circumvent our patents. See “Risk Factors—Risks Related to Our Intellectual Property—Our proprietary rights may not adequately protect our intellectual property and potential products, and if we cannot obtain adequate protection of our intellectual property and potential products, we may not be able to successfully market our potential products.”

We depend upon the skills, knowledge and experience of our scientific and technical personnel, as well as that of our advisors, consultants and other contractors, none of which is patentable. To help protect our proprietary know-how, which is not patentable, and inventions for which patents may be difficult to obtain or enforce, we rely on trade secret protection and confidentiality agreements to protect our interests. To this end, we require all of our employees, consultants, advisors and other contractors to enter into confidentiality agreements that prohibit the disclosure of confidential information and, where applicable, require disclosure and assignment to us of the ideas, developments, discoveries and inventions important to our business.

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In-License Agreement

In August 2011, Former Puma entered into an agreement pursuant to which Pfizer, or Licensor, agreed to grant to Former Puma aWe license the worldwide licenseexclusive rights for the development, manufacture and commercialization of neratinib (oral), neratinib (intravenous), PB357, and certain related compounds. Pursuant to the terms of the agreement, the license would not become effective until Former Puma closed a capital raising transaction in which it raised at least $25 million in aggregate net proceeds and had a net worth of at least $22.5 million. Upon the closing of the financing that preceded the Merger, this condition was satisfied.

We assumed the license agreement, in accordance with its terms, in the Merger. The license is exclusive with respect to certain patent rights owned or licensed bycompounds from Pfizer. Under the license agreement, the LicensorPfizer is obligated to transfer to us certain information, records, regulatory filings, materials and inventory controlled by the LicensorPfizer and relating to or useful for developing these compounds and to continue to conduct certain ongoing clinical studies until a certain time. After that time, we are obligated to continue such studies pursuant to an approved development plan, including after the license agreement terminates for reasons unrelated to the Licensor’sPfizer’s breach of the license agreement, subject to certain specified exceptions. We are also obligated to commence a new clinical trial for a product containing one of these compounds within a specified period of time and use commercially reasonable efforts to complete such trial and achieve certain milestones as provided in a development plan. If certain of our out-of-pocket costs in completing such studies exceed a mutually agreed amount, the LicensorPfizer will pay for certain additional out-of-pocket costs to complete such studies. We must use commercially reasonable efforts to develop and commercialize products containing these compounds in specified major-market countries and other countries in which we believe it is commercially reasonable to develop and commercialize such products.

As consideration for the license, we are required to make payments totaling $187.5 million upon the achievementachievements of certain milestones if all such milestones are achieved. In connection with the FDA approval of NERLYNX in July 2017 we triggered a one-time milestone payment. In June 2020, we entered into a letter agreement, or the Letter Agreement, with Pfizer relating to the method of payment associated with a one-time milestone payment under the license agreement with Pfizer. The Letter Agreement permits us to make the milestone payment in installments with portions of the amount payable to Pfizer (including interest) made in June and November 2020 for approximately $20.6 million in the aggregate and the remaining portion to be made in September 2021 for approximately $21.9 million. Unpaid portions of the milestone payment will accrue interest at 6.25% per annum until paid. The installment payments and accrued interest are included in accrued in-licensed rights on the accompanying consolidated balance sheets.

The license agreement originally stipulated that should we commercialize any of the compounds licensed from the LicensorPfizer or any products containing any of these compounds, we will be obligated to pay to the LicensorPfizer incremental annual royalties between approximately 10% and 20% of net sales of all such products, subject, in some circumstances, to certain reductions.

In July 2014, the Companywe signed an amendment to the license agreement with the Licensor. The amendment to the license agreement providesPfizer that, among other things reduced the Company would be solely responsible for the expenses incurred or accrued in conducting the ongoing legacy clinical trials after December 31, 2013.  These costs were previously the responsibility of the Licensor.

In addition, under the amended agreement, annual royalties to be paid on net sales of licensed products were reduced from a tiered royalty rate structure ranging between 10% to 20% to a fixed rate in the low to mid-teens.  The Licensor and the Company have agreed to continue to cooperate to effect the transfer to the Company of certain records, regulatory filings, materials and inventory controlled by the Licensor as promptly as reasonably practicable.

Our royalty obligation continues, on a product-by-product and country-by-country basis, until the later of (i) the last to expire valid claim of a licensed patent covering the applicable licensed product in such country, or (ii) the earlier of generic competition for such licensed product reaching a certain level of sales in such country or expiration of a certain time period after first commercial sale of such licensed product in such country. When sublicensing the rights granted to us under the license agreement with the Licensor to a third party, the same milestone and royalty payments are required. We can terminate the license agreement at will at any time after April 4, 2013, or for safety concerns, in each case upon specified advance notice. Each party may terminate the license agreement if the other party fails to cure any breach of a material obligation by such other party within a specified time period. The LicensorPfizer may terminate the license agreement in the event of our bankruptcy, receivership, insolvency or similar proceeding. The license agreement contains other customary clauses and terms as are common in similar agreements in the industry.

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Sub-License Agreements

In November 2017 and January 2018, we entered into three exclusive license agreements with STA, Medison and CANbridge granting them the right to seek the regulatory approval and, if approved, commercialize NERLYNX in South East Asia, Israel and in greater China, respectively.  Under each of the agreements, we are entitled to upfront and milestone payments throughout the term of the applicable agreement, as well as significant double-digit royalties calculated as a percentage of net sales of the licensed products in the respective territory.  The description below provides a summary of our agreements with Specialised Therapeutics and CANbridge.

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Specialised Therapeutics Agreement

On November 20, 2017, we entered into a licensesub-license agreement, or the Specialised Therapeutics Agreement, with Specialised Therapeutics Asia Pte Ltd., or STA. Pursuant to the Specialised Therapeutics Agreement, we granted to STA, under certain of our intellectual property rights relating to neratinib, an exclusive, (including with respect to us and our affiliates), sublicensable (under certain circumstances) license to commercialize any pharmaceutical product containing neratinib in finished form or, for purposes of this description, the Licensed Product, for the extended adjuvant treatment of adult patients with early stage HER2-positive breast cancer and HER2-positive metastatic breast cancer in Australia, Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, New Zealand, Papua New Guinea, Philippines, Singapore, Thailand, Timor-Leste and Vietnam, or the STA Territory.

The Specialised Therapeutics Agreement sets forth the parties’ respective obligations with respect to the development, commercialization, and supply of the Licensed Product.licensed product. Within the STA Territory, STA will be generally responsible for regulatory and commercialization activities, and we will be solely responsible for the manufacturing and supply of the Licensed Productlicensed product under a supply agreement that will be entered into between the parties.

Pursuant to the Specialised Therapeutics Agreement, we are entitled toreceived an upfront payment and otherwill potentially receive additional regulatory milestone paymentspayments. In addition, we will receive double-digit royalties on sales of up to $4.5 million, payable upon achievement of the milestone events specified in the Specialised Therapeutics Agreement. Furthermore, we are entitled to receive significant double digit royaltieslicensed products, calculated as a percentage of net sales of Licensed Products inlicensed products throughout the STA Territory.

The term of the Specialised Therapeutics Agreement continues, on a country-by-country basis, until the later of (i) the expiration or abandonment of the last patent covering the Licensed Productlicensed product or (ii) the earlier of (a) the date upon which sales of generic versions of Licensed Productlicensed product reach a specified level in such country, or (b) the tenth anniversary of the first commercial sale of the Licensed Productlicensed product in such country. The Specialised Therapeutics Agreement may be terminated by either party if the other party commits a material breach, subject to a customary cure period, or if the other party is insolvent. The Specialised Therapeutics Agreement will also terminate upon the termination of the supply agreement for Licensed Productslicensed products between the parties.

CANbridge Agreement

On January 30, 2018, we entered into an exclusive licensea sub-license agreement, or the CANbridge Agreement, with CANbridge BIOMED Limited, or CANbridge. Pursuant to the CANbridge Agreement, we granted to CANbridge, under certain of our intellectual property rights relating to neratinib, an exclusive, sublicensable (under certain circumstances) license to develop and commercialize any pharmaceutical product containing neratinib or, for purposes of this description, the Licensed Product, for the treatment of human disease, or for purposes of this description, the Field, in the People’s Republic of China, or the CANbridge Territory, including mainland China, Hong Kong, Macao, and Taiwan,Taiwan.

In July 2020, we filed a request for arbitration against CANbridge, in connection with the CANbridge Agreement, and CANbridge subsequently filed its response to our request for arbitration and brought counterclaims. On February 24, 2021, we and CANbridge resolved our dispute, which is described further in the section entitled “Item 3. Legal Proceedings” below. As part of the settlement, we and CANbridge agreed to enter into a termination agreement, or each,the CANbridge Termination Agreement, to terminate the CANbridge Agreement and all agreements related to the CANbridge Agreement, effective as of the same date as the settlement. Subject to the terms of the CANbridge Termination Agreement, we agreed to pay CANbridge a CANbridge Region.one-time termination fee of $20.0 million to return all rights to neratinib in Greater China back to us and assist with the transfer of such rights to us.

Medison Agreement:

During the first quarter of 2018, we entered into a sub-license agreement, or the Medison Agreement, with Medison Pharma Ltd., or Medison. Pursuant to the Medison Agreement, we granted to Medison, under certain of our intellectual property rights relating to neratinib, an exclusive license to commercialize neratinib and certain related compounds and participate in the named patient supply in Israel, or the Medison Territory, subject to the terms of the Medison Agreement and the related supply agreement. Pursuant to the Medison Agreement, we will potentially receive milestone payments due to us upon successful completion of certain separate, distinct performance obligations. In addition, we are entitled to receive double-digit royalties on sales of licensed products, calculated as a percentage of net sales of licensed products in the Medison Territory.

Pint Agreement

On March 30, 2018, we entered into a sub-license agreement, or the Pint Agreement, with Pint Pharma International SA, or Pint. Pursuant to the Pint Agreement, we granted to Pint, under certain of our intellectual property rights relating to neratinib, an exclusive, sublicensable (under certain circumstances) license to develop and commercialize any product containing neratinib and certain related compounds in Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama, Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela, French Guiana, the Falkland Islands, and Mexico, or the Pint Territory.

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The CANbridgePint Agreement sets forth the parties’ respective obligations with respect to the development, commercialization, and supply of the Licensed Product. CANbridgelicensed product. Pint will, at its expense, develop the Licensed Productlicensed product for the purpose of obtaining regulatory approval in the Field and in the CANbridgePint Territory, subject to our consent to conduct such development activities and approval of certain aspects of clinical studies conducted by CANbridge.Pint. Within the CANbridgePint Territory, CANbridgePint will also be solely responsible at its expense, for regulatory and commercialization activities. We will be solely responsible subject to certain exceptions, for the manufacturing and supply of the Licensed Productlicensed product under a supply agreement that will be entered into between the parties.parties, subject to certain exceptions therein.

Pursuant to the CANbridgePint Agreement, we will receivereceived an upfront payment of $30 million and will potentially receive additional regulatory milestone payments totaling up to $40 million and sales-based milestone payments totaling up to $185 million.payments. In addition, we are entitled to receive significant double-digit royalties on sales of licensed products, calculated as a percentage of net sales of licensed products throughout the Licensed Products in the CANbridgePint Territory.

