<?xml version="1.0" encoding="utf-8"?>
<!--XBRL document created with Toppan Merrill Bridge  11.3.0.1 -->
<!--Based on XBRL 2.1-->
<!--Created on: 5/12/2026 7:27:19 PM-->
<!--Modified on: 5/12/2026 7:27:19 PM-->
<xsd:schema targetNamespace="http://www.xoma.com/20260331" attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:dei="http://xbrl.sec.gov/dei/2025" xmlns:deprecated="http://www.xbrl.org/2009/role/deprecated" xmlns:dtr="http://www.xbrl.org/2009/dtr" xmlns:ref="http://www.xbrl.org/2006/ref" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xl="http://www.xbrl.org/2003/XLink" xmlns:us-gaap="http://fasb.org/us-gaap/2025" xmlns:utr="http://www.xbrl.org/2009/utr" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:country="http://xbrl.sec.gov/country/2025" xmlns:us-roles="http://fasb.org/us-roles/2025" xmlns:enum2="http://xbrl.org/2020/extensible-enumerations-2.0" xmlns:net="http://www.xbrl.org/2009/role/net" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:dtr-types="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:srt="http://fasb.org/srt/2025" xmlns:xbrldi="http://xbrl.org/2006/xbrldi" xmlns:negated="http://www.xbrl.org/2009/role/negated" xmlns:attributeFormDefault="unqualified" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xoma="http://www.xoma.com/20260331" xmlns:ecd="http://xbrl.sec.gov/ecd/2025" xmlns:ecd-sub="http://xbrl.sec.gov/ecd-sub/2025">
  <xsd:annotation>
    <xsd:appinfo>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedBalanceSheets" id="StatementCondensedConsolidatedBalanceSheets">
        <link:definition>995200100 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedStatementsOfOperations" id="StatementCondensedConsolidatedStatementsOfOperations">
        <link:definition>995200200 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedStatementsOfComprehensiveIncome" id="StatementCondensedConsolidatedStatementsOfComprehensiveIncome">
        <link:definition>995200300 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedStatementsOfCashFlows" id="StatementCondensedConsolidatedStatementsOfCashFlows">
        <link:definition>995200600 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesCashCashEquivalentsAndRestrictedCashDetails" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesCashCashEquivalentsAndRestrictedCashDetails">
        <link:definition>99940201 - Disclosure - Basis of Presentation and Significant Accounting Policies - Cash, Cash Equivalents and Restricted Cash (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsIntangibleAssetsNetFutureAmortizationExpenseDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsIntangibleAssetsNetFutureAmortizationExpenseDetails">
        <link:definition>99940303 - Disclosure - Condensed Consolidated Financial Statements Details - Intangible Assets, Net - Future Amortization Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsNetIncomeLossPerShareDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsNetIncomeLossPerShareDetails">
        <link:definition>99940304 - Disclosure - Condensed Consolidated Financial Statements Details - Net Income (Loss) Per Share (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsAccruedAndOtherLiabilitiesDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsAccruedAndOtherLiabilitiesDetails">
        <link:definition>99940306 - Disclosure - Condensed Consolidated Financial Statements Details - Accrued and Other Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsOtherIncomeExpenseNetDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsOtherIncomeExpenseNetDetails">
        <link:definition>99940307 - Disclosure - Condensed Consolidated Financial Statements Details - Other Income (Expense), Net (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsPurchaseConsiderationDetails" id="DisclosureAcquisitionsPurchaseConsiderationDetails">
        <link:definition>99940602 - Disclosure - Acquisitions - Purchase Consideration (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsNetAssetsAcquiredDetails" id="DisclosureAcquisitionsNetAssetsAcquiredDetails">
        <link:definition>99940603 - Disclosure - Acquisitions - Net Assets Acquired (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureFairValueMeasurementsFinancialAssetsAndLiabilitiesCarriedAtFvOnRecurringBasisDetails" id="DisclosureFairValueMeasurementsFinancialAssetsAndLiabilitiesCarriedAtFvOnRecurringBasisDetails">
        <link:definition>99940701 - Disclosure - Fair Value Measurements - Financial Assets and Liabilities Carried at FV on Recurring Basis (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsMaturityOfOperatingLeaseLiabilitiesDetails" id="DisclosureLeaseAgreementsMaturityOfOperatingLeaseLiabilitiesDetails">
        <link:definition>99940802 - Disclosure - Lease Agreements - Maturity of Operating Lease Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebtBalanceDetailsCalc2" id="DisclosureLongTermDebtBalanceDetailsCalc2">
        <link:definition>40802 - Disclosure - Long-Term Debt - Balance (Details) Calc 2</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsGrossDifferenceDetails" id="DisclosureLeaseAgreementsGrossDifferenceDetails">
