0001401667 PUMA BIOTECHNOLOGY, INC. false --12-31 Q3 2025 0 362 0.0001 0.0001 100,000,000 100,000,000 50,384,274 50,384,274 49,105,834 49,105,834 0 0 0 0 7.0 2.1 3 3 7 0 0.1 5.417 5 5 0.2 0.7 0.1 0.3 2.4 7.3 2.4 7.3 9.7 9.7 9.7 2.0 3 false false false false Other research and development expense include regulatory affairs, pharmacovigilance, quality assurance, chemical manufacturing and other costs. 0001401667 2025-01-01 2025-09-30 xbrli:shares 0001401667 2025-11-03 thunderdome:item iso4217:USD 0001401667 2025-09-30 0001401667 2024-12-31 iso4217:USD xbrli:shares 0001401667 us-gaap:ProductMember 2025-07-01 2025-09-30 0001401667 us-gaap:ProductMember 2024-07-01 2024-09-30 0001401667 us-gaap:ProductMember 2025-01-01 2025-09-30 0001401667 us-gaap:ProductMember 2024-01-01 2024-09-30 0001401667 us-gaap:RoyaltyMember 2025-07-01 2025-09-30 0001401667 us-gaap:RoyaltyMember 2024-07-01 2024-09-30 0001401667 us-gaap:RoyaltyMember 2025-01-01 2025-09-30 0001401667 us-gaap:RoyaltyMember 2024-01-01 2024-09-30 0001401667 2025-07-01 2025-09-30 0001401667 2024-07-01 2024-09-30 0001401667 2024-01-01 2024-09-30 0001401667 us-gaap:CommonStockMember 2025-06-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2025-06-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2025-06-30 0001401667 us-gaap:RetainedEarningsMember 2025-06-30 0001401667 2025-06-30 0001401667 us-gaap:CommonStockMember 2025-07-01 2025-09-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2025-07-01 2025-09-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2025-07-01 2025-09-30 0001401667 us-gaap:RetainedEarningsMember 2025-07-01 2025-09-30 0001401667 us-gaap:CommonStockMember 2025-09-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2025-09-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2025-09-30 0001401667 us-gaap:RetainedEarningsMember 2025-09-30 0001401667 us-gaap:CommonStockMember 2024-06-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2024-06-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2024-06-30 0001401667 us-gaap:RetainedEarningsMember 2024-06-30 0001401667 2024-06-30 0001401667 us-gaap:CommonStockMember 2024-07-01 2024-09-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2024-07-01 2024-09-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2024-07-01 2024-09-30 0001401667 us-gaap:RetainedEarningsMember 2024-07-01 2024-09-30 0001401667 us-gaap:CommonStockMember 2024-09-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2024-09-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2024-09-30 0001401667 us-gaap:RetainedEarningsMember 2024-09-30 0001401667 2024-09-30 0001401667 us-gaap:CommonStockMember 2024-12-31 0001401667 us-gaap:AdditionalPaidInCapitalMember 2024-12-31 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2024-12-31 0001401667 us-gaap:RetainedEarningsMember 2024-12-31 0001401667 us-gaap:CommonStockMember 2025-01-01 2025-09-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2025-01-01 2025-09-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2025-01-01 2025-09-30 0001401667 us-gaap:RetainedEarningsMember 2025-01-01 2025-09-30 0001401667 us-gaap:CommonStockMember 2023-12-31 0001401667 us-gaap:AdditionalPaidInCapitalMember 2023-12-31 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2023-12-31 0001401667 us-gaap:RetainedEarningsMember 2023-12-31 0001401667 2023-12-31 0001401667 us-gaap:CommonStockMember 2024-01-01 2024-09-30 0001401667 us-gaap:AdditionalPaidInCapitalMember 2024-01-01 2024-09-30 0001401667 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2024-01-01 2024-09-30 0001401667 us-gaap:RetainedEarningsMember 2024-01-01 2024-09-30 xbrli:pure 0001401667 2022-10-31 0001401667 us-gaap:OperatingSegmentsMember 2025-07-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember 2024-07-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember 2025-01-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember 2024-01-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:ClinicalResearchMember 2025-07-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:ClinicalResearchMember 2024-07-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:ClinicalResearchMember 2025-01-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:ClinicalResearchMember 2024-01-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:MedicalAffairsMember 2025-07-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:MedicalAffairsMember 2024-07-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:MedicalAffairsMember 2025-01-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:MedicalAffairsMember 2024-01-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:OtherResearchAndDevelopmentMember 2025-07-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:OtherResearchAndDevelopmentMember 2024-07-01 2024-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:OtherResearchAndDevelopmentMember 2025-01-01 2025-09-30 0001401667 us-gaap:OperatingSegmentsMember pbyi:OtherResearchAndDevelopmentMember 2024-01-01 2024-09-30 0001401667 us-gaap:EmployeeStockOptionMember 2025-07-01 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember 2024-07-01 2024-09-30 0001401667 us-gaap:EmployeeStockOptionMember 2025-01-01 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember 2024-01-01 2024-09-30 0001401667 us-gaap:WarrantMember 2025-07-01 2025-09-30 0001401667 us-gaap:WarrantMember 2024-07-01 2024-09-30 0001401667 us-gaap:WarrantMember 2025-01-01 2025-09-30 0001401667 us-gaap:WarrantMember 2024-01-01 2024-09-30 0001401667 pbyi:UnvestedRestrictedStockUnitsMember 2025-07-01 2025-09-30 0001401667 pbyi:UnvestedRestrictedStockUnitsMember 2024-07-01 2024-09-30 0001401667 pbyi:UnvestedRestrictedStockUnitsMember 2025-01-01 2025-09-30 0001401667 pbyi:UnvestedRestrictedStockUnitsMember 2024-01-01 2024-09-30 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CorporateBondSecuritiesMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2025-09-30 0001401667 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:FairValueMeasurementsRecurringMember 2025-09-30 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:CashEquivalentsMember us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2024-12-31 0001401667 us-gaap:FairValueMeasurementsRecurringMember us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2024-12-31 0001401667 us-gaap:FairValueMeasurementsRecurringMember us-gaap:CommercialPaperMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel1Member us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel2Member us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:FairValueInputsLevel3Member us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:FairValueMeasurementsRecurringMember 2024-12-31 0001401667 us-gaap:CashEquivalentsMember 2025-09-30 0001401667 us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2025-09-30 0001401667 us-gaap:CorporateBondSecuritiesMember 2025-09-30 0001401667 us-gaap:CommercialPaperMember 2025-09-30 0001401667 us-gaap:CashEquivalentsMember 2024-12-31 0001401667 us-gaap:USGovernmentAgenciesDebtSecuritiesMember 2024-12-31 0001401667 us-gaap:CommercialPaperMember 2024-12-31 0001401667 srt:EuropeMember 2025-09-30 utr:Y 0001401667 us-gaap:ComputerEquipmentMember 2025-09-30 0001401667 pbyi:TelephoneEquipmentMember 2025-09-30 0001401667 us-gaap:FurnitureAndFixturesMember 2025-09-30 utr:sqft 0001401667 pbyi:LeaseAgreementOneMember 2011-12-31 0001401667 pbyi:LeaseAgreementOneMember 2025-07-31 0001401667 pbyi:LeaseAgreementOneMember 2025-07-01 2025-07-31 0001401667 pbyi:LeaseAgreementTwoMember 2012-06-30 0001401667 pbyi:LeaseAgreementTwoMember 2012-06-01 2012-06-30 0001401667 stpr:CA 2019-02-28 0001401667 stpr:CA 2019-02-01 2019-02-28 0001401667 pbyi:LeaseAgreementOneMember 2024-12-01 2024-12-31 0001401667 stpr:CA 2025-04-01 0001401667 stpr:CA 2023-08-31 0001401667 stpr:CA 2023-08-01 2023-08-31 0001401667 us-gaap:OtherNonoperatingIncomeExpenseMember 2025-07-01 2025-09-30 0001401667 us-gaap:OtherNonoperatingIncomeExpenseMember 2024-07-01 2024-09-30 0001401667 us-gaap:OtherNonoperatingIncomeExpenseMember 2025-01-01 2025-09-30 0001401667 us-gaap:OtherNonoperatingIncomeExpenseMember 2024-01-01 2024-09-30 0001401667 us-gaap:LeaseholdImprovementsMember 2025-09-30 0001401667 us-gaap:LeaseholdImprovementsMember 2024-12-31 0001401667 us-gaap:ComputerEquipmentMember 2024-12-31 0001401667 pbyi:TelephoneEquipmentMember 2024-12-31 0001401667 us-gaap:FurnitureAndFixturesMember 2024-12-31 0001401667 pbyi:PfizerLicenseAgreementMember 2022-01-01 2022-12-31 0001401667 pbyi:PfizerLicenseAgreementMember 2023-03-31 0001401667 pbyi:PfizerLicenseAgreementMember 2025-07-01 2025-09-30 0001401667 pbyi:PfizerLicenseAgreementMember 2024-07-01 2024-09-30 0001401667 pbyi:PfizerLicenseAgreementMember 2025-01-01 2025-09-30 0001401667 pbyi:PfizerLicenseAgreementMember 2024-01-01 2024-09-30 0001401667 pbyi:PfizerLicenseAgreementMember 2025-09-30 0001401667 pbyi:NotePurchaseAgreementMember 2025-01-01 2025-09-30 0001401667 pbyi:OxfordFinanceLimitedLiabilityCompanyMember pbyi:SecuredPromissoryNotesMember 2021-07-23 0001401667 pbyi:NotePurchaseAgreementMember 2021-07-23 0001401667 pbyi:NotePurchaseAgreementMember 2021-07-23 2021-07-23 0001401667 pbyi:NotePurchaseAgreementMember 2022-09-16 0001401667 pbyi:NotePurchaseAgreementMember us-gaap:SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember 2022-09-16 2022-09-16 0001401667 pbyi:NotePurchaseAgreementMember pbyi:AdjustedSecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember 2022-09-16 2022-09-16 0001401667 pbyi:NotePurchaseAgreementMember 2024-06-30 0001401667 pbyi:NotePurchaseAgreementMember 2024-01-01 2024-06-30 0001401667 pbyi:NotePurchaseAgreementMember 2025-09-30 0001401667 pbyi:AthyriumNotesMember 2025-09-30 0001401667 pbyi:AthyriumNotesMember 2024-12-31 0001401667 pbyi:NotePurchaseAgreementMember 2025-07-01 2025-09-30 0001401667 pbyi:NotePurchaseAgreementMember 2024-07-01 2024-09-30 0001401667 pbyi:NotePurchaseAgreementMember 2024-01-01 2024-09-30 0001401667 2011-10-31 0001401667 us-gaap:CommonStockMember 2012-10-31 0001401667 2024-06-18 0001401667 pbyi:EquityIncentivePlanTwentyElevenMember 2024-06-18 2024-06-18 0001401667 pbyi:EquityIncentivePlanTwentyElevenMember 2025-09-30 0001401667 pbyi:EmployeeAndNonemployeeStockOptionMember 2025-01-01 2025-09-30 0001401667 pbyi:EmployeeAndNonemployeeStockOptionMember 2024-01-01 2024-09-30 0001401667 pbyi:EmploymentInducementIncentiveAwardPlanTwentySeventeenMember srt:MaximumMember 2025-01-01 2025-09-30 0001401667 pbyi:EmploymentInducementIncentiveAwardPlanTwentySeventeenMember 2025-01-01 2025-09-30 0001401667 pbyi:EmploymentInducementIncentiveAwardPlanTwentySeventeenMember 2021-07-15 2021-07-15 0001401667 pbyi:EmploymentInducementIncentiveAwardPlanTwentySeventeenMember 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2025-07-01 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2024-07-01 2024-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2025-01-01 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2024-01-01 2024-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:ResearchAndDevelopmentExpenseMember 2025-07-01 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:ResearchAndDevelopmentExpenseMember 2024-07-01 2024-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:ResearchAndDevelopmentExpenseMember 2025-01-01 2025-09-30 0001401667 us-gaap:EmployeeStockOptionMember us-gaap:ResearchAndDevelopmentExpenseMember 2024-01-01 2024-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2025-07-01 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2024-07-01 2024-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2025-01-01 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:SellingGeneralAndAdministrativeExpensesMember 2024-01-01 2024-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:ResearchAndDevelopmentExpenseMember 2025-07-01 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:ResearchAndDevelopmentExpenseMember 2024-07-01 2024-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:ResearchAndDevelopmentExpenseMember 2025-01-01 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember us-gaap:ResearchAndDevelopmentExpenseMember 2024-01-01 2024-09-30 0001401667 pbyi:The2011And2017PlansMember 2024-12-31 0001401667 pbyi:The2011And2017PlansMember 2025-01-01 2025-09-30 0001401667 pbyi:The2011And2017PlansMember 2025-09-30 0001401667 pbyi:NonvestedStockOptionsMember 2025-09-30 0001401667 pbyi:NonvestedStockOptionsMember 2025-01-01 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember 2025-01-01 2025-06-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember 2025-01-01 2025-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember 2024-01-01 2024-09-30 0001401667 us-gaap:RestrictedStockUnitsRSUMember 2024-12-31 0001401667 pbyi:First3OfEachParticipantsContributionsMember 2025-01-01 2025-09-30 0001401667 pbyi:SecondTwoPercentOfEachParticipantsContributionsMember 2025-01-01 2025-09-30 0001401667 2014-07-18 0001401667 2020-06-01 2020-06-30 0001401667 2021-09-01 2021-09-30 0001401667 pbyi:TakedaMember 2022-10-31 0001401667 pbyi:AstrazenecaLitigationMember us-gaap:SubsidiaryOfCommonParentMember 2021-09-22 2023-12-31
Table of Contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

☒ | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended September 30, 2025

OR

☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission File Number: 001-35703

PUMA BIOTECHNOLOGY, INC.

(Exact name of registrant as specified in its charter)

Delaware | 77-0683487
(State or other jurisdiction of incorporation or organization) | (I.R.S. Employer Identification Number)

10880 Wilshire Boulevard, Suite 2150, Los Angeles, CA 90024

(Address of principal executive offices) (Zip code)

(424) 248-6500

(Registrant’s telephone number, including area code)

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

Title of each class | Trading Symbol(s) | Name of each exchange on which registered
Common Stock, par value $0.0001 per share | PBYI | The NASDAQ Stock Market LLC (NASDAQ Global Select Market)

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

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

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

Large accelerated filer | ☐ | Accelerated filer | ☒
Non-accelerated filer | ☐ | Smaller reporting company | ☒
Emerging growth company | ☐ |  |

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

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

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date. 50,391,107 shares of Common Stock, par value $0.0001 per share, were outstanding as of November 3, 2025.

Table of Contents

PUMA BIOTECHNOLOGY, INC.

- INDEX -

| Page
PART I – FINANCIAL INFORMATION: | 1
Item 1. | Financial Statements (Unaudited): | 1
| Condensed Consolidated Balance Sheets as of September 30, 2025 and December 31, 2024 | 1
| Condensed Consolidated Statements of Operations for the Three and Nine Months Ended September 30, 2025 and 2024 | 2
| Condensed Consolidated Statements of Comprehensive Income for the Three and Nine Months Ended September 30, 2025 and 2024 | 3
| Condensed Consolidated Statements of Stockholders’ Equity for the Three and Nine Months Ended September 30, 2025 and 2024 | 4
| Condensed Consolidated Statements of Cash Flows for the Nine Months Ended September 30, 2025 and 2024 | 6
| Notes to the Unaudited Condensed Consolidated Financial Statements | 7
Item 2. | Management’s Discussion and Analysis of Financial Condition and Results of Operations | 27
Item 3. | Quantitative and Qualitative Disclosures About Market Risk | 35
Item 4. | Controls and Procedures | 35
PART II – OTHER INFORMATION: | 36
Item 1. | Legal Proceedings | 36
Item 1A. | Risk Factors | 38
Item 2. | Unregistered Sales of Equity Securities and Use of Proceeds | 38
Item 3. | Defaults Upon Senior Securities | 38
Item 4. | Mine Safety Disclosures | 39
Item 5. | Other Information | 39
Item 6. | Exhibits | 39
Signatures | 40

Table of Contents

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q, (this “Quarterly Report”), contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). Any statements about our expectations, beliefs, plans, objectives, assumptions, future events or performance are not historical facts and may be forward looking. These forward-looking statements include, but are not limited to, statements about:

| • | the commercialization of NERLYNX® (neratinib) tablets (“NERLYNX”);

| • | the development of our drug candidates, including when we expect to undertake, initiate and complete clinical trials of our drug candidates;

| • | the anticipated timing of regulatory filings;

| • | the regulatory approval of our drug candidates;

| • | our use of clinical research organizations (“CRO”) and other contractors;

| • | our ability to find collaborative partners for research, development and commercialization of potential products;

| • | efforts of our sub-licensees to obtain regulatory approval and commercialize NERLYNX in areas outside the United States;

| • | our ability to market any of our products;

| • | our expectations regarding our costs and expenses;

| • | our anticipated capital requirements and estimates regarding our needs for additional financing;

| • | our ability to compete against other companies and research institutions;

| • | our ability to secure adequate protection for our intellectual property;

| • | our intention and ability to vigorously defend against any litigation to which we are or may become party;

| • | our ability to in-license additional drugs;

| • | our ability to attract and retain key personnel; and

| • | our ability to obtain adequate financing on favorable terms or at all.

