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  <xsd:element abstract="true" id="pbyi_MedicalAffairsMember" name="MedicalAffairsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_MilestonePayment" name="MilestonePayment" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_MilestonePaymentsMaximumAmount" name="MilestonePaymentsMaximumAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="pbyi_NonvestedStockOptionsMember" name="NonvestedStockOptionsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_NotePurchaseAgreementMember" name="NotePurchaseAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_NoteToFinancialStatementDetailsTextual" name="NoteToFinancialStatementDetailsTextual" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_NotesToFinancialStatements" name="NotesToFinancialStatements" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_NotesToFinancialStatementsAbstract" name="NotesToFinancialStatementsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_NumberOfSubsidiaries" name="NumberOfSubsidiaries" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_OrdinarySharesOwnershipPercentage" name="OrdinarySharesOwnershipPercentage" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="pbyi_OtherResearchAndDevelopmentMember" name="OtherResearchAndDevelopmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_OxfordFinanceLimitedLiabilityCompanyMember" name="OxfordFinanceLimitedLiabilityCompanyMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_PercentageOfUnpaidPortionOfMilestonePaymentsInterestRate" name="PercentageOfUnpaidPortionOfMilestonePaymentsInterestRate" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:percentItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_PfizerLicenseAgreementMember" name="PfizerLicenseAgreementMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_PolicyTable" name="PolicyTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_PostMarketingCommitmentLiabilityCurrent" name="PostMarketingCommitmentLiabilityCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PotentialMilestonePayments" name="PotentialMilestonePayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PrepaidCROServicesCurrent" name="PrepaidCROServicesCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PrepaidCROServicesNoncurrent" name="PrepaidCROServicesNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PrepaidExpenseAndOtherAssetsTableTextBlock" name="PrepaidExpenseAndOtherAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_PrepaidExpenseAndOtherAssetsTextBlock" name="PrepaidExpenseAndOtherAssetsTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_PrepaidInsuranceNoncurrent" name="PrepaidInsuranceNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PrepaidOtherClinicalDevelopmentCurrent" name="PrepaidOtherClinicalDevelopmentCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PrepaidOtherClinicalDevelopmentExpenseNoncurrent" name="PrepaidOtherClinicalDevelopmentExpenseNoncurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_PrepaidProfessionalFessCurrent" name="PrepaidProfessionalFessCurrent" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="pbyi_ResearchAndDevelopmentMember" name="ResearchAndDevelopmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_RoyaltyRevenueReceivable" name="RoyaltyRevenueReceivable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element id="pbyi_ScheduleOfAccountsReceivableTableTextBlock" name="ScheduleOfAccountsReceivableTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_ScheduleOfDeferredFinancingCostsTableTextBlock" name="ScheduleOfDeferredFinancingCostsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_SecondTwoPercentOfEachParticipantsContributionsMember" name="SecondTwoPercentOfEachParticipantsContributionsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_SecuredPromissoryNotesMember" name="SecuredPromissoryNotesMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_SellingGeneralAndAdministrativeMember" name="SellingGeneralAndAdministrativeMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsInitialContractualTerm" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsInitialContractualTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_SubleaseAgreementPotentialMilestonePayments" name="SubleaseAgreementPotentialMilestonePayments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="pbyi_TakedaMember" name="TakedaMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_TelephoneEquipmentMember" name="TelephoneEquipmentMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_The2011And2017PlansMember" name="The2011And2017PlansMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_TradeAccountsReceivableNetExcludingLicenseRevenueReceivable" name="TradeAccountsReceivableNetExcludingLicenseRevenueReceivable" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="pbyi_UnvestedRestrictedStockUnitsMember" name="UnvestedRestrictedStockUnitsMember" nillable="true" substitutionGroup="xbrli:item" type="dtr-types:domainItemType" xbrli:periodType="duration"/>