        <link:definition>99940803 - Disclosure - Lease Agreements - Gross Difference (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsLeaseCostsDetails" id="DisclosureLeaseAgreementsLeaseCostsDetails">
        <link:definition>99940805 - Disclosure - Lease Agreements - Lease Costs (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebtBalanceDetails" id="DisclosureLongTermDebtBalanceDetails">
        <link:definition>99940902 - Disclosure - Long-Term Debt - Balance (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebtAggregateProjectedFuturePrincipalAndDiscountsDetails" id="DisclosureLongTermDebtAggregateProjectedFuturePrincipalAndDiscountsDetails">
        <link:definition>99940903 - Disclosure - Long-Term Debt - Aggregate Projected Future Principal and Discounts (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebtInterestExpenseDetails" id="DisclosureLongTermDebtInterestExpenseDetails">
        <link:definition>99940904 - Disclosure - Long-Term Debt - Interest Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommitmentsAndContingenciesContingentConsiderationDetails" id="DisclosureCommitmentsAndContingenciesContingentConsiderationDetails">
        <link:definition>99941102 - Disclosure - Commitments and Contingencies - Contingent Consideration (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSegmentAndGeographicInformationSegmentInformationDetails" id="DisclosureSegmentAndGeographicInformationSegmentInformationDetails">
        <link:definition>99941502 - Disclosure - Segment and Geographic Information - Segment Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DocumentDocumentAndEntityInformation" id="DocumentDocumentAndEntityInformation">
        <link:definition>995200090 - Document - Document and Entity Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedBalanceSheetsParenthetical" id="StatementCondensedConsolidatedBalanceSheetsParenthetical">
        <link:definition>995200105 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedStatementsOfStockholdersEquity" id="StatementCondensedConsolidatedStatementsOfStockholdersEquity">
        <link:definition>995200500 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsTables" id="DisclosureAcquisitionsTables">
        <link:definition>99930603 - Disclosure - Acquisitions (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsTables" id="DisclosureLeaseAgreementsTables">
        <link:definition>99930803 - Disclosure - Lease Agreements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansTables" id="DisclosureStockBasedCompensationAndOtherBenefitPlansTables">
        <link:definition>99931203 - Disclosure - Stock-Based Compensation and Other Benefit Plans (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesConcentrationOfRiskDetails" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesConcentrationOfRiskDetails">
        <link:definition>99940202 - Disclosure - Basis of Presentation and Significant Accounting Policies - Concentration of Risk (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPurchaseOfRightsToFutureMilestonesRoyaltiesAndCommercialPaymentsDetails" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPurchaseOfRightsToFutureMilestonesRoyaltiesAndCommercialPaymentsDetails">
        <link:definition>99940203 - Disclosure - Basis of Presentation and Significant Accounting Policies - Purchase of Rights to Future Milestones, Royalties, and Commercial Payments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesIncomeTaxesAndShareRepurchasesDetails" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesIncomeTaxesAndShareRepurchasesDetails">
        <link:definition>99940204 - Disclosure - Basis of Presentation and Significant Accounting Policies - Income Taxes and Share Repurchases (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesAccountingPronouncementsDetails" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesAccountingPronouncementsDetails">
        <link:definition>99940205 - Disclosure - Basis of Presentation and Significant Accounting Policies - Accounting Pronouncements (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsEquitySecuritiesDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsEquitySecuritiesDetails">
        <link:definition>99940301 - Disclosure - Condensed Consolidated Financial Statements Details - Equity Securities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsIntangibleAssetsNetGeneralInformationDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsIntangibleAssetsNetGeneralInformationDetails">
        <link:definition>99940302 - Disclosure - Condensed Consolidated Financial Statements Details - Intangible Assets, Net - General Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsOutstandingSecuritiesConsideredAntiDilutiveDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsOutstandingSecuritiesConsideredAntiDilutiveDetails">