These statements are often, but not always, made through the use of words or phrases such as “anticipate,” “estimate,” “plan,” “project,” “continuing,” “ongoing,” “expect,” “believe,” “intend” and similar words or phrases. Accordingly, these statements involve estimates, assumptions and uncertainties that could cause actual results to differ materially from those expressed in them. Discussions containing these forward-looking statements may be found throughout this Quarterly Report, including, in Part I, the section entitled “Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.” These forward-looking statements involve risks and uncertainties, including the risks discussed in Part I, Item 1A. “Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2024, and this Quarterly Report on Form 10-Q, that could cause our actual results to differ materially from those in the forward-looking statements. Such risks should be considered in evaluating our prospects and future financial performance. We undertake no obligation to update the forward-looking statements or to reflect events or circumstances after the date of this document.

Table of Contents

Part I – FINANCIAL INFORMATION

Item 1. | FINANCIAL STATEMENTS

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

CONDENSED CONSOLIDATED BALANCE SHEETS

(in thousands, except share and per share data)

(unaudited)

|  | September 30, 2025 |  |  | December 31, 2024 |
ASSETS |  |  |  |  |  |  |  |
Current assets: |  |  |  |  |  |  |  |
Cash and cash equivalents |  | $ | 53,525 |  |  | $ | 69,219 |
Marketable securities |  |  | 40,863 |  |  |  | 31,746 |
Accounts receivable, net of allowance for credit loss of $0 and $362 |  |  | 33,565 |  |  |  | 32,011 |
Inventory |  |  | 9,476 |  |  |  | 8,724 |
Prepaid expenses, current |  |  | 3,830 |  |  |  | 5,867 |
Restricted cash, current |  |  | 2,091 |  |  |  | — |
Other assets, current |  |  | 230 |  |  |  | 91 |
Total current assets |  |  | 143,580 |  |  |  | 147,658 |
Lease right-of-use assets, net |  |  | 6,147 |  |  |  | 4,579 |
Property and equipment, net |  |  | 305 |  |  |  | 515 |
Intangible assets, net |  |  | 43,827 |  |  |  | 51,131 |
Restricted cash, long-term |  |  | — |  |  |  | 2,091 |
Deferred tax assets |  |  | 7,075 |  |  |  | 7,075 |
Prepaid expenses and other, long-term |  |  | 1,928 |  |  |  | 284 |
Total assets |  | $ | 202,862 |  |  | $ | 213,333 |
LIABILITIES AND STOCKHOLDERS’ EQUITY |  |  |  |  |  |  |  |
Current liabilities: |  |  |  |  |  |  |  |
Accounts payable |  | $ | 6,386 |  |  | $ | 5,509 |
Accrued expenses, current |  |  | 37,116 |  |  |  | 36,898 |
Lease liabilities, current |  |  | 2,470 |  |  |  | 5,540 |
Post-marketing commitment liability |  |  | 2,858 |  |  |  | 2,835 |
Current portion of long-term debt |  |  | 33,716 |  |  |  | 45,329 |
Other liabilities, current |  |  | 182 |  |  |  | — |
Total current liabilities |  |  | 82,728 |  |  |  | 96,111 |
Lease liabilities, long-term |  |  | 4,866 |  |  |  | 1,494 |
Post-marketing commitment liability, long-term |  |  | — |  |  |  | 1,763 |
Long-term debt, net |  |  | — |  |  |  | 21,719 |
Other liabilities, long-term |  |  | — |  |  |  | 121 |
Total liabilities |  |  | 87,594 |  |  |  | 121,208 |
Commitments and contingencies (Note 12) |  |  |  |  |  |  |  |
Stockholders’ equity: |  |  |  |  |  |  |  |
Common stock - $.0001 par value per share; 100,000,000 shares authorized; 50,384,274 shares issued and outstanding at September 30, 2025 and 49,105,834 issued and outstanding at December 31, 2024 |  |  | 5 |  |  |  | 5 |
Additional paid-in capital |  |  | 1,412,457 |  |  |  | 1,407,000 |
Accumulated other comprehensive income |  |  | 19 |  |  |  | 6 |
Accumulated deficit |  |  | (1,297,213 | ) |  |  | (1,314,886 | )
Total stockholders’ equity |  |  | 115,268 |  |  |  | 92,125 |
Total liabilities and stockholders’ equity |  | $ | 202,862 |  |  | $ | 213,333 |

See Accompanying Notes to the Unaudited Condensed Consolidated Financial Statements

1

Table of Contents

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except share and per share data)

(unaudited)

|  | For the Three Months Ended September 30, |  |  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Revenues: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Product revenue, net |  | $ | 51,902 |  |  | $ | 56,136 |  |  | $ | 144,194 |  |  | $ | 140,810 |
Royalty revenue |  |  | 2,573 |  |  |  | 24,406 |  |  |  | 8,724 |  |  |  | 30,581 |
Total revenue |  |  | 54,475 |  |  |  | 80,542 |  |  |  | 152,918 |  |  |  | 171,391 |
Operating costs and expenses: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cost of sales |  |  | 12,173 |  |  |  | 29,097 |  |  |  | 35,030 |  |  |  | 50,483 |
Selling, general and administrative |  |  | 16,817 |  |  |  | 16,819 |  |  |  | 52,468 |  |  |  | 63,541 |
Research and development |  |  | 15,912 |  |  |  | 12,547 |  |  |  | 45,227 |  |  |  | 39,766 |
Total operating costs and expenses |  |  | 44,902 |  |  |  | 58,463 |  |  |  | 132,725 |  |  |  | 153,790 |
Income from operations |  |  | 9,573 |  |  |  | 22,079 |  |  |  | 20,193 |  |  |  | 17,601 |
Other income (expenses): |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Interest income |  |  | 1,044 |  |  |  | 1,282 |  |  |  | 3,101 |  |  |  | 3,498 |
Interest expense |  |  | (1,489 | ) |  |  | (3,100 | ) |  |  | (5,503 | ) |  |  | (9,831 | )
Other income |  |  | 115 |  |  |  | 347 |  |  |  | 884 |  |  |  | 594 |
Total other expenses, net |  |  | (330 | ) |  |  | (1,471 | ) |  |  | (1,518 | ) |  |  | (5,739 | )
Net income before income taxes |  | $ | 9,243 |  |  | $ | 20,608 |  |  | $ | 18,675 |  |  | $ | 11,862 |
Income tax expense |  |  | (399 | ) |  |  | (291 | ) |  |  | (1,002 | ) |  |  | (889 | )
Net income |  | $ | 8,844 |  |  | $ | 20,317 |  |  | $ | 17,673 |  |  | $ | 10,973 |
Net income per share of common stock—basic |  | $ | 0.18 |  |  | $ | 0.41 |  |  | $ | 0.35 |  |  | $ | 0.23 |
Net income per share of common stock—diluted |  | $ | 0.17 |  |  | $ | 0.41 |  |  | $ | 0.35 |  |  | $ | 0.22 |
Weighted-average shares of common stock outstanding—basic |  |  | 50,339,456 |  |  |  | 49,008,464 |  |  |  | 49,881,181 |  |  |  | 48,498,579 |
Weighted-average shares of common stock outstanding—diluted |  |  | 50,929,893 |  |  |  | 49,173,361 |  |  |  | 50,334,553 |  |  |  | 49,025,103 |

See Accompanying Notes to the Unaudited Condensed Consolidated Financial Statements

2

Table of Contents

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(in thousands)

(unaudited)

|  | For the Three Months Ended September 30, |  |  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Net income |  | $ | 8,844 |  |  | $ | 20,317 |  |  | $ | 17,673 |  |  | $ | 10,973 |
Other comprehensive income: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Unrealized gain on available-for-sale securities, net of tax of $0 |  |  | 33 |  |  |  | 58 |  |  |  | 13 |  |  |  | 30 |
Comprehensive income |  | $ | 8,877 |  |  | $ | 20,375 |  |  | $ | 17,686 |  |  | $ | 11,003 |

See Accompanying Notes to the Unaudited Condensed Consolidated Financial Statements

3

Table of Contents

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(in thousands, except share data)

(unaudited)

For the Three Months Ended September 30, 2025 |  |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |  |  | Accumulated |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  | Additional |  |  | Other |  |  |  |  |  |  |  |  |
|  | Common Stock |  |  | Paid-in |  |  | Comprehensive |  |  | Accumulated |  |  |  |  |
|  | Shares |  |  | Amount |  |  | Capital |  |  | Income (Loss) |  |  | Deficit |  |  | Total |
Balance at June 30, 2025 |  |  | 49,892,725 |  |  | $ | 5 |  |  |  | 1,410,784 |  |  |  | (14 | ) |  |  | (1,306,057 | ) |  |  | 104,718 |
Stock-based compensation |  |  | — |  |  |  | — |  |  |  | 1,673 |  |  |  | — |  |  |  | — |  |  |  | 1,673 |
Shares issued or restricted stock units vested under employee stock plans |  |  | 491,549 |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |
Unrealized gain on available-for-sale securities |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 33 |  |  |  | — |  |  |  | 33 |
Net income |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 8,844 |  |  |  | 8,844 |
Balance at September 30, 2025 |  |  | 50,384,274 |  |  | $ | 5 |  |  | $ | 1,412,457 |  |  | $ | 19 |  |  | $ | (1,297,213 | ) |  | $ | 115,268 |

For the Three Months Ended September 30, 2024 |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |  |  | Accumulated |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  | Additional |  |  | Other |  |  |  |  |  |  |  |  |
|  | Common Stock |  |  | Paid-in |  |  | Comprehensive |  |  | Accumulated |  |  |  |  |
|  | Shares |  |  | Amount |  |  | Capital |  |  | Income (Loss) |  |  | Deficit |  |  | Total |
Balance at June 30, 2024 |  |  | 48,460,120 |  |  | $ | 5 |  |  | $ | 1,403,044 |  |  | $ | (32 | ) |  | $ | (1,354,508 | ) |  |  | 48,509 |
Stock-based compensation |  |  | — |  |  |  | — |  |  |  | 2,054 |  |  |  | — |  |  |  | — |  |  |  | 2,054 |
Shares issued or restricted stock units vested under employee stock plans |  |  | 607,228 |  |  |  | — |  |  |  | 150 |  |  |  | — |  |  |  | — |  |  |  | 150 |
Unrealized gain on available-for-sale securities |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 58 |  |  |  | — |  |  |  | 58 |
Net income |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 20,317 |  |  |  | 20,317 |
Balance at September 30, 2024 |  |  | 49,067,348 |  |  | $ | 5 |  |  | $ | 1,405,248 |  |  | $ | 26 |  |  | $ | (1,334,191 | ) |  | $ | 71,088 |

See Accompanying Notes to the Unaudited Condensed Consolidated Financial Statements

4

Table of Contents

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(in thousands, except share data)

(unaudited)

For the Nine Months Ended September 30, 2025 |
|  |  |  |  |  |  |  |  |  |  |  |  |  | Accumulated |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  | Additional |  |  | Other |  |  |  |  |  |  |  |  |
|  | Common Stock |  |  | Paid-in |  |  | Comprehensive |  |  | Accumulated |  |  |  |  |
|  | Shares |  |  | Amount |  |  | Capital |  |  | Income |  |  | Deficit |  |  | Total |
Balance at December 31, 2024 |  |  | 49,105,834 |  |  | $ | 5 |  |  | $ | 1,407,000 |  |  | $ | 6 |  |  | $ | (1,314,886 | ) |  | $ | 92,125 |
Stock-based compensation |  |  | — |  |  |  | — |  |  |  | 5,327 |  |  |  | — |  |  |  | — |  |  |  | 5,327 |
Shares issued or restricted stock units vested under employee stock plans |  |  | 1,278,440 |  |  |  | — |  |  |  | 130 |  |  |  | — |  |  |  | — |  |  |  | 130 |
Unrealized gain on available-for-sale securities |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 13 |  |  |  | — |  |  |  | 13 |
Net income |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 17,673 |  |  |  | 17,673 |
Balance at September 30, 2025 |  |  | 50,384,274 |  |  | $ | 5 |  |  | $ | 1,412,457 |  |  | $ | 19 |  |  | $ | (1,297,213 | ) |  | $ | 115,268 |

For the Nine Months Ended September 30, 2024 |
|  |  |  |  |  |  |  |  |  |  |  |  |  | Accumulated |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  | Additional |  |  | Other |  |  |  |  |  |  |  |  |
|  | Common Stock |  |  | Paid-in |  |  | Comprehensive |  |  | Accumulated |  |  |  |  |
|  | Shares |  |  | Amount |  |  | Capital |  |  | Income (Loss) |  |  | Deficit |  |  | Total |
Balance at December 31, 2023 |  |  | 47,646,787 |  |  | $ | 5 |  |  | $ | 1,398,605 |  |  | $ | (4 | ) |  | $ | (1,345,164 | ) |  | $ | 53,442 |
Stock-based compensation |  |  | — |  |  |  | — |  |  |  | 6,493 |  |  |  | — |  |  |  | — |  |  |  | 6,493 |
Shares issued or restricted stock units vested under employee stock plans |  |  | 1,420,561 |  |  |  | — |  |  |  | 150 |  |  |  | — |  |  |  | — |  |  |  | 150 |
Unrealized gain on available-for-sale securities |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 30 |  |  |  | — |  |  |  | 30 |
Net income |  |  | — |  |  |  | — |  |  |  | — |  |  |  | — |  |  |  | 10,973 |  |  |  | 10,973 |
Balance at September 30, 2024 |  |  | 49,067,348 |  |  | $ | 5 |  |  | $ | 1,405,248 |  |  | $ | 26 |  |  | $ | (1,334,191 | ) |  | $ | 71,088 |

See Accompanying Notes to the Unaudited Condensed Consolidated Financial Statements

5

Table of Contents

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

(unaudited)

|  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |
Operating activities: |  |  |  |  |  |  |  |
Net income |  | $ | 17,673 |  |  | $ | 10,973 |
Adjustments to reconcile net income to net cash provided by operating activities: |  |  |  |  |  |  |  |
Depreciation and amortization |  |  | 8,281 |  |  |  | 8,683 |
Stock-based compensation |  |  | 5,327 |  |  |  | 6,493 |
Provision for credit loss recovery |  |  | (362 | ) |  |  | (121 | )
Disposal of property and equipment |  |  | 4 |  |  |  | — |
Changes in operating assets and liabilities: |  |  |  |  |  |  |  |
Accounts receivable, net |  |  | (1,192 | ) |  |  | (6,685 | )
Inventory, net |  |  | (752 | ) |  |  | 4,407 |
Prepaid expenses and other |  |  | 393 |  |  |  | 2,382 |
Other current assets |  |  | (139 | ) |  |  | 676 |
Accounts payable |  |  | 877 |  |  |  | 620 |
Operating lease assets and liabilities, net |  |  | (1,266 | ) |  |  | (1,164 | )
Accrued expenses and other |  |  | 279 |  |  |  | (2,059 | )
Post-marketing commitment liability |  |  | (1,740 | ) |  |  | (894 | )
Net cash provided by operating activities |  |  | 27,383 |  |  |  | 23,311 |
Investing activities: |  |  |  |  |  |  |  |
Purchase of property and equipment |  |  | (107 | ) |  |  | (40 | )
Purchase of available-for-sale securities |  |  | (61,204 | ) |  |  | (60,956 | )
Maturity of available-for-sale securities |  |  | 52,100 |  |  |  | 42,878 |
Net cash used in investing activities |  |  | (9,211 | ) |  |  | (18,118 | )
Financing activities: |  |  |  |  |  |  |  |
Net proceeds from shares issued under employee stock plans |  |  | 130 |  |  |  | 150 |
Payment of debt |  |  | (33,330 | ) |  |  | (22,220 | )
Payment of exit costs |  |  | (666 | ) |  |  | (445 | )
Net cash used in financing activities |  |  | (33,866 | ) |  |  | (22,515 | )
Net decrease in cash, cash equivalents and restricted cash |  |  | (15,694 | ) |  |  | (17,322 | )
Cash, cash equivalents and restricted cash, beginning of period |  |  | 71,310 |  |  |  | 86,676 |
Cash, cash equivalents and restricted cash, end of period |  |  | 55,616 |  |  |  | 69,354 |
Supplemental disclosures of non-cash investing and financing activities: |  |  |  |  |  |  |  |
Property and equipment purchases in accounts payable |  | $ | — |  |  | $ | 20 |
Supplemental disclosure of cash flow information: |  |  |  |  |  |  |  |
Interest paid |  | $ | 4,838 |  |  | $ | 8,483 |
Income taxes paid |  | $ | 1,277 |  |  | $ | 1,170 |

See Accompanying Notes to the Unaudited Condensed Consolidated Financial Statements

6

Table of Contents

PUMA BIOTECHNOLOGY, INC. AND SUBSIDIARY

NOTES TO THE UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

Note 1—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 of HER2-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 has one subsidiary, Puma Biotechnology, B.V., a Netherlands company. This subsidiary was established for the purpose of legal representation in the European Union (“EU”). The condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany accounts and transactions have been eliminated.