The term of the CANbridgePint Agreement continues, on a CANbridge Region-by-CANbridge Regioncountry-by-country basis, until (i) the later of (i) the expiration or abandonment of the last licensed patent covering the Licensed Productlicensed product in such CANbridge Regioncountry, or (ii) the earlier of (x)(a) the date upon which sales of generic versions of the Licensed Productlicensed product reach a specified level in such CANbridge Region,country, or (y)(b) the tenth anniversary of the first commercial sale of the Licensed Productlicensed product in such CANbridge Region.country. The CANbridgePint Agreement may be terminated by either party if the other party commits a material breach, subject to a customary cure period, or if the other party is insolvent; providedinsolvent. Pint may also terminate the Pint Agreement at will, for certain safety concerns.

Knight Agreement

On January 9, 2019, we entered into a sub-license agreement, or the Knight Agreement, with Knight Therapeutics, Inc., or Knight. Pursuant to the Knight Agreement, we granted to Knight, under certain of the our intellectual property rights relating to neratinib, an exclusive, sublicensable (under certain circumstances) license (i) to commercialize any product containing neratinib and certain related compounds in Canada, or the Knight Territory, (ii) to seek and maintain regulatory approvals for the licensed products in the Knight Territory and (iii) to manufacture the licensed products anywhere in the world solely for the development and commercialization of the licensed products in the Knight Territory for human use, subject to the terms of the Knight Agreement and a supply agreement to be negotiated and executed by the parties.

Under the terms of the Knight Agreement, we will be solely responsible for the manufacturing and supply of the licensed products to Knight, but under limited circumstances Knight may obtain the right to manufacture the licensed products under the supply agreement.

The Knight Agreement sets forth the parties’ respective obligations with respect to the commercialization of the licensed products. Within the Knight Territory, we will be solely responsible for obtaining the regulatory approval for the indication of extended adjuvant treatment of HER2-positive early stage breast cancer, or the Initial Indication, and Knight will use commercially reasonable efforts to prepare, file and manage regulatory filings for any other indications in the field of human use. Promptly after obtaining the regulatory approval for the Initial Indication in the Knight Territory, we will transfer such regulatory approval to Knight, and Knight will own and hold any regulatory approvals for the licensed products in the Knight Territory in its name.

Pursuant to the Knight Agreement, we received an upfront payment and will potentially receive additional regulatory and commercial milestone payments. In addition, we are entitled to receive double-digit royalties on sales of licensed products, calculated as a percentage of net sales of licensed products in the Knight Territory.

The term of the Knight Agreement continues, on a licensed product-by-licensed product basis, until the later of (i) the expiration or abandonment of the last valid claim of the licensed patents that covers such licensed product in the Territory, or (ii) the earlier of (a) the time when generic competitors to such licensed product have achieved a specified level in such country, or (b) ten (10) years following the date of first commercial sale of such licensed product in the Territory. The Knight Agreement may be terminated by either party if CANbridge materially breachesthe other party commits a material breach, subject to a customary cure period, or if the other party is insolvent.

Pierre Fabre Agreement

On March 29, 2019, we entered into a sub-license agreement, or the Pierre Fabre Agreement, with Pierre Fabre Medicament SAS, or Pierre Fabre. Pursuant to the Pierre Fabre Agreement, we granted to Pierre Fabre under certain of our intellectual property rights relating to neratinib an exclusive, sub-licensable (under certain circumstances) license to develop, manufacture and commercialize any pharmaceutical product containing neratinib for therapeutic and prophylactic indications for human or veterinary use in European countries excluding Russia and Ukraine, along with countries in North Africa and francophone countries of West Africa, or the Pierre Fabre Territory. On November 25, 2019, we entered into a license amendment, or the First Pierre Fabre Amendment, with Pierre Fabre to extend Pierre Fabre’s licensed territory to the Middle East, South Africa, Sudan and Turkey, or together with the Pierre Fabre Territory, the First Pierre Fabre Territory.

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On February 24, 2021, we entered into a second license amendment, or the Second Pierre Fabre Amendment, with Pierre Fabre to further extend Pierre Fabre’s licensed territory to Greater China, or the Second Pierre Fabre Territory, which includes mainland China, Taiwan, Hong Kong and Macao, or each a China Region.

Pursuant to the Pierre Fabre Agreement, we received an upfront payment and will potentially receive additional regulatory and sales-based milestone payments based on regulatory and sales activities in the First Pierre Fabre Territory. Pursuant to the Second Pierre Fabre Amendment, we will receive an upfront payment of $50 million, as well as additional regulatory and sales-based milestone payments up to $240 million based solely on regulatory and sales activities in the Second Pierre Fabre Territory. In addition, we will receive double-digit royalties based on sales of the licensed products in the First Pierre Fabre Territory, on the one hand, and double-digit royalties based on sales of the licensed products in the Second Pierre Fabre Territory, on the other hand. For the purposes of calculating royalties, sales of the licensed products in the Second Pierre Fabre Territory will be excluded from the sales of licensed products made in the First Pierre Fabre Territory.

Under the terms of the Pierre Fabre Agreement, as amended, we are obligated to supply Pierre Fabre with the licensed products in accordance with the related supply agreement. Pierre Fabre will be responsible for conducting additional clinical studies and leading regulatory activities in connection with the European Medicines Agency, or EMA, and Greater China.

The term of the Pierre Fabre Agreement, as amended, continues until, on a country-by-country basis, the later of (i) the expiration or abandonment of the last licensed patent covering the licensed product in such country and (ii) the earlier of (a) the date upon which sales of generic versions of the licensed product reach a specified level in such country, or (b) the tenth anniversary of the first commercial sale of a licensed product in such country.

The Pierre Fabre Agreement, as amended, may be terminated by either party, in its developmententirety, if the other party commits a material breach, subject to a cure period, or commercialization obligations in a particular CANbridge Region, weif the other party is insolvent, and Pierre Fabre may terminate the CANbridgePierre Fabre Agreement, solelyas amended, at its convenience or if there is evidence of safety issues with the licensed product. Pierre Fabre may terminate the Pierre Fabre Agreement, as amended, on a territory-by-territory basis, by terminating only the First Pierre Fabre Territory or the Second Pierre Fabre Territory, for any of the foregoing reasons. We may terminate the Pierre Fabre Agreement, as amended, on a China Region-by-China Region bases or, under certain circumstances, in the entire Second Pierre Fabre Territory if Pierre Fabre is in material violation of certain anti-corruption laws.

Bixink Agreement

During the second quarter of 2020, we entered into a sub-license agreement, or the Bixink Agreement, with Bixink Therapeutics Co., Ltd., or Bixink. The Bixink Agreement granted intellectual property rights and set forth the respective obligations with respect to development, commercialization and supply of NERLYNX in South Korea, or the Bixink Territory. The Bixink Agreement includes potential milestone payments due to us upon successful completion of certain performance obligations, such CANbridge Region. CANbridgeas achieving regulatory approvals. In addition, we are entitled to receive double-digit royalties on sales of licensed products, calculated as a percentage of net sales of licensed products throughout the Bixink Territory.

Manufacturing

We do not currently have our own manufacturing facilities. We intend to continue to use our financial resources to accelerate commercialization of NERLYNX and development of our drug candidates rather than diverting resources to establish our own manufacturing facilities. We intend to meet our pre-clinical and clinical trial manufacturing requirements by establishing relationships with third-party manufacturers and other service providers to perform these services for us. While our drug candidates were being developed by Pfizer, both the drug substance and drug product were manufactured by third-party contractors. We are currently using the same third-party contractors to manufacture, supply, store and distribute our products in clinical trials and commercial quantities.

Should any of our other drug candidates obtain marketing approval, we anticipate establishing relationships with third-party manufacturers and other service providers in connection with commercial production of our products. We have some flexibility in securing other manufacturers to produce our drug candidates; however, our alternatives may terminatebe limited due to proprietary technologies or methods used in the agreement at its convenience.manufacture of some of our drug candidates.

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Government Regulation

United States—FDA Process

The research, development, testing, manufacture, labeling, promotion, advertising, distribution and marketing, among other things, of drug products are extensively regulated by governmental authorities in the United States and other countries. In the United States, the FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, or the FDCA, and its implementing regulations.

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Failure to comply with the applicable U.S. requirements may subject us to administrative or judicial sanctions, such as FDA refusal to approve pending NDAs, warning letters, fines, civil penalties, product recalls, product seizures, total or partial suspension of production or distribution, injunctions and/or criminal prosecution.

Drug Approval Process. None of our drug product candidates may be marketed in the United States until the drug has received FDA approval. The steps required before a drug may be marketed in the United States generally include the following:

The development and approval process requires substantial time, effort and financial resources, and we cannot be certain that any approvals for our product candidates will be granted on a timely basis, if at all.

Pre-clinical tests include laboratory evaluation of product chemistry, toxicity and formulation, as well as animal studies. The conduct of the pre-clinical tests and formulation of the compounds for testing must comply with federal regulations and requirements. The results of the pre-clinical tests, together with manufacturing information and analytical data, are submitted to the FDA as part of an IND, which must become effective before human clinical trials may begin. An IND will automatically become effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions about the conduct of the trial, such as whether human research subjects will be exposed to an unreasonable health risk. In such a case, the IND sponsor and the FDA must resolve any outstanding FDA concerns or questions before clinical trials can proceed. We cannot be sure that submission of an IND will result in the FDA allowing clinical trials to begin.

Clinical trials involve administration of the investigational drug to human subjects under the supervision of qualified investigators. Clinical trials are conducted under protocols detailing the objectives of the study, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each protocol must be provided to the FDA as part of a separate submission to the IND. Further, an Institutional Review Board, or IRB for each medical center proposing to conduct the clinical trial must review and approve the study protocol and informed consent information for study subjects for any clinical trial before it commences at that center, and the IRB must monitor the study until it is completed. There are also requirements governing reporting of ongoing clinical trials and clinical trial results to public registries. Study subjects must sign an informed consent form before participating in a clinical trial.

Clinical trials necessary for product approval typically are conducted in three sequential phases, but the phases may overlap. Phase I usually involves the initial introduction of the investigational drug into a limited population, typically healthy humans, to evaluate its short-term safety, dosage tolerance, metabolism, pharmacokinetics and pharmacologic actions, and, if possible, to gain an early indication of its effectiveness. Phase II usually involves trials in a limited patient population to (i) evaluate dosage tolerance and appropriate dosage; (ii) identify possible adverse effects and safety risks; and (iii) evaluate preliminarily the efficacy of the drug for specific targeted indications. Multiple Phase II clinical trials may be conducted by the sponsor to obtain information prior to beginning larger and more expensive Phase III clinical trials. Phase III trials, commonly referred to as pivotal studies, are undertaken in an expanded patient population at multiple, geographically dispersed clinical trial centers to further evaluate clinical efficacy and test further for safety by using the drug in its final form. There canPost-approval trials, sometimes referred to as Phase IV studies, may be no assurance thatconducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, the FDA may mandate the performance of Phase I, Phase II or Phase III testing will be completed successfully within any specified periodIV clinical trials as a condition of time, if at all. approval of an NDA.