        <link:definition>99940305 - Disclosure - Condensed Consolidated Financial Statements Details - Outstanding Securities Considered Anti-Dilutive (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsSummaryOfRoyaltyReceivableActivitiesDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsSummaryOfRoyaltyReceivableActivitiesDetails">
        <link:definition>99940401 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Summary of Royalty Receivable Activities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsFullyRecoveredViractaDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsFullyRecoveredViractaDetails">
        <link:definition>99940402 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Fully Recovered - Viracta (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsUnderEirMethodDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsUnderEirMethodDetails">
        <link:definition>99940403 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Under EIR Method (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsEirMethodAffitechDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsEirMethodAffitechDetails">
        <link:definition>99940404 - Disclosure - Royalty and Commercial Payment Purchase Agreements - EIR Method - Affitech (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsEirMethodAptevoDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsEirMethodAptevoDetails">
        <link:definition>99940405 - Disclosure - Royalty and Commercial Payment Purchase Agreements - EIR Method - Aptevo (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsUnderCostRecoveryMethodDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsUnderCostRecoveryMethodDetails">
        <link:definition>99940406 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Under Cost Recovery Method (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodLadrxDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodLadrxDetails">
        <link:definition>99940407 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Cost Recovery Method - LadRx (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodCastleCreekDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodCastleCreekDetails">
        <link:definition>99940408 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Cost Recovery Method - Castle Creek (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodKurosDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodKurosDetails">
        <link:definition>99940409 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Cost Recovery Method - Kuros (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodPalobiofarmaDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodPalobiofarmaDetails">
        <link:definition>99940410 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Cost Recovery Method - Palobiofarma (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodTwistBioscienceDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodTwistBioscienceDetails">
        <link:definition>99940411 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Cost Recovery Method - Twist Bioscience (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodDareDetails" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsCostRecoveryMethodDareDetails">
        <link:definition>99940412 - Disclosure - Royalty and Commercial Payment Purchase Agreements - Cost Recovery Method - Dare (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLicenseCollaborationAndOtherArrangementsRezoluteLicenseAgreementDetails" id="DisclosureLicenseCollaborationAndOtherArrangementsRezoluteLicenseAgreementDetails">
        <link:definition>99940501 - Disclosure - License, Collaboration, and Other Arrangements - Rezolute License Agreement (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLicenseCollaborationAndOtherArrangementsTakedaCollaborationAgreementAndTakedaRevenueShareAgreementDetails" id="DisclosureLicenseCollaborationAndOtherArrangementsTakedaCollaborationAgreementAndTakedaRevenueShareAgreementDetails">
        <link:definition>99940502 - Disclosure - License, Collaboration, and Other Arrangements - Takeda Collaboration Agreement and Takeda Revenue Share Agreement (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLicenseCollaborationAndOtherArrangementsBioinventLicenseAgreementDetails" id="DisclosureLicenseCollaborationAndOtherArrangementsBioinventLicenseAgreementDetails">
        <link:definition>99940503 - Disclosure - License, Collaboration, and Other Arrangements - BioInvent License Agreement (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLicenseCollaborationAndOtherArrangementsRepareAcquisitionAndXenotherapeuticsArrangerLetterAndSaleOfFutureRevenueStreamsDetails" id="DisclosureLicenseCollaborationAndOtherArrangementsRepareAcquisitionAndXenotherapeuticsArrangerLetterAndSaleOfFutureRevenueStreamsDetails">
        <link:definition>99940504 - Disclosure - License, Collaboration, and Other Arrangements - Repare Acquisition and XenoTherapeutics Arranger Letter and Sale of Future Revenue Streams (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsGenerationBioAcquisitionDetails" id="DisclosureAcquisitionsGenerationBioAcquisitionDetails">