The Company has incurred significant operating losses since its inception. While the Company has previously reported net income, we cannot assure that we will continue to do so and will need to continue to generate significant revenue to sustain operations and successfully commercialize neratinib. In 2017, the Company received U.S. Food and Drug Administration (“FDA”) approval for its first product, NERLYNX® (neratinib), formerly known as PB272 (neratinib, oral), for the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy. 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 metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting.

In 2018, 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 positive HER2-overexpressed/amplified breast cancer and who are less than one 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, 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.

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, 2025, no milestones had been accrued as the underlying contingencies were not probable or estimable.

The Company has reported net income of approximately $17.7 million and cash provided by operations of approximately $27.4 million for the nine months ended September 30, 2025. The Company’s commercialization, research and development or marketing efforts may require funding in addition to the cash and cash equivalents and marketable securities totaling approximately $94.4 million at September 30, 2025.

The Company believes that its existing cash and cash equivalents and marketable securities as of September 30, 2025 and proceeds that will become available to the Company through product sales and sub-license payments are sufficient to satisfy its operating cash needs, including amounts due under the Company’s Note Purchase Agreement with Athyrium Opportunities IV Co-Invest 1 LP (“Athyrium”) (see Note 9—Debt), for at least one year after the filing of the Quarterly Report on Form 10-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. While the Company has been successful in raising capital in the past, there can be no 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. Additionally, the terms of the Company’s Note Purchase Agreement place restrictions on the Company’s ability to operate the business and on the Company’s financial flexibility, and the Company may be unable to achieve the revenue necessary to satisfy the minimum revenue and cash balance covenants as specified in the agreement.

Since its inception through September 30, 2025, the Company’s financing has primarily consisted of proceeds from product, royalty and license revenue, public offerings of its common stock, private equity placements, and various debt instruments.

7

Table of Contents

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 our consolidated financial position as of September 30, 2025. Such adjustments are of a normal and recurring nature. The condensed consolidated balance sheet as of December 31, 2024 was derived from audited annual financial statements but does not contain all of the footnote disclosures from the audited annual financial statements. The condensed consolidated results of operations for the quarter ended September 30, 2025 are not necessarily indicative of the consolidated results of operations that may be expected for the fiscal year ending December 31, 2025.

The Company does not 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 our 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.

Note 2—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.

Segment Reporting:

Management has determined that the Company operates in one reporting segment, which is the development and commercialization of innovative products to enhance cancer care. The Company derives our global product, license and royalty revenue through the sales of NERLYNX®. The majority of our royalty revenue is derived from our sub-licensee sales into China. The accounting policies of this operating segment are the same as those described below in Note 2–Significant Accounting Policies.

Our Chief Operating Decision Maker (“CODM”) is our President, Chief Executive Officer and Chairman of the Board, Alan H. Auerbach. The CODM primarily uses our Consolidated Statement of Operations and related revenues, expenses and net income (loss) in evaluating the performance of the single operating segment and determining how to allocate resources of the Company as a whole, including our 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:

|  | For the Three Months Ended September 30, |  |  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Cost of sales |  | $ | 12,173 |  |  | $ | 29,097 |  |  | $ | 35,030 |  |  | $ | 50,483 |
General and administrative |  |  | 6,142 |  |  |  | 6,136 |  |  |  | 18,860 |  |  |  | 30,074 |
Commercialization |  |  | 9,623 |  |  |  | 9,241 |  |  |  | 30,330 |  |  |  | 29,139 |
Research and development: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Clinical research and development |  |  | 7,789 |  |  |  | 5,667 |  |  |  | 21,881 |  |  |  | 16,547 |
Medical affairs |  |  | 1,323 |  |  |  | 1,220 |  |  |  | 4,107 |  |  |  | 3,414 |
Other research and development (1) |  |  | 6,179 |  |  |  | 5,048 |  |  |  | 17,190 |  |  |  | 17,640 |
Operating costs and expenses |  |  | 43,229 |  |  |  | 56,409 |  |  |  | 127,398 |  |  |  | 147,297 |
Stock based compensation |  |  | 1,673 |  |  |  | 2,054 |  |  |  | 5,327 |  |  |  | 6,493 |
Total operating costs and expenses |  | $ | 44,902 |  |  | $ | 58,463 |  |  | $ | 132,725 |  |  | $ | 153,790 |

(1) Other research and development expense include 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.

8

Table of Contents

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”), 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 is not included in the denominator when calculating diluted earnings per common share if the effect of such common stock equivalent would be anti-dilutive.

Our potentially dilutive securities include potential common shares related to our stock options and RSUs granted in connection with the Puma Biotechnology, Inc. 2011 Incentive Award Plan and the Puma Biotechnology, Inc. 2017 Employment Inducement Incentive Award 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 our stock options in periods in which the option exercise price is greater than the average market price of our 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:

|  | For the Three Months Ended |  |  | For the Nine Months Ended |
|  | September 30, |  |  | September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Options outstanding |  |  | 2,947,276 |  |  |  | 3,850,575 |  |  |  | 3,718,413 |  |  |  | 3,850,575 |
Warrant outstanding |  |  | 2,116,250 |  |  |  | 2,116,250 |  |  |  | 2,116,250 |  |  |  | 2,116,250 |
Unvested restricted stock units |  |  | 229,495 |  |  |  | 751,139 |  |  |  | 354,821 |  |  |  | 751,139 |
Totals |  |  | 5,293,021 |  |  |  | 6,717,964 |  |  |  | 6,189,484 |  |  |  | 6,717,964 |

The 2,116,250 shares underlying the warrant will not have an impact on our diluted net income per share until the average market price of our common stock exceeds the exercise price of $16 per share (see Note 10—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):

|  | For the Three Months Ended September 30, |  |  | For the Nine Months Ended September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Numerator: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income |  | $ | 8,844 |  |  | $ | 20,317 |  |  | $ | 17,673 |  |  | $ | 10,973 |
Denominator: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average common stock outstanding for basic net income per share |  |  | 50,339,456 |  |  |  | 49,008,464 |  |  |  | 49,881,181 |  |  |  | 48,498,579 |
Net effect of dilutive common stock equivalents |  |  | 590,437 |  |  |  | 164,897 |  |  |  | 453,372 |  |  |  | 526,524 |
Weighted average common stock outstanding for diluted net income per share |  |  | 50,929,893 |  |  |  | 49,173,361 |  |  |  | 50,334,553 |  |  |  | 49,025,103 |
Net income per share of common stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basic |  | $ | 0.18 |  |  | $ | 0.41 |  |  | $ | 0.35 |  |  | $ | 0.23 |
Diluted |  | $ | 0.17 |  |  | $ | 0.41 |  |  | $ | 0.35 |  |  | $ | 0.22 |

Revenue Recognition:

Under ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”), 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 in exchange for those goods or services. The Company had no 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.

The Company recognizes revenue on 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 (upon delivery). Product revenue is recorded net of applicable reserves for variable consideration, including discounts and allowances. The Company’s payment terms range between 10 and 68 days.

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

9

Table of Contents

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 is one year or less. However, no such costs were incurred during the nine months ended September 30, 2025 and 2024, respectively.

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 in accordance with Accounting Standards Update (“ASU”) ASU 2013-1, Balance Sheet (Topic 210): Clarifying the Scope of Disclosures about Offsetting Assets and Liabilities, 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 ASC 606 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 may be 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 will not 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 would not likely occur in a future period for the estimates detailed below as of September 30, 2025, and, therefore, the transaction price was not reduced further during the quarter ended September 30, 2025. 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 are not 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 receivables, 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 an insignificant number of returns to date and believes that returns of its products will continue to be minimal.

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 has not 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 have not been paid or for which an invoice has not 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.

10

Table of Contents

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 ASC 606. The terms of these agreements may contain multiple performance obligations, which may include licenses and research and development activities. The Company evaluates these agreements under ASC 606 to determine the distinct performance obligations. Non-refundable, upfront fees that are not contingent on any future performance and require no 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 are not satisfied. The Company’s payment terms range between the execution date of the sub-license agreement and 45 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 will not 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.

Since 2018, 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 include one-time upfront payments when each sub-license agreement was executed and potential additional one-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, 2025, the total potential milestone payments that would be due to the Company upon achievement of all respective performance obligations under the sub-license agreements is 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 ASC 606, the Company recognizes revenue when the related sales occur in accordance with the sales-based royalty exception under ASC 606-10-55-65.

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 between 10 and 60 days.

Royalty Expenses:

Royalties incurred in connection with the Company’s license agreement with Pfizer, as disclosed in Note 12—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 Note 12—Commitments and Contingencies).

11

Table of Contents

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 other third-party costs, salaries and employee benefits, stock-based compensation expense, supplies and materials, and allocations of various overhead costs. Clinical trial expenses include, but are not limited to, investigator fees, site costs, comparator drug costs, and CRO costs. In the normal course of business, the Company contracts with third 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.

In instances where the Company enters into agreements with third 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 does not 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 may be 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 Topic 718, Compensation-Stock Compensation (“ASC 718”) 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 ASC 718, employee and non-employee option grants are generally valued at the grant date and those valuations do not 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. As allowed by ASC 718, the Company’s estimate of expected volatility is based on its average volatility using its expective life, or approximately the last six 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.

Warrants:

Warrants (see Note 10—Stoc kholders’ 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. As allowed by ASC 718, the Company’s estimate of expected volatility is based on its average volatility using its past nine 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.

12

Table of Contents

Income Taxes:

The Company follows ASC Topic 740, Income Taxes (“ASC 740”) 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 than not that the asset will not 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 ASC 740, the Company may recognize the tax benefit from an uncertain tax position only if it is more likely than not 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 than 50% likelihood of being realized upon ultimate settlement. ASC 740 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, 2025, the Company’s uncertain tax positions include a reserve for its research and development credits.

On July 4, 2025, the “One Big Beautiful Bill” was signed into law, which includes significant changes to federal tax law and other regulatory provisions that may impact the Company. As of the date of these financial statements, the Company has evaluated the impact of the changes to Section 174 – Amortization of research and experimental expenditures on the valuation allowance release. The Company intends to deduct the capitalized costs over two years. This deduction reduces the amount of net operating losses being utilized but results in a net zero change to the deferred tax asset balance. Therefore, the Company has concluded that it remains reasonable to maintain the $7.0 million estimate for the valuation allowance release as of September 30, 2025 as the facts and circumstances supporting the deferred tax asset have not materially changed.

Financial Instruments:

The carrying value of financial instruments, such as cash equivalents, accounts receivable and accounts payable, approximate 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 of three 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 will lapse at the end of the respective lease terms through 2 026. At each of the periods ended September 30, 2025 and December 31, 2024, the Company had restricted cash in the amount of approximately $2.1 million.

Investment Securities:

The Company classifies all investment securities (short-term and long-term) as available-for-sale, as the sale of such securities may be 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 ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): 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 Topic 820, Fair Value Measurement (“ASC 820”) 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 ASC 820, 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. ASC 820 creates a three-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 Level 1 having the highest priority and Level 3 having the lowest.

| Level 1: | Quoted prices in active markets for identical assets or liabilities.

13

Table of Contents

| Level 2: | Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets.

| Level 3: | Valuations derived from valuation techniques in which one or more significant inputs are unobservable.

Following are the major categories of assets measured at fair value on a recurring basis as of September 30, 2025 and December 31, 2024, using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3) (in thousands):

September 30, 2025 |  | Level 1 |  |  | Level 2 |  |  | Level 3 |  |  | Total |
Cash equivalents |  | $ | 8,007 |  |  | $ | 39,574 |  |  | $ | — |  |  | $ | 47,581 |
U.S. Government securities |  |  | 20,449 |  |  |  | — |  |  |  | — |  |  |  | 20,449 |
Corporate Bonds |  |  | — |  |  |  | 962 |  |  |  | — |  |  |  | 962 |
Commercial paper |  |  | — |  |  |  | 19,452 |  |  |  | — |  |  |  | 19,452 |
|  | $ | 28,456 |  |  | $ | 59,988 |  |  | $ | — |  |  | $ | 88,444 |

December 31, 2024 |  | Level 1 |  |  | Level 2 |  |  | Level 3 |  |  | Total |
Cash equivalents |  | $ | 16,996 |  |  | $ | 38,102 |  |  | $ | — |  |  | $ | 55,098 |
U.S. Government securities |  |  | 17,568 |  |  |  | — |  |  |  | — |  |  | $ | 17,568 |
Commercial paper |  |  | — |  |  |  | 14,178 |  |  |  | — |  |  |  | 14,178 |
Totals |  | $ | 34,564 |  |  | $ | 52,280 |  |  | $ | — |  |  | $ | 86,844 |

The Company’s investments in commercial paper 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):

| Maturity |  | Amortized |  |  | Unrealized |  |  | Estimated |
September 30, 2025 | (in years) |  | Cost |  |  | Gains |  |  | Losses |  |  | Fair Value |
Cash equivalents |  | $ | 47,583 |  |  | $ | 1 |  |  | $ | (3 | ) |  | $ | 47,581 |
U.S. Government securities | Less than 1 |  |  | 20,433 |  |  |  | 17 |  |  |  | (1 | ) |  |  | 20,449 |
Corporate Bonds | Less than 1 |  |  | 962 |  |  |  | — |  |  |  | — |  |  |  | 962 |
Commercial paper | Less than 1 |  |  | 19,447 |  |  |  | 7 |  |  |  | (2 | ) |  |  | 19,452 |
Totals |  | $ | 88,425 |  |  | $ | 25 |  |  | $ | (6 | ) |  | $ | 88,444 |

| Maturity |  | Amortized |  |  | Unrealized |  |  | Estimated |
December 31, 2024 | (in years) |  | Cost |  |  | Gains |  |  | Losses |  |  | Fair Value |
Cash equivalents |  | $ | 55,095 |  |  | $ | 3 |  |  | $ | — |  |  | $ | 55,098 |
U.S. Government securities | Less than 1 |  |  | 17,564 |  |  | $ | 6 |  |  | $ | (2 | ) |  | $ | 17,568 |
Commercial paper | Less than 1 |  |  | 14,179 |  |  |  | 7 |  |  |  | (8 | ) |  |  | 14,178 |
Totals |  | $ | 86,838 |  |  | $ | 16 |  |  | $ | (10 | ) |  | $ | 86,844 |

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 and restricted cash in excess of the Federal Deposit Insurance Corporation and the Securities Investor Protection Corporation insured limits at September 30, 2025 were approximately $54.9 million. The Company does not 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.