Furthermore, we,the sponsor, the FDA or an IRB may suspend clinical trials at any time on various grounds, including a finding that the subjects or patients are being exposed to an unacceptable health risk. Moreover,Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution, such as in the FDA may approvecircumstances where the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. In addition, some clinical trials are overseen by an NDA for a product candidate, but require thatindependent group of qualified experts organized by the sponsor, conduct additional clinical trials to further assess the drug after NDA approval underknown as a post-approval commitment. Post-approval trials are typically referred to as Phase IV clinical trials.   

data safety monitoring board or committee.

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Depending on its charter, this group may determine whether a trial may move forward at designated check points based on access to certain data from the trial.

During the development of a new drug, sponsors are given an opportunity to meet with the FDA at certain points. These points may be prior to submission of an IND, at the end of Phase II clinical testing, and before an NDA is submitted. Meetings at other times may be requested. These meetings can provide an opportunity for the sponsor to share information about the data gathered to date, for the FDA to provide advice, and for the sponsor and the FDA to reach an agreementconsensus on the next phase of development. Sponsors typically use the end of a Phase II meeting to discuss their Phase II clinical results and present their plans for the pivotal Phase III clinical trial that they believe will support approvalsubmission of the new drug. an NDA.

A sponsor may request an SPA to reach an agreement with the FDA that the protocol design, clinical endpoints, and statistical analyses are acceptable to support regulatory approval of the product candidate with respect to effectiveness in the indication studied. If such an agreement is reached, it will be documented and made part of the administrative record, and it will be binding on the FDA except in limited circumstances, such as if the FDA identifies a substantial scientific issue essential to determining the safety or effectiveness of the product after clinical studies begin, if the relevant data, assumptions, or information provided by the sponsor in a request for SPA change are found to be false statements or misstatements or omit relevant facts, or if the sponsor fails to follow the protocol that was agreed upon with the FDA. A documented SPA may be modified, and such modification will be deemed binding on the FDA review division, except under the circumstances described above, if FDA and the sponsor agree in writing to modify the protocol and such modification is intended to improve the study. There is no guarantee that a study will ultimately be adequate to support an approval, even if the study is subject to an SPA.

Concurrent with clinical trials, companies usually complete additional animal safety studies and must also develop additional information about the chemistry and physical characteristics of the drug and finalize a process for manufacturing the product in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the drug candidate and the manufacturer must develop methods for testing the quality, purity and potency of the final drugs. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the drug candidate does not undergo unacceptable deterioration over its shelf life.

Assuming successful completion of the required clinical testing, the results of pre-clinical studies and of clinical trials, together with other detailed information, including information on the manufacture and composition of the drug, are submitted to the FDA in the form of an NDA requesting approval to market the product for one or more indications. An NDA must be accompanied by a significant user fee, which is waived for the first NDA submitted by a qualifying small business. In August 2017,

The FDA reviews an NDA to determine, among other things, whether a product is safe and effective for its intended use and whether its manufacturing is cGMP-compliant to assure and preserve the Foodproduct’s identity, strength, quality and purity. Under the Prescription Drug Administration ReauthorizationUser Fee Act, or FDARA, was signed into law. Among other things, FDARA reauthorizesPDUFA, guidelines that are currently in effect, the FDA’s authorityFDA has a goal of ten months from the date of “filing” of a standard NDA for a new molecular entity to collect user feesreview and act on the submission. This review typically takes twelve months from industry participantsthe date the NDA is submitted to fund reviews of marketing applications for new drugs.

The testing and approval process requires substantial time, effort and financial resources.FDA because the FDA has approximately two months to make a “filing” decision after the application is submitted. The FDA willconducts a preliminary review of all NDAs within the NDA and may deem itfirst 60 days after submission, before accepting them for filing, to be inadequatedetermine whether they are sufficiently complete to support approval, and we cannot be sure that any approval will be granted on a timely basis, if at all.permit substantive review. The FDA may request additional information rather than accept an NDA for filing. In this event, the NDA must be resubmitted with the additional information. The resubmitted application also is subject to a filing review before the FDA accepts it for filing and substantive review.

The FDA also may refer thean application for a novel drug to the appropriatean advisory committee. An advisory committee typicallyis a panel of independent experts, including clinicians for review, evaluation and other scientific experts, that reviews, evaluates and provides a recommendation as to whether the application should be approved.approved and under what conditions. The FDA is not bound by the recommendations of thean advisory committee, but it typically followsconsiders such recommendations.recommendations carefully when making decisions.

Before approving an NDA, the FDA inspects the facility or the facilities at which the drug and/or its active pharmaceutical ingredient is manufactured and will not approve the product unless the manufacturing is in compliance with cGMPs.cGMPs and adequate to assure consistent production of the product within required specifications. Additionally, before approving an NDA, the FDA will typically inspect one or more clinical sites to assure compliance with GCPs. If the FDA evaluatesdetermines that the NDA and theapplication, manufacturing process or manufacturing facilities are deemednot acceptable, it will outline the deficiencies in the submission and often will request additional testing or information. Notwithstanding the submission of any requested additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

After the FDA evaluates an NDA, it will issue an approval letter or in some cases a Complete Response Letter. TheAn approval letter authorizes commercial marketing of the drug for specific indications. As a condition of NDA approval, the FDA may require post-marketing testing and surveillance to monitor the drug’s safety or efficacy, or impose other conditions. A Complete Response Letter indicates that the review cycle of the application is complete and the application iswill not ready for approval.be approved in its present form. A Complete Response Letter usually describes the specific deficiencies in the NDA identified by the FDA and may require additional clinical data and/or additional pivotal Phase III clinical trial(s), and/or other significant, expensive and time-consuming requirements related to clinical trials, pre-clinical studies or

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manufacturing. Even if such additional information is submitted, the FDA may ultimately decide that the NDA does not satisfy the criteria for approval. Data from clinical trials

If regulatory approval of a product is not always conclusivegranted, such approval will be granted for particular indications and may entail limitations on the indicated uses for which such product may be marketed. For example, the FDA may interpret data differently than we or our collaborators interpret data. Alternatively, the FDA could also approve the NDA with a Risk Evaluation and Mitigation Strategy to mitigate risks of the drug, which could include medication guides, physician communication plans, or elements to assure safe use, such as restricted distribution methods, patient registries or other risk minimization tools. Once the FDA approves a drug, the FDA may withdraw product approval if ongoing regulatory requirements are not met or if safety problems occur after the product reaches the market. In addition, the FDA may require testing, including Phase IV clinical trials, and surveillance programs to monitor the safety effects of approved products that have been commercialized. The FDA has the power to prevent or limit further marketing of a product based on the results of these post-marketing programs or other information. In addition, new government requirements, including those resulting from new legislation, may be established, or the FDA’s policies may change, which could impact the timeline for regulatory approval or otherwise impact ongoing development programs.

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Expedited Review and Approval Programs. The FDA has various programs, including fast track designation, priority review, accelerated approval, and breakthrough therapy designation, which are intended to expedite or simplify the process for reviewing certain drugs and/orand in the case of accelerated approval, provide for approval on the basis of surrogate or intermediate endpoints. Even if a drug qualifies for one or more of these programs, the FDA may later decide that the drug no longer meets the conditions for qualification or that the time period for FDA review or approval will not be shortened. Generally, drugs that may be eligible for these programs are those for serious or life-threatening diseases or conditions, those with the potential to address unmet medical needs, and those that offer meaningful benefits over existing treatments. Fast track designation, breakthrough therapy designation, priority review and accelerated approval do not change the standards for approval but may expedite the development or approval process.

For example, fast track designation is designed to facilitate the development and expedite the review of drugs designed to treat serious or life-threatening diseases or conditions and which demonstrate the potential to address an unmet medical need. Priorityneed for such diseases or conditions. Fast track designation applies to the combination of the product and the specific indication for which it is being studies. The sponsor of a fast track product candidate has opportunities for more frequent interactions with the FDA review team during development. With regard to a fast track-designated product, the FDA may also consider for review sections of the NDA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the NDA, the FDA agrees to accept sections of the NDA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the NDA. Any product submitted to the FDA for approval, including a product with a fast track designation, may also be eligible for other types of FDA programs intended to expedite development and review, such as priority review and accelerated approval. A product is eligible for priority review if it is designed to give drugs fortreat a serious conditions that offercondition, and if approved, would provide a significant improvement in safety or effectiveness compared to available products. The FDA will attempt to direct additional resources to the evaluation of an initialapplication for a new drug designated for priority review in an effort to facilitate the review. The FDA endeavors to review applications with priority review designations within six months of the 60-day filing date if the drug is aas compared to ten months for review of new molecular entity as compared to a standardNDAs under its current PDUFA review time of 10 months. Although fast track designation and priority review do not affect the standards for approval, the FDA will attempt to facilitate early and frequent meetings with a sponsor of a fast track designated drug and expedite review of the application for a drug designated for priority review. The FDA may also initiate review of sections of an NDA before the application is complete for drugs with fast track designation. This “rolling review” is available if the applicant provides and the FDA approves a schedule for submission of portions of the application. Drugsgoals.

Drug products intended for serious or life threatening conditions are alsomay be eligible for accelerated approval which provides an earlier approval of drugs, including fast track products, upon a determination that the product has an effect on a surrogate endpoint, which is a laboratory measurement or physical sign used as an indirect or substitute measurement representing a clinically meaningful outcome, or an effect on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality and that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity or prevalence of the condition and the availability or lack of alternative treatments. As a condition of approval, the FDA may require that a sponsor of a drug receiving accelerated approval perform post-marketing clinical trials. Finally, breakthrough therapy designation, which was established bytrials to verify or characterize the anticipated effect on irreversible morbidity or mortality or other clinical benefit. Products receiving accelerated approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required clinical trials in a timely manner, or if such trials fail to verify the predicted clinical benefit. In addition, the FDA currently requires pre-approval of promotional materials as a condition for accelerated approval.

The Food and Drug Administration Safety and Innovation Act or FDASIA,established a category of drugs referred to as “breakthrough therapies” that may be eligible to receive breakthrough therapy designation. A sponsor may seek FDA designation of a product candidate as a “breakthrough therapy” if the product is for drugs intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. Drugs designated as breakthrough therapies receive all the benefits of a fast track designation, as well as intensive guidance on efficient drug development and organizational commitment involving senior managers in the FDA. We may seek to utilize one or more of these expedited programs for our product candidates in the future, but even if we were to obtain fast track designation, priority review, accelerated approval and/or breakthrough therapy designation, there is no guarantee that it would result in a quicker review or approval of our products, if any.

Post-Approval Requirements. After a drug has been approved by the FDA for sale, the FDA may require that certain post-approval requirements be satisfied, including the conduct of additional clinical studies. In addition, certain changes to an approved product, such as adding new indications, making certain manufacturing changes, or making certain additional labeling claims, are subject to further FDA

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review and approval. Before a company can market products for additional indications, it must obtain additional approvals from the FDA. Obtaining approval for a new indication generally requires that additional clinical studies be conducted. A company cannot be sure that any additional approval for new indications for any product candidate will be approved on a timely basis, or at all.