        <link:definition>99940601 - Disclosure - Acquisitions - Generation Bio Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsReconciliationOfNetAssetsAcquiredToTotalPurchaseConsiderationDetails" id="DisclosureAcquisitionsReconciliationOfNetAssetsAcquiredToTotalPurchaseConsiderationDetails">
        <link:definition>99940604 - Disclosure - Acquisitions - Reconciliation of Net Assets Acquired to Total Purchase Consideration (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsLavaAcquisitionDetails" id="DisclosureAcquisitionsLavaAcquisitionDetails">
        <link:definition>99940605 - Disclosure - Acquisitions - LAVA Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsHillevaxAcquisitionDetails" id="DisclosureAcquisitionsHillevaxAcquisitionDetails">
        <link:definition>99940606 - Disclosure - Acquisitions - HilleVax Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsTurnstoneAcquisitionDetails" id="DisclosureAcquisitionsTurnstoneAcquisitionDetails">
        <link:definition>99940607 - Disclosure - Acquisitions - Turnstone Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsMuralAcquisitionDetails" id="DisclosureAcquisitionsMuralAcquisitionDetails">
        <link:definition>99940608 - Disclosure - Acquisitions - Mural Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsKinnateAcquisitionDetails" id="DisclosureAcquisitionsKinnateAcquisitionDetails">
        <link:definition>99940609 - Disclosure - Acquisitions - Kinnate Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitionsPulmokineAcquisitionDetails" id="DisclosureAcquisitionsPulmokineAcquisitionDetails">
        <link:definition>99940610 - Disclosure - Acquisitions - Pulmokine Acquisition (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureFairValueMeasurementsMilestoneAssetMilestoneContingentConsiderationAndPrvInterestAndWarrantsDetails" id="DisclosureFairValueMeasurementsMilestoneAssetMilestoneContingentConsiderationAndPrvInterestAndWarrantsDetails">
        <link:definition>99940702 - Disclosure - Fair Value Measurements - Milestone Asset, Milestone Contingent Consideration and PRV Interest and Warrants (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsLeasedFacilitiesDetails" id="DisclosureLeaseAgreementsLeasedFacilitiesDetails">
        <link:definition>99940801 - Disclosure - Lease Agreements - Leased Facilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebtAgreementDetails" id="DisclosureLongTermDebtAgreementDetails">
        <link:definition>99940901 - Disclosure - Long-Term Debt - Agreement (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommonStockWarrantsDetails" id="DisclosureCommonStockWarrantsDetails">
        <link:definition>99941001 - Disclosure - Common Stock Warrants (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommitmentsAndContingenciesCollaborativeAgreementsRoyaltiesAndMilestonePaymentsDetails" id="DisclosureCommitmentsAndContingenciesCollaborativeAgreementsRoyaltiesAndMilestonePaymentsDetails">
        <link:definition>99941101 - Disclosure - Commitments and Contingencies - Collaborative Agreements, Royalties and Milestone Payments (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansEsppDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansEsppDetails">
        <link:definition>99941201 - Disclosure - Stock Based Compensation and Other Benefit Plans - ESPP (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlans2010PlanStockOptionsAndFvAssumptionsDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlans2010PlanStockOptionsAndFvAssumptionsDetails">
        <link:definition>99941202 - Disclosure - Stock Based Compensation and Other Benefit Plans - 2010 Plan Stock Options and FV Assumptions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansCashOutAgreementDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansCashOutAgreementDetails">
        <link:definition>99941203 - Disclosure - Stock Based Compensation and Other Benefit Plans - Cash-Out Agreement (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansStockOptionActivityDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansStockOptionActivityDetails">
        <link:definition>99941204 - Disclosure - Stock Based Compensation and Other Benefit Plans - Stock Option Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansPerformanceStockUnitAwardsDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansPerformanceStockUnitAwardsDetails">
        <link:definition>99941205 - Disclosure - Stock Based Compensation and Other Benefit Plans - Performance Stock Unit Awards (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansPerformanceStockUnitAwardsFairValueDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansPerformanceStockUnitAwardsFairValueDetails">
        <link:definition>99941206 - Disclosure - Stock Based Compensation and Other Benefit Plans - Performance Stock Unit Awards Fair Value (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansPerformanceStockUnitAwardsActivityDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansPerformanceStockUnitAwardsActivityDetails">