14

Table of Contents

The Company relies exclusively on third 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 those third parties fail to provide sufficient quantities of product or fail to do so at acceptable quality levels or prices. The Company has no experience in drug formulation or manufacturing and does not 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 by third-party contractors. The Company is using the same third-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 with one or more of these third-party contractors, it could experience delays in the development or commercialization efforts as it locates and qualifies new manufacturers. The Company intends to rely on one or more third-party contractors to manufacture the commercial supply of drugs.

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 a first-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 is first 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, approximately $4.8 million is located at contract manufacturing organizations in Europe as of September 30, 2025.

The Company’s inventory balances are as follows:

|  | September 30, 2025 |  |  | December 31, 2024 |
Raw materials |  | $ | 3,642 |  |  | $ | 7,183 |
Work-in-process (materials, labor and overhead) |  |  | 5,395 |  |  |  | 758 |
Finished goods (materials, labor and overhead) |  |  | 439 |  |  |  | 783 |
Total inventories |  | $ | 9,476 |  |  | $ | 8,724 |

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, and seven 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 Topic 360, Property, Plant, and Equipment (“ASC 360”). 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 the three months ended September 30, 2025 and 2024.

Leases:

ASC Topic 842, Leases, as adopted in the first quarter of 2019, requires 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 ASC 360. 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 the two continues to be presented as a single lease cost. If a lease is planned to be abandoned with no intention of subleasing, the ROU asset should be assessed for impairment.

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 Note 5—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 do not 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.

15

Table of Contents

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

• The term of the lease has been modified or there has been a change in the Company’s assessment of a purchase option being exercised, in which case the lease liability is remeasured by discounting the revised lease payments using a revised discount

rate;

• A lease contract is modified, and the lease modification is not accounted for as a separate lease, in which case the lease liability is remeasured by discounting the revised lease payments using a revised discount rate; and

• The lease payments are adjusted due to changes in the index or a change in expected payment under a guaranteed residual value, in which cases the lease liability is remeasured by discounting the revised lease payments using the initial discount rate.

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 are not 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, 2025 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 has no 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 may exist. Events that could result in an impairment, or trigger an interim impairment assessment, include the receipt of additional clinical or non-clinical data regarding one 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.

Recently Issued Accounting Standards:

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The ASU requires the annual financial statements to include consistent categories and greater disaggregation of information in the rate reconciliation, and income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for the Company’s annual reporting periods beginning after December 15, 2024. Adoption is either with a prospective method or a fully retrospective method of transition. Early adoption is permitted. The Company is currently evaluating the effect that adoption of ASU 2023-09 will have on its consolidated financial statements.

In November 2024, the FASB issued ASU 2024-03, 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. We are currently evaluating the impact of adopting this ASU on its consolidated financial statements and related disclosures.

Note 3—Accounts Receivable, Net:

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

|  | September 30, 2025 |  |  | December 31, 2024 |
Trade accounts receivable |  | $ | 30,811 |  |  | $ | 26,362 |
Royalty revenue receivable |  |  | 2,754 |  |  |  | 6,011 |
Total accounts receivable |  | $ | 33,565 |  |  | $ | 32,373 |
Allowance for credit losses |  |  | 0 |  |  |  | (362 | )
Total accounts receivable, net |  | $ | 33,565 |  |  | $ | 32,011 |

16

Table of Contents

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, 2025 and December 31, 2024.

For all accounts receivable, the Company recognizes credit losses based on lifetime expected losses to selling, general and administrative expense in the condensed consolidated statements of operations. In determining estimated credit losses, the Company evaluates its historical loss rates, current economic conditions and reasonable and supportable forecasts of future economic conditions. The Company recorded a recovery to the provision for credit loss of $0.1 million for each of the three months ended September 30, 2025 and 2024. The Company recorded a recovery to the provision for credit loss of $0.4 and $0.1 million for the nine months ended September 30, 2025 and 2024, respectively.

Note 4—Prepaid Expenses and Other:

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

|  | September 30, 2025 |  |  | December 31, 2024 |
Current: |  |  |  |  |  |  |  |
CRO services |  | $ | 74 |  |  | $ | 81 |
Other clinical development |  |  | 383 |  |  |  | 347 |
Insurance |  |  | 218 |  |  |  | 1,078 |
Professional fees |  |  | 940 |  |  |  | 731 |
Prepaid Taxes |  |  | 409 |  |  |  | 21 |
Other |  |  | 1,806 |  |  |  | 3,609 |
|  |  | 3,830 |  |  |  | 5,867 |
Long-term: |  |  |  |  |  |  |  |
CRO services |  |  | 15 |  |  |  | 52 |
Insurance |  |  | 9 |  |  |  | 11 |
Other clinical development |  |  | 74 |  |  |  | 102 |
Other |  |  | 1,830 |  |  |  | 119 |
|  |  | 1,928 |  |  |  | 284 |
Totals |  | $ | 5,758 |  |  | $ | 6,151 |

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

Note 5—Leases:

In December 2011, the Company entered into a non-cancelable operating lease for office space in Los Angeles, California, which was subsequently amended in November 2012, December 2013, March 2014, July 2015 and December 2017. The initial term of the lease was for seven years and commenced on December 10, 2011. As amended, the Company rents approximately 65,656 square feet. The term of the lease runs until March 2026. In July 2025, the Company executed an amendment to its office space in Los Angeles, California to surrender certain suites effective March 31, 2026 and extend the lease term for the remaining 26,700 rentable square feet for an additional five years and five months through August 31, 2031. Base rent escalates annually and is abated from April 2026 through August 2026. Lease payments also include variable charges for the Company’s proportionate share of building operating expenses and real estate taxes based on a 2026 base year. The Company has the option to renew such lease for an additional five year term. Management determined that the renewal option is not reasonably certain to occur. The Company accounted for this amendment as a lease modification. There was no change in the lease classification as a result of this modification and the Company continues to recognize such a lease as an operating lease. The Company remeasured its ROU assets and operating lease liabilities using an updated incremental borrowing rate. The change in ROU assets and operating lease liabilities related to this lease modification amounted to $4.1 million.

In June 2012, the Company entered into a long-term lease agreement for office space in South San Francisco, California, which was subsequently amended in May 2014 and July 2015. As amended, the Company rents approximately 29,470 square feet. The term of this lease runs until March 2026, with the option to extend for an additional five-year term, and rents payable by the Company increase approximately 3% per year. The Company provided the landlord an automatically renewable stand-by letter of credit in the amount of $1.1 million. The stand-by letter of credit is collateralized by a high-yield savings account, which is classified as restricted cash, current on the accompanying consolidated balance sheets.

Total rent expense for the three and nine months ended September 30, 2025 was approximately $1.1 million and $3.4 million, respectively. Total rent expense for the three and nine months ended September 30, 2024 was approximately $1.2 million and $3.7 million, respectively. For purposes of determining straight-line rent expense, the lease term is calculated from the date the Company first 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 may be 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 therefore not 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.

17

Table of Contents

Supplemental cash flow information related to leases for the nine months ended September 30, 2025: |  |  |  |
Operating cash flows used for operating leases (in thousands) |  | $ | 4,813 |
Right-of-use assets obtained in exchange for new operating lease liabilities |  |  | 4,123 |
Weighted-average remaining lease term (in years) |  |  | 5.9 |
Weighted average discount rate |  |  | 12.4 | %

Future minimum lease payments as of September 30, 2025 were as follows (in thousands):

|  | Amount |
2025 (remaining) |  | $ | 1,508 |
2026 |  |  | 1,913 |
2027 |  |  | 1,248 |
2028 |  |  | 1,292 |
2029 |  |  | 1,337 |
Thereafter |  |  | 2,335 |
Total minimum lease payments |  | $ | 9,634 |
Less: imputed interest |  |  | (2,298 | )
Total lease liabilities |  | $ | 7,336 |

In February 2019, the Company entered into a long-term sublease agreement for 12,429 square feet of the office space in Los Angeles, California. The term of the lease ran until March 2026 and rent amounts payable to the Company increased approximately 3% per year. The February 2019 sublease was terminated in December 2024. As a result, the Company received $0.7 million, which approximated the sublease rental payments on the remaining lease term. During the three month period ended March 31, 2025, the Company signed another sublease agreement for the 12,429 square feet of office space with a sublease commencement date of April 1, 2025.

In August 2023, the Company entered into a long-term sublease agreement for 13,916 square feet of the office space in Los Angeles, California, which commenced in November 2023. The term of the lease runs until March 2026 and the rent amounts payable to the Company increase approximately 3% per year. The Company has recorded sublease income in other income (expenses) in the condensed consolidated statements of operations since November 2023.

The Company recorded operating sublease income of $0.2 million for each of the three months ended September 30, 2025 and 2024, and approximately $0.7 million for each of the nine months ended September 30, 2025 and 2024, respectively, in other income (expenses) in the condensed consolidated statements of operations.

The future minimum lease payments to be received as of September 30, 2025, were as follows (in thousands):

|  | Amount |
2025 |  | $ | 132 |
2026 |  |  | 132 |
Total |  | $ | 264 |

Note 6—Property and Equipment, Net:

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

|  | September 30, 2025 |  |  | December 31, 2024 |
Leasehold improvements |  | $ | 3,779 |  |  | $ | 3,779 |
Computer equipment |  |  | 756 |  |  |  | 2,150 |
Telephone equipment |  |  | — |  |  |  | 95 |
Furniture and fixtures |  |  | 2,359 |  |  |  | 2,359 |
Total property and equipment |  |  | 6,894 |  |  |  | 8,383 |
Less: accumulated depreciation |  |  | (6,589 | ) |  |  | (7,868 | )
Property and equipment, net |  | $ | 305 |  |  | $ | 515 |

For the three and nine months ended September 30, 2025 and 2024, the Company incurred depreciation expense of $0.1 million and $0.3 million, respectively.

Note 7—Intangible Assets, Net:

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

|  | September 30, 2025 |  |  | December 31, 2024 |
Acquired and in-licensed rights |  | $ | 102,500 |  |  | $ | 102,500 |
Less: accumulated amortization |  |  | (58,673 | ) |  |  | (51,369 | )
Total intangible assets, net |  | $ | 43,827 |  |  | $ | 51,131 |

18

Table of Contents

For each of the three and nine months ended September 30, 2025 and 2024, the Company incurred amortization expense of $2.4 million and $7.3 million, respectively. The estimated remaining useful life of the intangible assets as of September 30, 2025 is 4.5 years.

Company reached a commercial milestone by achieving aggregate worldwide net sales of $250.0 million in calendar year 2022, resulting in a payment to Pfizer of $12.5 million during the three 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 through 2030. The Company recorded amortization expense related to its intangible assets of approximately $2.4 million and $7.3 million for the three and nine months ended September 30, 2025 and 2024, respectively. As of September 30, 2025, estimated future amortization expense related to the Company’s intangible assets is approximately $2.4 million for the remainder of 2025 and $9.7 million for each year starting 2026 through 2029, and $2.4 million for 2030.

Note 8—Accrued Expenses:

Accrued expenses consisted of the following (in thousands):

|  | September 30, 2025 |  |  | December 31, 2024 |
Current: |  |  |  |  |  |  |  |
Accrued royalties |  | $ | 8,901 |  |  | $ | 10,169 |
Accrued CRO services |  |  | 2,666 |  |  |  | 1,035 |
Accrued variable consideration |  |  | 11,301 |  |  |  | 10,829 |
Accrued bonus |  |  | 5,647 |  |  |  | 7,976 |
Accrued compensation |  |  | 5,420 |  |  |  | 4,368 |
Accrued other clinical development |  |  | 590 |  |  |  | 935 |
Accrued professional fees |  |  | 454 |  |  |  | 341 |
Accrued legal fees |  |  | 1,049 |  |  |  | 1,095 |
Accrued manufacturing costs |  |  | 917 |  |  |  | 39 |
Other |  |  | 171 |  |  |  | 111 |
|  | $ | 37,116 |  |  | $ | 36,898 |
Long-term: |  |  |  |  |  |  |  |
Accrued other liabilities |  |  | — |  |  |  | 121 |
|  |  | — |  |  |  | 121 |
Totals |  | $ | 37,116 |  |  | $ | 37,019 |

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 severance, commissions and vacation.

Note 9—Debt:

Long term debt consisted of the following (in thousands):

|  | September 30, 2025 |  | Maturity Date
Total debt, inclusive of $2.0 million exit payment |  | $ | 102,000 |  | July 23, 2026
Less: unamortized debt issuance costs and discounts |  |  | (291 | ) |
Less: current portion |  |  | (33,716 | ) |
Less: debt repayment |  |  | (67,993 | ) |
Total long-term debt, net |  | $ | (0 | ) |

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, 2021 by 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 require a 2.0% exit payment to be made on each payment of principal. The borrowings under the Athyrium Notes, together with cash on hand, were used to repay the Company’s outstanding indebtedness, including the applicable exit and prepayment fees owed to lenders under its prior credit facility with Oxford. The Athyrium Notes are secured by substantially all of the Company’s assets. The Company incurred $1.9 million of deferred financing costs with the initial borrowing of the Athyrium Notes.

19

Table of Contents

Interest on the Athyrium Notes is calculated in part based on the Secured Overnight Financing Rate (“SOFR”), which replaced the “London Interbank Offering Rate” as the floating benchmark for interest rate calculations applicable to the Athyrium Notes pursuant to the terms of the Third Amendment to Note Purchase Agreement dated as of September 16, 2022.

Following the effectiveness of the Third Amendment, the Athyrium Notes bear 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 of three months plus (y) 0.26161% (26.161 basis points) and (ii) three and one-half of one percent (3.50%) per annum. Interest is payable quarterly on the last business day of March, June, September and December each year. In the second quarter of 2024, the Company began paying the principal payments required to be made quarterly at 11.11% of the original face amount. The remaining balance will be paid at maturity. Each principal payment also includes a 2.0% exit payment. Each quarterly principal payment approximates $11.1 million, and each quarterly exit fee payment approximates $0.2 million. As of September 30, 2025, the effective interest rate for the loan was 12.99%.

As of September 30, 2025, the Company may prepay the outstanding principal balance of the notes, in whole or in part, without premium or penalty.

The Athyrium Notes include affirmative and negative covenants applicable to the Company. The affirmative covenants include, among others, covenants requiring the Company to maintain its legal existence and governmental approvals, deliver certain financial reports, maintain insurance coverage, and satisfy certain requirements regarding deposit accounts. The negative covenants include, among others, restrictions on the Company’s transferring collateral, incurring additional indebtedness, engaging in mergers or acquisitions, paying dividends or making other distributions, making investments, creating liens, selling assets and suffering a change in control, in each case subject to certain exceptions. The Company is also required to maintain minimum cash balances and achieve certain minimum product revenue targets, measured as of the last day of each fiscal quarter on a trailing year-to-date basis. As of September 30, 2025, the Company was in compliance with such covenants.

As of September 30, 2025, the principal balance outstanding under the Athyrium Notes was $33.3 million and exit fees were $0.7 million, representing all of the Company’s debt.

The future minimum principal and exit payments under the Athyrium Notes as of September 30, 2025 are as follows (in thousands):

|  | Amount |
2025 |  |  | 11,332 |
2026 |  |  | 22,675 |
Total |  | $ | 34,007 |

Debt Issuance Costs and Discounts:

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

|  | September 30, 2025 |  |  | December 31, 2024 |
Debt issuance costs and discounts (Athyrium Notes) |  | $ | 5,410 |  |  | $ | 5,410 |
Less: accumulated amortization |  |  | (5,119 | ) |  |  | (4,454 | )
Included in current portion of debt |  | $ | 291 |  |  | $ | 956 |

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. For the three and nine months ended September 30, 2025, the Company recorded approximately $0.1 million and $0.5 million of interest expense, respectively. For the three and nine months ended September 30, 2024, the Company recorded approximately $0.2 million and $0.7 million of interest expense, respectively.