If post-approval conditions are not satisfied, the FDA may withdraw its approval of the drug. In addition, holders of an approved NDA are required to (i) report certain adverse reactions to the FDA and maintain pharmacovigilance programs to proactively look for these adverse events; (ii) comply with certain requirements concerning advertising and promotional labeling for their products; and (iii) continue to have quality control and manufacturing procedures conform to cGMPs after approval. The FDA periodically inspects the sponsor’s records related to safety reporting and/or manufacturing facilities; this latter effort includes assessment of ongoing compliance with cGMPs. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain cGMP compliance. We use third-party manufacturers to produce our products in clinical and commercial quantities, and future FDA inspections may identify compliance issues at the facilities of our contract manufacturers that may disrupt production or distribution, or require substantial resources to correct. In addition, discovery of problems with a product after approval may result in restrictions on a product, manufacturer or holder of an approved NDA, including, among other things:

restrictionsThe FDA closely regulates the marketing, labeling, advertising and promotion of drugs. A company can make only those claims relating to safety and efficacy that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe legally available products for uses that are not described in the product’s labeling and that differ from those tested and approved by the FDA. Such off-label uses are common across medical specialties. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the marketing or manufacturingsubject of the product, complete withdrawaloff-label use of the product from the market or product recalls;

their products.

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Patent Term Restoration and Marketing Exclusivity. Depending upon the timing, duration and specifics of FDA approval of the use of our drugs, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent restoration term of up to five years as compensation for patent term lost during product development and the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product’s approval date. The patent term restoration period is generally one-half the time between the effective date of an IND and the submission date of an NDA, plus the time between the submission date of an NDA and the approval of that application. Only one patent applicable to an approved drug is eligible for the extension and the extension must be requested prior to expiration of the patent. The U.S. Patent and Trademark Office, or USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we intendWe have filed for patent term extension for two U.S. patents, U.S. Patent No. 7,399,865 and U.S. Patent No. 9,211,291. We elected to apply patent term extension to U.S. Patent No. 7,399,865.  The USPTO has determined that U.S. Patent No. 7,399,865 is eligible for restorationsfive years of patent term for some of our currently owned or licensed patents to add patent life beyond their current expiration date, depending on the expected length of clinical trials and other factors involved in the submission of the relevant NDA.  extension. Once extended, U.S. Patent No. 7,399,865 will expire December 29, 2030.

Data and market exclusivity provisions under the FDCA also can delay the submission or the approval of certain applications. The FDCA provides a five-year period of non-patent data exclusivity within the United States to the first applicant to gain approval of an NDA for a new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or ion responsible for the action of the drug substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application, or ANDA, or an NDA submitted under section 505(b)(2) of the FDCA by another company for another version of such drug where the applicant does not own or have a legal right of reference to all the data required for approval. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement. Currently, ten U.S. Patents are listed in the patent data under the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, or the Orange Book, in connection with neratinib: U.S. Patent Nos. 7,399,865, 7,982,043, 8,518,446, 8,669,273, 8,790,708, 9,139,558, 9,211,291, 9,265,784, 9,630,946, and 10,035,788, with expected patent expiration dates ranging from October 2025 to July 2031. The FDCA also provides three years of marketing exclusivity for an NDA, 505(b)(2) NDA or supplement to an existing NDA if new clinical investigations, other than bioavailability

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studies, conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application, for example, for new indications, dosages or strengths of an existing drug. This three-year exclusivity covers only the conditions associated with the new clinical investigations and does not prohibit the FDA from approving ANDAs or 505(b)(2) NDAs for drugs containing the original active agent.agent or from accepting and reviewing an application referencing the approved drug’s application. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA; however, an applicant submitting a full NDA would be required to conduct, or obtain a right of reference to all of the pre-clinical studies adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.Marketing approval for neratinib was obtained in the United States on July 17, 2017, which provided five years of regulatory exclusivity. Marketing approval for neratinib in combination with capecitabine was obtained in the United States on February 25, 2020, which provided three years of regulatory exclusivity. The earliest a generic may challenge any of the U.S. Patents listed in the Orange Book in connection with neratinib by filing an ANDA is in July 2021.

Foreign Regulation

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

In the European Economic Area, or EEA, which is comprised of the Member States of the EU plus Norway, Iceland and Liechtenstein, medicinal products can only be commercialized after obtaining a Marketing Authorization, or MA. There are two types of MAs:

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Under the above described procedures, before granting the MA, the EMA or the competent authorities of the Member States of the EEA assess the risk-benefit balance of the product on the basis of scientific criteria concerning its quality, safety and efficacy.

As in the United States, it may be possible in foreign countries to obtain a period of market and/or data exclusivity that would have the effect of postponing the entry into the marketplace of a competitor’s generic product. For example, if any of our products receive marketing approval in the EEA, we expect they will benefit from eight years of data exclusivity and 10 years of marketing exclusivity. An additional non-cumulative one-year period of marketing exclusivity is possible if during the data exclusivity period (the first eight years of the 10-year marketing exclusivity period), we obtain an authorization for one or more new therapeutic indications that are deemed to bring a significant clinical benefit compared to existing therapies. The data exclusivity period begins on the date of the product’s first marketing authorization in the EEA and prevents generics from relying on the marketing authorization holder’s pharmacological, toxicological and clinical data for a period of eight years. After eight years, a generic product application may be submitted, and generic companies may rely on the marketing authorization holder’s data. However, a generic cannot launch until two years later (or a total of 10 years after the first marketing authorization in the EU of the innovator product), or three years later (or a total of 11 years after the first marketing authorization in the EU of the innovator product) if the marketing authorization holder obtains marketing authorization for a new indication with significant clinical benefit within the eight-year data exclusivity

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period. In Japan, our products may be eligible for eight years of data exclusivity. There can be no assurance that we will qualify for such regulatory exclusivity, or that such exclusivity will prevent competitors from seeking approval solely on the basis of their own studies.

When conducting clinical trials in the EU, we must adhere to the provisions of the European Union Clinical Trials Directive (Directive 2001/20/EC) and the laws and regulations of the EU Member States implementing them. These provisions require, among other things, that the prior authorization of an Ethics Committee and the competent Member State authority is obtained before commencing the clinical trial. In April 2014, the EU passed the Clinical Trials Regulation (Regulation 536/2014), which will replace the current Clinical Trials Directive. To ensure that the rules for clinical trials are identical throughout the European Union, the EU Clinical Trials Regulation was passed as a regulation that is directly applicable in all EU member states. All clinical trials performed in the European Union are required to be conducted in accordance with the Clinical Trials Directive until the Clinical Trials Regulation becomes applicable. According to the current plans of the EMA, the Clinical Trials Regulation is expected to become applicable in late 2021 but could be delayed.

Coverage and Reimbursement

In the United States and internationally, sales of NERLYNX and any other products that we market in the future, and our ability to generate revenues on such sales, are dependent, in significant part, on the availability of adequate coverage and reimbursement from third-party payors, such as state and federal governments, managed care providers and private insurance plans. Private insurers, such as health maintenance organizations and managed care providers, have implemented cost-cutting and reimbursement initiatives and likely will continue to do so in the future. These include establishing formularies that govern the drugs and biologics that will be offered and the out-of-pocket obligations of member patients for such products. We may need to conduct pharmacoeconomic studies to demonstrate the cost-effectiveness of our products for formulary coverage and reimbursement. Even with such studies, our products may be considered less safe, less effective or less cost-effective than existing products, and third-party payors may not provide coverage and reimbursement for our product candidates, in whole or in part.

In addition, particularly in the United States and increasingly in other countries, we are required to provide discounts and pay rebates to state and federal governments and agencies in connection with purchases of our products that are reimbursed by such entities. It is possible that future legislation in the United States and other jurisdictions could be enacted to potentially impact reimbursement rates for the products we are developing and may develop in the future and could further impact the levels of discounts and rebates paid to federal and state government entities. Any legislation that impacts these areas could impact, in a significant way, our ability to generate revenues from sales of products that, if successfully developed, we bring to market.

Political, economic and regulatory influences are subjecting the healthcare industry in the United States to fundamental changes. There have been, and we expect there will continue to be, legislative and regulatory proposals to change the healthcare system in ways that could significantly affect our future business. For example, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act, or collectively, the ACA, enacted in March 2010, substantially changeschanged the way healthcare is financed by both governmental and private insurers. Among other cost containment measures, ACA establishes:established:

We expect that the current presidential administration and U.S. Congress will likely continue to seek to modify, repeal or otherwise invalidate all, orreplace certain provisionsaspects of the ACA. Most recently,By way of example, the Tax Cuts and Jobs Act was enacted, which, among other things, removes penalties for not complying with the Affordable Care Act’sACA’s individual mandate to carry health insurance. ThereOn December 14, 2018, a U.S. District Court Judge in the Northern District of Texas, ruled that the individual mandate is still uncertainty with respecta critical and inseverable feature of the ACA, and therefore, because it was repealed as part of the Tax Act, the remaining provisions of the ACA are invalid as well. On December 18, 2019, the U.S. Court of Appeals for the Fifth Circuit ruled that the individual mandate was unconstitutional and remanded the case back to the District Court to determine whether the remaining provisions of the ACA are invalid as well. The U.S. Supreme Court is currently reviewing the case, although it remains unclear when or how the Supreme Court will rule. It is also unclear how other efforts to challenge, repeal or replace the ACA will impact President Trump’s administration and the U.S. Congress may have, if any, and any changes will likely take time to unfold, and could have an impact on coverage and reimbursement for healthcare items and services covered by plans that were authorized by ACA.

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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, among other things, included aggregate reductions to Medicare payments to providers of 2% per fiscal year, which went into effect on April 1, 2013 and, due to subsequent legislative amendments to the statute, will remain

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in effect through 20252030, with the exception of a temporary suspension from May 1, 2020 through March 31, 2021, unless additional Congressional action is taken. The American Taxpayer Relief Act of 2012, among other things, reduced Medicare payments to several types of providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. Individual states in the United States have also become increasingly active in passing legislation and implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. Recently, there has also been heightened governmental scrutiny over the manner in which drug manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed bills designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. For example, the 21st Century Cures Act changes the reimbursement methodology for infusion drugs and biologics furnished through durable medical equipment in an attempt to remedy over- and underpayment of certain drugs.

Similar political, economic and regulatory developments are occurring in the EU and may affect the ability of pharmaceutical companies to profitably commercialize their products. 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. 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 the ability of pharmaceutical companies to commercialize their products. In international markets, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies.

In the future, there may continue to be additional proposals relating to the reform of the U.S. healthcare system.system and international healthcare systems. Future legislation, or regulatory actions implementing recent or future legislation may have a significant effect on our business. Our ability to successfully commercialize products depends in part on the extent to which reimbursement for the costs of our products and related treatments will be available in the United States and worldwide from government health administration authorities, private health insurers and other organizations. The adoption of certain proposals could limit the prices we are able to charge for our products, the amounts of reimbursement available for our products, and limit the acceptance and availability of our products. Therefore, substantial uncertainty exists as to the reimbursement status of newly approved health care products by third-party payors.

