PUMA BIOTECHNOLOGY, INC.

Note1—Business and Basis of Presentation:

Business and Liquidity:

Puma Biotechnology, Inc., (the “Company”) is a biopharmaceutical company based in Los Angeles, California that develops and commercializes innovative products to enhance cancer care and improve treatment outcomes for patients. The Company is currently commercializing NERLYNX®, an oral version of neratinib (“NERLYNX”), for the treatment ofHER2-positive breast cancer. Additionally, the Company in-licensed, and is responsible for the global development and commercialization of, alisertib. Alisertib is a selective, small molecule inhibitor of Aurora Kinase A that is designed to disrupt mitosis leading to apoptosis of rapidly proliferating tumor cells dependent on Aurora Kinase. The Company believes alisertib has potential application in the treatment of a range of different cancer types, including hormone receptor-positive breast cancer, triple-negative breast cancer, and small cell lung cancer.

The Company hasone subsidiary, Puma Biotechnology, B.V., a Netherlands company. This subsidiary was established for the purpose of legal representation in the European Union (“EU”). The consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated.

The accompanying consolidated financial statements of the Company and its subsidiary have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”).

The Company has incurred significant operating losses since its inception. While the Company has reported net income, the Company cannot ensure that it will continue to do so and will need to continue to generate significant revenue to sustain operations and successfully commercialize neratinib. In2017, the Company received U.S. Food and Drug Administration (“FDA”) approval for itsfirst product, NERLYNX® (neratinib), formerly known asPB272 (neratinib, oral), for the extended adjuvant treatment of adult patients with early stageHER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy. Following FDA approval in* July 2017,*NERLYNX became available by prescription in the United States, and the Company commenced commercialization.

In* February 2020,NERLYNX was also approved by the FDA in combination with capecitabine for the treatment of adult patients with advanced or metastaticHER2*-positive breast cancer who have receivedtwo or more prior anti-HER2-based regimens in the metastatic setting.

In2018, the European Commission (“EC”) granted marketing authorization for NERLYNX in the EU for the extended adjuvant treatment of adult patients with early stage hormone receptor-positiveHER2-overexpressed/amplified breast cancer and who are less thanone year from the completion of prior adjuvant trastuzumab-based therapy.

The Company is required to make substantial payments to Pfizer upon the achievement of certain milestones and has contractual obligations for clinical trial contracts.

The Company has entered into other exclusive sub-license agreements with various parties to pursue regulatory approval, if necessary, and commercialize NERLYNX, if approved, in many regions outside the United States, including Europe (excluding Ukraine), Australia, Canada, China, Southeast Asia, Israel, South Korea, Russia and various countries and territories in Central America, South America, Africa, and the Middle East. The Company plans to continue to pursue commercialization of NERLYNX in other countries outside the United States, if approved.

7

In* September 2022,the Company entered into an exclusive license agreement with a subsidiary of Takeda Pharmaceutical Company Limited (“Takeda”) to license the worldwide research and development and commercial rights to alisertib, a selective, small-molecule, orally administered inhibitor of Aurora Kinase A. Alisertib is an adenosine triphosphate–competitive and reversible inhibitor of Aurora Kinase A and results in disruption of mitosis, leading to apoptosis of rapidly proliferating tumor cells that are dependent on Aurora Kinase A. Alisertib has been tested in clinical trials in patients with metastatic cancers, including breast cancer, small cell lung cancer, head and neck cancer, ovarian cancer, peripheral T-cell lymphoma and acute myeloid leukemia. Under the terms of the exclusive license agreement, the Company assumed sole responsibility for the global development and commercialization of alisertib. The Company paid Takeda an upfront license fee of $7.0 million in October 2022,and Takeda is eligible to receive potential future milestone payments of up to $287.3 million upon the Company’s achievement of certain regulatory and commercial milestones over the course of the exclusive license agreement, as well as tiered royalty payments for any net sales of alisertib. As of September 30, 2026*,no milestones had been accrued as the underlying contingencies werenot probable.

The Company has reported net income of approximately $10.4 million and cash provided by operations of approximately $31.6 million for thenine months ended* September 30, 2026*. The Company’s commercialization, research and development or marketing efforts* mayrequire funding in addition to the cash and cash equivalents and marketable securities totaling approximately $108.6 million at September 30, 2026*.

The Company believes that its existing cash and cash equivalents and marketable securities as of* September 30, 2026* and proceeds that are expected to become available to the Company through product sales and sub-license payments are sufficient to satisfy its operating cash needs for at leastone year after the filing of the Quarterly Report on Form10-Q in which these financial statements are included. The Company continues to remain dependent, in part, on its ability to obtain sufficient funding to sustain operations and continue to successfully commercialize neratinib in the United States. On* May 4, 2026,* the Company paid $11.5 million to Athyrium Opportunities IV Co-Invest1 LP ("Athyrium"), consisting of principal, interest and exit fees due under the2021 Note Purchase Agreement. This payment was made ahead of the maturity date of* July 23, 2026,reduced the principal balance outstanding under the Athyrium Notes tozero and terminated all remaining obligations of the Company under the2021* Note Purchase Agreement, other than customary continuing indemnification obligations. While the Company has been successful in raising capital in the past, there can beno assurance that it will be able to do so in the future. The Company’s ability to obtain funding* may*be adversely impacted by uncertain market and economic conditions, including the Company’s success in commercializing neratinib and unfavorable decisions of regulatory authorities or adverse clinical trial results. The outcome of these matters cannot be predicted at this time.

Since its inception through* September 30, 2026*, the Company’s financing has consisted primarily of proceeds from product, royalty and license revenue, public offerings of its common stock, private equity placements, and various debt instruments.

In the opinion of management, the included disclosures are adequate, and the accompanying unaudited condensed consolidated financial statements contain all adjustments necessary for a fair statement of its consolidated financial position as of* September 30, 2026*. Such adjustments are of a normal and recurring nature. The condensed consolidated balance sheet as of* December 31, 2025* was derived from audited annual financial statements but doesnot contain all of the footnote disclosures from the audited annual financial statements. The condensed consolidated results of operations for the quarter ended* September 30, 2026* arenot necessarily indicative of the consolidated results of operations that* maybe expected for the fiscal year ending December 31, 2026*.

The Company doesnot believe that tariffs imposed or proposed to be imposed by the United States, particularly with the EU and China, will have a material impact on its product costs or results of operations. However, shifts in trade policies in the United States and other countries have been rapidly evolving and are difficult to predict. The ultimate impact of any announced or future tariffs will depend on various factors, including what tariffs are ultimately implemented, the timing of implementation and the amount, scope and nature of such tariffs and potential exclusions from the application of those tariffs.

Note2—Significant Accounting Policies:

The significant accounting policies followed in the preparation of these unaudited consolidated financial statements are as follows:

Principles of Consolidation:

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation.

8

Segment Reporting:

Management has determined that the Company operates inone reporting segment, which is the development and commercialization of innovative products to enhance cancer care. The Company derives its global product, license, and royalty revenue through the sales of NERLYNX®. The majority of the Company's royalty revenue is derived from its sub-licensee sales into China. The accounting policies of this operating segment are the same as those described below in Note2—Significant Accounting Policies.

The Company's Chief Operating Decision Maker (“CODM”) is its President, Chief Executive Officer and Chairman of the Board, Alan H. Auerbach. The CODM primarily uses the Company's Consolidated Statement of Operations and related revenues, expenses, and net income in evaluating the performance of the single operating segment and determining how to allocate resources of the Company as a whole, including its sales force and related marketing, research and development programs, including alisertib, and licensing strategy. Consolidated revenue, expenses and net income are also used to monitor budget versus actual results.

In addition to the significant expense categories included within consolidated net income presented on the Company's Condensed Consolidated Statements of Operations, see below for disaggregated amounts that comprise operating expenses:

(1) Other research and development expense includes regulatory affairs, pharmacovigilance, quality assurance, chemical manufacturing, and other costs.

Use of Estimates:

The preparation of consolidated financial statements in conformity with Generally Accepted Accounting Principles (“GAAP”) in the United States requires management to make estimates and assumptions that affect reported amounts of assets and liabilities, and disclosure of contingent assets and liabilities at the date of the balance sheet, and reported amounts of revenues and expenses for the period presented. Accordingly, actual results could differ from those estimates.

Significant estimates include estimates for variable consideration for which reserves were established. These estimates are included in the calculation of net revenues and include trade discounts and allowances, product returns, provider chargebacks and discounts, government rebates, payor rebates, and other incentives, such as voluntary patient assistance, and other allowances that are offered within contracts between the Company and its customers, payors, and other indirect customers relating to the Company’s sale of its products. Other significant estimates include those related to the valuation of deferred income taxes, legal and other expense accruals.

Net Income per Share of Common Stock:

Basic net income per share of common stock is computed by dividing net income available to common stockholders by the weighted-average number of shares of common stock outstanding during the periods presented, as required by Accounting Standards Codification (“ASC”)260, Earnings per Share. For purposes of calculating diluted net income per share of common stock, the denominator includes both the weighted-average number of shares of common stock outstanding and the number of dilutive common stock equivalents, such as stock options, restricted stock units (“RSUs”), and warrants. A common stock equivalent isnot included in the denominator when calculating diluted earnings per common share if the effect of such common stock equivalent would be anti-dilutive.