Note 10—Stockholders’ Equity:

Common Stock:

The Company issued 55,882 and 64,118 shares of common stock upon exercise of stock options during the nine months ended September 30, 2025 and 2024, respectively. The Company issued 1,222,558 and 1,356,443 shares of common stock upon vesting of RSUs during the nine months ended September 30, 2025 and 2024, 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 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.

In connection with the closing of a public offering in October 2012, the exercise price and number of shares underlying the warrant issued to Mr. Auerbach were established and, accordingly, the final value of the warrant became fixed. Pursuant to the terms of the warrant, as amended in June 2021, Mr. Auerbach may exercise the warrant to acquire 2,116,250 shares of the Company’s common stock at $16 per share until October 4, 2026.

20

Table of Contents

Stock Options and Restricted Stock Units:

The Company’s 2011 Plan, as amended, was adopted by the Company’s Board of Directors on September 15, 2011. Pursuant to the 2011 Plan, the Company may grant incentive stock options and nonqualified stock options, as well as other forms of equity-based compensation. Incentive stock options may be granted only to employees, while consultants, employees, officers, and directors are eligible for the grant of nonqualified options under the 2011 Plan. The maximum term of stock options granted under the 2011 Plan is 10 years and the awards generally vest over a three-year period. The exercise price of incentive stock options granted under the 2011 Plan must be at least equal to the fair value of such shares on the date of grant. On June 18, 2024, the stockholders of the Company approved an amendment to the Company’s 2011 Plan, increasing the number of authorized shares of the Company’s common stock, par value $0.0001 per share, that may become issuable under the 2011 Plan by 3,000,000 shares and extending the period during which incentive stock options may be granted. As of September 30, 2025 a total of 17,529,412 shares of the Company’s common stock have been reserved for issuance under the 2011 Plan.

All of the options awarded by the Company have been “plain vanilla options” as determined by the SEC Staff Accounting Bulletin 107 - Share Based Payment. As of September 30, 2025, 4,518,398 shares of the Company’s common stock are issuable upon the exercise of outstanding stock options and vesting of RSUs granted under the 2011 Plan and 3,310,878 shares of the Company’s common stock are available for future issuance under the 2011 Plan. The fair value of options granted to employees and nonemployees was estimated using the Black-Scholes Option Pricing Method (see Note 2—Significant Accounting Policies) with the following weighted-average assumptions used during the nine months ended September 30, 2025:

|  | 2025 |  |  | 2024 |
Dividend yield |  |  | 0.0 | % |  |  | 0.0 | %
Expected volatility |  |  | 81.5 | % |  |  | 85.8 | %
Risk-free interest rate |  |  | 4.4 | % |  |  | 4.1 | %
Expected life in years |  |  | 5.55 |  |  |  | 5.55 |

The Company’s 2017 Plan, as amended, was adopted by the Company’s Board of Directors on April 27, 2017. Pursuant to the 2017 Plan, the Company may grant 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 the 2017 Plan is 10 years and the awards generally vest over a three-year period. The exercise price of stock options granted und er the 2017 Plan must be at least equal to the fair market value of such shares on the date of grant. On July 15, 2021, the Board of Directors adopted an amendment to the 2017 Plan to increase the number of shares of the Company’s common stock reserved for issuance thereunder by 1,000,000 share s. As of September 30, 2025 a total of 3,000,000 shares of the Company’s common stock have been reserved for issuance under the 2017 Plan. As of September 30, 2025, a total of 393,800 shares of the Company’s common stock are issuable upon the exercise of outstanding stock options and vesting of RSUs granted under the 2017 Plan and 1,328,505 shares of the Company’s common stock are available for future issuance under the 2017 Plan.

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

|  | For the Three Months Ended |  |  | For the Nine Months Ended |
|  | September 30, |  |  | September 30, |
|  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
Stock-based compensation: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Options: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Selling, general, and administrative |  | $ | 236 |  |  | $ | 386 |  |  | $ | 781 |  |  | $ | 1,247 |
Research and development |  |  | 31 |  |  |  | 57 |  |  |  | 124 |  |  |  | 234 |
Restricted stock units: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Selling, general, and administrative |  |  | 815 |  |  |  | 1,056 |  |  |  | 2,497 |  |  |  | 3,081 |
Research and development |  |  | 591 |  |  |  | 555 |  |  |  | 1,925 |  |  |  | 1,931 |
Total stock-based compensation expense |  | $ | 1,673 |  |  | $ | 2,054 |  |  | $ | 5,327 |  |  | $ | 6,493 |

Activity with respect to options granted under the 2011 Plan and 2017 Plan is summarized as follows:

Stock Option Roll Forward:

|  | Shares |  |  | Weighted Average Exercise Price |  |  | Weighted Average Remaining Contractual Term (years) |  |  | Aggregate Intrinsic Value (in thousands) |
Outstanding at December 31, 2024 |  |  | 4,051,928 |  |  | $ | 33.80 |  |  |  |  |  |  |  |  |
Granted |  |  | 492,514 |  |  |  | 2.78 |  |  |  |  |  |  |  |  |
(Forfeited) |  |  | (84,954 | ) |  |  | 3.57 |  |  |  |  |  |  |  |  |
(Exercised) |  |  | (55,882 | ) |  |  | 2.33 |  |  |  |  |  |  |  |  |
(Expired) |  |  | (850,176 | ) |  |  | 60.00 |  |  |  |  |  |  |  |  |
Outstanding at September 30, 2025 |  |  | 3,553,430 |  |  | $ | 21.73 |  |  |  | 5.1 |  |  | $ | 2,774 |
Vested and expected to vest at September 30, 2025 |  |  | 3,553,430 |  |  | $ | 21.73 |  |  |  | 5.1 |  |  | $ | 2,774 |
Exercisable |  |  | 3,147,703 |  |  | $ | 24.07 |  |  |  | 4.6 |  |  | $ | 1,964 |

21

Table of Contents

At September 30, 2025, total estimated unrecognized employee compensation cost related to non-vested stock options granted prior to that date was approximately $0.7 million, which is expected to be recognized over a weighted-average period o f 1.1 years. At September 30, 2025, the total estimated unrecognized employee compensation cost related to non-vested RSUs was approximately $3.8 million, which is expected to be recognized over a weighted-average period of 1.3 years. The weighted-average grant date fair value of options granted during the nine months ended September 30, 2025 and 2024 was $1.95 and $4.57 per share, respectively. The weighted average grant date fair value of RSUs awarded during the nine months ended September 30, 2025 and 2024 was $3.34 and $5.89 per share, respectively.

Restricted Stock Unit Roll Forward:

|  | Shares |  |  | Weighted Average Grant-Date Fair Value |
Nonvested shares at December 31, 2024 |  |  | 1,289,449 |  |  | $ | 5.14 |
Granted |  |  | 1,406,086 |  |  | $ | 3.34 |
(Forfeited) |  |  | (114,209 | ) |  | $ | 4.02 |
(Vested) |  |  | (1,222,558 | ) |  | $ | 4.60 |
Nonvested shares at September 30, 2025 |  |  | 1,358,768 |  |  | $ | 3.86 |

Note 11—401(k) Savings Plan:

During 2012, the Company adopted a 401(k) savings plan for the benefit of its employees. The Company is required to make matching contributions to the 401(k) plan equal to 100% of the first 3% of wages deferred by each participating employee and 50% on the next 2% of wages deferred by each participating employee. The Company incurred expenses for employer matching contributions of approximately $1.4 million and $1.4 million for the nine months ended September 30, 2025 and 2024, respectively.

Note 12—Commitments and Contingencies:

Contractual Obligations:

Contractual obligations represent future cash commitments and liabilities under agreements with third 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 clinical research organizations, which include potential payments we may be required to make under our 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 of PB272 (neratinib, oral), PB272 (neratinib, intravenous) and PB357, 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 containing one 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. From the closing date of the agreement through December 31, 2011, Pfizer continued to conduct the existing clinical trials on behalf of the Company at Pfizer’s sole expense. At the Company’s request, Pfizer agreed to continue to perform certain services in support of the existing clinical trials at the Company’s expense. These services would continue through the completion of the transitioned clinical trials. The license agreement “capped” the out-of-pocket expense the Company would incur to complete the then existing clinical trials. All agreed upon costs incurred by the Company above the “cost cap” would be reimbursed by Pfizer. The Company exceeded the “cost cap” during the fourth quarter of 2012. In accordance with the license agreement, the Company billed Pfizer for agreed upon costs above the “cost cap” until December 31, 2013.

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.

22

Table of Contents

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 July of 2017, the Company triggered a one-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 a one-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 year 2022, resulting in a payment to Pfizer of $12.5 million during the three 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 through 2030. 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 after first 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 a third 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.

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 will assume sole responsibility for the global development and commercialization of alisertib. Takeda received an upfront license fee of $7.0 million in October 2022 and 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, 2025.

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, and no 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 but not 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 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 in Eshelman 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 in Eshelman v. Puma Biotechnology, Inc., et al. The Company is seeking recovery of the entire amount awarded in Eshelman 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 defendant 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 the Eshelman v. Puma Biotechnology, Inc., et al. 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 in Eshelman 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. The Supreme Court has not decided whether to accept the case for review.

23

Table of Contents

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”) and 10,596,162 (“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 as not 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, 2024 and April 29, 2024 orders. 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 the three 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 are not invalid. The jury awarded damages to Wyeth for past acts of infringement through December 31, 2023, in the amount of $107,500,000. A separate bench trial related to certain equitable claims and defenses raised by AstraZeneca was held before Judge Kennelly on June 20 and 25, 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 had not 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 under 35 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 appeal. That motion was granted on May 16, 2025. On June 6, 2025, Wyeth filed its reply brief. Briefing on the appeal is now complete, and the parties await further order from the Court.

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 of three patents listed on the China Patent Information Registration Platform for Marketed Drugs (“Chinese Orange Book”), namely, Chinese Patent Nos. ZL201410082103.7, ZL201080060546.6, and ZL200880118789.3 (the “’789 patent” and collectively, the “NERLYNX® Patents”), alleging in a Type 4.2 patent declaration that its generic version of NERLYNX does not 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 for nine months. On July 11, 2022, CNIPA decided that claims 5 and 6 of Patent No. ZL200880118789.3 are not eligible for registration in the Chinese Orange Book on the ground that these two pharmaceutical method-of-use claims fall within the scope of “patents of crystalline forms,” which are not eligible for listing in the Chinese Orange Book. On September 9, 2022, CNIPA decided that the generic drug in Acebright’s ANDA does not fall within the protection scope of claims 1, 3, 5 and 6 of Patent No. ZL201410082103.7 and claims 1-4, 7 and 9-13 of Patent No. ZL201080060546.6. The three 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 2023 at the Beijing Intellectual Property Court (“BJIPC”). The three appeals were accepted by BJIPC on February 20, 2023. The Company also filed three civil complaints based on the three NERLYNX® Patents against Acebright with the BJIPC in July 2022 and 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 withdrew two civil lawsuits and two appeals in relation to Chinese Patent Nos. ZL201410082103.7 and ZL201080060546.6 at the BJIPC. On May 24, 2023, the BJIPC accepted the Company’s withdrawal request. On July 24, 2023, the Company withdrew the one remaining civil lawsuit and one appeal in relation to Chinese Patent No. 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 GuoYaoZhunZi H20234141.

On December 28, 2023, the Company filed a civil lawsuit against Acebright for infringement of the ’789 patent under Article 11 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.

24

Table of Contents

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) Su 01 Min Chu 2192 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 for examining evidence and debating merits of party arguments.

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 application No. is CYHS2202006. Aosaikang made Type 4.2 declarations against the four Orange Book Patents ZL201410082103.7, ZL201080060546.6, ZL200880118789.3 and ZL201710057547.9, alleging that its generic version of NERLYNX does not fall within the scope of the claims of the Orange Book patents. Aosaikang also alleged that Patents ZL200880118789.3 and ZL201710057547.9 are not eligible for Chinese Orange Book listing.

On December 28, 2022, the Company submitted four Article 76 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 the four Orange Book patents. On January 6, 2023, the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos. ZL201410082103.7 and ZL201080060546.6. Also on January 6, 2023, the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos. ZL200880118789.3 and ZL201710057547.9, alleging that the listed claims are not 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 are not eligible for listing in the Chinese Orange Book. On January 28, 2023, the Company requested the NMPA to institute a nine-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 does not fall within the protection scope of claims 1, 3, 5 and 6 of Patent No. ZL201410082103.7 and claims 1-4, 7 and 9-13 of Patent No. ZL201080060546.6. The two 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 GuoYaoZhunZi H20249180.

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 application No. is CYHS2202095. On December 23, 2022, Convalife made Type 4.2 declarations against the four Orange Book Patents ZL201410082103.7, ZL201080060546.6, ZL200880118789.3 and ZL201710057547.9, alleging that its generic version of NERLYNX does not fall within the scope of the claims of the Orange Book patents. Convalife also alleged that Patents ZL200880118789.3 and ZL201710057547.9 are not eligible for Chinese Orange Book listing.

On February 1, 2023, the Company submitted four Article 76 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 the four Orange Book patents. On February 3, 2023, the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos. ZL201410082103.7 and ZL201080060546.6. Also on February 3, 2023, the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos. ZL200880118789.3 and ZL201710057547.9, alleging that the listed claims are not 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 are not eligible for listing in the Chinese Orange Book. On February 24, 2023, the Company requested the NMPA to institute a nine-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 does not fall within the protection scope of claims 1, 3, 5 and 6 of Patent No. ZL201410082103.7 and claims 1-4, 7 and 9-13 of Patent No. ZL201080060546.6. The two 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 GuoYaoZhunZi H20244222.

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 application No. is CYHS2300221. On January 28, 2023, Kelun made Type 4.2 declarations against the four Orange Book Patents ZL201410082103.7, ZL201080060546.6, ZL200880118789.3 and ZL201710057547.9, alleging that its generic version of NERLYNX does not fall within the scope of the claims of the Orange Book patents. Kelun also alleged that Patents ZL200880118789.3 and ZL201710057547.9 are not eligible for Chinese Orange Book listing.

On March 13, 2023, the Company submitted four Article 76 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 the four 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 and ZL201710057547.9, alleging that the listed claims are not 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 are not 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 and ZL201080060546.6. On April 17, 2023, the Company requested the NMPA to institute a nine-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 the two requests for administrative determination in relation to Chinese Patent Nos. ZL201410082103.7 and ZL201080060546.6 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 GuoYaoZhunZi H20255337.

25

Table of Contents

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 application No. is CYHS2402776. On August 26, 2024, Demai made a Type 4.2 declaration against Orange Book Patent ZL201410082103.7, alleging that its generic version of NERLYNX does not 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 Patent No. ZL201080060546.6 and on October 8, 2024, the Company filed a lawsuit against Demai at the BJIPC based on Nerlynx Patent No. ZL201410082103.7. On February 13, 2025, the Company withdrew the lawsuits from BJIPC, filed an Article 76 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 Patent No. 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 a nine-month stay on Demai’s ANDA.

Hexal European Patent Opposition

An Opposition was filed by Hexal AG (“Hexal”) on August 3, 2016 against European Patent No. EP2416774 which was licensed from Pfizer in 2011, and which claims neratinib for use in a method for treating HER-2/neu overexpressed/amplified cancer and improving IDFS, wherein the method comprises delivering neratinib therapy to HER-2/neu overexpressed/amplified cancer patients following the completion of at least one year of trastuzumab adjuvant therapy, and wherein the neratinib therapy comprises treating the cancer patients with neratinib for at least twelve months. An oral hearing was held December 8, 2017, wherein the patent was maintained as granted. 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, we 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, namely EP15188350.1, was granted with the European patent number EP3000467 on March 1, 2023. Oppositions against EP3000467 were filed by Hexal AG (“Hexal”) on November 3, 2023, by Alfred E. Tiefenbacher (GmbH & Co. KG) on November 28, 2023 and 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, and eleven are in active prosecution. The patentee response to the notice of opposition was filed on April 15, 2024, following which, all three 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, including six auxiliary requests. Alfred E. Tiefenbacher and Hexal AG filed their responses to the summons to oral proceedings on February 6 and 7, 2025, respectively. Hexal filed a further brief on March 19, 2025. Oral proceedings took place on April 9 and 10, 2025. EP3000467 was upheld as amended after the first instance hearing based on Auxiliary Request 1, 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. The first instance decision may be appealed. Hexal filed an appeal on June 6, 2025, Generics [UK] Limited filed an appeal on June 20, 2025 and Wyeth filed an appeal on June 30, 2025. One European divisional application is pending in the same family, namely EP 23157078.8. A response to the European Search Opinion (ESO) for this application was filed February 14, 2024. The first office action was issued on January 28, 2025 with a response to the first office action filed on July 22, 2025.