Sales and Marketing

The FDA regulates all advertising and promotion activities for products under its jurisdiction prior to and after approval, including standards and regulations for direct-to-consumer advertising, dissemination of off-label information, industry-sponsored scientific and educational activities and promotional activities involving the Internet. Drugs may be marketed only for the approved indications and in accordance with the provisions of the approved label. Further, if there are any modifications to the drug, including changes in indications, labeling, or manufacturing processes or facilities, we may be required to submit and obtain FDA approval of a new or supplemental NDA, which may require us to collect additional data or conduct additional pre-clinical studies and clinical trials. Failure to comply with applicable FDA requirements may subject a company to adverse publicity, enforcement action by the FDA, corrective advertising, consent decrees and the full range of civil and criminal penalties available to the FDA.

Physicians may prescribe legally available drugs for uses that are not described in the drug’s labeling and that differ from those tested by us and approved by the FDA. Such off-label uses are common across medical specialties, and often reflect a physician’s belief that the off-label use is the best treatment for the patient. The FDA does not regulate the behavior of physicians in their choice of treatments, but FDA regulations do impose stringent restrictions on manufacturers’ communications regarding off-label uses. Failure to comply with applicable FDA requirements may subject a company to adverse publicity, enforcement action by the FDA, corrective advertising, consent decrees and the full range of civil and criminal penalties available to the FDA.

Outside the United States, our ability to market a product is contingent upon obtaining marketing authorization from the appropriate regulatory authorities. The requirements governing marketing authorization, pricing and reimbursement vary widely from country to country.

Manufacturing

We do not currently have our own manufacturing facilities. We intend to continue to use our financial resources to accelerate commercialization of NERLYNX and development of our drug candidates rather than diverting resources to establish our own manufacturing facilities. We intend to meet our pre-clinical and clinical trial manufacturing requirements by establishing relationships with third-party manufacturers and other service providers to perform these services for us. While our drug candidates were being developed by Pfizer, both the drug substance and drug product were manufactured by third-party contractors. We are currently using the same third-party contractors to manufacture, supply, store and distribute our products in clinical trials and commercial quantities.  We believe that we have manufactured sufficient quantities of the drug to support at least the first year of launch in the extended adjuvant breast cancer indication and plan to continue to manufacture the drug in 2018 to further support the commercial launch of the drug.  

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Should any of our other drug candidates obtain marketing approval, we anticipate establishing relationships with third-party manufacturers and other service providers in connection with commercial production of our products. We have some flexibility in securing other manufacturers to produce our drug candidates; however, our alternatives may be limited due to proprietary technologies or methods used in the manufacture of some of our drug candidates.

Other Healthcare Laws

We may also be subject to various federal and state laws pertaining to health care “fraud and abuse,” including anti-kickback laws and false claims laws, data privacy and security laws and transparency laws.  Anti-kickback laws make it illegal for a prescription drug manufacturer to solicit, offer, receive,

The federal Anti-Kickback Statute, or payAKS, prohibits, among other things, any person or entity from knowingly and willfully soliciting, receiving, offering or paying any remuneration, directly or indirectly, overtly or covertly, in exchange for,cash or in kind, to induce or reward either the referral of business, includingan individual for, or the purchase, order or prescriptionrecommendation of an item or service reimbursable, in whole or in part, under a particular drug. Duefederal healthcare program, such as the Medicare and Medicaid programs. The term “remuneration” has been broadly interpreted to the breadthinclude anything of value. There are a number of statutory exceptions and regulatory safe harbors protecting some common activities from prosecution; however, these are drawn narrowly and require strict compliance in order to offer protection. Additionally, a person or entity does not need to have actual knowledge of the statutory provisionsstatute or specific intent to violate it in order to have committed a violation.

Federal civil and the absence of guidance in the form of regulations and very few court decisions addressing industry practices, it is possible that our practices might be challenged under anti-kickback or similar laws. Falsecriminal false claims laws, such as the federal False Claims Act, or FCA, prohibit anyoneindividuals or entities from, among other things, knowingly and willingly presenting, or causing to be presented for payment to third-party payors (including Medicare and Medicaid) claims for reimbursed drugs or services that are false, fictitious or fraudulent claims for payment or approval by the federal government, including federal health care programs, such as Medicare and Medicaid, and knowingly making, using or causing to be made or used a false record or statement material to a false or fraudulent claim, or knowingly making a false statement to improperly avoid, decrease or conceal an obligation to pay money to the federal government. Private individuals can bring “qui tam” actions under the FCA, on behalf of the government and such individuals, commonly known as “whistleblowers,” may share in amounts paid by the entity to the government in fines or settlement. Moreover, a claim including items or services not provided as claimed,resulting from a violation of the AKS constitutes a false or claimsfraudulent claim for medically unnecessary itemspurposes of the FCA.

The federal Civil Monetary Penalties law prohibits, among other things, offering or services. In addition, some state prohibitions applytransferring remuneration to a federal healthcare beneficiary that a person knows or should know is likely to influence the referral of patients for healthcarebeneficiary’s decision to order or receive items or services reimbursedreimbursable by any source, not only the Medicare and Medicaid programs. Our activities relating to the sale and marketing of our products may be subject to scrutiny under any of these laws.government from a particular provider or supplier.

The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created new federal criminal statutes that prohibit knowingly and willfully executing, or attempting to execute, a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any money or property owned by, or under the control or custody of, any healthcare benefit program, including private third-party payors and knowingly and willfully falsifying, concealing or covering up by trick, scheme or device, a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Like the AKS, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

The federal transparency requirements under the Physician Payments Sunshine Act, created under the ACA, requires, among other things, certain manufacturers of drugs, devices, biologics and medical supplies reimbursed under Medicare, Medicaid, or the Children’s Health Insurance Program to annually report to CMS information related to payments and other transfers of value provided to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), certain other healthcare professionals beginning in 2022, and teaching hospitals and physician ownership and investment interests, including such ownership and investment interests held by a physician’s immediate family members.

There are also state and foreign law equivalents of each of the above federal laws, such as state anti-kickback and false claims laws, that may impose similar or more prohibitive restrictions, and may apply to items or services reimbursed by any non-governmental third-party payors, including private insurers. Similar restrictions are also imposed on the promotion and marketing of medicinal products in the EU and other countries. Laws (including those governing promotion, marketing and anti-kickback provisions), industry regulations and professional codes of conduct often are strictly enforced.

Violations of fraud and abuse laws may be punishable by criminal and/or civil sanctions, including fines and civil monetary penalties, the possibility of exclusion from federal health care programs (including Medicare and Medicaid) and corporate integrity agreements, which impose, among other things, rigorous operational and monitoring requirements on companies. Similar sanctions and penalties also may be imposed upon executive officers and employees, including criminal sanctions against executive officers under the so-called “responsible corporate officer” doctrine, even in situations where the executive officer did not intend to violate the law and was unaware of any wrongdoing. Given the penalties that may be imposed on companies and individuals if convicted, allegations of such violations often result in settlements even if the company or individual being investigated admits no wrongdoing. Settlements often include significant civil sanctions, including fines and civil monetary penalties, and corporate integrity agreements. If the government were to allege or determine that we or our executive officers had violated these laws, our business could be harmed. In addition, private individuals have the ability to bring similar actions.

We

Data Privacy and Security

Pharmaceutical companies may also be subject to U.S. federal and state and foreign health information privacy, security and data breach notification laws, which may govern the collection, use, disclosure and protection of health-related and other personal information. In the U.S., HIPAA imposes privacy, security and security regulation by both the federal governmentbreach reporting obligations with respect to individually identifiable

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health information upon “covered entities” (health plans, health care clearinghouses and the states in which we conduct our business. HIPAA, as amended by the Health Information Technology and Clinical Health Act, or HITECH,certain health care providers), and their respective implementing regulations, including the final omnibus rule published on January 25, 2013, imposes specified requirements relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s privacy and security standards directly applicable to “businessbusiness associates,” defined as independent contractors individuals or agents of covered entities that create, receive,received, maintain or transmit protected health information in connection with providing a service for or on behalf of a covered entity. HITECH also increasedHIPAA mandates the civilreporting of certain breaches of health information to HHS, affected individuals and criminal penaltiesif the breach is large enough, the media. Entities that are found to be in violation of HIPAA as the result of a breach of unsecured protected health information, a complaint about privacy practices or an audit by HHS, may be imposed against covered entities,subject to significant civil, criminal and administrative fines and penalties and/or additional reporting and oversight obligations if required to enter into a resolution agreement and corrective action plan with HHS to settle allegations of HIPAA non-compliance. Even when HIPAA does not apply, according to the Federal Trade Commission or the FTC, failing to take appropriate steps to keep consumers’ personal information secure constitutes unfair acts or practices in or affecting commerce in violation of Section 5(a) of the Federal Trade Commission Act. The FTC expects a company’s data security measures to be reasonable and appropriate in light of the sensitivity and volume of consumer information it holds, the size and complexity of its business, associates and possibly other persons,the cost of available tools to improve security and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorney’s fees and costs associated with pursuing federal civil actions. reduce vulnerabilities. Individually identifiable health information is considered sensitive data that merits stronger safeguards.

In addition, certain state and non-U.S. laws, such as the European Union General Data Protection Regulation, or the GDPR, govern the privacy and security of healthpersonal information, including health-related information in certain circumstances, some of which are more stringent than HIPAA and many of which differ from each other in significant ways and may not have the same effect, thus complicating compliance efforts.

Failure to comply with these laws, where applicable, can result in the imposition of significant civil and/or criminal penalties and private litigation. For example, the California Consumer Privacy Act, or CCPA, went into effect January 1, 2020, which, among other things, creates new data privacy obligations for covered companies and provides new privacy rights to California residents, including the right to opt out of certain disclosures of their information. The CCPA also creates a private right of action with statutory damages for certain data breaches, thereby potentially increasing risks associated with a data breach. Although the law includes limited exceptions for health-related information, including for “protected health information” maintained by a covered entity or business associate and clinical trial data, it may regulate or impact our processing of personal information depending on the context. Further, there are federal transparencythe California Privacy Rights Act, or the CPRA, recently passed in California. The CPRA will impose additional data protection obligations on covered companies doing business in California, including additional consumer rights processes, limitations on data uses, new audit requirements for higher risk data, and opt outs for certain uses of sensitive data. It will also create a new California data protection agency authorized to issue substantive regulations and could result in increased privacy and information security enforcement. The majority of the provisions will go into effect on January 1, 2023, and additional compliance investment and potential business process changes may be required. In Europe, the GDPR went into effect in May 2018 and introduces strict requirements for processing the personal data of European Union data subjects. Companies that must comply with the GDPR face increased compliance obligations and risk, including more robust regulatory enforcement of data protection requirements and an increasing numberpotential fines for noncompliance of state laws that require manufacturersup to disclose€20 million or 4% of the annual global revenues of the noncompliant company, whichever is greater. Relatedly, following the United Kingdom’s withdrawal from the EEA and make reports to the governmentEuropean Union, and the expiry of pricing and marketing information as well as any “transfer of value” made or distributed to physicians, teaching hospitals and other healthcare providers. Many of these laws contain ambiguities as to what is requiredthe transition period, companies have to comply with the laws. GivenGDPR and the lack of clarity in laws and their implementation, our future reporting actions could be subjectGDPR as incorporated into United Kingdom national law, the latter regime having the ability to separately fine up to the penalty provisionsgreater of the applicable state and/£17.5 million or federal authorities.