9

The Company's potentially dilutive securities include potential common shares related to its stock options and RSUs granted in connection with the Puma Biotechnology, Inc.2011 Incentive Award Plan (“2011 Plan”) and the Puma Biotechnology, Inc.2017 Employment Inducement Incentive Award Plan (“2017 Plan”). Diluted earnings per share (“Diluted EPS”) considers the impact of potentially dilutive securities except in periods in which there is a loss because the inclusion of the potential common shares would have an anti-dilutive effect. Diluted EPS excludes the impact of potential common shares related to the Company's stock options in periods in which the option exercise price is greater than the average market price of its common stock for the period. The following potentially dilutive outstanding common stock equivalents for the respective periods were excluded from diluted net income per share because of their anti-dilutive effect:

The 2,116,250 shares underlying the warrant wouldnot have an impact on the Company's diluted net income per share until the average market price of its common stock exceeded the exercise price of $16 per share. The warrant expired on October4, 2026. (see Note10—Stockholders’ Equity).

A reconciliation of the numerators and denominators of the basic and diluted net income per share of common stock computations is as follows (in thousands, except share and per share amounts):

Revenue Recognition:

Under ASC Topic606, Revenue from Contracts with Customers(“ASC606”), the Company recognizes revenue when its customer obtains control of the promised goods or services in an amount that reflects the consideration that the entity expects to be entitled to in exchange for those goods or services. The Company hadno contracts with customers until the FDA approved NERLYNX on* July 17, 2017.*Subsequent to receiving FDA approval, the Company entered into a limited number of arrangements with specialty pharmacies and specialty distributors in the United States to distribute NERLYNX. These arrangements are the Company’s initial contracts with customers. The Company has determined that these sales channels with customers are similar.

Product Revenue, Net:

The Company sells NERLYNX to a limited number of specialty pharmacies and specialty distributors in the United States. These customers subsequently resell the Company’s products to patients and certain medical centers or hospitals. In addition to distribution agreements with these customers, the Company enters into arrangements with healthcare providers and payors that provide for government mandated and/or privately negotiated rebates, chargebacks, and discounts with respect to the purchase of the Company’s products.

10

The Company recognizes revenue from product sales when the specialty pharmacy or specialty distributor, as applicable, obtains control of the Company’s product, which occurs at a point in time. Revenue from product sales is recognized at the amount of transaction price the Company expects to be entitled to in exchange for transferring those products, which is net of estimates for variable consideration, including discounts and allowances. The Company’s payment terms range between 10 and68 days.

Product revenue also consists of product sales under sub-license agreements to the Company's sub-licensees, who then sell into their respective international territories.

Shipping and handling costs for product shipments occur prior to the customer obtaining control of the goods and are recorded in cost of sales.

If taxes relating to product sales should be collected from customers and remitted to governmental authorities, they will be excluded from revenue. The Company expenses incremental costs of obtaining a contract when incurred if the expected amortization period of the asset that the Company would have recognized isone year or less. However,no such costs were incurred during thenine months ended* September 30, 2026and2025*.

Reserves for Variable Consideration:

Revenue from product sales is recorded at the net sales price (transaction price), which includes estimates of variable consideration for which reserves are established. Components of variable consideration include trade discounts and allowances, product returns, provider chargebacks and discounts, government rebates, payor rebates, and other incentives, such as voluntary patient assistance, and other allowances that are offered within contracts between the Company and its customers, payors, and other indirect customers relating to the Company’s sale of its products. These reserves, as detailed below, are based on the related sales, and are classified as reductions of accounts receivable, net when the right of offset exists or as a current liability. These estimates take into consideration a range of possible outcomes that are probability-weighted in accordance with the expected value method in ASC606 for relevant factors such as current contractual and statutory requirements, specific known market events and trends, industry data, and forecasted customer buying and payment patterns. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the respective underlying contracts.

The amount of variable consideration that is included in the transaction price* maybe constrained and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized under the contract willnot* occur in a future period. The Company’s analyses also contemplated application of the constraint in accordance with the guidance, under which it determined a significant reversal of revenue wouldnot likely occur in a future period for the estimates detailed below as of* September 30, 2026*, and, therefore, the transaction price wasnot reduced further during the quarter ended* September 30, 2026*. Actual amounts of consideration ultimately received* may*differ from the Company’s estimates. If actual results in the future vary from the Company’s estimates, the Company will adjust these estimates, which would affect net product revenue and earnings in the period such variances become known.

Trade Discounts and Allowances:

The Company generally provides customers with discounts, which include incentive fees that are explicitly stated in the Company’s contracts and are recorded as a reduction of revenue in the period the related product revenue is recognized. The reserve for discounts is established in the same period that the related revenue is recognized, together with reductions to accounts receivable, net on the consolidated balance sheets. In addition, the Company compensates its customers for sales order management, data, and distribution services. The Company has determined such services received to date arenot distinct from the Company’s sale of products to its customers and, therefore, these payments have been recorded as a reduction of revenue within the condensed consolidated statements of operations.

Product Returns:

Consistent with industry practice, the Company offers the specialty pharmacies and specialty distributors that are its customers limited product return rights for damaged and expiring product, provided it is within a specified period around the product expiration date as set forth in the applicable individual distribution agreement. The Company estimates the amount of its product sales that* may*be returned by its customers and records this estimate as a reduction of revenue in the period the related product revenue is recognized, as well as a reduction to accounts receivable, net on the consolidated balance sheets. The Company currently estimates product returns using its own sales information, including its visibility into the inventory remaining in the distribution channel. The Company has had an insignificant number of returns to date and believes that returns of its products will continue to be minimal.

11

Provider Chargebacks and Discounts:

Chargebacks for fees and discounts to providers represent the estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices charged to its customers who directly purchase the product from the Company. Customers charge the Company for the difference between what they pay for the product and the ultimate selling price to the qualified healthcare providers. The reserve for chargebacks is established in the same period that the related revenue is recognized, resulting in a reduction of product revenue and a reduction to accounts receivable, net on the consolidated balance sheets. Chargeback amounts are generally determined at the time of resale to the qualified healthcare provider by customers, and the Company generally issues credits for such amounts within a few weeks of the customer’s notification to the Company of the resale. Chargebacks consist of credits the Company expects to issue for units that remain in the distribution channel at each reporting period end that the Company expects will be sold to qualified healthcare providers and chargebacks that customers have claimed, but for which the Company hasnot yet issued a payment.

Government Rebates:

The Company is subject to discount obligations under state Medicaid programs and Medicare. These reserves are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue, net, and the establishment of a current liability, which is included in accrued expenses on the condensed consolidated balance sheets. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that havenot been paid or for which an invoice hasnot yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period.

Payor Rebates:

The Company contracts with certain private payor organizations, primarily insurance companies and pharmacy benefit managers, for the payment of rebates with respect to utilization of its products. The Company estimates these rebates and records such estimates in the same period the related revenue is recognized, resulting in a reduction of product revenue, net, and the establishment of a current liability, which is included in accrued expenses on the consolidated balance sheets.

Other Incentives:

Other incentives the Company offers include voluntary patient assistance programs, such as the co-pay assistance program, which are intended to provide financial assistance to qualified commercially insured patients with prescription drug co-payments required by payors. The calculation of the accrual for co-pay assistance is based on an estimate of claims and the cost per claim that the Company expects to receive associated with product that has been recognized as revenue but remains in the distribution channel at the end of each reporting period. The adjustments are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue and the establishment of a current liability, which is included as a component of accrued expenses on the consolidated balance sheets.

License Revenue:

The Company also recognizes license revenue under certain of the Company’s sub-license agreements that are within the scope of ASC606. The terms of these agreements* maycontain multiple performance obligations, which mayinclude licenses and research and development activities. The Company evaluates these agreements under ASC606* to determine the distinct performance obligations. Non-refundable, upfront fees that arenot contingent on any future performance and requireno consequential continuing involvement by the Company, are recognized as revenue when the license term commences and the licensed data, technology or product is delivered. The Company defers recognition of non-refundable upfront license fees if the performance obligations arenot satisfied. The Company’s payment terms range between the execution date of the sub-license agreement and45 days.

Prior to recognizing revenue, the Company makes estimates of the transaction price, including variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized willnot occur and when the uncertainty associated with the variable consideration is subsequently resolved.

If there are multiple distinct performance obligations, the Company allocates the transaction price to each distinct performance obligation based on its relative standalone selling price. The standalone selling price is generally determined based on the prices charged to customers or using expected cost-plus margin. Revenue is recognized by measuring the progress toward complete satisfaction of the performance obligations using an input measure.

12

Since2018, the Company has entered into sub-license agreements with certain sub-licensees in territories outside of the United States. These sub-licensing agreements grant certain intellectual property rights and set forth various obligations with respect to actions such as development, pursuit and maintenance of regulatory approvals, commercialization and supply of NERLYNX in the sub-licensees’ respective territories.

License fees under the sub-license agreements includeone-time upfront payments when each sub-license agreement was executed and potential additionalone-time milestone payments due to the Company upon successful completion of certain performance obligations, such as achieving regulatory approvals or sales target thresholds, and potential double-digit royalties on sales of the licensed product, calculated as a percentage of net sales of the licensed product throughout each sub-licensee’s respective territory.

As of* September 30, 2026*, the total potential milestone payments that would be due to the Company upon achievement of all respective performance obligations under the sub-license agreements are approximately $579.8 million. At this time, the Company cannot estimate if or when these milestone-related performance obligations might be achieved.

Royalty Revenue:

For sub-license agreements that are within the scope of ASC606, the Company recognizes revenue when the related sales occur in accordance with the sales-based royalty exception under ASC606-10-55-65.

Royalty revenue consists of consideration earned related to international sales of NERLYNX made by the Company’s sub-licensees in their respective territories. The Company recognizes royalty revenue when the performance obligations have been satisfied. The Company’s payment terms range between10 and60 days.

Royalty Expenses:

Royalties incurred in connection with the Company’s license agreement with Pfizer, as disclosed in Note12—Commitments and Contingencies, are expensed to cost of sales as revenue from product sales is recognized.