26

Table of Contents

Item 2. | MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our unaudited condensed consolidated financial statements and the notes thereto included in Item 1 in this Quarterly Report on Form 10-Q, (this “Quarterly Report”). The following discussion should also be read in conjunction with our audited consolidated financial statements and the notes thereto and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in our Annual Report on Form 10-K for the year ended December 31, 2024.

Unless otherwise provided in this Quarterly Report, references to the “Company,” “we,” “us,” and “our” refer to Puma Biotechnology, Inc., a Delaware corporation, together with its wholly owned subsidiary.

Overview

We are a biopharmaceutical company that develops and commercializes innovative products to enhance cancer care and improve treatment outcomes for patients. We are currently commercializing NERLYNX, an oral version of neratinib, for the treatment of certain HER2-positive breast cancers. Additionally, in 2022, we in-licensed and became 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 that are dependent on Aurora Kinase A. Prior to our licensing alisertib from Takeda, alisertib was tested in over 1,300 patients who were treated across 22 company-sponsored trials resulting in a large, well-characterized clinical safety database. Based on information in this database, we believe 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. We intend to pursue development of alisertib initially in small cell lung cancer and hormone receptor-positive breast cancer.

NERLYNX is currently approved in the United States for two indications: the extended adjuvant treatment of adult patients with early stage HER2-overexpressed/amplified breast cancer following adjuvant trastuzumab-based therapy and for use in combination with capecitabine for the treatment of adult patients with advanced or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting.

We currently market NERLYNX in the United States using our direct specialty sales force consisting of approximately 38 sales specialists. Our sales specialists are supported by an experienced sales leadership team consisting of several regional business leaders and a Vice President of sales, as well as experienced professionals in marketing, managed markets, access and reimbursement, research, and sales planning and operations. Outside the United States, we seek to enter into exclusive sub-license agreements with third parties to pursue regulatory approval, if necessary, and commercialize NERLYNX, if approved. As of September 30, 2025, NERLYNX has received approval for the treatment of certain patients with extended adjuvant or metastatic HER2-positive breast cancer in over 40 countries outside the United States. We are currently party to several sub-licenses in various regions outside the United States, including Europe, Australia, Canada, China, Southeast Asia, Israel, South Korea, Russia and various countries and territories in Central America, South America, Africa and the Middle East.

In September 2022, we entered into an exclusive license agreement with Takeda Pharmaceutical Company Limited (“Takeda”) to license the worldwide research and development and commercial rights to alisertib. Alisertib is an investigational, reversible, ATP-competitive inhibitor that is designed to be highly selective for Aurora Kinase A. Inhibition of Aurora Kinase A can lead to disruption of mitotic spindle apparatus assembly, disruption of chromosome segregation, and inhibition of cell proliferation. In clinical trials to date, alisertib has shown single agent activity and activity in combination with other cancer drugs in the treatment of many different types of cancers, including hormone receptor-positive breast cancer, triple-negative breast cancer, small cell lung cancer and head and neck cancer. We initiated the ALISertib in CAncer (ALISCA™ -Lung1) Phase II trial (PUMA-ALI-4201) of alisertib monotherapy for the treatment of patients with extensive stage small cell lung cancer in February 2024, and we commenced the ALISCA™ -Breast1 Phase II trial (PUMA-ALI-1201) in November of 2024.

Under the terms of the exclusive license agreement, we assumed sole responsibility for the global development and commercialization of alisertib. We paid Takeda an upfront license fee of $7.0 million in October 2022, and it is eligible to receive potential future milestone payments of up to $287.3 million upon our 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. We recorded in-process research and development expense of $7.0 million during the year ended December 31, 2022, in connection with the upfront payment related to the asset acquisition. As of September 30, 2025, no milestones had been accrued as the underlying contingencies were not probable or estimable.

Our expenses to date have been related to hiring staff, commencing company-sponsored clinical trials, building out of our corporate infrastructure and, since 2017, the commercial launch of NERLYNX. Going forward, we anticipate significant expenses as we continue to develop alisertib in 2025. Accordingly, our success depends not only on the safety and efficacy of our drug candidates, but also on our ability to finance product development. To date, our major sources of working capital have been proceeds from product and license revenue, public offerings of our common stock, proceeds from our credit facility and sales of our common stock in private placements. We intend to satisfy our near-term liquidity requirements through a combination of our existing cash and cash equivalents and marketable securities as of September 30, 2025, and proceeds that will become available to us through product sales, royalties and sub-license milestone payments. However, this intention is based on assumptions that may prove to be wrong. Changes may occur that would consume our available capital faster than anticipated, including changes in and progress of our development activities, the impact of commercialization efforts, acquisition of additional drug candidates and changes in regulation. Some of these developments have had and may continue to have an adverse effect on our revenue and thus could have an adverse effect on our ability to satisfy the minimum revenue and cash balance covenants contained in the Athyrium Notes.

Critical Accounting Policies

As of the date of the filing of this Quarterly Report, we believe there have been no material changes to our critical accounting policies and estimates during the nine months ended September 30, 2025 from our accounting policies at December 31, 2024, as reported in our Annual Report on Form 10-K for the fiscal year ended December 31, 2024.

27

Table of Contents

Summary of Income and Expenses

Product revenue, net:

Product revenue, net consists of revenue from sales of NERLYNX. We sell NERLYNX to a limited number of specialty pharmacies and specialty distributors in the United States. We record revenue at the net sales price, which includes an estimate for variable consideration for which reserves are established. Variable consideration consists of trade discounts and allowances, product returns, provider chargebacks and discounts, government rebates and other incentives.

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

License revenue:

License revenue consists of consideration earned for performance obligations satisfied pursuant to our sub-license agreements.

Royalty revenue:

Royalty revenue consists of consideration earned related to product sales made by our sub-licensees in their respective territories pursuant to our sub-license agreements.

Cost of sales:

Cost of sales consists of third-party manufacturing costs, freight, and indirect overhead costs associated with sales of NERLYNX. Cost of product sales also includes period costs related to royalty charges payable to Pfizer, the amortization of milestone payments made under our license agreement with Pfizer, certain inventory manufacturing services, inventory adjustment charges, unabsorbed manufacturing and overhead costs, and manufacturing variances. Cost of sales includes applicable license termination fees.

Selling, general and administrative expenses:

Selling, general and administrative expenses (“SG&A expenses”) consist primarily of salaries and payroll-related costs, stock-based compensation expense, professional fees, business insurance, rent, general legal activities, credit loss expense and other corporate expenses. We expense SG&A expenses as they are incurred.

Research and development expenses:

Research and development expenses (“R&D expenses”) include costs associated with services provided by consultants who conduct and perform clinical services on our behalf and contract organizations for the manufacturing of clinical materials. During the three and nine months ended September 30, 2025 and 2024, our R&D expenses consisted primarily of clinical research organization (“CRO fees”); fees paid to consultants; salaries and related personnel costs; and stock-based compensation. We expense our R&D expenses as they are incurred. Internal R&D expenses primarily consist of payroll-related costs and also include equipment costs, travel expenses and supplies.

Tariffs:

We do not believe that tariffs imposed or proposed to be imposed by the United States, particularly with the European Union and China, will have a material impact on our 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.

Taxes:

On July 4, 2025, the “One Big Beautiful Bill” was signed into law, which includes significant changes to federal tax law and other regulatory provisions that may impact us. As of the date of these financial statements, we have evaluated the impact of the changes to Section 174 – Amortization of research and experimental expenditures on the valuation allowance release. We intend to deduct the capitalized costs over two years. This deduction reduces the amount of net operating losses being utilized but results in a net zero change to the deferred tax asset balance. Therefore, we have concluded that it remains reasonable to maintain the $7.0 million estimate for the valuation allowance release as of September 30, 2025 as the facts and circumstances supporting the deferred tax asset have not materially changed.

Results of Operations

Three Months Ended September 30, 2025 Compared to Three Months Ended September 30, 2024

Total revenue:

Total revenue for the three months ended September 30, 2025 was approximately $54.5 million, compared to $80.5 million for the three months ended September 30, 2024. This decrease in total revenue was due to a decrease in product revenue, net of approximately $4.2 million and a decrease in royalty revenue of $21.8 million.

Product revenue, net:

Product revenue, net was approximately $51.9 million for the three months ended September 30, 2025, compared to $56.1 million for the three months ended September 30, 2024. This decrease in product revenue, net, compared to the three months ended September 30, 2024, was attributable to a decrease in product supply revenue to our international licensees (reduction in China sales), partially offset by an increase in domestic sales resulting from an 8% increase in bottles of NERLYNX sold in the U.S. market and an increase in net selling price. This increase in gross domestic sales was partially offset by greater deductions to gross revenue for variable consideration, primarily related to government chargebacks.

28

Table of Contents

Royalty revenue:

Royalty revenue was approximately $2.6 million for the three months ended September 30, 2025, compared to approximately $24.4 million for the three months ended September 30, 2024. The decrease was primarily due to timing of sales made into China by our sub-licensee.

Cost of sales:

Cost of sales was approximately $12.2 million for the three months ended September 30, 2025, compared to approximately $29.1 million for the three months ended September 30, 2024. The decrease was primarily due to timing of sales made into China by our sub-licensee and the related cost of products shipped and royalty expense.

Selling, general and administrative expenses:

SG&A expenses were approximately $16.8 million for the three months ended September 30, 2025, compared to approximately $16.8 million for the three months ended September 30, 2024. SG&A expenses for the three months ended September 30, 2025 and 2024 were as follows:

Selling, general, and administrative expenses |  | For the Three Months Ended |  |  | Change |
(in thousands) |  | September 30, |  |  | $ |  |  | % |
|  | 2025 |  |  | 2024 |  |  | 2025/2024 |  |  | 2025/2024 |
Payroll and related costs |  | $ | 8,445 |  |  | $ | 7,646 |  |  | $ | 799 |  |  |  | 10.4 | %
Provision for credit loss recovery |  |  | (213 | ) |  |  | (48 | ) |  |  | (165 | ) |  |  | 343.8 | %
Professional fees and expenses |  |  | 4,277 |  |  |  | 4,523 |  |  |  | (246 | ) |  |  | -5.4 | %
Travel and meetings |  |  | 1,266 |  |  |  | 1,204 |  |  |  | 62 |  |  |  | 5.1 | %
Facilities and equipment costs |  |  | 1,176 |  |  |  | 1,249 |  |  |  | (73 | ) |  |  | -5.8 | %
Stock-based compensation |  |  | 1,051 |  |  |  | 1,443 |  |  |  | (392 | ) |  |  | -27.2 | %
Other |  |  | 815 |  |  |  | 802 |  |  |  | 13 |  |  |  | 1.6 | %
|  | $ | 16,817 |  |  | $ | 16,819 |  |  | $ | (2 | ) |  |  | 0.0 | %

SG&A expenses remained virtually unchanged for the three months ended September 30, 2025, compared to the same period in 2024, primarily attributable to the following:

| ● | an increase in credit loss recovery of approximately $0.2 million, primarily related to the payment history of a customer receivable;

| ● | a decrease in professional fees and expenses of approximately $0.3 million, primarily related to legal fees associated with the AstraZeneca litigation in the prior year; and

| ● | a decrease in stock-based compensation expense of approximately $0.4 million, primarily due to newer awards at a lower grant price.

Partially offset by:

| ● | an increase in payroll and related costs of approximately $0.8 million, primarily due to an increase in bonus related payroll costs as well as increases in our healthcare insurance premiums.

Research and development expenses:

R&D expenses were approximately $15.9 million for the three months ended September 30, 2025, compared to approximately $12.6 million for the three months ended September 30, 2024. R&D expenses for the three months ended September 30, 2025 and 2024, were as follows:

Research and development expenses |  | For the Three Months Ended |  |  | Change |
(in thousands) |  | September 30, |  |  | $ |  |  | % |
|  | 2025 |  |  | 2024 |  |  | 2025/2024 |  |  | 2025/2024 |
Clinical trial expense |  | $ | 5,473 |  |  | $ | 3,674 |  |  | $ | 1,799 |  |  |  | 49.0 | %
Internal R&D |  |  | 8,517 |  |  |  | 7,578 |  |  |  | 939 |  |  |  | 12.4 | %
Consultant and contractors |  |  | 1,300 |  |  |  | 684 |  |  |  | 616 |  |  |  | 90.1 | %
Stock-based compensation |  |  | 622 |  |  |  | 611 |  |  |  | 11 |  |  |  | 1.8 | %
|  | $ | 15,912 |  |  | $ | 12,547 |  |  | $ | 3,365 |  |  |  | 26.8 | %

R&D expenses increased by approximately $3.4 million for the three months ended September 30, 2025, compared to the same period in 2024, primarily attributable to the following:

| ● | an increase in clinical trial expense of approximately $1.8 million, primarily due to increased alisertib study activity;

| ● | an increase in internal R&D expense of approximately $0.9 million, primarily due to increased payroll and healthcare costs; and

| ● | an increase in consultants and contractors expense of approximately $0.6 million, primarily due to increased alisertib study activity.

29

Table of Contents

Other income (expenses):

Other income (expenses) |  | For the Three Months Ended |  |  | Change |
(in thousands) |  | September 30, |  |  | $ |  |  | % |
|  | 2025 |  |  | 2024 |  |  | 2025/2024 |  |  | 2025/2024 |
Interest income |  | $ | 1,044 |  |  | $ | 1,282 |  |  | $ | (238 | ) |  |  | -18.6 | %
Interest expense |  |  | (1,489 | ) |  |  | (3,100 | ) |  |  | 1,611 |  |  |  | -52.0 | %
Other income |  |  | 115 |  |  |  | 347 |  |  |  | (232 | ) |  |  | -66.9 | %
|  | $ | (330 | ) |  | $ | (1,471 | ) |  | $ | 1,141 |  |  |  | -77.6 | %

Interest income:

For the three months ended September 30, 2025, we recognized approximately $1.0 million in interest income, compared to approximately $1.3 million of interest income for the three months ended September 30, 2024. The decrease in interest income was primarily the result of lower investment balances and timing of investments.

Interest expense:

For the three months ended September 30, 2025 , we recognized approximately $1.5 million in interest expense, compared to approximately $3.1 million of interest expense for the three months ended September 30, 2024 . The decrease in interest expense was primarily related to a lower debt balance as we began paying down our debt principal during the three months ended September 30, 2024.

Other income:

For the three months ended September 30, 2025 , we recognized approximately $0.1 million in other income, compared to approximately $0.3 million of other income for the three months ended September 30, 2024 . The decrease in other income was primarily due to unfavorable exchange rates in Euro-denominated transactions.

Nine Months Ended September 30, 2025 Compared to Nine Months Ended September 30, 2024

Total revenue:

Total revenue for the nine months ended September 30, 2025 was approximately $152.9 million, compared to $171.4 million for the nine months ended September 30, 2024. This $18.5 million decrease in total revenue was due to a decrease in royalty revenue of $21.9 million, partially offset by an increase in product revenue, net of approximately $3.4 million.

Product revenue, net:

Product revenue, net was approximately $144.2 million for the nine months ended September 30, 2025, compared to $140.8 million for the nine months ended September 30, 2024. This increase in product revenue, net, compared to the nine months ended September 30, 2024, was attributable to an increase in domestic sales resulting from a 3% increase in bottles of NERLYNX sold in the U.S. market and an increase in net selling price, partially offset by an increase in deductions to gross revenue for variable consideration, primarily related to government chargebacks.

Royalty revenue:

Royalty revenue was approximately $8.7 million and $30.6 million for the nine months ended September 30, 2025 and September 30, 2024 respectively. The decrease in royalty revenue was primarily due to a decrease in sales to our international licensees (reduction in China sales).