Our activities could be subject to challenge for the reasons discussed above due to the breadth4% of these laws and the increasing attention being given to them by law enforcement authorities. The costs of defending such claims, as well as any sanctions imposed or negative public perceptions resulting therefrom, could require us to restructure our operations and have a material adverse effect on our financial performance.

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Similar rigid restrictions are imposed on the promotion and marketing of medicinal products in the EU and other countries. Laws (including those governing promotion, marketing and anti-kickback provisions), industry regulations and professional codes of conduct often are strictly enforced. Even in those countries where we may not be directly responsible for the promotion and marketing of our drug candidates, if approved, any inappropriate activity by international distribution partners could have adverse implications for us.global turnover.

Other Laws and Regulatory Processes

We are subject to a variety of financial disclosure and securities trading regulations as a public company in the United States with securities traded on the NASDAQ Global Select Market, including laws relating to the oversight activities of the Securities and Exchange Commission, or the SEC, and the rules and regulations of The NASDAQ Stock Market LLC. In addition, the Financial Accounting Standards Board, or FASB, the SEC, and other bodies that have jurisdiction over the form and content of our accounts, our financial statements and other public disclosure are constantly discussing and interpreting proposals and existing pronouncements designed to ensure that companies best display relevant and transparent information relating to their respective businesses.

Our present and future business has been and will continue to be subject to various other laws and regulations. Various laws, regulations and recommendations relating to safe working conditions, laboratory practices, experimental use of animals, and the purchase, storage, movement, import and export, and use and disposal of hazardous or potentially hazardous substances used in connection with our research work are or may be applicable to our activities. Certain agreements entered into by us involving exclusive license rights or acquisitions may be subject to national or supranational antitrust regulatory control, the effect of which cannot be predicted. The extent of government regulation that might result from future legislation or administrative action cannot accurately be predicted.

Research and Development Expenses

Research and development activities, which include personnel costs, research supplies, clinical and pre-clinical study costs, are the primary source of our overall expenses. Such expenses related to the research and development of our product candidates totaled $207.8$97.7 million for the year ended December 31, 2017, $222.82020, $132.9 million for the year ended December 31, 20162019 and $208.5$164.9 million for the year ended December 31, 2015.2018.

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Human Capital

Health, Wellness, and Safety

As of December 31, 2017,2020, our workforce consisted of 267 full-time employees reporting out of our two offices in the United States - Los Angeles, CA and San Francisco, CA - along with a field-based commercial team. We are an equal opportunity employer and believe strongly in hiring a diverse, equitable, and inclusive workforce. This is reflected in our numbers with our total workforce being approximately 58% women, 40% ethnically diverse and 75% over the age of 40. The following table summarizes our workforce by location for the years ended December 31, 2020 and December 31, 2019:

We believe that the safety and health of our employees and their families is essential to our business. Our culture is driven by a desire to do what is right, and we had 318strive to support the well-being of our employees. Beginning in March 2020, we have supported our employees and government efforts to curb the COVID-19 pandemic through a multi-faceted, communication, infrastructure, and behavior modification and enforcement effort that includes:

Our financial, medical, and mental health benefits that were already in place prior to the COVID-19 pandemic were designed to help employees through crisis, and we further expanded our offerings to create appropriate “work from home” conditions for success and wellness, to include:

Compensation & Benefits

We know that developing and keeping great people is a vital part of whom areour competitive edge and essential to providing the best patient care. For this reason, we offer a robust total compensation package in an effort to attract and engage high caliber employees.

Since 2019, we have offered personalized total compensation statements to all full-time employees. In 2017, we hired 125 full-timeThese statements provide a transparent view of each employee’s monetary and non-monetary benefits. Employee’s total compensation represents a broad spectrum of plans and programs designed to reward and motivate employees throughout their careers.

Our total rewards package consists of competitive market-based salary and cash target bonus based on geography for sales, marketingevery employee. Bonus opportunity and other commercial product launch activities related to NERLYNX. We believe our relationsequity compensation increase as a percentage of total compensation based on level of responsibility with our employees are good. Over the course of the next year, we anticipate hiring up to 6 full-time employees devoted to clinical activities, 8 full-time employees for medical affairs, 8 full-time employees for the regulatory and quality assurance function, 4 full-time employees for logistics and distribution, 10 full-time employees for sales, marketing and commercial related activities, and 2 full-time employees for general and administrative activities. actual bonus payout based on performance.

In addition to competitive salaries and performance incentives, we intendoffer employees 100% employer-paid benefits that include medical, dental, vision, life insurance, paid time off and family leave, 401(k) match, fertility benefits, volunteer days and more. Our

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benefit programs are constantly evolving to meet our employees’ needs and renew our commitment to them as a vital resource to our continued success.

Culture and Communication

How we conduct our business is just as important as what we do. Our core values are the principles that guide our company strategy and our individual actions. At all times we strive to distinguish ourselves as a respected biopharmaceutical company that is differentiated by top talent and innovative products to enhance cancer care.

All employees are responsible for upholding our core values, including to be patient-centric, to communicate, collaborate, innovate and be respectful, as well as for adhering to our Code of Ethics. These values nurture an inclusive workforce striving for excellence that puts the well-being of our patients first. We continue to use CROsutilize our Human Resources Information System, or HRIS, platform to track human capital metrics, employee demographics and third partiesturnover. The majority of our employees have obtained advanced degrees in their professions, and we support their continued development with individualized development plans and objectives, mentoring, coaching, training and conference attendance.

Communication is critical in our ability to performcontinuously enhance our clinical studiescompany culture and manufacturing.create a more inclusive environment. The implementation and distribution of quarterly company newsletters have allowed us to share what is important and impactful to us as a business. It also allows for us to share stories and events that have affected our employees and co-workers across the country on both a personal and professional level. We hold town halls with our leaders to speak with employees about our vision and to receive feedback on matters important to them. Additionally, we have dynamic information technology systems, which allow for a more synergistic atmosphere.

Corporate Information and History

Our principal executive offices are located at 10880 Wilshire Boulevard, Suite 2150, Los Angeles, California 90024 and our telephone number is (424) 248-6500. Our internet address is www.pumabiotechnology.com. Our annual, quarterly and current reports, and any amendments to those reports, filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934 may be accessed free of charge through our website after we have electronically filed or furnished such material with the SEC. We also make available free of charge on or through our website our Code of Business Conduct and Ethics, Corporate Governance Guidelines, Audit Committee Charter, Compensation Committee Charter, and Nominating and Corporate Governance Committee Charter and Research and Development Committee Charter. We will disclose on a current report on Form 8-K or on our website information any amendment or waiver of the Code of Business Conduct and Ethics for our executive officers and directors. Any amendment or waiver disclosed on our website will remain available on our website for at least 12 months after the initial disclosure.

The reference to www.pumabiotechnology.com (including any other reference to such address in this Annual Report) is an inactive textual reference only, meaning that the information contained on or accessible from the website is not part of this Annual Report on Form 10-K and is not incorporated in this report by reference.

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We were originally incorporated in the State of Delaware in April 2007 under the name Innovative Acquisitions Corp. We were a “shell” company registered under the Exchange Act with no specific business plan or purpose until we acquired Puma Biotechnology, Inc., a privately-held Delaware corporation formed on September 15, 2010, or Former Puma, in the Merger.October 2011. As a result of this transaction, Former Puma become our wholly-owned subsidiary and subsequently merged with and into us, at which time we adopted Former Puma’s business plan and changed our name to “Puma Biotechnology, Inc.”

The Merger was accounted for as a reverse acquisition whereby Former Puma was deemed to be the acquirer for accounting and financial reporting purposes and we were deemed to be the acquired party. Consequently, our financial statements prior to the Merger reflect the assets and liabilities and the historical operations of Former Puma from its inception on September 15, 2010, through the closing of the Merger on October 4, 2011. Our financial statements after completion of the Merger include the assets and liabilities of us and Former Puma, the historical operations of Former Puma, and the operations of us following the closing date of the Merger.

The merger of a private operating company into a non-operating public shell corporation with nominal net assets is considered to be a capital transaction, in substance, rather than a business combination, for accounting purposes. Accordingly, we treated this transaction as a capital transaction without recording goodwill or adjusting any of our other assets or liabilities.

In November 2012, we established and incorporated Puma Biotechnology Ltd, a wholly owned subsidiary, for the sole purpose of serving as our legal representative in the United Kingdom and the European Union in connection with our clinical trial activity in those countries.

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In addition to the other information contained in this Annual Report, the following risk factors should be considered carefully in evaluating our company. Our business, financial condition, liquidity or results of operations could be materially adversely affected by any of these risks. Our business, financial condition, liquidity orand results of operations could be materially adversely affected by any of these risks. The risks and uncertainties described below are not the only ones we face. Additional risks and uncertainties that we are unaware of, or that we currently believe are not material, may also become important factors that affect us.

Risks Related to our BusinessFinancial Condition and Capital Requirements

We have a limitedhistory of operating historylosses and are not profitable and may never become profitable.

We have a limited operating history, and, until recently, we have focused our efforts and resources primarily on obtaining regulatory approval for NERLYNX (neratinib) and on acquiring and developing our pharmaceutical technologies, raising capital and recruiting personnel.  On July 17, 2017, the FDA approved our first product, NERLYNX, for the extended adjuvant treatment of early stage, HER2-positive breast cancer in the United States, which became commercially available in the United States on July 31, 2017.  We have a history of operating losses, with net losses of $292.0$60.0 million, $75.6 million, and $113.6 million for the fiscal year ended December 31, 2017 and $276.0 million and $239.3 million for the fiscal years ended December 31, 20162020, 2019 and 2015,2018, respectively. As of December 31, 2017,2020, we had an accumulated deficit of approximately $1,088.5$1.3 billion, outstanding indebtedness of approximately $98.3 million and cash and cash equivalents of $85.3 million.

Although we received FDA approvalWe have devoted substantially all of our resources to identifying, acquiring and commenceddeveloping NERLYNX and to its commercialization of NERLYNX in the United States,indications for which it has received regulatory approval. Biopharmaceutical development is a highly speculative undertaking and involves a substantial degree of risk. We anticipate that we expectwill continue to incur substantialoperating losses for the foreseeable future as our efforts to commercialize NERLYNX in existing indications, and develop NERLYNX for additional indications continue.

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 marketing authorization for NERLYNX in the European Union 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. Although we have begun to commercialize NERLYNX in the U.S. and Europe in these indications, we continue to experience net losses and may never become profitable. Moreover, even if we succeed in developing and commercializing one or more of other drug candidates, we may never become profitable.are continuing to develop NERLYNX for additional indications. The successful development and commercialization of any drug candidate will require us to perform a variety of functions, including:

We will likely need to raise additional capital in order to fund our business and generate significant revenue in order to achieve and maintain profitability. We may not be able to generate this revenue raise additional capital or achieve profitability in the future. As a result, we expect our losses to continue for the foreseeable future. Accordingly, we cannot assure you that we will achieve profitability in the future or that, if we do become profitable, we will sustain profitability. Our failure to achieve or maintain profitability could negatively impact the value of our common stock.