        <link:definition>99941207 - Disclosure - Stock Based Compensation and Other Benefit Plans - Performance Stock Unit Awards Activity (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansRestrictedStockUnitAwardsDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansRestrictedStockUnitAwardsDetails">
        <link:definition>99941208 - Disclosure - Stock Based Compensation and Other Benefit Plans - Restricted Stock Unit Awards (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlansStockBasedCompensationExpenseDetails" id="DisclosureStockBasedCompensationAndOtherBenefitPlansStockBasedCompensationExpenseDetails">
        <link:definition>99941209 - Disclosure - Stock Based Compensation and Other Benefit Plans - Stock-based Compensation Expense (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCapitalStockDividendsDetails" id="DisclosureCapitalStockDividendsDetails">
        <link:definition>99941301 - Disclosure - Capital Stock - Dividends (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCapitalStockBvfOwnershipDetails" id="DisclosureCapitalStockBvfOwnershipDetails">
        <link:definition>99941302 - Disclosure - Capital Stock - BVF Ownership (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCapitalStockAtmAgreementsDetails" id="DisclosureCapitalStockAtmAgreementsDetails">
        <link:definition>99941303 - Disclosure - Capital Stock - ATM Agreements (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCapitalStockStockRepurchaseProgramDetails" id="DisclosureCapitalStockStockRepurchaseProgramDetails">
        <link:definition>99941304 - Disclosure - Capital Stock - Stock Repurchase Program (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSegmentAndGeographicInformationGeographicRegionsDetails" id="DisclosureSegmentAndGeographicInformationGeographicRegionsDetails">
        <link:definition>99941503 - Disclosure - Segment and Geographic Information - Geographic Regions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSubsequentEventsDetails" id="DisclosureSubsequentEventsDetails">
        <link:definition>99941601 - Disclosure - Subsequent Events (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/StatementCondensedConsolidatedStatementsOfConvertiblePreferredStock" id="StatementCondensedConsolidatedStatementsOfConvertiblePreferredStock">
        <link:definition>995200400 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureDescriptionOfBusiness" id="DisclosureDescriptionOfBusiness">
        <link:definition>995210101 - Disclosure - Description of Business</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPolicies" id="DisclosureBasisOfPresentationAndSignificantAccountingPolicies">
        <link:definition>995210201 - Disclosure - Basis of Presentation and Significant Accounting Policies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetails" id="DisclosureCondensedConsolidatedFinancialStatementsDetails">
        <link:definition>995210301 - Disclosure - Condensed Consolidated Financial Statements Details</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreements" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreements">
        <link:definition>995210401 - Disclosure - Royalty and Commercial Payment Purchase Agreements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLicenseCollaborationAndOtherArrangements" id="DisclosureLicenseCollaborationAndOtherArrangements">
        <link:definition>995210501 - Disclosure - License, Collaboration, and Other Arrangements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureAcquisitions" id="DisclosureAcquisitions">
        <link:definition>995210601 - Disclosure - Acquisitions</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureFairValueMeasurements" id="DisclosureFairValueMeasurements">
        <link:definition>995210701 - Disclosure - Fair Value Measurements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreements" id="DisclosureLeaseAgreements">
        <link:definition>995210801 - Disclosure - Lease Agreements</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebt" id="DisclosureLongTermDebt">
        <link:definition>995210901 - Disclosure - Long-Term Debt</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommonStockWarrants" id="DisclosureCommonStockWarrants">
        <link:definition>995211001 - Disclosure - Common Stock Warrants</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommitmentsAndContingencies" id="DisclosureCommitmentsAndContingencies">
        <link:definition>995211101 - Disclosure - Commitments and Contingencies</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStockBasedCompensationAndOtherBenefitPlans" id="DisclosureStockBasedCompensationAndOtherBenefitPlans">
        <link:definition>995211201 - Disclosure - Stock-Based Compensation and Other Benefit Plans</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCapitalStock" id="DisclosureCapitalStock">
        <link:definition>995211301 - Disclosure - Capital Stock</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureIncomeTaxes" id="DisclosureIncomeTaxes">
