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  <xs:element id="arwr_NumberOfDistinctPerformanceObligations" abstract="false" name="NumberOfDistinctPerformanceObligations" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="arwr_AdditionalTenantImprovementAllowanceInterestPerAnnum" abstract="false" name="AdditionalTenantImprovementAllowanceInterestPerAnnum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="arwr_NonCashInterestExpenseLiabilityRelatedToSaleOfFutureRoyalties" abstract="false" name="NonCashInterestExpenseLiabilityRelatedToSaleOfFutureRoyalties" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_CommonStockCapitalSharesValueReservedForFutureIssuance" abstract="false" name="CommonStockCapitalSharesValueReservedForFutureIssuance" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_VisirnaTherapeuticsIncMember" abstract="true" name="VisirnaTherapeuticsIncMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_CashFlowOperatingActivitiesLesseeCashReceivedForAmountsIncludedInMeasurementOfLeaseLiabilitiesAbstract" abstract="true" name="CashFlowOperatingActivitiesLesseeCashReceivedForAmountsIncludedInMeasurementOfLeaseLiabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="arwr_HeldToMaturitySecuritiesAndMarketableSecuritiesTableTableTextBlock" abstract="false" name="HeldToMaturitySecuritiesAndMarketableSecuritiesTableTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:textBlockItemType"/>
  <xs:element id="arwr_OrganizationAndSignificantAccountingPoliciesTable" abstract="true" name="OrganizationAndSignificantAccountingPoliciesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="arwr_TwoThousandFourEquityIncentivePlanTwoThousandThirteenEquityIncentivePlanTwoThousandTwentyOneEquityIncentivePlanAndInducementGrantsMember" abstract="true" name="TwoThousandFourEquityIncentivePlanTwoThousandThirteenEquityIncentivePlanTwoThousandTwentyOneEquityIncentivePlanAndInducementGrantsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_MilestonePaymentReceivableUponReceiptOfRoyaltyPayments" abstract="false" name="MilestonePaymentReceivableUponReceiptOfRoyaltyPayments" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_UpfrontMilestonePaymentReceived" abstract="false" name="UpfrontMilestonePaymentReceived" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCompensationPercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseCompensationPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="arwr_TaxIncrementFinancingAward" abstract="false" name="TaxIncrementFinancingAward" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_PercentageOfCommissionOnAggregateGrossProceedsFromSaleOfCommonStock" abstract="false" name="PercentageOfCommissionOnAggregateGrossProceedsFromSaleOfCommonStock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="arwr_MaximumAdditionalTenantImprovementAllowance" abstract="false" name="MaximumAdditionalTenantImprovementAllowance" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_LaboratoryAndOfficeFacilityMember" abstract="true" name="LaboratoryAndOfficeFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_DeferredTaxLiabilitiesStateTaxes" abstract="false" name="DeferredTaxLiabilitiesStateTaxes" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_DebtSecuritiesHeldToMaturityAccumulatedUnrecognizedLossCurrent" abstract="false" name="DebtSecuritiesHeldToMaturityAccumulatedUnrecognizedLossCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_ProceedsFromSaleOfFutureRoyalties" abstract="false" name="ProceedsFromSaleOfFutureRoyalties" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_JNJ3989AROHBVAgreementMember" abstract="true" name="JNJ3989AROHBVAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_AdditionalRemainingDevelopmentRegulatoryAndSalesMilestonesPayments" abstract="false" name="AdditionalRemainingDevelopmentRegulatoryAndSalesMilestonesPayments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_ScheduleOfHeldToMaturitySecuritiesAndMarketableSecuritiesLineItems" abstract="true" name="ScheduleOfHeldToMaturitySecuritiesAndMarketableSecuritiesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="arwr_DebtSecuritiesHeldToMaturityAccumulatedUnrecognizedGainCurrent" abstract="false" name="DebtSecuritiesHeldToMaturityAccumulatedUnrecognizedGainCurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_CollaborationAndLicenseAgreementsMember" abstract="true" name="CollaborationAndLicenseAgreementsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_ResearchEquipmentGross" abstract="false" name="ResearchEquipmentGross" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_CommercialNotesMember" abstract="true" name="CommercialNotesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_OperatingLossCarryforwardsSubjectToExpiration" abstract="false" name="OperatingLossCarryforwardsSubjectToExpiration" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_CommercialMilestonePaymentsAtFirstCommercialSale" abstract="false" name="CommercialMilestonePaymentsAtFirstCommercialSale" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_MilestonePaymentReceivableUponAchievementOfEnrollmentInPhase3ClinicalTrial" abstract="false" name="MilestonePaymentReceivableUponAchievementOfEnrollmentInPhase3ClinicalTrial" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_DeferredTaxAssetsInProcessResearchAndDevelopmentCost" abstract="false" name="DeferredTaxAssetsInProcessResearchAndDevelopmentCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_VeronaTechnologyParkMember" abstract="true" name="VeronaTechnologyParkMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_PercentageOfEligibleToReceiveTieredRoyaltiesOnNetSales" abstract="false" name="PercentageOfEligibleToReceiveTieredRoyaltiesOnNetSales" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="arwr_SalesRelatedMilestonePayments" abstract="false" name="SalesRelatedMilestonePayments" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_TwoThousandsFourEquityIncentivePlanMember" abstract="true" name="TwoThousandsFourEquityIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_FacilitiesMember" abstract="true" name="FacilitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_RoyaltiesLiabilityNoncurrent" abstract="false" name="RoyaltiesLiabilityNoncurrent" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_TakedaPharmaceuticalsUnitedStatesOfAmericaIncorporatedMember" abstract="true" name="TakedaPharmaceuticalsUnitedStatesOfAmericaIncorporatedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_CollaborationAndLicenseAgreementsAbstract" abstract="true" name="CollaborationAndLicenseAgreementsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="arwr_PatrickOBrienMember" abstract="true" name="PatrickOBrienMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="arwr_CashReceivedAsDueUnderCollaborationAgreement" abstract="false" name="CashReceivedAsDueUnderCollaborationAgreement" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_TechnologyLicenseCommitmentsMember" abstract="true" name="TechnologyLicenseCommitmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_ResearchFacilityInSanDiegoMember" abstract="true" name="ResearchFacilityInSanDiegoMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_NumberOfOptionsToRenew" abstract="false" name="NumberOfOptionsToRenew" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="arwr_NumberOfDistinctBundle" abstract="false" name="NumberOfDistinctBundle" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="arwr_ComputersSoftwareOfficeEquipmentAndFurnitureGross" abstract="false" name="ComputersSoftwareOfficeEquipmentAndFurnitureGross" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_MilestonePaymentEarned" abstract="false" name="MilestonePaymentEarned" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="arwr_GlaxosmithklineIntellectualPropertyLimitedMember" abstract="true" name="GlaxosmithklineIntellectualPropertyLimitedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="arwr_EmployeeContributionNextTwoPercentMember" abstract="true" name="EmployeeContributionNextTwoPercentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
</xs:schema>