Legal Contingencies and Expense:

For legal contingencies, the Company accrues a liability for an estimated loss if the potential loss from any claim or legal proceeding is considered probable and the amount can be reasonably estimated. Legal fees and expenses are expensed as incurred based on invoices or estimates provided by legal counsel. The Company periodically evaluates available information, both internal and external, relative to such contingencies and adjusts the accrual, as necessary. The Company determines whether a contingency should be disclosed by assessing whether a material loss is deemed reasonably possible. In determining whether a loss should be accrued, the Company evaluates, among other factors, the degree of probability of an unfavorable outcome and the ability to make a reasonable estimate of the amount of the loss (see Note12—Commitments and Contingencies).

Research and Development Expenses:

Research and development expenses are charged to operations as incurred. The major components of research and development costs include clinical manufacturing costs, clinical trial expenses, consulting and otherthird-party costs, salaries and employee benefits, stock-based compensation expense, supplies and materials, and allocations of various overhead costs. Clinical trial expenses include, but arenot limited to, investigator fees, site costs, comparator drug costs, and CRO costs. In the normal course of business, the Company contracts withthird parties to perform various clinical trial activities in the ongoing development of potential products. The financial terms of these agreements are subject to negotiation and variations from contract to contract and* may*result in uneven payment flows. Payments under the contracts depend on factors such as the achievement of certain events, the successful enrollment of patients and the completion of portions of the clinical trial or similar conditions. The Company’s accruals for clinical trials are based on estimates of the services received and efforts expended pursuant to contracts with numerous clinical trial sites, cooperative groups and CROs. As actual costs become known, the Company adjusts its accruals in that period.

13

In instances where the Company enters into agreements withthird parties for clinical trials and other consulting activities, upfront amounts are recorded to prepaid expenses and other in the accompanying consolidated balance sheets and expensed as services are performed or as the underlying goods are delivered. If the Company doesnot expect the services to be rendered or goods to be delivered, any remaining capitalized amounts for non-refundable upfront payments are charged to expense immediately. Amounts due under such arrangements* maybe either fixed fee or fee for service, and may*include upfront payments, monthly payments, and payments upon the completion of milestones or receipt of deliverables.

Costs related to the acquisition of technology rights and patents for which development work is still in process are charged to operations as incurred and considered a component of research and development costs.

Stock-Based Compensation:

Stock Option Awards:

ASC Topic718, Compensation—Stock Compensation (“ASC718”) requires the fair value of all share-based payments to employees and non-employees, including grants of stock options, to be recognized in the statement of operations over the requisite service period. Under ASC718, employee and non-employee option grants are generally valued at the grant date and those valuations donot change once they have been established. The fair value of each option award is estimated on the grant date using the Black-Scholes Option Pricing Method. The Company’s estimate of expected volatility is based on its average volatility using its expected life, or approximately the lastsix years of publicly traded history. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant valuation. Option forfeitures are estimated when the option is granted to reduce the option expense to be recognized over the life of the award. The estimated forfeiture rate considers historical employee turnover rates stratified into employee pools, actual forfeiture experience and other factors. The option expense is adjusted upon the actual forfeiture of a stock option grant, and the Company periodically revises the estimated forfeiture rate in subsequent periods if actual forfeitures differ from those estimates. Due to its limited history of stock option exercises, the Company uses the simplified method to determine the expected life of the option grants. Compensation expense related to modified stock options is measured based on the fair value for the awards as of the modification date. Any incremental compensation expense arising from the excess of the fair value of the awards on the modification date compared to the fair value of the awards immediately before the modification date is recognized at the modification date or ratably over the requisite service period, as appropriate.

Restricted Stock Units:

RSUs are valued on the grant date and the fair value of the RSUs is equal to the market price of the Company’s common stock on the grant date. The RSU expense is recognized over the requisite service period. When the requisite service period begins prior to the grant date (because the service inception date occurs prior to the grant date), the Company is required to begin recognizing compensation cost before there is a measurement date (i.e., the grant date). The service inception date is the beginning of the requisite service period. If the service inception date precedes the grant date, accrual of compensation cost for periods before the grant date shall be based on the fair value of the award at the reporting date. In the period in which the grant date occurs, cumulative compensation cost shall be adjusted to reflect the cumulative effect of measuring compensation cost based on fair value at the grant date rather than the fair value previously used at the service inception date (or any subsequent reporting date). RSU forfeitures are estimated when the RSU is granted to reduce the RSU expense to be recognized over the life of the award. The estimated forfeiture rate considers historical employee turnover rates stratified into employee pools, actual forfeiture experience, and other factors. The RSU expense is adjusted upon the actual forfeiture of an RSU grant and the Company periodically revises the estimated forfeiture rate in subsequent periods if actual forfeitures differ from those estimates. Compensation expense related to modified RSUs is measured based on the fair value for the awards as of the modification date. Any incremental compensation expense arising from the excess of the fair value of the awards on the modification date compared to the fair value of the awards immediately before the modification date is recognized at the modification date or ratably over the requisite service period, as appropriate.

14

Warrants**:**

Warrants (see Note10—Stockholders’ Equity for further details) granted to employees and non-employees are normally valued at the fair value of the instrument on the grant date and are recognized in the statement of operations over the requisite service period. When the requisite service period precedes the grant date and a market condition exists in the warrant, the Company values the warrant using the Monte Carlo Simulation Method. When the terms of the warrant become fixed, the Company values the warrant using the Black-Scholes Option Pricing Method. The Company’s estimate of expected volatility is based on its average volatility using its pastnine years of publicly traded history. The risk-free rate for periods within the contractual life of the warrant is based on the U.S. Treasury yield curve in effect at the time of grant valuation. In determining the value of the warrant until the terms are fixed, the Company factors in the probability of the market condition occurring and several possible scenarios. When the requisite service period precedes the grant date and is deemed to be complete, the Company records the fair value of the warrant at the time of issuance as an equity stock-based compensation transaction. The grant date is determined when all pertinent information, such as exercise price and quantity are known.

Income Taxes:

The Company follows ASC Topic740, Income Taxes(“ASC740”), which requires recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Under this method, deferred tax assets and liabilities are based on the differences between the consolidated financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Deferred tax assets are reduced by a valuation allowance to the extent management concludes it is more likely thannot that the asset willnot be realized. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled.

The standard addresses the determination of whether tax benefits claimed or expected to be claimed on a tax return should be recorded in the consolidated financial statements. Under ASC740, the Company* mayrecognize the tax benefit from an uncertain tax position only if it is more likely thannot* that the tax position will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such a position should be measured based on the largest benefit that has a greater than50% likelihood of being realized upon ultimate settlement. ASC740 also provides guidance on de-recognition, classification, interest and penalties on income taxes, accounting in interim periods and requires increased disclosures. As of* September 30, 2026*, the Company’s uncertain tax positions include a reserve for its research and development credits.

Financial Instruments:

The carrying value of financial instruments, such as cash equivalents, accounts receivable and accounts payable, approximates their fair value because of their short-term nature. The carrying value of long-term debt approximates its fair value as the principal amounts outstanding are subject to variable interest rates that are based on market rates that are regularly reset.

Cash and Cash Equivalents:

The Company classifies all highly liquid instruments with an original maturity ofthree months or less as cash equivalents.

Restricted Cash:

Restricted cash represents cash held at financial institutions that is pledged as collateral for stand-by letters of credit for office leases. The lease-related letters of credit were terminated, and the related cash collateral was released, during thenine months ended* September 30, 2026.The Company hadno restricted cashfor the period ended September 30, 2026*, compared to $2.1 million for the period ended * December 31, 2025*.

15

Investment Securities:

The Company classifies all investment securities (short-term and long-term) as available-for-sale, as the sale of such securities* maybe required prior to maturity to implement management’s strategies. These securities are carried at fair value, with the unrealized gains and losses reported as a component of accumulated other comprehensive income in stockholders’ equity until realized. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis. In accordance with ASU2016*-13, Financial Instruments—Credit Losses (Topic326*): Measurement of Credit Losses on Financial Instruments*, credit losses on available-for-sale securities are reported using an expected loss model and recorded to an allowance. Premiums and discounts are amortized or accreted over the life of the related security as an adjustment to yield using the straight-line method. Interest income is recognized when earned.

Assets Measured at Fair Value on a Recurring Basis:

ASC Topic820, Fair Value Measurement(“ASC820”) provides a single definition of fair value and a common framework for measuring fair value as well as disclosure requirements for fair value measurements used in financial statements. Under ASC820, fair value is determined based upon the exit price that would be received by a company to sell an asset or paid by a company to transfer a liability in an orderly transaction between market participants, exclusive of any transaction costs. Fair value measurements are determined by either the principal market or the most advantageous market. The principal market is the market with the greatest level of activity and volume for the asset or liability. Absent a principal market to measure fair value, the Company uses the most advantageous market, which is the market from which the Company would receive the highest selling price for the asset or pay the lowest price to settle the liability, after considering transaction costs. However, when using the most advantageous market, transaction costs are only considered to determine which market is the most advantageous and these costs are then excluded when applying a fair value measurement. ASC820 creates athree-level hierarchy to prioritize the inputs used in the valuation techniques to derive fair values. The basis for fair value measurements for each level within the hierarchy is described below, with Level1 having the highest priority and Level3 having the lowest.

Following are the major categories of assets measured at fair value on a recurring basis as of* September 30, 2026*, and* December 31, 2025*, using quoted prices in active markets for identical assets (Level1), significant other observable inputs (Level2), and significant unobservable inputs (Level3) (in thousands):

16

The Company’s investments in commercial paper, corporate bonds and U.S. government securities are exposed to price fluctuations. The fair value measurements for commercial paper, corporate bonds and U.S. government securities are based upon the quoted prices of similar items in active markets multiplied by the number of securities owned.