Cost of sales:

Cost of sales was approximately $35.0 million for the nine months ended September 30, 2025, compared to approximately $50.5 million for the nine months ended September 30, 2024. The decrease was primarily due to timing of sales made into China by our sub-licensee and the related cost of products shipped and royalty expense.

Selling, general and administrative expenses:

SG&A expenses were approximately $52.5 million for the nine months ended September 30, 2025, compared to approximately $63.5 million for the nine months ended September 30, 2024. SG&A expenses for the nine months ended September 30, 2025 and 2024 were as follows:

Selling, general, and administrative expenses |  | For the Nine Months Ended |  |  | Change |
(in thousands) |  | September 30, |  |  | $ |  |  | % |
|  | 2025 |  |  | 2024 |  |  | 2025/2024 |  |  | 2025/2024 |
Payroll and related costs |  | $ | 25,749 |  |  | $ | 23,703 |  |  | $ | 2,046 |  |  |  | 8.6 | %
Provision for credit loss recovery |  |  | (362 | ) |  |  | (121 | ) |  |  | (241 | ) |  |  | 199.2 | %
Professional fees and expenses |  |  | 13,861 |  |  |  | 25,139 |  |  |  | (11,278 | ) |  |  | -44.9 | %
Travel and meetings |  |  | 4,014 |  |  |  | 4,244 |  |  |  | (230 | ) |  |  | -5.4 | %
Facilities and equipment costs |  |  | 3,517 |  |  |  | 3,732 |  |  |  | (215 | ) |  |  | -5.8 | %
Stock-based compensation |  |  | 3,278 |  |  |  | 4,328 |  |  |  | (1,050 | ) |  |  | -24.3 | %
Other |  |  | 2,411 |  |  |  | 2,516 |  |  |  | (105 | ) |  |  | -4.2 | %
|  | $ | 52,468 |  |  | $ | 63,541 |  |  | $ | (11,073 | ) |  |  | -17.4 | %

30

Table of Contents

SG&A expenses decreased by approximately $11.1 million for the nine months ended September 30, 2025, compared to the same period in 2024, primarily attributable to the following:

| ● | an increase in provision for credit loss of approximately $0.2 million, primarily related to the payment history of a customer receivable;

| ● | a decrease in professional fees and expenses of approximately $11.3 million, primarily related to legal fees associated with the AstraZeneca litigation in the prior year; and

| ● | a decrease in stock-based compensation expense of approximately $1.1 million, primarily due to newer awards at a lower grant price.

Partially offset by:

| ● | an increase in payroll and related costs of approximately $2.0 million, primarily due to the severance costs related to the departure of our Chief Commercial Officer, increased headcount in our sales team as well as increases in our healthcare insurance premiums.

Research and development expenses:

R&D expenses were approximately $45.2 million for the nine months ended September 30, 2025, compared to approximately $39.8 million for the nine months ended September 30, 2024. R&D expenses for the nine months ended September 30, 2025 and 2024, were as follows:

Research and development expenses |  | For the Nine Months Ended |  |  | Change |
(in thousands) |  | September 30, |  |  | $ |  |  | % |
|  | 2025 |  |  | 2024 |  |  | 2025/2024 |  |  | 2025/2024 |
Clinical trial expense |  | $ | 14,752 |  |  | $ | 11,363 |  |  | $ | 3,389 |  |  |  | 29.8 | %
Internal R&D |  |  | 25,153 |  |  |  | 24,193 |  |  |  | 960 |  |  |  | 4.0 | %
Consultant and contractors |  |  | 3,273 |  |  |  | 2,045 |  |  |  | 1,228 |  |  |  | 60.0 | %
Stock-based compensation |  |  | 2,049 |  |  |  | 2,165 |  |  |  | (116 | ) |  |  | -5.4 | %
|  | $ | 45,227 |  |  | $ | 39,766 |  |  | $ | 5,461 |  |  |  | 13.7 | %

R&D expenses increased by approximately $5.5 million compared to the nine months ended September 30, 2024, primarily attributable to the following:

| ● | an increase in clinical trial expense of approximately $3.4 million, primarily due to increased alisertib study activity; and

| ● | an increase in consultants and contractors expense of approximately $1.2 million, primarily due to increased alisertib study activity.

Other income (expenses):

Other income (expenses) |  | For the Nine Months Ended |  |  | Change |
(in thousands) |  | September 30, |  |  | $ |  |  | % |
|  | 2025 |  |  | 2024 |  |  | 2025/2024 |  |  | 2025/2024 |
Interest income |  | $ | 3,101 |  |  | $ | 3,498 |  |  | $ | (397 | ) |  |  | -11.3 | %
Interest expense |  |  | (5,503 | ) |  |  | (9,831 | ) |  |  | 4,328 |  |  |  | -44.0 | %
Other income |  |  | 884 |  |  |  | 594 |  |  |  | 290 |  |  |  | 48.8 | %
|  | $ | (1,518 | ) |  | $ | (5,739 | ) |  | $ | 4,221 |  |  |  | -73.5 | %

Interest income:

For the nine months ended September 30, 2025, we recognized approximately $3.1 million in interest income, compared to approximately $3.5 million of interest income for the nine months ended September 30, 2024. The decrease in interest income was primarily the result of lower investment balances and timing of investments.

Interest expense:

For the nine months ended September 30, 2025 , we recognized approximately $5.5 million in interest expense, compared to approximately $9.8 million of interest expense for the nine months ended September 30, 2024 . The decrease in interest expense was primarily related to a lower debt balance as we began paying down our debt principal during the nine months ended September 30, 2024.

Other income:

For the nine months ended September 30, 2025 , we recognized approximately $0.9 million in other income, compared to approximately $0.6 million of other income for the nine months ended September 30, 2024 . The increase in other income was primarily due to favorable exchange rates in Euro-denominated transactions.

31

Table of Contents

Liquidity and Capital Resources

The following table, which summarizes our liquidity and capital resources as of September 30, 2025 and December 31, 2024 and for the nine months ended September 30, 2025 and 2024, is intended to supplement the more detailed discussion that follows:

|  | As of |  |  | As of |
Liquidity and capital resources (in thousands) |  | September 30, 2025 |  |  | December 31, 2024 |
Cash and cash equivalents |  | $ | 53,525 |  |  | $ | 69,219 |
Marketable securities |  | $ | 40,863 |  |  | $ | 31,746 |
Working capital |  | $ | 60,852 |  |  | $ | 51,547 |
Current portion of long-term debt |  | $ | 33,716 |  |  | $ | 45,329 |
Long-term debt |  | $ | - |  |  | $ | 21,719 |
Stockholders’ equity |  | $ | 115,268 |  |  | $ | 92,125 |

|  | Nine Months Ended |  |  | Nine Months Ended |
|  | September 30, 2025 |  |  | September 30, 2024 |
Cash provided by (used in): |  |  |  |  |  |  |  |
Operating activities |  | $ | 27,383 |  |  | $ | 23,311 |
Investing activities |  |  | (9,211 | ) |  |  | (18,118 | )
Financing activities |  |  | (33,866 | ) |  |  | (22,515 | )
Net decrease in cash, cash equivalents and restricted cash |  | $ | (15,694 | ) |  | $ | (17,322 | )

On October 26, 2023, we implemented a reduction in our workforce of approximately 5% across the Company. We incurred approximately $0.4 million in related costs, which included severance payments and insurance premiums. These costs were recorded in the fourth quarter of 2023. All payments related to this plan were paid as of June 30, 2024.

Operating Activities:

Cash provided by operating activities for the nine months ended September 30, 2025 was $27.4 million and consisted of net income of approximately $17.7 million, adjusted for non-cash items of approximately $13.2 million, which included stock-based compensation of $5.3 million, depreciation and amortization of $8.3 million and provision for credit loss recovery of $0.4 million. Total changes in cash flows from operations were due to an increase in working capital, primarily related to an increase in accounts receivable of $1.2 million, an increase in inventory of $0.8 million, a decrease of post-marketing commitment liability of $1.7 million, a decrease in operating lease assets and liabilities, net, of $1.3 million and an increase in accrued expenses and other of approximately $0.3 million, partially offset by a decrease in prepaid and other expenses of $0.4 million and an increase in accounts payable of $0.9 million.

Cash provided by operating activities for the nine months ended September 30, 2024 was $23.3 million and consisted of net income of approximately $11.0 million, adjusted for non-cash items of approximately $15.1 million, including stock-based compensation of $6.5 million, depreciation and amortization of $8.7 million and provision for credit loss of $0.1 million. Total changes in cash flows from operations were due to a decrease in working capital, primarily related to an increase in accounts receivable of approximately $6.7 million (primarily sales to China) and a decrease in accrued expenses and other of approximately $2.1 million, partially offset by a decrease in inventory of $4.4 million (primarily sales to China) and a decrease in prepaid expenses and other of $2.4 million.

Investing Activities:

Cash used in investing activities for the nine months ended September 30, 2025 was approximately $9.2 million, compared to net cash used in investing activities of approximately $18.1 million for the same period in 2024. Cash used in investing activities for the nine months ended September 30, 2025 was primarily due to the purchase of available-for-sale securities of approximately $61.2 million, partially offset by the maturity of available-for-sale securities of approximately $52.1 million.

Cash used in investing activities for the nine months ended September 30, 2024 was approximately $18.1 million, compared to net cash used in investing activities of approximately $11.0 million for the same period in 2023. Cash used in investing activities was primarily due to the purchase of available-for-sale securities of approximately $61.0 million, offset by the maturity of available-for-sale securities of approximately $42.9 million.

Financing Activities:

Cash used in financing activities for the nine months ended September 30, 2025 was approximately $33.9 million, including $33.3 million related to the payment of principal and $0.7 million related exit fees, on our debt with Athyrium, partially offset by $0.1 million in proceeds from shares issued under employee stock plans.

Cash used in financing activities for the nine months ended September 30, 2024 was approximately $22.5 million. Of this amount, $22.7 million related to the payment of principal, as well as exit fees, on our debt with Athyrium, partially offset by approximately $0.2 million of proceeds from employee stock options exercised.

32

Table of Contents

Athyrium Note Purchase Agreement:

We issued senior notes for an aggregate principal amount of $100.0 million pursuant to the note purchase agreement dated July 23, 2021 by us, and our 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 require a 2.0% exit payment to be made on each payment of principal. The borrowings under the Athyrium Notes, together with cash on hand, were used to repay our outstanding indebtedness, including the applicable exit and prepayment fees owed to lenders under our prior credit facility with Oxford. The Athyrium Notes are secured by substantially all of our assets. We incurred $1.9 million of deferred financing costs with the initial borrowing of the Athyrium Notes.

Interest on the Athyrium Notes is calculated in part based on the Secured Overnight Financing Rate (“SOFR”), which replaced the “London Interbank Offering Rate” as the floating benchmark for interest rate calculations applicable to the Athyrium Notes pursuant to the terms of the Third Amendment to the Note Purchase Agreement dated as of September 16, 2022 (the “Third Amendment”).

Following the effectiveness of the Third Amendment, the Athyrium Notes bear 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 of three months plus (y) 0.26161% (26.161 basis points) and (ii) three and one-half of one percent (3.50%) per annum. Interest is payable quarterly on the last business day of March, June, September and December each year. In the second quarter of 2024, we began paying the principal payments required to be made quarterly at 11.11% of the original face amount. The remaining balance will be paid at maturity. Each principal payment also includes a 2.0% exit payment. Each quarterly principal payment approximates $11.1 million, and each quarterly exit fee payment approximates $0.2 million. As of September 30, 2025, the effective interest rate for the loan was 12.99%.

As of September 30, 2025, we may prepay the outstanding principal balance of the notes, in whole or in part, without premium or penalty.

The Athyrium Notes include affirmative and negative covenants applicable to us. The affirmative covenants include, among others, covenants requiring us to maintain our legal existence and governmental approvals, deliver certain financial reports, maintain insurance coverage, and satisfy certain requirements regarding deposit accounts. The negative covenants include, among others, restrictions on our transferring collateral, incurring additional indebtedness, engaging in mergers or acquisitions, paying dividends or making other distributions, making investments, creating liens, selling assets and suffering a change in control, in each case subject to certain exceptions. We are also required to maintain minimum cash balances and achieve certain minimum product revenue targets, measured as of the last day of each fiscal quarter on a trailing year-to-date basis. As of September 30, 2025, we were in compliance with such covenants.

As of September 30, 2025, the principal balance outstanding under the Athyrium Notes was $33.3 million and represents all of our debt. We are in compliance with all applicable covenants under the Athyrium Notes.

Current and Future Financing Needs:

We have spent, and expect to continue to spend, substantial amounts in connection with implementing our business strategy, including our planned product development efforts, our clinical trials, our R&D efforts and our commercialization efforts.

We may choose to begin new R&D efforts, or we may choose to launch additional marketing efforts. For example, we in-licensed alisertib from Takeda in 2022 and assumed sole responsibility for its global development and commercialization. These efforts will require funding in addition to the cash and cash equivalents totaling approximately $53.5 million and approximately $40.9 million in marketable securities available at September 30, 2025. While our consolidated financial statements have been prepared on a going concern basis, we may incur significant losses in the future and will need to generate significant revenue to sustain operations and successfully commercialize neratinib and develop alisertib. While we have been successful in raising financing in the past, there can be no assurance that we will be able to do so in the future. Our ability to obtain funding may be adversely impacted by uncertain market conditions, our success in commercializing neratinib, our success in developing alisertib, unfavorable decisions of regulatory authorities or adverse clinical trial results. The outcome of these matters cannot be predicted at this time. We believe that our existing cash and cash equivalents and marketable securities as of September 30, 2025, and proceeds that will become available to us through product sales and sub-license payments are sufficient to satisfy our operating cash and capital needs for at least one year after the filing of this Quarterly Report.

In addition, we have based our estimate of capital needs on assumptions that may prove to be wrong. Changes may occur that would consume our available capital faster than anticipated, including changes in and progress of our development activities, the impact of commercialization efforts, acquisitions of additional drug candidates and changes in regulation. Potential sources of financing include strategic relationships, public or private sales of equity or debt and other sources of funds. We may seek to access the public or private equity markets when conditions are favorable due to our long-term capital requirements. If we raise funds by selling additional shares of common stock or other securities convertible into common stock, the ownership interests of our existing stockholders will be diluted. If we are not able to obtain financing when needed, we may be unable to carry out our business plan. As a result, we may have to significantly limit our operations, and our business, financial condition and results of operations would be materially harmed. In such an event, we will be required to undertake a thorough review of our programs, and the opportunities presented by such programs, and allocate our resources in the manner most prudent.

Non-GAAP Financial Measures

In addition to our operating results, as calculated in accordance with Generally Accepted Accounting Principles (“GAAP”) we use certain non-GAAP financial measures when planning, monitoring, and evaluating our operational performance. The following table presents our net income and net income per share, as calculated in accordance with GAAP, as adjusted to remove the impact of stock-based compensation. For the three and nine months ended September 30, 2025, stock-based compensation represented approximately 5.1% and 5.5% of our operating expenses, respectively, compared to 7.0% and 6.3% for the same respective periods in 2024, in each case excluding cost of sales. Our management believes that these non-GAAP financial measures are useful to enhance understanding of our financial performance, are more indicative of our operational performance and facilitate a better comparison among fiscal periods. These non-GAAP financial measures are not, and should not be viewed as, substitutes for GAAP reporting measures.