  <xsd:element id="pbyi_UpfrontLicenseFee" name="UpfrontLicenseFee" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-10-stockholders-equity-options-award-assumptions-details" name="statement-statement-note-10-stockholders-equity-options-award-assumptions-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-10-stockholders-equity-restricted-stock-units-details" name="statement-statement-note-10-stockholders-equity-restricted-stock-units-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-10-stockholders-equity-stock-option-activity-details" name="statement-statement-note-10-stockholders-equity-stock-option-activity-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-10-stockholders-equity-stockbased-compensation-expense-details" name="statement-statement-note-10-stockholders-equity-stockbased-compensation-expense-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-10-stockholders-equity-tables" name="statement-statement-note-10-stockholders-equity-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-assets-measured-at-fair-value-on-recurring-basis-details" name="statement-statement-note-2-significant-accounting-policies-assets-measured-at-fair-value-on-recurring-basis-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-inventory-balance-details" name="statement-statement-note-2-significant-accounting-policies-inventory-balance-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-potentially-dilutive-securities-not-included-in-calculation-of-diluted-net-loss-per-share-details" name="statement-statement-note-2-significant-accounting-policies-potentially-dilutive-securities-not-included-in-calculation-of-diluted-net-loss-per-share-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-segment-information-details" name="statement-statement-note-2-significant-accounting-policies-segment-information-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-summary-of-cash-equivalents-and-shortterm-investment-details" name="statement-statement-note-2-significant-accounting-policies-summary-of-cash-equivalents-and-shortterm-investment-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-summary-of-reconciliation-of-numerators-and-denominators-of-basic-and-diluted-net-income-loss-per-share-of-common-stock-computations-details" name="statement-statement-note-2-significant-accounting-policies-summary-of-reconciliation-of-numerators-and-denominators-of-basic-and-diluted-net-income-loss-per-share-of-common-stock-computations-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-2-significant-accounting-policies-tables" name="statement-statement-note-2-significant-accounting-policies-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-3-accounts-receivable-net-schedule-of-accounts-receivable-net-details" name="statement-statement-note-3-accounts-receivable-net-schedule-of-accounts-receivable-net-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-3-accounts-receivable-net-tables" name="statement-statement-note-3-accounts-receivable-net-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-4-prepaid-expenses-and-other-prepaid-expenses-and-other-details" name="statement-statement-note-4-prepaid-expenses-and-other-prepaid-expenses-and-other-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-4-prepaid-expenses-and-other-tables" name="statement-statement-note-4-prepaid-expenses-and-other-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-5-leases-future-minimum-lease-payments-details" name="statement-statement-note-5-leases-future-minimum-lease-payments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-5-leases-supplemental-cash-flow-information-related-to-leases-details" name="statement-statement-note-5-leases-supplemental-cash-flow-information-related-to-leases-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-5-leases-tables" name="statement-statement-note-5-leases-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-6-property-and-equipment-net-property-and-equipment-details" name="statement-statement-note-6-property-and-equipment-net-property-and-equipment-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-6-property-and-equipment-net-tables" name="statement-statement-note-6-property-and-equipment-net-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-7-intangible-assets-net-intangible-assets-details" name="statement-statement-note-7-intangible-assets-net-intangible-assets-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-7-intangible-assets-net-tables" name="statement-statement-note-7-intangible-assets-net-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-8-accrued-expenses-composition-of-current-and-longterm-accrued-expenses-details" name="statement-statement-note-8-accrued-expenses-composition-of-current-and-longterm-accrued-expenses-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-8-accrued-expenses-tables" name="statement-statement-note-8-accrued-expenses-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-9-debt-future-minimum-principal-payments-details" name="statement-statement-note-9-debt-future-minimum-principal-payments-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-9-debt-schedule-of-debt-issuance-costs-and-discounts-details" name="statement-statement-note-9-debt-schedule-of-debt-issuance-costs-and-discounts-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-9-debt-schedule-of-long-term-debt-details" name="statement-statement-note-9-debt-schedule-of-long-term-debt-details" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-9-debt-schedule-of-long-term-debt-details-parentheticals" name="statement-statement-note-9-debt-schedule-of-long-term-debt-details-parentheticals" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-note-9-debt-tables" name="statement-statement-note-9-debt-tables" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
  <xsd:element abstract="true" id="pbyi_statement-statement-significant-accounting-policies-policies" name="statement-statement-significant-accounting-policies-policies" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration"/>
</xsd:schema>