The following tables summarize the Company’s cash equivalents and short-term investments (in thousands):

Concentration of Risk:

Financial instruments, which potentially subject the Company to concentrations of credit risk, principally consist of cash and cash equivalents, marketable securities, and accounts receivable, net. The Company’s cash and cash equivalents in excess of the Federal Deposit Insurance Corporation and the Securities Investor Protection Corporation insured limits at* September 30, 2026* were approximately $41.0 million. The Company doesnot believe it is exposed to any significant credit risk due to the quality nature of the financial instruments in which the money is held. Pursuant to the Company’s internal investment policy, investments must be rated A-1/P-1 or better by Standard and Poor’s Rating Service and Moody’s Investors Service at the time of purchase.

The Company sells its products in the United States primarily through specialty pharmacies and specialty distributors. Therefore, wholesale distributors and large pharmacy chains account for a large portion of its accounts receivables, net and product revenues, net. The creditworthiness of its customers is continuously monitored, and the Company has internal policies regarding customer credit limits. The Company estimates an allowance for credit loss primarily based on the creditworthiness of its customers, historical payment patterns, aging of receivable balances and general economic conditions.

The Company’s success depends on its ability to successfully commercialize NERLYNX. The Company currently has a single product and limited commercial sales experience, which makes it difficult to evaluate its current business, predict its future prospects and forecast financial performance and growth. The Company has invested a significant portion of its efforts and financial resources in the development and commercialization of the lead product, NERLYNX, and expects NERLYNX to constitute the vast majority of product revenue for the foreseeable future.

The Company relies exclusively onthird parties to formulate and manufacture NERLYNX and its drug candidates. The commercialization of NERLYNX and any other drug candidates, if approved, could be stopped, delayed, or made less profitable if thosethird parties fail to provide sufficient quantities of product or fail to do so at acceptable quality levels or prices. The Company hasno experience in drug formulation or manufacturing and doesnot intend to establish its own manufacturing facilities. The Company lacks the resources and expertise to formulate or manufacture NERLYNX and other drug candidates. While the drug candidates were developed by Pfizer, both the drug substance and drug product are manufactured bythird-party contractors. The Company is using the samethird-party contractors to manufacture, supply, store and distribute drug supplies for clinical trials and the commercialization of NERLYNX. If the Company is unable to continue its relationships withone or more of thesethird-party contractors, it could experience delays in the development or commercialization efforts as it locates and qualifies new manufacturers. The Company intends to rely onone or morethird-party contractors to manufacture the commercial supply of drugs.

17

Inventory:

The Company values its inventories at the lower of cost and estimated net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials and manufacturing overhead, on afirst-in,first-out basis and uses standard costing. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and it writes down any excess and obsolete inventories to their estimated realizable value in the period in which the impairment isfirst identified. Such impairment charges, should they occur, are recorded within the cost of sales in the condensed consolidated statements of operations. The determination of whether inventory costs will be realizable requires estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory* may*be required, which would be recorded as a cost of sales in the condensed consolidated statements of operations.

The Company capitalizes inventory costs associated with the Company’s products after regulatory approval, if any, when, based on management’s judgment, future commercialization is considered probable, and the future economic benefit is expected to be realized. Inventory that can be used in either the production of clinical or commercial product is recorded as research and development expense when selected for use in a clinical trial. Starter kits, provided to patients prior to insurance approval, are expensed by the Company to selling, general and administrative expense as incurred. Of the total inventory amounts noted below, approxi mately $10.3 million is located at contract manufacturing organizations in Europe as of* September 30, 2026*.

The Company’s inventory balances are as follows:

Property and Equipment, Net:

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the useful lives of the assets, which is generally three years for computer hardware and software, three years for phone equipment, andseven years for furniture and fixtures. Leasehold improvements are amortized using the straight-line method over the lesser of the useful life or the lease term. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is credited or charged to operations. Repairs and maintenance costs are expensed as incurred.

The Company reviews its long-lived assets used in operations for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset* may**not* be recoverable, as required by ASC Topic360, Property, Plant, and Equipment(“ASC360”). The Company performs a recoverability test by comparing the sum of the estimated undiscounted cash flows over the life of the asset to its carrying value on the consolidated balance sheet. If the undiscounted cash flows used in the recoverability test are less than the carrying value, the Company would then determine the fair value of the long-lived asset and recognize an impairment loss for the amount in excess of the carrying value. No impairments were recorded during thethree months ended* September 30, 2026* and2025.

Leases:

ASC Topic842,** Leasesrequires lessees to recognize most leases on the balance sheet with a corresponding right-of-use asset (“ROU asset”). ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. The assets and lease liabilities are recognized at the lease commencement date based on the estimated present value of fixed lease payments over the lease term. ROU assets are evaluated for impairment using the long-lived assets impairment guidance, as required by ASC360**. A significant indication of impairment of an ROU asset would include a change in the extent or manner in which the asset is being used. The Company must make assumptions that underlie the most significant and subjective estimates in determining whether any impairment exists. Those estimates, and the underlying assumptions, include estimates of future cash flow utilizing market lease rates and determination of fair value. If an ROU asset related to an operating lease is impaired, the carrying value of the ROU asset post-impairment should be amortized on a straight-line basis through the earlier of the end of the useful life of the ROU asset or the end of the lease term. Post impairment, a lessee must calculate the amortization of the ROU asset and interest expense on the lease liability separately, although the sum of thetwo continues to be presented as a single lease cost. If a lease is planned to be abandoned withno intention of subleasing, the ROU asset should be assessed for impairment.

18

Leases are classified as financing or operating, which will drive the expense recognition pattern. The Company elects to exclude short-term leases if and when the Company has them. For additional information, see Note5—Leases.

The Company leases office space and copy machines, all of which are operating leases. Most leases include the option to renew, and the exercise of the renewal options is at the Company’s sole discretion. Options to extend or terminate a lease are considered in the lease term to the extent that the option is reasonably certain of exercise. The leases donot include options to purchase the leased property. The depreciable life of assets and leasehold improvements is limited by the expected lease term. Covenants imposed by the leases include letters of credit required to be obtained by the lessee.

The Company is required to remeasure the lease liability and make an adjustment in the following instances:

The incremental borrowing rate (“IBR”) represents the rate of interest the Company would expect to pay on a collateralized basis to borrow an amount equal to the lease payments under similar terms. As the implicit rate on the Company’s leases isnot readily determinable, the Company uses its IBR based on the information available at the commencement date in determining the present value of lease payments. The Company’s average IBR for existing leases as of* September 30, 2026* is 12.4%.

License Fees and Intangible Assets:

The Company expenses amounts paid to acquire licenses associated with products under development when the ultimate recoverability of the amounts paid is uncertain and the technology hasno alternative future use when acquired. Acquisitions of technology licenses are charged to expense or capitalized based upon the asset achieving technological feasibility in accordance with management’s assessment regarding the ultimate recoverability of the amounts paid and the potential for alternative future use. The Company has determined that technological feasibility for its drug candidates is reached when the requisite regulatory approvals are obtained to make the product available for sale. The Company capitalizes technology licenses upon reaching technological feasibility.

The Company maintains definite-lived intangible assets related to the license agreement with Pfizer. These assets are amortized over their remaining useful lives, which are estimated based on the shorter of the remaining patent life or the estimated useful life of the underlying product. Intangible assets are amortized using the economic consumption method if anticipated future revenues can be reasonably estimated. The straight-line method is used when future revenues cannot be reasonably estimated. Amortization costs are recorded as part of cost of sales.

The Company assesses its intangible assets for impairment if indicators are present or changes in circumstance suggest that impairment* mayexist. Events that could result in an impairment, or trigger an interim impairment assessment, include the receipt of additional clinical or non-clinical data regardingone* of the Company’s drug candidates or a potentially competitive drug candidate, changes in the clinical development program for a drug candidate, or new information regarding potential sales of the drug. If impairment indicators are present or changes in circumstance suggest that impairment* may*exist, the Company performs a recoverability test by comparing the sum of the estimated undiscounted cash flows of each asset to its carrying value on the consolidated balance sheet. If the undiscounted cash flows used in the recoverability test are less than the carrying value, the Company would determine the fair value of the intangible asset and recognize an impairment loss if the carrying value of the intangible asset exceeds its fair value.

19

Recently Issued Accounting Standards:

In* November 2024,the FASB issued ASU2024*-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures: The ASU requires more detailed information about specified categories of expenses included in certain expense captions presented on the face of the income statement. This ASU is effective for fiscal years beginning after* December 15, 2026,and for interim periods within fiscal years beginning after December 15, 2027.Early adoption is permitted. The amendments may*be applied either (1) prospectively to financial statements issued for reporting periods after the effective date of this ASU or (2) retrospectively to all prior periods presented in the financial statements. The Company is currently evaluating the impact of adopting this ASU on its consolidated financial statements and related disclosures.

Note3—Accounts Receivable, Net:

Accounts receivable, net consisted of the following (in thousands):

Trade accounts receivable consist entirely of amounts owed from the Company’s customers related to product sales. Royalty revenue receivable represents amounts owed related to royalty revenue recognized based on the Company’s sub-licensees’ sales in their respective territories in the periods ended* September 30, 2026* and* December 31, 2025*.

For all accounts receivable, the Company recognizes lifetime expected credit losses in selling, general and administrative expense in the condensed consolidated statements of operations. In estimating expected credit losses, the Company considers historical loss rates, current economic conditions, and reasonable and supportable forecasts of future economic conditions.

The Company recordedno provision for, or recovery of, credit losses for thethree andnine months ended* September 30, 2026,compared to recoveries of $0.2 million and $0.4 million for thethree* andnine months ended* September 30, 2025,*respectively.

Note4—Prepaid Expenses and Other:

Prepaid expenses and other consisted of the following (in thousands):

Other current prepaid amounts consist primarily of deposits, signing bonuses, licenses, subscriptions and software. Other long-term prepaid amounts consist primarily of funding for commercial copay support programs.