Our success depends on our ability to successfully commercialize NERLYNX.  We are currently a single product company with limited commercial sales experience, which makes it difficult to evaluate our current business, predict our future prospects and forecast our financial performance and growth.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 was approved by the FDA for the extended adjuvant treatment of early stage, HER2-positive breast cancer in the United States on July 17, 2017,we currently receive product revenue, and we expect NERLYNX to constitute the vast majority of our product revenue for the foreseeable future. OurBy 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 our ability to effectively commercializethe commercial success of NERLYNX. Successful commercialization of NERLYNX is subject to many risks. We have never,the first product that we, as an organization, have launched orand commercialized, a product, and there is no guarantee that we will be able to do so successfully with NERLYNX.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.

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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 potentialsuccess of NERLYNX will be limited. Thus, significant uncertainty remains regarding the commercial potential of NERLYNX. Moreover,We believe our ability to effectively generateincrease product revenue from NERLYNX will depend on our ability to, among other things:

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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 sufficient quantities, in compliance with requirementsseveral countries outside the United States. The failure of the FDA and similar foreign regulatory agencies, if NERLYNX is approved by such foreign regulatory agencies, and at acceptable quality and pricing levels in orderthese sub-licensees to meet commercial demand;

Any disruption inhinder our ability to generate product revenue from the sale of NERLYNX will have a material and adverse impact onrevenue. These uncertainties, combined with our results of operations.

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

Our strategy is to build our sales, marketing and distribution capabilities to successfully commercialize NERLYNX in the United States. While we are continuing to establish our commercial team and hire our U.S. sales force, we have limited experience commercializing pharmaceutical products as an organization. In order to successfully market NERLYNX, we must continue to build our sales, marketing, managerial, compliance, and related capabilities or make arrangements with third parties to perform these services. If we are unable to establish adequate sales, marketing, and distribution capabilities, whether independently or with third parties, we may not be able to appropriately commercialize NERLYNX and may not become profitable.

Included in our strategy in the United States is a direct sales force to commercialize NERLYNX.  These efforts will continue to be expensive and time-consuming, and we cannot be certain that we will be able to successfully develop this capability.  NERLYNX is a newly-marketed drug and, therefore, none of the members of our sales force has ever promoted NERLYNX prior to its commercial launch. In addition, we must train our sales force to ensure that a consistent and appropriate message about NERLYNX is being delivered to our potential customers. If we are unable to effectively train our sales force and equip them with effective materials, including medical and sales literature to help them inform and educate potential customers about the benefits of NERLYNX and its proper administration, our efforts to successfully commercialize NERLYNX 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 NERLYNX would be limited, and we would not be able to generate product revenue successfully.

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There are risks involved both with establishing our own salesselling and marketing capabilities,NERLYNX, make it difficult to evaluate our current business, predict our future prospects and with entering into arrangements with third parties to perform these services. For example, any efforts to develop a direct sales and marketing organization are subject to numerous risks, including:

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 establish 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.

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. We expectAs we continue to commercialize NERLYNX, our costs and expenses tomay increase in the future as we commercialize NERLYNX, includingdue 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:

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While our consolidated financial statements have been prepared on a going concern basis, we expect to continue incurring 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. The Company entered intoWe are party to a loan agreementcredit facility with Silicon Valley Bank, or SVB, and Oxford Finance LLC, or Oxford, providing for term loans equaling a term loantotal of up to $100 million, subject to funding in two tranches.  The Company received gross proceeds of $50 million from the first tranche of the credit facility upon closing on October 31, 2017 and intends to use the funds for general corporate purposes and to further support NERLYNX commercial initiatives.  The second tranche of $50 million may be drawn at the Company’s option subject to the achievement of certain revenue milestones.  The loan willwhich mature on OctoberJune 1, 2024. As of December 31, 2022.2020, we had $100 million in principal amounts outstanding. 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, unfavorable decisions of regulatory authorities or adverse clinical trial results. The outcome of these matters cannot be predicted at this time.    Additionally, even though we have commenced the commercialization of NERLYNX, 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 NERLYNX would be limited, and we would not be able to generate product revenue successfully. There are risks involved both with establishing our own sales and marketing capabilities and with entering into arrangements with third parties to perform these services. For example, any efforts to develop a direct sales and marketing organization would be subject to numerous risks, including:

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 proposed 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 establish sales, marketing and distribution capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our proposed products.

Our independent registered public accounting firm has expressed substantial doubt about our ability to continue as a going concern.

Our historical consolidated financial statements have been prepared under the assumption that we will continue as a going concern. Our independent registered public accounting firm has issued a report on our audited consolidated financial statements for the year ended December 31, 2017 that included an explanatory paragraph referring to our significant operating losses and expressing substantial doubt in our ability to continue as a going concern. Our ability to continue as a going concern is dependent upon our ability to obtain additional equity financing or other capital, attain further operating efficiencies, reduce expenditures, and, ultimately, to generate revenue. Our consolidated financial statements do not include any adjustments that might result from the outcome of this uncertainty. However, if adequate funds are not available to us when we need it, we will be required to curtail our operations which would, in turn, further raise substantial doubt about our ability to continue as a going concern.  The doubt regarding our potential ability to continue as a going concern may adversely affect our ability to obtain new financing on reasonable terms or at all.  Additionally, if we are unable to continue as a going concern, our stockholders may lose some or all of their investment in the Company.  

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The terms of our credit facility place 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 credit facility or to satisfy the minimum revenue covenants.

The terms of our credit facility place restrictions on our ability to operate our business and our financial flexibility. On October 31, 2017, we entered into a loan and security agreement, which we refer to as the credit facility, with SVB as administrative and collateral agent, and the lenders party thereto from time to time, including SVB and Oxford pursuant to which the lenders agreed to make term loans available to us in an aggregate amount of $100 million, consisting of (i) a Term Loan A in an aggregate amount of $50 million available on the effective date and (ii) a Term Loan B in an aggregate amount of $50 million available to be drawn at our option between March 31, 2018 and June 30, 2018 provided we have achieved a specified minimum revenue milestone and no event of default is occurring.  As of December 31, 2017,2020, we had $50$100 million in principal amounts outstanding under the credit facility.  We cannot assure you that we will achieve the revenue milestone that will trigger our ability to draw the Term Loan B, and accordingly, we may never be able to borrow the additional $50 million provided for in the credit facility. The credit facility is secured by substantially all of our personal property, other than our intellectual property.

The credit facility includes affirmative and negative covenants applicable to us, our current subsidiarysubsidiaries and any subsidiaries we create in the future. The affirmative covenants include, among others, covenants requiring us to maintain our legal existence and governmental approvals, deliver certain financial reports, maintain insurance coverage and satisfy certain requirements regarding deposit accounts. We must also achieve product revenue, measured as of the last day of each fiscal quarter on a trailing 3-month basis, that is (i) greater than or equalyear to 70% of the revenue target set forth in our board-approved projections for the 2017 fiscal year, (ii) greater than or equal to 50% of the revenue target set forth in our board-approved projections for the 2018 fiscal year, and (iii) greater than or equal to 50% of the revenue target set forth in our board-approved projections for the 2019 fiscal year.date basis. New minimum revenue levels will be established for each subsequent fiscal year by mutual agreement of us, SVBOxford, as administrativecollateral agent, and the lenders.lender. The negative covenants include, among others, restrictions on us transferring collateral, incurring additional indebtedness, engaging in mergers or acquisitions, paying dividends or making other distributions, making investments, creating liens, selling assets and suffering a change in control, in each case subject to certain exceptions. These 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 revenue requirements provided for in the credit facility. Our failure to satisfy the revenue, or any other, covenant could result in an event of default under the loan.

The credit facility also includes events of default, the occurrence and continuation of which could cause interest to be charged at the rate that is otherwise applicable plus 5% and would provide SVB,Oxford, as collateral agent, with the right to exercise remedies against us and the collateral securing the credit facility, including foreclosure against the property securing the credit facilities,facility, including our cash. These events of default include, among other things, our failure to pay principal or interest due under the credit facility, a breach of certain covenants under the credit facility, our insolvency, a material adverse change, the occurrence of any default under certain other indebtedness in an amount greater than $500,000 and one or more judgments against us in an amount greater than $500,000 individually or in the aggregate.aggregate that remains unsatisfied, unvacated, or unstayed for a period of 10 days after its entry.

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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 of our strategy is to continue to build our sales, marketing and distribution capabilities to commercialize NERLYNX successfully in the United States. In order to market NERLYNX successfully, we must continue to build our sales, marketing, managerial, compliance, and related capabilities or make arrangements with third parties to perform these services. If we are unable to establish and maintain adequate sales, marketing, and distribution capabilities, whether independently or with third parties, we may not be able to commercialize NERLYNX appropriately and may not become profitable.

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 NERLYNX 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 establish 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 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 2020, two customers individually comprised approximately 33% and 21%, 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.

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Even though the FDA and EC have granted approval of NERLYNX for the extended adjuvant treatment of early stage, HER2-positive breast cancer and the FDA has granted approval for NERLYNX for the treatment of 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 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 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 NERLYNX 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 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 grants is limited to those specific diseases and indications for which a product is deemed to be safe and effective by the FDA. 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, andin 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 approval required for new formulations, any new indication for an approved product also requires FDA 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 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. 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 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 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 regulations or guidelines, we may be subject to warnings from, or enforcement action by, these authorities. In addition, our failure to follow FDA rules and guidelines relating to promotion and advertising may cause the FDA 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.

Health care reform measures may hinder or prevent our products’ and product 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:

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Since its enactment, there have been judicial and Congressional challenges to certain aspects of the ACA. As a result, there have been delays in the implementation of, and action taken to repeal or replace, certain aspects of the ACA. By way of example, the Tax Cuts and Job Act was enacted, which, among other things, removes the penalties for not complying with the ACA’s individual mandate to carry health insurance. On December 14, 2018, a U.S. District Court Judge in the Northern District of Texas, ruled that the individual mandate is a critical and inseverable feature of the ACA, and therefore, because it was repealed as part of the Tax Act, the remaining provisions of the ACA are invalid as well. On December 18, 2019, the U.S. Court of Appeals for the Fifth Circuit ruled that the individual mandate was unconstitutional and remanded the case back to the District Court to determine whether the remaining provisions of the ACA are invalid as well. The U.S. Supreme Court is currently reviewing the case, although it remains unclear when or how the Supreme Court will rule. It is also unclear how other efforts to challenge, repeal or replace the ACA will impact the ACA or our business. We cannot predict the ultimate content, timing or effect of any healthcare reform legislation or the impact of potential legislation on us.

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 aggregate reductions to Medicare payments to 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, with the exception of a temporary suspension from May 1, 2020 through March 31, 2021, 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 over the manner in which drug manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed bills designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. For example, the 21st Century Cures Act changes the reimbursement methodology for infusion drugs and biologics furnished through durable medical equipment in an attempt to remedy over- and underpayment of certain drugs. We cannot predict all of the ways in which future federal or state legislative or administrative changes relating to healthcare reform will affect our business.

