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<!-- RR Donnelley Xcelerate Taxonomy Schema, based on XBRL 2.1  http://www.rrdonnelley.com/ -->
<!-- Version: 6.21.0 -->
<!-- Round: 4 -->
<!-- Creation date: 2014-08-05T09:20:27Z -->
<!-- Copyright (c) 2005-2013 R.R. Donnelley & Sons Company All Rights Reserved. -->
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        <link:definition>115 - Disclosure - Autoliv Manufacturing and Supply Agreement</link:definition>
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        <link:definition>125 - Disclosure - Fair Value Accounting - Financial Assets by Major Security Type and Liability Measured at Fair Value on Recurring Basis (Detail)</link:definition>
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        <link:definition>140 - Disclosure - Autoliv Manufacturing and Supply Agreement - Additional Information (Detail)</link:definition>
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  <element name="AverageBalanceDuringPeriodOfLoanSecuritized" id="alxa_AverageBalanceDuringPeriodOfLoanSecuritized" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CancelledUnsecuredDebt" id="alxa_CancelledUnsecuredDebt" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CashCashEquivalentsAndInvestmentsLineItems" id="alxa_CashCashEquivalentsAndInvestmentsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CashCashEquivalentsAndInvestmentsTable" id="alxa_CashCashEquivalentsAndInvestmentsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="CashEquivalentsAmortizedCost" id="alxa_CashEquivalentsAmortizedCost" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="CashEquivalentsUnrealizedGainLoss" id="alxa_CashEquivalentsUnrealizedGainLoss" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ClassOfWarrantOrRightContractualTermOfWarrantsOrRights" id="alxa_ClassOfWarrantOrRightContractualTermOfWarrantsOrRights" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DebtInstrumentNumberOfInstallmentPayments" id="alxa_DebtInstrumentNumberOfInstallmentPayments" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="DocumentAndEntityInformationAbstract" id="alxa_DocumentAndEntityInformationAbstract" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EligibleCashReceiptForAdditionalMilestonePayments" id="alxa_EligibleCashReceiptForAdditionalMilestonePayments" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EligibleCashReceiptForMilestonePayments" id="alxa_EligibleCashReceiptForMilestonePayments" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EmployeeStockPurchasePlanCurrentOfferingPeriod" id="alxa_EmployeeStockPurchasePlanCurrentOfferingPeriod" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EquityIncentivePlanEffectiveDate" id="alxa_EquityIncentivePlanEffectiveDate" type="xbrli:dateItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EstimatedPerformancePeriodOfAgreement" id="alxa_EstimatedPerformancePeriodOfAgreement" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EvergreenProvisionsOfDirectorsPlanMember" id="alxa_EvergreenProvisionsOfDirectorsPlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="EvergreenProvisionsOfTwoThousandFivePlanMember" id="alxa_EvergreenProvisionsOfTwoThousandFivePlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="GrupoFerrerMember" id="alxa_GrupoFerrerMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="IncreaseDecreaseInNetLossPerShareResultedFromChangeInFairValueOfContingentLiability" id="alxa_IncreaseDecreaseInNetLossPerShareResultedFromChangeInFairValueOfContingentLiability" type="num:perShareItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InterestAndOtherIncomeExpenseNet" id="alxa_InterestAndOtherIncomeExpenseNet" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InterestExpensesAmortizationPeriod" id="alxa_InterestExpensesAmortizationPeriod" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InterestReserve" id="alxa_InterestReserve" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="InterestReserveDescription" id="alxa_InterestReserveDescription" type="xbrli:stringItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LicenseAgreementsLineItems" id="alxa_LicenseAgreementsLineItems" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LicenseAgreementsTable" id="alxa_LicenseAgreementsTable" type="xbrli:stringItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrldt:hypercubeItem"/>
  <element name="LicenseAgreementTermPeriod" id="alxa_LicenseAgreementTermPeriod" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="LongTermDebtMaturityYear" id="alxa_LongTermDebtMaturityYear" type="xbrli:gYearItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NewNoteMember" id="alxa_NewNoteMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfChemicalHeatPackagesProduced" id="alxa_NumberOfChemicalHeatPackagesProduced" type="xbrli:integerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfLeaseRenewalOptions" id="alxa_NumberOfLeaseRenewalOptions" type="xbrli:decimalItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="NumberOfManufacturingFacilities" id="alxa_NumberOfManufacturingFacilities" type="xbrli:positiveIntegerItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OperatingLeasesMaturityPeriod" id="alxa_OperatingLeasesMaturityPeriod" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="OriginalNoteMember" id="alxa_OriginalNoteMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PaymentForContingentConsiderationBusinessAcquisition" id="alxa_PaymentForContingentConsiderationBusinessAcquisition" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PaymentsToFormerStockholdersUnderCollaborativeArrangement" id="alxa_PaymentsToFormerStockholdersUnderCollaborativeArrangement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="PurchasePriceToEliminateContingentConsiderationUnderCollaborativeArrangement" id="alxa_PurchasePriceToEliminateContingentConsiderationUnderCollaborativeArrangement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RestrictedCashAmortizedCost" id="alxa_RestrictedCashAmortizedCost" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RestrictedCashFairValueDisclosure" id="alxa_RestrictedCashFairValueDisclosure" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="RightToBorrowAssetReclassifiedAsDebtDiscount" id="alxa_RightToBorrowAssetReclassifiedAsDebtDiscount" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="debit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementAwardMaximumAnnualAdditionalShares" id="alxa_ShareBasedCompensationArrangementAwardMaximumAnnualAdditionalShares" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementAwardMaximumContractualTerm" id="alxa_ShareBasedCompensationArrangementAwardMaximumContractualTerm" type="xbrli:durationItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardProposedSharesReservedForFutureIssuance" id="alxa_ShareBasedCompensationArrangementByShareBasedPaymentAwardProposedSharesReservedForFutureIssuance" type="xbrli:sharesItemType" abstract="false" xbrli:periodType="instant" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="StockPurchaseRightsMember" id="alxa_StockPurchaseRightsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TermLoanAgreementFairValueOfOutstandingBorrowings" id="alxa_TermLoanAgreementFairValueOfOutstandingBorrowings" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="instant" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TevaPharmaceuticalsUsaIncMember" id="alxa_TevaPharmaceuticalsUsaIncMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndFiveEmployeeStockPurchasePlanMember" id="alxa_TwoThousandAndFiveEmployeeStockPurchasePlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndFiveEquityIncentivePlanMember" id="alxa_TwoThousandAndFiveEquityIncentivePlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="TwoThousandAndFiveNonEmployeeDirectorsStockOptionPlanMember" id="alxa_TwoThousandAndFiveNonEmployeeDirectorsStockOptionPlanMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UnvestedRestrictedStockUnitsMember" id="alxa_UnvestedRestrictedStockUnitsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UnvestedStockOptionAwardsMember" id="alxa_UnvestedStockOptionAwardsMember" type="nonnum:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="UpfrontCashReceivedUnderCollaborativeArrangement" id="alxa_UpfrontCashReceivedUnderCollaborativeArrangement" type="xbrli:monetaryItemType" abstract="false" xbrli:periodType="duration" xbrli:balance="credit" nillable="true" substitutionGroup="xbrli:item"/>
  <element name="WeightedAverageCostOfCapital" id="alxa_WeightedAverageCostOfCapital" type="num:percentItemType" abstract="false" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item"/>
</schema>