20

Note5—Leases:

In* December 2011,the Company entered into a non-cancelable operating lease for office space in Los Angeles, California, with an initial term ofseven years commencing on December 10, 2011.The lease was subsequently amended in November 2012,** December 2013,** March 2014,** July 2015and December 2017.*

In* July 2025,the Company executed an additional lease amendment to surrender certain suites effective March 31, 2026,and extend the lease term for the remaining 26,700 rentable square feet through August 31, 2031,an extension offive years andfive* months. Under the amended lease, base rent escalates annually, with rent abated from* April 2026through August 2026.Lease payments also include variable charges for the Company's proportionate share of building operating expenses and real estate taxes, based on a2026* base year. The Company has the option to renew the lease for an additional five-year term; however, management determined that exercise of this option isnot reasonably certain.

In connection with the lease, the Company maintained an automatically renewable standby letter of credit, collateralized by a high-yield savings account classified as long-term restricted cash. Following the execution of the* July 2025lease amendment, the related cash collateral was reclassified to restricted cash, current, as the letter of credit requirement was scheduled to terminate within12* months. The letter of credit, which totaled $1.0 million immediately prior to its termination, wasno longer required effective* March 31, 2026,*and the related cash collateral was released from restriction.

In* June 2012,the Company entered into a long-term operating lease for office space in South San Francisco, California, which was subsequently amended in May 2014and July 2015.As amended, the Company leased approximately 29,470 square feet of office space. The lease expired on March 31, 2026,and wasnot* renewed.

In connection with the lease, the Company maintained an automatically renewable standby letter of credit, collateralized by a high-yield savings account classified as long-term restricted cash. As the lease approached expiration, the related cash collateral was reclassified to restricted cash, current, based on the anticipated release of the letter of credit within12 months. The letter of credit, which totaled $1.1 million immediately prior to its termination, remained in effect for60 days following the lease expiration. The letter of credit was subsequently terminated, and the related cash collateral was released from restriction during thethree months ended* September 30, 2026.*

Total rent expense for thethree months ended* September* 30, 2026 and2025 was approximately $0.3 million and $1.1 million, respectively. Total rent expense for thenine months ended* September 30, 2026* and2025, was approximately $1.7 million and $3.4 million, respec tively. Forpurposes of determining straight-line rent expense, the lease term is calculated from the date the Companyfirst takes possession of the facility, including any periods of free rent and any renewal option periods that the Company is reasonably certain of exercising. The Company’s office leases generally have contractually specified minimum rent and annual rent increases that are included in the measurement of the ROU asset and related lease liability. Additionally, under these lease arrangements, the Company* maybe required to pay directly, or reimburse the lessors, for real estate taxes, insurance, utilities, maintenance, and other operating costs. Such amounts are generally variable and thereforenot* included in the measurement of the ROU asset and related lease liability but are instead recognized as variable lease expense in selling, general and administrative costs in the condensed consolidated statements of operations when they are incurred.

21

Future minimum lease payments as of* September 30, 2026* were as follows (in thousands):

In* August 2023,the Company entered into a sublease agreement for 13,916 square feet of office space in Los Angeles, California, which commenced in November 2023and expired on March 31, 2026.In thefirst* quarter of2025, the Company entered into an additional sublease agreement for 12,429 square feet of office space in Los Angeles, California, which commenced on* April 1, 2025,and expired on March 31, 2026.*

The Company recordedno operating sublease income for thethree months ended* September 30, 2026*, compared to $0.2 million for thethree months ended* September 30, 2025*. For thenine months ended* September 30, 2026* and2025, the Company recorded operating sublease income of $0.2 million and $0.7 million, respectively. Sublease income was recognized in other income (expenses) in the condensed consolidated statements of operations.

Note6—Property and Equipment, Net:

Property and equipment, net consisted of the following (in thousands):

The Company recorded nominal depreciation expense for thethree months ended* September 30, 2026*, compared to$0.1 million for thethree months ended* September 30, 2025*. For thenine months ended* September 30, 2026* and2025, depreciation expense was$0.1 million and$0.3 million, respectively.

Note7—Intangible Assets, Net:

Intangible assets, net consisted of the following (in thousands):

For thethree months ended* September 30, 2026and2025,* the Company incurred amortization expense of $2.4 million in each period. For thenine months ended* September 30, 2026and2025,* the Company incurred amortization expense of $7.3 million in each period. The estimated remaining useful life of the intangible assets as of* September 30, 2026* is 3.5 years.

As of* September 30, 2026*, estimated future amortization expense related to the Company’s intangible assets is approximately $2.4 million for the remainder of2026 and $9.7 million for each year starting2027 through2029, and $2.4 million for2030.

22

Note8—Accrued Expenses:

Accrued expenses consisted of the following (in thousands):

Accrued variable consideration represents estimates of adjustments to product revenue, net for which reserves are established. Accrued royalties represent royalties incurred in connection with the Company’s license agreement with Pfizer. Accrued CRO services, accrued other clinical development expenses, and accrued legal fees represent the Company’s estimates of such costs and are recognized as incurred. Accrued compensation includes commissions and vacation.

Note9—Debt:

Athyrium Note Purchase Agreement:

The Company issued senior notes for an aggregate principal amount of $100.0 million pursuant to a note purchase agreement dated* July 23, 2021by the Company, and its subsidiary, and Athyrium, as Administrative Agent, and certain other investor parties (the “Note Purchase Agreement”), with an initial maturity date of July 23, 2026 (*the “Athyrium Notes”). The Athyrium Notes were issued for face amount of $100.0 million net of an original issue discount of $1.5 million. The Athyrium Notes also required a 2.0% exit payment to be made on each payment of principal.

Following the effectiveness of the Third Amendment, the Athyrium Notes bore interest at an annual rate equal to the sum of (a)eight percent (8.00%) plus (b) the lesser of (i) the sum of (x)three-month term SOFR for an interest period ofthree months plus (y)0.26161% (26.161 basis points) and (ii)three andone-half ofone percent (3.50%) per annum. Interest was payable quarterly on the last business day of* March,** June,** September,and Decembereach year. In thesecond* quarter of2024, the Company began paying principal payments required to be made quarterly at 11.11% of the original face amount. Each principal payment also included a 2.0% exit payment. Each quarterly principal payment approximated $11.1 million, and each quarterly exit fee payment approximated $0.2 million. Immediately prior to repayment described below, the effective interest rate for the Athyrium Notes was 12.99%.

On* May 4, 2026,the Company paid $11.5 million to Athyrium Opportunities IV Co-Invest1* LP, consisting of principal, interest and exit fees due under the2021 Note Purchase Agreement. This payment was made ahead of the maturity date of* July 23, 2026,reduced the principal balance outstanding under the Athyrium Notes tozero and terminated all remaining obligations of the Company under the2021* Note Purchase Agreement, other than customary continuing indemnification obligations.

Debt Issuance Costs and Discounts:

Debt issuance costs and discounts consist of the following (in thousands):

23

Debt issuance costs and discounts are financing costs related to the Company’s outstanding debt. Amortization of debt issuance costs is expensed using the effective interest method and is included in interest expense in the condensed consolidated statement of operations. The Company recorded nominal amounts of interest expense for thethree months ended* September 30, 2026,and $0.1 million of interest expense for thenine* months ended* September 30, 2026*. For thethree andnine months ended* September 30, 2025,*the Company recorded approximately $0.1 million and $0.5 million of interest expense, respectively.

Note10—Stockholders’** Equity:**

Common Stock:

The Company issued 50,000 shares and 55,882 shares of common stock upon exercise of stock options during thenine months ended* September 30, 2026and2025*, respectively. The Company issued 1,230,920 and 1,222,558 shares of common stock upon vesting of RSUs during thenine months ended* September 30, 2026and2025*, respectively.

Authorized Shares:

The Company has 100,000,000 shares of stock authorized for issuance, all of which are common stock, par value $0.0001 per share.

Warrants:

In* October 2011,*the Company issued an anti-dilutive warrant to Alan H. Auerbach, the Company’s founder and Chief Executive Officer (the “Auerbach Warrant”). The Auerbach Warrant was issued to provide Mr. Auerbach with the right to maintain ownership of at least 20% of the Company’s common stock in the event that the Company raised capital through the sale of its securities in the future.

Pursuant to the terms of the Auerbach Warrant, as amended in* June 2021,Mr. Auerbach's option to exercise the Auerbach Warrant to acquire 2,116,250 shares of the Company’s common stock at $16 per share expired on October 4, 2026.*

Stock Options and Restricted Stock Units:

The Company’s2011 Plan, as amended, was adopted by the Company’s Board of Directors on* September 15, 2011.Pursuant to the2011* Plan, the Company* maygrant incentive stock options and nonqualified stock options, as well as other forms of equity-based compensation. Incentive stock options maybe granted only to employees, while consultants, employees, officers, and directors are eligible for the grant of nonqualified options under the2011* Plan. The maximum term of stock options granted under the2011 Plan is 10 years and the awards generally vest over atwo-year period. The exercise price of incentive stock options granted under the2011 Plan must be at least equal to the fair value of such shares on the date of grant. As of* September 30, 2026*, a total of 17,529,412 shares of the Company’s common stock have been reserved for issuance under the2011 Plan.