33

Table of Contents

Reconciliation of GAAP Net Income to Non-GAAP Adjusted Net Income and

GAAP Net Income Per Share to Non-GAAP Adjusted Net Income Per Share

(in thousands except share and per share data)

|  | For the Three Months Ended September 30, |  |  |  | For the Nine Months Ended September 30, |  |
|  | 2025 |  |  |  | 2024 |  |  |  | 2025 |  |  |  | 2024 |  |
GAAP net income |  | $ | 8,844 |  |  |  | $ | 20,317 |  |  |  | $ | 17,673 |  |  |  | $ | 10,973 |  |
Adjustments: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stock-based compensation - |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Selling, general and administrative (1) |  |  | 1,051 |  |  |  |  | 1,442 |  |  |  |  | 3,278 |  |  |  |  | 4,328 |  |
Research and development (2) |  |  | 622 |  |  |  |  | 612 |  |  |  |  | 2,049 |  |  |  |  | 2,165 |  |
Non-GAAP adjusted net income |  | $ | 10,517 |  |  |  | $ | 22,371 |  |  |  | $ | 23,000 |  |  |  | $ | 17,466 |  |
GAAP net income per share—basic |  | $ | 0.18 |  |  |  | $ | 0.41 |  |  |  | $ | 0.35 |  |  |  | $ | 0.23 |  |
Adjustment to net income (as detailed above) |  |  | 0.03 |  |  |  |  | 0.05 |  |  |  |  | 0.11 |  |  |  |  | 0.13 |  |
Non-GAAP adjusted basic net income per share |  | $ | 0.21 |  | (3) |  | $ | 0.46 |  | (4) |  | $ | 0.46 |  | (3) |  | $ | 0.36 |  | (4)
GAAP net income per share—diluted |  | $ | 0.17 |  |  |  | $ | 0.41 |  |  |  | $ | 0.35 |  |  |  | $ | 0.22 |  |
Adjustment to net income (as detailed above) |  |  | 0.04 |  |  |  |  | 0.04 |  |  |  |  | 0.11 |  |  |  |  | 0.14 |  |
Non-GAAP adjusted diluted net income per share |  | $ | 0.21 |  | (5) |  | $ | 0.45 |  | (6) |  | $ | 0.46 |  | (5) |  | $ | 0.36 |  | (6)

(1) To reflect a non-cash charge to operating expense for selling, general, and administrative stock-based compensation.
(2) To reflect a non-cash charge to operating expense for research and development stock-based compensation.
(3) Non-GAAP adjusted basic net income per share was calculated based on 50,339,456 and 49,881,181 weighted-average shares of common stock outstanding for the three and nine months ended September 30, 2025, respectively.
(4) Non-GAAP adjusted basic net income per share was calculated based on 49,008,464 and 48,498,579 weighted-average shares of common stock outstanding for the three and nine months ended September 30, 2024, respectively.
(5) Non-GAAP adjusted diluted net income per share was calculated based on 50,929,893 and 50,334,553 weighted-average shares of common stock outstanding for the three and nine months ended September 30, 2025, respectively.
(6) Non-GAAP adjusted diluted net income per share was calculated based on 49,173,361 and 49,025,103 weighted-average shares of common stock outstanding for the three and nine months ended September 30, 2024, respectively.

Off-Balance Sheet Arrangements

We do not have any “off-balance sheet arrangements,” as defined by SEC regulations.

Contractual Obligations

There have been no material changes outside the ordinary course of business to our contractual obligations and commitments as described in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the year ended December 31, 2024.

34

Table of Contents

Item 3. | QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

Some of the securities that we invest in have market risk in that a change in prevailing interest rates may cause the principal amount of the cash equivalents to fluctuate. Financial instruments that potentially subject us to significant concentrations of credit risk consist primarily of cash and cash equivalents. We invested our excess cash primarily in cash equivalents such as money market investments as of September 30, 2025. The primary objectives of our investment activities are to ensure liquidity and to preserve principal while at the same time maximizing the income we receive from our cash and cash equivalents without significantly increasing risk. Additionally, we established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.

Because of the short-term maturities of our cash equivalents, we do not believe that a 10% increase in interest rates would have a material effect on the realized value of our cash equivalents.

We also have interest rate exposure as a result of borrowings outstanding under the Athyrium Notes. As of September 30, 2025 the aggregate outstanding principal amounts of the Athyrium Notes was $33.3 million. The Athyrium Notes bear interest at a rate per annum equal to the sum of 8.00% plus the adjusted three-month term SOFR and the lesser of (a) the sum of (i) three-month term SOFR and (ii) 0.26161% (26.161 basis points) and (b) three and one-half of one percent (3.50%) per annum. If overall interest rates had increased by one hundred basis points during the quarter ended September 30, 2025, our interest expense would have increased by $0.3 million.

Item 4. | CONTROLS AND PROCEDURES

Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in our reports under the Exchange Act, is recorded, processed, summarized and reported within the timelines specified in the SEC’s rules and forms, and that such information is accumulated and communicated to our management, including our Chief Executive Officer and Chief Financial Officer, as appropriate, to allow timely decisions regarding required disclosures. In designing and evaluating the disclosure controls and procedures, management recognized that any controls and procedures, no matter how well designed and operated, can only provide reasonable assurance of achieving the desired control objectives and in reaching a reasonable level of assurance, management was required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, we have evaluated the effectiveness of our disclosure controls and procedures (as defined under Exchange Act Rule 13a-15(e)), as of September 30, 2025. Based on that evaluation, our Chief Executive Officer and Chief Financial Officer have concluded that these disclosure controls and procedures were effective as of September 30, 2025.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting during the three months ended September 30, 2025 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

35

Table of Contents

PART II – OTHER INFORMATION

Item 1. | LEGAL PROCEEDINGS

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 in Eshelman 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 in Eshelman v. Puma Biotechnology, Inc., et al. The Company is seeking recovery of the entire amount awarded in Eshelman 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 defendant 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 the Eshelman v. Puma Biotechnology, Inc., et al. 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 in Eshelman 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. The Supreme Court has not decided whether to accept the case for review.

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”) and 10,596,162 (“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 as not 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, 2024 and April 29, 2024 orders. 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 the three 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 are not invalid. The jury awarded damages to Wyeth for past acts of infringement through December 31, 2023, in the amount of $107,500,000. A separate bench trial related to certain equitable claims and defenses raised by AstraZeneca was held before Judge Kennelly on June 20 and 25, 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 had not 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 under 35 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 appeal. That motion was granted on May 16, 2025. On June 6, 2025, Wyeth filed its reply brief. Briefing on the appeal is now complete, and the parties await further order from the Court.

36

Table of Contents

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 of three patents listed on the China Patent Information Registration Platform for Marketed Drugs (“Chinese Orange Book”), namely, Chinese Patent Nos. ZL201410082103.7, ZL201080060546.6, and ZL200880118789.3 (the “’789 patent” and collectively, the “NERLYNX® Patents”), alleging in a Type 4.2 patent declaration that its generic version of NERLYNX does not 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 for nine months. On July 11, 2022, CNIPA decided that claims 5 and 6 of Patent No. ZL200880118789.3 are not eligible for registration in the Chinese Orange Book on the ground that these two pharmaceutical method-of-use claims fall within the scope of “patents of crystalline forms,” which are not eligible for listing in the Chinese Orange Book. On September 9, 2022, CNIPA decided that the generic drug in Acebright’s ANDA does not fall within the protection scope of claims 1, 3, 5 and 6 of Patent No. ZL201410082103.7 and claims 1-4, 7 and 9-13 of Patent No. ZL201080060546.6. The three 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 2023 at the Beijing Intellectual Property Court (“BJIPC”). The three appeals were accepted by BJIPC on February 20, 2023. The Company also filed three civil complaints based on the three NERLYNX® Patents against Acebright with the BJIPC in July 2022 and 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 withdrew two civil lawsuits and two appeals in relation to Chinese Patent Nos. ZL201410082103.7 and ZL201080060546.6 at the BJIPC. On May 24, 2023, the BJIPC accepted the Company’s withdrawal request. On July 24, 2023, the Company withdrew the one remaining civil lawsuit and one appeal in relation to Chinese Patent No. 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 GuoYaoZhunZi H20234141.

On December 28, 2023, the Company filed a civil lawsuit against Acebright for infringement of the ’789 patent under Article 11 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) Su 01 Min Chu 2192 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 for examining evidence and debating merits of party arguments.

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 application No. is CYHS2202006. Aosaikang made Type 4.2 declarations against the four Orange Book Patents ZL201410082103.7, ZL201080060546.6, ZL200880118789.3 and ZL201710057547.9, alleging that its generic version of NERLYNX does not fall within the scope of the claims of the Orange Book patents. Aosaikang also alleged that Patents ZL200880118789.3 and ZL201710057547.9 are not eligible for Chinese Orange Book listing.

On December 28, 2022, the Company submitted four Article 76 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 the four Orange Book patents. On January 6, 2023, the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos. ZL201410082103.7 and ZL201080060546.6. Also on January 6, 2023, the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos. ZL200880118789.3 and ZL201710057547.9, alleging that the listed claims are not 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 are not eligible for listing in the Chinese Orange Book. On January 28, 2023, the Company requested the NMPA to institute a nine-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 does not fall within the protection scope of claims 1, 3, 5 and 6 of Patent No. ZL201410082103.7 and claims 1-4, 7 and 9-13 of Patent No. ZL201080060546.6. The two 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 GuoYaoZhunZi H20249180.

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 application No. is CYHS2202095. On December 23, 2022, Convalife made Type 4.2 declarations against the four Orange Book Patents ZL201410082103.7, ZL201080060546.6, ZL200880118789.3 and ZL201710057547.9, alleging that its generic version of NERLYNX does not fall within the scope of the claims of the Orange Book patents. Convalife also alleged that Patents ZL200880118789.3 and ZL201710057547.9 are not eligible for Chinese Orange Book listing.

On February 1, 2023, the Company submitted four Article 76 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 the four Orange Book patents. On February 3, 2023, the CNIPA accepted the Company’s request for administrative determination in relation to Patent Nos. ZL201410082103.7 and ZL201080060546.6. Also on February 3, 2023, the CNIPA declined to accept the Company’s request for administrative determination in relation to Patent Nos. ZL200880118789.3 and ZL201710057547.9, alleging that the listed claims are not 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 are not eligible for listing in the Chinese Orange Book. On February 24, 2023, the Company requested the NMPA to institute a nine-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 does not fall within the protection scope of claims 1, 3, 5 and 6 of Patent No. ZL201410082103.7 and claims 1-4, 7 and 9-13 of Patent No. ZL201080060546.6. The two 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 GuoYaoZhunZi H20244222.

37

Table of Contents

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 application No. is CYHS2300221. On January 28, 2023, Kelun made Type 4.2 declarations against the four Orange Book Patents ZL201410082103.7, ZL201080060546.6, ZL200880118789.3 and ZL201710057547.9, alleging that its generic version of NERLYNX does not fall within the scope of the claims of the Orange Book patents. Kelun also alleged that Patents ZL200880118789.3 and ZL201710057547.9 are not eligible for Chinese Orange Book listing.

On March 13, 2023, the Company submitted four Article 76 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 the four 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 and ZL201710057547.9, alleging that the listed claims are not 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 are not 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 and ZL201080060546.6. On April 17, 2023, the Company requested the NMPA to institute a nine-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 the two requests for administrative determination in relation to Chinese Patent Nos. ZL201410082103.7 and ZL201080060546.6 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 GuoYaoZhunZi H20255337.

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 application No. is CYHS2402776. On August 26, 2024, Demai made a Type 4.2 declaration against Orange Book Patent ZL201410082103.7, alleging that its generic version of NERLYNX does not 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 Patent No. ZL201080060546.6 and on October 8, 2024, the Company filed a lawsuit against Demai at the BJIPC based on Nerlynx Patent No. ZL201410082103.7. On February 13, 2025, the Company withdrew the lawsuits from BJIPC, filed an Article 76 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 Patent No. 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 a nine-month stay on Demai’s ANDA.

Hexal European Patent Opposition

An Opposition was filed by Hexal AG (“Hexal”) on August 3, 2016 against European Patent No. EP2416774 which was licensed from Pfizer in 2011, and which claims neratinib for use in a method for treating HER-2/neu overexpressed/amplified cancer and improving IDFS, wherein the method comprises delivering neratinib therapy to HER-2/neu overexpressed/amplified cancer patients following the completion of at least one year of trastuzumab adjuvant therapy, and wherein the neratinib therapy comprises treating the cancer patients with neratinib for at least twelve months. An oral hearing was held December 8, 2017, wherein the patent was maintained as granted. 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, we 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, namely EP15188350.1, was granted with the European patent number EP3000467 on March 1, 2023. Oppositions against EP3000467 were filed by Hexal AG (“Hexal”) on November 3, 2023, by Alfred E. Tiefenbacher (GmbH & Co. KG) on November 28, 2023 and 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, and eleven are in active prosecution. The patentee response to the notice of opposition was filed on April 15, 2024, following which, all three 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, including six auxiliary requests. Alfred E. Tiefenbacher and Hexal AG filed their responses to the summons to oral proceedings on February 6 and 7, 2025, respectively. Hexal filed a further brief on March 19, 2025. Oral proceedings took place on April 9 and 10, 2025. EP3000467 was upheld as amended after the first instance hearing based on Auxiliary Request 1, 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. The first instance decision may be appealed. Hexal filed an appeal on June 6, 2025, Generics [UK] Limited filed an appeal on June 20, 2025 and Wyeth filed an appeal on June 30, 2025. One European divisional application is pending in the same family, namely EP 23157078.8. A response to the European Search Opinion (ESO) for this application was filed February 14, 2024. The first office action was issued on January 28, 2025 with a response to the first office action filed on July 22, 2025.

Item 1A. | RISK FACTORS

Under Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2024, we identified important factors that could affect our financial performance and could cause our actual results for future periods to differ materially from our anticipated results or other expectations, including those expressed in any forward-looking statements made in this Quarterly Report. Except as described below, there has been no material change in our risk factors subsequent to the filing of our prior reports referenced above. However, the risks described in our reports are not the only risks we face. Additional risks and uncertainties that we currently deem to be immaterial or not currently known to us, as well as other risks reported from time to time in our reports to the SEC, also could cause our actual results to differ materially from our anticipated results or other expectations.

Item 2. | UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

Recent Sales of Unregistered Securities

None.

Purchases of Equity Securities by the Issuer and Affiliated Purchasers

None.

Item 3. | DEFAULTS UPON SENIOR SECURITIES

None.

38

Table of Contents

Item 4. | MINE SAFETY DISCLOSURES

Not applicable.

Item 5. | OTHER INFORMATION

Trading Plans

During the three months ended September 30, 2025, no director or officer (as defined in Rule 16a-1(f) under the Exchange Act) of the Company adopted or terminated a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as each term is defined in Item 408(a) of Regulation S-K.

Item 6. | EXHIBITS

| (a) | Exhibits required by Item 601 of Regulation S-K.

Exhibit Number |  | Description
3.1 |  | Second Amended and Restated Certificate of Incorporation of the Company, as filed with the Secretary of State of the State of Delaware on June 14, 2016 (filed as Exhibit 3.1 to the Company’s Current Report on Form 8-K filed with the SEC on June 15, 2016, and incorporated herein by reference)
3.2 |  | Fifth Amended and Restated Bylaws of the Company (filed as Exhibit 3.1 to the Company’s Current Report on Form 8-K filed with the SEC on June 24, 2025, and incorporated herein by reference)
10.1+ |  | Eighth Amendment to Note Purchase Agreement and Fourth Amendment to Disclosure Letter, dated October 6, 2025, by and between the Company and Athyrium Opportunities IV Co-Invest 1 LP, as Administrative Agent
10.2 |  | Sixth Amendment to Office Lease, dated July 23, 2025, by and between the Company and DE PARK AVENUE 10880, LLC (filed as Exhibit 10.2 to the Company’s Quarterly Report on Form 10-Q filed with the SEC on August 7, 2025, and incorporated herein by reference)
31.1+ |  | Certification of Principal Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 with respect to the registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2025
31.2+ |  | Certification of Principal Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002, with respect to the registrant’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2025
32.1++ |  | Certification of Principal Executive Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
32.2++ |  | Certification of Principal Financial Officer pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
101.INS+ |  | Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document.
101.SCH+ |  | Inline XBRL Taxonomy Extension Schema Document
101.CAL+ |  | Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF+ |  | Inline XBRL Taxonomy Extension Definition Linkbase Document
101.LAB+ |  | Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE+ |  | Inline XBRL Taxonomy Extension Linkbase Document
104+ |  | Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)
+ |  | Filed herewith
++ |  | Furnished herewith

39

Table of Contents

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

| PUMA BIOTECHNOLOGY, INC.
Date: November 6, 2025 | By: | /s/ Alan H. Auerbach
|  | Alan H. Auerbach
|  | President and Chief Executive Officer
|  | (Principal Executive Officer)
Date: November 6, 2025 | By: | /s/ Maximo F. Nougues
|  | Maximo Nougues
|  | Chief Financial Officer
|  | (Principal Financial and Accounting Officer)

40