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

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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 international markets, reimbursement and healthcare payment systems vary significantly by country, and many countries have instituted price ceilings on specific products and therapies.

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. 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 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 and state healthcare 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 and state 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:

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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 requirements, including those laws that require the reporting of true, complete and accurate information to the FDA, 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.

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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, as administered by CMS, 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. In some cases, such as with the Medicaid Drug Rebate Program, the rebates are based on pricing and rebate calculations that we report on a monthly and quarterly basis to the government agencies that administer the programs. Pricing and rebate calculations are complex, vary among products and programs, and are often subject to interpretation by governmental or regulatory agencies and the courts. The terms, scope and complexity of these government pricing programs change frequently. Responding to current and future changes may increase our costs and the complexity of compliance will be time consuming.

In addition, there is increased focus by the Office of Inspector General on the methodologies used by manufacturers to calculate average manufacturer price, or AMP, and best price, or BP, to assess manufacturer compliance with reporting requirements under the Medicaid Drug Rebate Program. We are liable for errors associated with our submission of pricing data and for any overcharging of government payors. For example, failure to submit monthly/quarterly AMP and BP data on a timely basis could result in a civil monetary penalty per day for each day the submission is late beyond the due date. 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.

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. In the event that CMS were to terminate our rebate agreement, no federal payments would be available under Medicaid or Medicare for our covered outpatient drugs.

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.

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 after this offering.

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.

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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:

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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.

Even though the FDA has granted approval of NERLYNX for the extended adjuvant treatment of early stage, HER2-positive breast cancer, the terms of the approval may limit its commercial potential.

Even though the FDA has granted approval of NERLYNX, the scope and terms of the approval may limit our ability to commercialize NERLYNX and, therefore, our ability to generate substantial sales revenue. The FDA has approved NERLYNX only for the extended adjuvant treatment of early stage, HER2-positive breast cancer. In connection with the FDA approval, we have committed to conduct the following post-marketing studies: (i) a physiologically-based pharmacokinetic, or PBPK, modeling/simulation study to evaluate the effect of repeat doses of a moderate CYP3A4 inhibitor on the single dose pharmacokinetics of neratinib and its active metabolites to assess the magnitude of increased drug exposure and to address the potential for excessive drug toxicity, or if the PBPK modeling/simulation is not feasible, a clinical pharmacokinetic trial, (ii) a PBPK modeling/simulation study or a clinical pharmacokinetic trial with repeat doses of a moderate CYP3A4 inducer on the single dose pharmacokinetics of neratinib and its active metabolites to assess the magnitude of decreased drug exposure and to determine appropriate dosing recommendations, (iii) a clinical pharmacokinetic trial to evaluate whether separating the dosing of H2-receptor antagonists and neratinib can minimize the drug-drug interaction potential, (iv) the submission of the final results of our 2-year carcinogenicity study in the rat, and (v) submission of certain trial data from our ongoing clinical trials. If we fail to comply with 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 could decide to withdraw approval, add warnings or narrow the approved indication in the product label.

We are heavily dependent on the success of NERLYNX, which is still under clinical development for various additional indications. While the FDA has approved NERLYNX for the extended adjuvant treatment of patients with early stage HER2-positive breast cancer,indications, and we cannot be certain that NERLYNX will receive regulatory approval for any other indication for which we may seek approval.

The FDA hasand the EC have both approved NERLYNX only 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 adult patients following adjuvant trastuzumab-based therapy.  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.  In June 2016, we submitted an MAA with the EMA. In August 2017, the Committee for Medicinal Products for Human Use of the EMA, or CHMP, issued its Day-180 List of Outstanding Issues in the process of their ongoing regulatory review of the MAA, requesting additional data analyses related to the safety and efficacy of neratinib and instituting a clock stop in order to allow the Company time to respond to this List of Outstanding Issues. The Company responded to the list in December 2017. The CHMP recently recommended refusal of our MAA for neratinib for the extended adjuvant treatment of early stage HER2-positive breast cancer but allowed us to request a re-examination which we intend to do.

Approval of NERLYNX by the FDA or the EC for the extended adjuvant treatment of early stage, HER2-positive breast cancer in adult patients following adjuvant trastuzumab-based therapyany particular indication does not ensure that a foreign jurisdiction will also approve NERLYNX for thatsuch indication, nor does it ensure that NERLYNX will be approved by the FDA 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:

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If we do not obtain regulatory approval of NERLYNX for other indications, whether in the United States or for any indication in foreignother jurisdictions, we will not be able to market NERLYNX for othersuch indications or in otherthose jurisdictions, which will limit our commercial revenue.

WeEven though the FDA has approved NERLYNX for the extended adjuvant treatment of early stage, HER2-positive breast cancer in adult patients following adjuvant trastuzumab-based therapy, and in combination with capecitabine, for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have no experiencereceived two or more prior anti-HER2 based regimens in the metastatic setting, we will be subject to ongoing obligations and continued regulatory review with regard to NERLYNX and any other drug formulation or manufacturing and plan to rely exclusively on third parties to formulate and manufacturecandidates that receive FDA approval, which may result in significant additional expense. Additionally, NERLYNX and our 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 disruption or loss of these relationships could delay our development and commercialization efforts.

We have no experience in drug formulation or manufacturing and do not intend to establish our own manufacturing facilities. We lack the resources and expertise to formulate or manufacture NERLYNX and our drug candidates. While our drug candidates were being developed by Pfizer, both the drug substance and drug product were manufactured by third-party contractors. We are using the same third-party contractors to manufacture, supply, store and distribute drug supplies for our clinical trials and the commercialization of NERLYNX. Ifregulatory approvals that we are unable to continue our relationships with one or more of these third-party contractors, we could experience delays in our development or commercialization efforts as we locate and qualify new manufacturers. We intend to rely on one or more third-party contractors to manufacture the commercial supply of our drugs.  Our anticipated future reliance on a limited number of third-party manufacturers exposes us to the following risks:

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Eachextensive and ongoing regulatory requirements. These requirements include submissions of these risks could delay oursafety and other post-marketing information and reports, registration, as well as continued compliance with cGMPs 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 policies may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval if any, of our drug candidatescandidates. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained, which would adversely affect our business, prospects and ability to achieve or sustain profitability.

We also cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative or executive action, either in the United States or abroad. For example, the results of the 2020 Presidential Election may impact our business and industry. Namely, the Trump administration has taken several executive actions, including the issuance of a number of Executive Orders, that could impose significant burdens on, or otherwise materially delay, FDA’s ability to engage in routine regulatory and oversight activities such as implementing statutes through rulemaking, issuance of guidance, and review and approval of marketing applications. It is difficult to predict whether or how these Executive Orders will be implemented, or whether

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Separately, in response to the COVID-19 pandemic, on March 10, 2020 the FDA announced its intention to postpone most inspections of foreign manufacturing facilities,and on March 18, 2020, the FDA temporarily postponed routine surveillance inspections of domestic manufacturing facilities. Subsequently, on July 10, 2020 the FDA announced its intention to resume certain pre-announced, on-site inspections of domestic manufacturing facilities subject to a risk-based prioritization system. The FDA intends to use this risk-based assessment system to identify the categories of regulatory activity that can occur within a given geographic area, ranging frommission critical inspections to resumption of all regulatory activities. Regulatory authorities outside the United States may adopt similar restrictions or other policy measures in response to the COVID-19 pandemic. If a prolonged government shutdown occurs, or if global health concerns continue to prevent the FDA or other regulatory authorities from conducting their regular inspections, reviews, or other regulatory activities, it could significantly impact the commercializationability of NERLYNX or our other drug candidates, or result in higher costs or deprive us of potential product revenue.

If our third-party manufacturers fail to manufacture NERLYNX in sufficient quantities and at acceptable quality and pricing levels, or fail to fully comply with cGMP regulations, we may face delays in commercialization or be unable to meet market demand, and may lose potential revenues.

The manufacture of NERLYNX requires significant expertise and capital investment, including the development of advanced manufacturing techniques, process controls and the use of specialized processing equipment. Our third-party manufacturers must comply with federal, state and foreign regulations, including the FDA’s regulations governing cGMP, enforced by the FDA through its facilities inspection program and by similaror other regulatory authorities in other jurisdictions where we do business. These requirements include, among other things, quality control, quality assuranceto timely review and the maintenance of records and documentation. The FDA or similar foreignprocess our regulatory authorities at any time may implement new standards, or change their interpretation and enforcement of existing standards for manufacture, packaging or testing of our products. Any failure by us or our third-party manufacturers to comply with applicable regulations may result in fines and civil penalties, suspension of production, product seizure or recall, operating restrictions, imposition ofsubmissions, which could have a consent decree, modification or withdrawal of product approval or criminal prosecution and would limit the availability of our product. Any manufacturing defect or error discovered after products have been produced and distributed also could result in significant consequences, including costly recall procedures, re-stocking costs, damage to our reputation and potential for product liability claims.

If our third-party manufacturers are unable to produce the required commercial quantities of NERLYNX to meet market demand for NERLYNXmaterial adverse effect on a timely basis or at all, or if they fail to comply with applicable laws for the manufacturing of NERLYNX, we will suffer damage to our reputation and commercial prospects and we will lose potential revenue.

We are substantially dependent on international third-party licensees for the development and commercialization of NERLYNX in several countries outside the United States. The failure of these licensees to meet their contractual, regulatory, and other obligations could adversely affect our business.

We have entered into exclusive license agreements with several third parties that provide these licensees exclusive rights to the development and commercialization of NERLYNX in South East Asia, Israel and greater China.  As a result, we are entirely dependent on these parties to achieve regulatory approval of NERLYNX for marketing in these countries and for the commercialization of NERLYNX, if approved.  The timing and amount of any milestone and royalty payments we may receive under these agreements, as well as the commercial success of NERLYNX, will depend on, among other things, the efforts, allocation of resources and successful commercialization of NERLYNX by the licensees.  We also depend on these third parties to comply with all applicable laws relative the development and commercialization of our products in those countries.  We do not control the individual efforts of these licensees and have limited ability to terminate these agreements if the licensees do not perform as anticipated. The failure of these licensees to devote sufficient time and effort to the development and commercialization of NERLYNX, or the failure of these licensees to meet their obligations to us, including for future royalty and milestone payments; to adequately deploy business continuity plans in the event of a crisis; and/or satisfactorily resolve significant disagreements with us or address other factors, could have an adverse impact on our financial results and operations. In addition, if these third parties violate, or are alleged to have violated, any laws or regulations during the performance of their obligations for us, it is possible that we could suffer financial and reputational harm or other negative outcomes, including possible legal consequences.

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

Although NERLYNX has been approved by the FDA approved NERLYNX for the extended adjuvant treatment of early stage, HER2-positive breast cancer, and 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 United States on July 17, 2017,metastatic setting, NERLYNX is still under development for various indications in the United States, and our other drug candidates are in development, as well, all of which will require extensive clinical testing before we can submit any NDA for regulatory approval. We cannot predict with any certainty that any NDA submitted by usor supplemental NDA seeking to expand the indication for NERLYNX will be approved by the FDA. 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.

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The commencement and completion ofWe do not know whether our future clinical trials maywill 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:

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