All of the options awarded by the Company have been “plain vanilla options” as determined by the SEC Staff Accounting Bulletin107—Share Based Payment.As of * September 30, 2026, 4,469,708 shares of the Company’s common stock are issuable upon the exercise of outstanding stock options and vesting of RSUs granted under the2011* Plan and 2,154,127 shares of the Company’s common stock are available for future issuance under the2011 Plan. The fair value of options granted to employees and nonemployees was estimated using the Black-Scholes Option Pricing Method (see Note2—Significant Accounting Policies) with the following weighted-average assumptions used during thenine months ended* September 30, 2026*:

The Company’s2017 Plan, as amended, was adopted by the Company’s Board of Directors on* April**27,* 2017. Pursuant to the2017 Plan, the Company* maygrant stock options and RSUs, as well as other forms of equity-based compensation, to employees as an inducement to join the Company. The maximum term of stock options granted under the2017* Plan is 10 years and the awards generally vest over athree-year period. The exercise price of stock options granted under the2017 Plan must be at least equal to the fair market value of such shares on the date of grant. As of* September 30, 2026*, a total of 512,604 shares of the Company’s common stock are issuable upon the exercise of outstanding stock options and vesting of RSUs granted under the2017 Plan and 1,110,473 shares of the Company’s common stock are available for future issuance under the2017 Plan.

24

Stock-based compensation expense was as follows (in thousands):

Activity with respect to options granted under the2011 Plan and2017 Plan is summarized as follows:

Stock Option Roll Forward:

At* September 30, 2026*, total estimated unrecognized employee compensation cost related to non-vested stock options granted prior to that date was approximately $1.1 million, which is expected to be recognized over a weighted-average period of 1.2 years. At * September 30, 2026*, the total estimated unrecognized employee compensation cost related to non-vested RSUs was approximately $7.9 million, which is expected to be recognized over a weighted-average period of 1.5 years. The weighted-average grant date fair value of options granted during the nine months ended* September 30, 2026and2025* was $4.37 and $1.95 per share, respectively. The weighted-average grant date fair value of RSUs awarded during the nine months ended* September 30, 2026and2025* was $6.97 and $3.34 per share, respecti vely.

Restricted Stock Unit Roll Forward:

Note11—401(k) Savings Plan:

During2012, the Company adopted a401(k) savings plan for the benefit of its employees. The Company is required to make matching contributions to the401(k) plan equal to 100% of the first3% of wages deferred by each participating employee and 50% on the next2% of wages deferred by each participating employee. The Company incurred expenses for employer-matching contributions of approximately $1.5 million and $1.4 million for thenine months ended* September 30, 2026and2025*, respectively.

25

Note12—Commitments and Contingencies:

Contractual Obligations:

Contractual obligations represent future cash commitments and liabilities under agreements withthird parties and exclude contingent liabilities for which the Company cannot reasonably predict future payment. The Company’s contractual obligations result primarily from obligations for various contract manufacturing organizations and CROs, which include potential payments the Company* maybe required to make under its agreements. The contracts also contain variable costs and milestones that are hard to predict as they are based on such things as patients enrolled and clinical trial sites. The timing of payments and actual amounts paid under contract manufacturing organization (“CMO”) and CRO agreements may*be different depending on the timing of receipt of goods or services or changes to agreed-upon terms or amounts for some obligations. Also, those agreements are cancelable upon written notice by the Company and, therefore,not long-term liabilities.

License Agreements:

Pfizer License Agreement

In* August 2011,the Company entered into an agreement pursuant to which Pfizer agreed to grant it a worldwide license for the development, manufacture, and commercialization ofPB272* (neratinib, oral),PB272 (neratinib, intravenous) andPB357, and certain related compounds. The license is exclusive with respect to certain patent rights owned by or licensed to Pfizer. Under the agreement, the Company is obligated to commence a new clinical trial for a product containingone of these compounds within a specified period of time and to use commercially reasonable efforts to complete clinical trials and to achieve certain milestones as provided in a development plan.

On* July 18, 2014,the Company entered into an amendment to the license agreement with Pfizer. The amendment amends the agreement to (1) reduce the royalty rate payable by the Company to Pfizer on sales of licensed products; (2) release Pfizer from its obligation to pay for certain out-of-pocket costs incurred or accrued on or after January 1, 2014*to complete certain ongoing clinical studies; and (3) provide that Pfizer and the Company will continue to cooperate to effect the transfer to the Company of certain records, regulatory filings, materials and inventory controlled by Pfizer as promptly as reasonably practicable.

As consideration for the license, the Company is required to make substantial payments upon the achievement of certain milestones totaling approximately $187.5 million if all such milestones are achieved. In connection with the FDA approval of NERLYNX in* Julyof2017,* the Company triggered aone-time milestone payment pursuant to the agreement. In* June 2020,the Company entered into a letter agreement (the “Letter Agreement”) with Pfizer relating to the method of payment associated with aone*-time milestone payment under the license agreement with Pfizer. The Letter Agreement permitted the Company to make the milestone payment in installments with the remaining amount payable to Pfizer (including interest). The milestone payment accrued interest at 6.25% per annum. The milestone payment including accrued interest of $1.8 million was paid in full in* September 2021.In addition, the Company reached a commercial milestone by achieving aggregate worldwide net sales of $250.0 million in calendar year2022,* resulting in a payment to Pfizer of $12.5 million during thethree months ended* March**31,* 2023. The Company capitalized the milestones as intangible assets and is amortizing the assets to cost of sales on a straight-line basis over the estimated useful life of the licensed patent through2030. Should the Company commercialize any more of the compounds licensed from Pfizer or any products containing any of these compounds, the Company will be obligated to pay Pfizer annual royalties at a fixed rate in the low-to-mid teens of net sales of all such products, subject to certain reductions and offsets in some circumstances. The Company’s royalty obligation continues, on a product-by-product and country-by-country basis, until the later of (1) the last to expire licensed patent covering the applicable licensed product in such country, or (2) the earlier of generic competition for such licensed product reaching a certain level in such country or expiration of a certain time period afterfirst commercial sale of such licensed product in such country. In the event that the Company sub-licenses the rights granted to the Company under the license agreement with Pfizer to athird party, the same milestone and royalty payments are required. The Company can terminate the license agreement at will, or for safety concerns, in each case upon specified advance notice.

26

Takeda License Agreement

In* September 2022,the Company entered into an exclusive license agreement with Takeda to license the worldwide research and development and commercial rights to alisertib, a selective, small-molecule, orally administered inhibitor of Aurora Kinase A. Under the terms of the exclusive license agreement, the Company assumed sole responsibility for the global development and commercialization of alisertib. Takeda received an upfront license fee of $7.0 million in October 2022and is eligible to receive potential future milestone payments of up to $287.3 million upon the Company’s achievement of certain regulatory and commercial milestones over the course of the exclusive license agreement, as well as tiered royalty payments for any net sales of alisertib.No milestones were achieved as of September 30, 2026*.

Legal Proceedings:

The Company records a liability in the consolidated financial statements for loss contingencies when a loss is known or considered probable and the amount can be reasonably estimated. If the reasonable estimate of a known or probable loss is a range, andno amount within the range is a better estimate than any other, the minimum amount of the range is accrued. If a loss is reasonably possible butnot known or probable, and can be reasonably estimated, the estimated loss or range of loss is disclosed. When determining the estimated loss or range of loss, significant judgment is required to estimate the amount and timing of a loss to be recorded. Legal accruals are adjusted as developments warrant.

Legal Malpractice Suit

On* September 17, 2020,the Company filed a lawsuit against Hedrick Gardner Kincheloe & Garofalo, L.L.P. and David L. Levy, the attorneys who previously represented the Company inEshelman v. Puma Biotechnology, Inc., et al*. in the Superior Court of Mecklenburg County, North Carolina. The Company is alleging legal malpractice based on the defendants’ negligent handling of the defense of the Company inEshelman v. Puma Biotechnology, Inc., et al. The Company is seeking recovery of the entire amount awarded inEshelman v. Puma Biotechnology, Inc., et al. and all legal fees and expenses incurred in appealing from the judgment and retrying the damages phase of the trial. On* November 23, 2020,the defendants filed an answer to the complaint denying the allegations of negligence. On August 19, 2022,the Company filed a voluntary dismissal of the legal malpractice action, without prejudice, to allow theEshelman v. Puma Biotechnology, Inc., et al*. action to conclude before proceedings. On* June 2, 2023,the Company re-filed the lawsuit against Hedrick Gardner Kincheloe & Garofalo, L.L.P. and David L. Levy, the attorneys who previously represented the Company inEshelman v. Puma Biotechnology, Inc., et al.* in the Superior Court of Mecklenburg County, North Carolina. On* August 22, 2023,the defendants filed motions to dismiss the case. These motions were presented at a hearing on February 20, 2024.The Superior Court Judge granted the motions to dismiss on March 20, 2024.The Company appealed this ruling to the North Carolina Court of Appeals. On September 3, 2025,the Court of Appeals reversed the dismissal of the Company’s claim for legal malpractice and remanded the case to the Superior Court for further proceedings. The defendants filed a petition for discretionary review of this decision by the North Carolina Supreme Court on October 8, 2025.On August 14, 2026,*the Supreme Court accepted the case for review.

27

Patent-Related Proceedings

AstraZeneca Litigation

On* September 22, 2021,the Company filed suit against AstraZeneca Pharmaceuticals, LP, AstraZeneca AB, and AstraZeneca PLC for infringement of United States Patent Nos.10,603,314 (“the‘314* patent”) and10,596,162 (“the*‘162* patent”) (Puma Biotechnology, Inc. et al. v. AstraZeneca Pharmaceuticals LP et al.,1:21CV01338 (D. Del.* Sep. 22, 2021)).The Company’s complaint alleges that AstraZeneca’s commercial manufacture, use, offer for sale, sale, distribution, and/or importation of Tagrisso® (osimertinib) products for the treatment of gefitinib and/or erlotinib-resistant non-small cell lung cancer infringes the‘314* and*‘162* patents. The Company is an exclusive licensee of the*‘314* and*‘162* patents under the Pfizer Agreement. Wyeth is a co-plaintiff. Plaintiffs seek a judgment that AstraZeneca’s product infringes the asserted patents and an award of monetary damages in an amount to be proven at trial. AstraZeneca AB and AstraZeneca Pharmaceuticals LP filed an answer and counterclaims on* November 5, 2021,including claims challenging the asserted patents asnot* infringed and/or invalid, and accusing plaintiffs of unclean hands and patent misuse. The parties stipulated to dismiss AstraZeneca PLC as a defendant and Pfizer as a Counterclaim Defendant on* December 10, 2021,which the Court so ordered on December 13, 2021.The Company filed its answer to AstraZeneca’s counterclaims on December 17, 2021,denying those claims. The case was reassigned to visiting Judge Matthew Kennelly of the Northern District of Illinois. A Markman Hearing was conducted on March 17, 2023,and the Court issued its claim construction decision on March 29, 2023.Fact discovery closed on May 19, 2023,and expert discovery closed on November 17, 2023.The Court denied the parties’ respective motions for summary judgment and Daubert motions, other than to clarify that Plaintiffs’ damages cannot extend to any time period before the asserted patents were issued. The Court granted AstraZeneca’s motion to dismiss the Company as a Plaintiff on constitutional standing grounds but denied the motion to dismiss Wyeth as a Plaintiff on constitutional standing grounds. On April 29, 2024,the Court granted AstraZeneca’s motion to dismiss AstraZeneca’s counterclaims against the Company, which removed the Company from the case. Wyeth remained in the case as a Plaintiff and counterclaim defendant. Under the Company’s worldwide exclusive license agreement with Pfizer, Inc. (the parent of Wyeth) as amended, the Company also maintains contractual rights to recover monetary damages in the AstraZeneca litigation, and those contractual rights are unaffected by the court’s March 18, 2024and April 29, 2024orders. A jury trial was held May 13-17, 2024. The jury found in favor of Wyeth and against AstraZeneca. In particular, the jury found that use of Tagrisso® according to each of thethree FDA-approved indications infringes the asserted claims of the‘314* and*‘162* patents, and that AstraZeneca induces that infringement. The jury further rejected AstraZeneca’s challenges to the validity of the patents, finding that they arenot invalid. The jury awarded damages to Wyeth for past acts of infringement through* December 31, 2023,in the amount of $107.5 million. A separate bench trial related to certain equitable claims and defenses raised by AstraZeneca was held before Judge Kennelly on June 20and25,* 2024. On* August 6, 2024,Judge Kennelly issued his ruling on the issues that were tried in the bench trial, finding for Wyeth and against AstraZeneca on all claims and defenses. The Court found that AstraZeneca hadnot* proved its claim that Wyeth’s asserted patents were invalid as indefinite, or that Wyeth had committed acts that would give rise to findings of unclean hands, implied waiver, or patent misuse. AstraZeneca filed a motion challenging the jury’s verdict and requesting a new trial. Wyeth filed a motion requesting supplemental damages for past infringement from* January 1, 2024,through the date of judgment; pre-and-post judgment interest, and ongoing royalties through the remaining term of the patents. Briefing on these motions from both sides was completed on July 16, 2024.On August 14, 2024,Judge Kennelly ruled on AstraZeneca’s motion challenging the jury’s verdict, granting it in part and denying it in part. The Court granted AstraZeneca’s motion for judgment as a matter of law that the'314* and*'162* patents are invalid under35 U.S.C. §112 for lacking enablement and adequate written description as to a particular claim limitation. In all other respects, the Court denied AstraZeneca’s motion. The Court entered its final and appealable judgment accordingly. The Company respectfully disagrees with the Court’s ruling regarding invalidity with respect to the particular claim limitation. Wyeth filed a notice of appeal on* September 12, 2024,appealing the District Court’s judgment as a matter of law, as well as other rulings and opinions of the Court adverse to Wyeth. On December 18, 2024,Wyeth filed its opening brief. On March 13, 2025,AstraZeneca filed its response brief. On March 20, 2025,non-parties Regeneron Pharmaceuticals, Inc. and Sanofi-Aventis U.S. LLC filed a motion for leave to file an amicus curiae brief in the Federal Circuit. The motion was granted on May 16, 2025.On June 6, 2025,Wyeth filed its reply brief and oral arguments were held on May 7, 2026.On July 9, 2026,*the Federal Circuit affirmed the judgment of the Delaware District Court, holding the patent claims at issue invalid. AstraZeneca’s request for certain reimbursable costs related to the district court litigation, some of which are opposed, remains pending.

28

Acebright China Litigation

On* January 18, 2022,Shanghai Acebright Pharmaceuticals Group Co., Ltd. (“Acebright”) filed an abbreviated new drug application (“ANDA”) with the National Medical Products Administration in China (“NMPA”) seeking approval to market a generic version of the Company’s NERLYNX® (neratinib) tablet,40mg in China. Acebright seeks approval prior to the expiration ofthree* patents listed on the China Patent Information Registration Platform for Marketed Drugs (“Chinese Orange Book”), namely, Chinese Patent Nos.ZL201410082103.7, ZL201080060546.6, andZL200880118789.3 (the*“’789* patent” and collectively, the “NERLYNX® Patents”), alleging in a Type4.2 patent declaration that its generic version of NERLYNX doesnot fall within the scope of the claims of NERLYNX® Patents listed in the Chinese Orange Book. The patent declaration of Acebright was published in the Chinese Orange Book on* January 19, 2022.On March 2, 2022,the Company filed petitions with the China National Intellectual Property Administration (“CNIPA”) and requested administrative determination that Acebright’s generic neratinib tablet falls within the scope of the claims of NERLYNX® Patents listed in the Chinese Orange Book. The Company’s request for administrative determination was accepted by CNIPA on March 18, 2022.The Company has notified NMPA of the acceptance of the request for administrative determination for NMPA to institute a stay of Acebright’s ANDA fornine* months. On* July 11, 2022,CNIPA decided that claims5* and6 of PatentNo. ZL200880118789.3 arenot eligible for registration in the Chinese Orange Book on the ground that thesetwo pharmaceutical method-of-use claims fall within the scope of “patents of crystalline forms,” which arenot eligible for listing in the Chinese Orange Book. On* September 9, 2022,CNIPA decided that the generic drug in Acebright’s ANDA doesnot* fall within the protection scope of claims1, 3, 5 and6 of PatentNo. ZL201410082103.7 and claims1-4, 7 and9-13 of PatentNo. ZL201080060546.6. Thethree CNIPA administrative decisions on NERLYNX® Patents have lifted the stay of Acebright’s ANDA by NMPA. The Company has appealed each CNIPA administrative decision in* January 2023at the Beijing Intellectual Property Court (“BJIPC”). Thethree* appeals were accepted by BJIPC on* February 20, 2023.The Company also filedthree* civil complaints based on thethree NERLYNX® Patents against Acebright with the BJIPC in* July 2022and requested court determination that Acebright’s generic neratinib tablet falls within the scope of the claims of NERLYNX® Patents. On May 6, 2023,the Company withdrewtwo* civil lawsuits andtwo appeals in relation to Chinese Patent Nos.ZL201410082103.7 andZL201080060546.6 at the BJIPC. On* May 24, 2023,the BJIPC accepted the Company’s withdrawal request. On July 24, 2023,the Company withdrew theone* remaining civil lawsuit andone appeal in relation to Chinese PatentNo. ZL200880118789.3 at the BJIPC. On* August 15, 2023,the BJIPC accepted the Company’s withdrawal request. On September 12, 2023,the NMPA approved Acebright’s ANDA to market a generic version of the Company’s NERLYNX® in China with the approval number of GuoYaoZhunZiH20234141.*

On* December 28, 2023,the Company filed a civil lawsuit against Acebright for infringement of the’789* patent under Article11 of the Chinese Patent Law before Jiangsu Nanjing Intermediate People’s Court. The Company’s complaint alleges that Acebright’s offer for sale of a generic version of the Company’s NERLYNX® product infringes the*’789* patent. The Company seeks a judgment that Acebright’s product infringes the*’789* patent and Acebright’s act of offer for sale shall be enjoined. On* January 2, 2024,Jiangsu Nanjing Intermediate People’s Court accepted the civil complaint. An oral hearing was held on June 19, 2024,during which the Company amended its complaint to allege that Acebright making, selling and offering to sell the generic version of NERLYNX® infringes the’789* patent. On* July 24, 2024,the Company submitted a request to withdraw the lawsuit. On August 8, 2024,*Jiangsu Nanjing Intermediate People’s Court accepted the withdrawal request.

On* September 27, 2024,the Company filed an additional patent infringement claim against Acebright at Jiangsu Nanjing Intermediate People’s Court. On October 14, 2024,the Court accepted the complaint and designated case number (2024) Su01* Min Chu2192 to this case. On* December 16, 2024,the Court conducted an evidence exchange hearing. On January 10, 2025,the Court conducted a hearing of party experts on the evaluation of evidence. On July 14, 2025,the Court conducted a hearing to examine evidence and debate merits of party arguments. On September 28, 2025,the Court issued afirst*-instance decision, deciding that Acebright’s product doesnot fall within the scope of the patent-in-suit, and Acebright didnot infringe the NERLYNX® Patents. The Court also decided that the Company’s enforcement efforts werenot malicious and didnot amount to unfair competition.

Aosaikang China Litigation

On* November 17, 2022,Jiangsu Aosaikang Pharmaceutical Co. Ltd. (“Aosaikang”) filed an ANDA with NMPA in China seeking approval to market a generic version of the Company’s NERLYNX®. The ANDA applicationNo.* isCYHS2202006. Aosaikang made Type4.2 declarations against thefour Orange Book PatentsZL201410082103.7, ZL201080060546.6, ZL200880118789.3 andZL201710057547.9, alleging that its generic version of NERLYNX doesnot fall within the scope of the claims of the Orange Book patents. Aosaikang also alleged that PatentsZL200880118789.3 andZL201710057547.9 arenot eligible for Chinese Orange Book listing.

29

On* December 28, 2022,the Company submittedfour* Article76 petitions against the Aosaikang ANDA with the CNIPA and requested administrative determination that Aosaikang’s generic neratinib tablet falls within the scope of the claims of thefour Orange Book patents. On* January 6, 2023,the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos.ZL201410082103.7 andZL201080060546.6.* Also on* January 6, 2023,the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos.ZL200880118789.3 andZL201710057547.9,* alleging that the listed claims arenot eligible for registration in the Chinese Orange Book on the ground that these pharmaceutical method-of-use claims fall within the scope of “patents of crystalline forms,” which arenot eligible for listing in the Chinese Orange Book. On* January 28, 2023,the Company requested the NMPA to institute anine*-month stay against Aosaikang ANDA starting from the CNIPA’s acceptance of the Company’s request for administrative determination. On* June 2, 2023,CNIPA decided that the generic drug in Aosaikang’s ANDA doesnot* fall within the protection scope of claims1, 3, 5 and6 of PatentNo. ZL201410082103.7 and claims1-4, 7 and9-13 of PatentNo. ZL201080060546.6. Thetwo CNIPA administrative decisions on NERLYNX® Patents have lifted the stay of Aosaikang’s ANDA by NMPA. On* October 22, 2024,the NMPA approved Aosaikang’s ANDA to market a generic version of the Company’s NERLYNX® in China with the approval number of GuoYaoZhunZiH20249180.*

Convalife China Litigation

Convalife Pharmaceuticals (Shanghai) Co., Ltd (“Convalife”) filed an ANDA with NMPA in China seeking approval to market a generic version of the Company’s NERLYNX®. The ANDA applicationNo. isCYHS2202095. On* December 23, 2022,Convalife made Type4.2* declarations against thefour Orange Book PatentsZL201410082103.7, ZL201080060546.6, ZL200880118789.3 andZL201710057547.9, alleging that its generic version of NERLYNX doesnot fall within the scope of the claims of the Orange Book patents. Convalife also alleged that PatentsZL200880118789.3 andZL201710057547.9 arenot eligible for Chinese Orange Book listing.

On* February 1, 2023,the Company submittedfour* Article76 petitions against the Convalife ANDA with the CNIPA and requested administrative determination that Convalife’s generic neratinib tablet falls within the scope of the claims of thefour Orange Book patents. On* February 3, 2023,the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos.ZL201410082103.7 andZL201080060546.6.* Also on* February 3, 2023,the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos.ZL200880118789.3 andZL201710057547.9,* alleging that the listed claims arenot eligible for registration in the Chinese Orange Book on the ground that these pharmaceutical method-of-use claims fall within the scope of “patents of crystalline forms,” which arenot eligible for listing in the Chinese Orange Book. On* February 24, 2023,the Company requested the NMPA to institute anine*-month stay against Convalife ANDA starting from the CNIPA’s acceptance of the Company’s request for administrative determination. On* June 2, 2023,CNIPA decided that the generic drug in Convalife’s ANDA doesnot* fall within the protection scope of claims1, 3, 5 and6 of PatentNo. ZL201410082103.7 and claims1-4, 7 and9-13 of PatentNo. ZL201080060546.6. Thetwo CNIPA administrative decisions on NERLYNX® Patents have lifted the stay of Convalife’s ANDA by NMPA. On* June 28, 2024,the NMPA approved Convalife’s ANDA to market a generic version of the Company’s NERLYNX® in China with the approval number of GuoYaoZhunZiH20244222.*

Kelun China Litigation

Hunan Kelun Pharmaceutical Co., Ltd. (“Kelun”) filed an ANDA with NMPA in China seeking approval to market a generic version of the Company’s NERLYNX®. The ANDA applicationNo. isCYHS2300221. On* January 28, 2023,Kelun made Type4.2* declarations against thefour Orange Book PatentsZL201410082103.7, ZL201080060546.6, ZL200880118789.3 andZL201710057547.9, alleging that its generic version of NERLYNX doesnot fall within the scope of the claims of the Orange Book patents. Kelun also alleged that PatentsZL200880118789.3 andZL201710057547.9 arenot eligible for Chinese Orange Book listing.

On* March 13, 2023,the Company submittedfour* Article76 petitions against the Kelun ANDA with the CNIPA and requested administrative determination that Kelun’s generic neratinib tablet falls within the scope of the claims of thefour Orange Book patents. On* March 21, 2023,the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos.ZL200880118789.3 andZL201710057547.9,* alleging that the listed claims arenot eligible for registration in the Chinese Orange Book on the ground that these pharmaceutical method-of-use claims fall within the scope of “patents of crystalline forms,” which arenot eligible for listing in the Chinese Orange Book. On* March 24, 2023,the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos.ZL201410082103.7 andZL201080060546.6.* On* April 17, 2023,the Company requested the NMPA to institute anine*-month stay against Kelun’s ANDA starting from the CNIPA’s acceptance of the Company’s request for administrative determination. On* September 14, 2023,the Company withdrew thetwo* requests for administrative determination in relation to Chinese Patent Nos.ZL201410082103.7 andZL201080060546.6 at the CNIPA. On* September 25, 2023,the CNIPA accepted the Company’s withdrawal request. On September 9, 2025,the NMPA approved Kelun’s ANDA to market a generic version of the Company’s NERLYNX® in China with the approval number of GuoYaoZhunZiH20255337.*

30

Demai Litigation

Zhengzhou Demai Pharmaceutical Co., Ltd (“Demai”) filed an ANDA with NMPA in China seeking approval to market a generic version of the Company’s NERLYNX®. The ANDA applicationNo. isCYHS2402776. On* August 26, 2024,Demai made a Type4.2* declaration against Orange Book PatentZL201410082103.7, alleging that its generic version of NERLYNX doesnot fall within the scope of the claims of this Orange Book patent. On* September 30, 2024,the Company filed a lawsuit against Demai at the BJIPC based on Nerlynx PatentNo.* ZL201080060546.6 and on* October 8, 2024,the Company filed a lawsuit against Demai at the BJIPC based on Nerlynx PatentNo.* ZL201410082103.7. On* February 13, 2025,the Company withdrew the lawsuits from BJIPC, filed an Article76* petition with the CNIPA against the Demai ANDA and requested administrative determination that Demai’s generic neratinib maleate tablet falls within the scope of the claims of Nerlynx PatentNo. ZL201080060546.6. On* February 21, 2025,the CNIPA accepted the Company’s petition and started examination. On March 18, 2025,the Company filed a request with the NMPA to set up anine*-month stay on Demai’s ANDA. On* November 4, 2025,the NMPA approved Demai’s ANDA to market a generic version of Puma’s NERLYNX® in China with the approval number of GuoYaoZhunZiH20255844.*

Hexal European Patent Opposition

An opposition was filed by Hexal AG (“Hexal”) on* August 3, 2016against European PatentNo.* EP2416774 which was licensed from Pfizer in2011, 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 leastone year of trastuzumab adjuvant therapy, and wherein the neratinib therapy comprises treating the cancer patients with neratinib for at leasttwelve months. An oral hearing was held on* December 8, 2017,wherein the patent was maintained as granted. Following an appeal filed by Hexal, the Board of Appeal of the European Patent Office rejected the claims as granted and all pending auxiliary requests during the oral hearing of September 2, 2021.Before issuance of a decision, the Company withdrew approval of the text in which the patent was granted and all pending auxiliary requests, thereby revoking the patent and concluding the appeal. One European divisional application, namelyEP15188350.1,* was granted with the European patent numberEP3000467 on* March 1, 2023.Oppositions againstEP3000467* were filed by Hexal on* November 3, 2023,by Alfred E. Tiefenbacher (GmbH & Co. KG) on November 28, 2023and by Generics (UK) Limited (“Generics”) on December 1, 2023.EP3000467 is used as the basic patent for Supplementary Protection Certificate applications for the EMA-approved NERLYNX® product,17 of which have been granted,three proceedings have been stayed, and11 are in active prosecution. The patentee response to the notice of opposition was filed on April 15, 2024,following which, allthree* opponents filed additional arguments in reply to the patentee’s submission. On* February 6, 2025,the Company filed its response to the summons to attend oral proceedings, includingsix* auxiliary requests. Alfred E. Tiefenbacher and Hexal filed their responses to the summons to oral proceedings on* February 6and7,* 2025, respectively. Hexal filed a further brief on* March 19, 2025.Oral proceedings took place on April 9and10,* 2025. EP3000467 was upheld as amended after thefirst instance hearing based on Auxiliary Request1, which covers the EMA approved indication for NERLYNX® as an extended adjuvant therapy for treating early stage hormone receptor-positive HER-2-overexpressed/amplified breast cancer. Hexal filed an appeal on* June 6, 2025,Generics filed an appeal on June 20, 2025and Wyeth filed an appeal on June 30, 2025.On September 5, 2025,Wyeth filed its grounds of appeal, includingnine* auxiliary requests. On the same day, Hexal filed its grounds of appeal. Generics filed its grounds of appeal on* September 4, 2025,and Alfred E. Tiefenbacher filed its grounds of appeal on September 1, 2025.On December 16, 2025,Alfred E. Tiefenbacher withdrew its appeal. Wyeth responded to the opponents’ grounds of appeal on January 12, 2026.On March 2, 2026,*Hexal withdrew its request for oral proceedings, but remains a party to the proceedings.

One European divisional application is pending in the same family, namely EP23157078.9. A response to the European Search Opinion (“ESO”) for this application was filed* February 14, 2024.Thefirst* office action was issued on* January 28, 2025with a response to thefirst* office action filed on* July 22, 2025.An intention to grant was issued in connection with EP23157078.9* on* September 22, 2026.*

31