        <link:definition>995211401 - Disclosure - Income Taxes</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSegmentAndGeographicInformation" id="DisclosureSegmentAndGeographicInformation">
        <link:definition>995211501 - Disclosure - Segment and Geographic Information</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSubsequentEvents" id="DisclosureSubsequentEvents">
        <link:definition>995211601 - Disclosure - Subsequent Events</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesPolicies">
        <link:definition>99920202 - Disclosure - Basis of Presentation and Significant Accounting Policies (Policies)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureBasisOfPresentationAndSignificantAccountingPoliciesTables" id="DisclosureBasisOfPresentationAndSignificantAccountingPoliciesTables">
        <link:definition>99930203 - Disclosure - Basis of Presentation and Significant Accounting Policies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCondensedConsolidatedFinancialStatementsDetailsTables" id="DisclosureCondensedConsolidatedFinancialStatementsDetailsTables">
        <link:definition>99930303 - Disclosure - Condensed Consolidated Financial Statements Details (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsTables" id="DisclosureRoyaltyAndCommercialPaymentPurchaseAgreementsTables">
        <link:definition>99930403 - Disclosure - Royalty and Commercial Payment Purchase Agreements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureFairValueMeasurementsTables" id="DisclosureFairValueMeasurementsTables">
        <link:definition>99930703 - Disclosure - Fair Value Measurements (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLongTermDebtTables" id="DisclosureLongTermDebtTables">
        <link:definition>99930903 - Disclosure - Long-Term Debt (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommonStockWarrantsTables" id="DisclosureCommonStockWarrantsTables">
        <link:definition>99931003 - Disclosure - Common Stock Warrants (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCommitmentsAndContingenciesTables" id="DisclosureCommitmentsAndContingenciesTables">
        <link:definition>99931103 - Disclosure - Commitments and Contingencies (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureCapitalStockTables" id="DisclosureCapitalStockTables">
        <link:definition>99931303 - Disclosure - Capital Stock (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSegmentAndGeographicInformationTables" id="DisclosureSegmentAndGeographicInformationTables">
        <link:definition>99931503 - Disclosure - Segment and Geographic Information (Tables)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureDescriptionOfBusinessDetails" id="DisclosureDescriptionOfBusinessDetails">
        <link:definition>99940101 - Disclosure - Description of Business (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsOperatingLeaseLiabilitiesDetails" id="DisclosureLeaseAgreementsOperatingLeaseLiabilitiesDetails">
        <link:definition>99940804 - Disclosure - Lease Agreements - Operating Lease Liabilities (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsStatementsOfCashFlowsSupplementalDisclosureDetails" id="DisclosureLeaseAgreementsStatementsOfCashFlowsSupplementalDisclosureDetails">
        <link:definition>99940806 - Disclosure - Lease Agreements - Statements of Cash Flows Supplemental Disclosure (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureLeaseAgreementsPresentValueOfOperatingLeasePaymentsAssumptionsDetails" id="DisclosureLeaseAgreementsPresentValueOfOperatingLeasePaymentsAssumptionsDetails">
        <link:definition>99940807 - Disclosure - Lease Agreements - Present Value of Operating Lease Payments, Assumptions (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureIncomeTaxesDetails" id="DisclosureIncomeTaxesDetails">
        <link:definition>99941401 - Disclosure - Income Taxes (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureSegmentAndGeographicInformationGeneralInformationDetails" id="DisclosureSegmentAndGeographicInformationGeneralInformationDetails">
        <link:definition>99941501 - Disclosure - Segment and Geographic Information - General Information (Details)</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
      <link:linkbaseRef xlink:type="simple" xlink:href="xoma-20260331_pre.xml" xlink:title="Presentation Links, all" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
      <link:linkbaseRef xlink:type="simple" xlink:href="xoma-20260331_cal.xml" xlink:title="Calculation Links, all" xlink:role="http://www.xbrl.org/2003/role/calculationLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
      <link:linkbaseRef xlink:type="simple" xlink:href="xoma-20260331_def.xml" xlink:title="Definition Links, all" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
      <link:linkbaseRef xlink:type="simple" xlink:href="xoma-20260331_lab.xml" xlink:title="Label Links, all" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" />
      <link:roleType roleURI="http://www.xoma.com/role/DisclosureStandardAndCustomAxisDomainDefaults" id="DisclosureStandardAndCustomAxisDomainDefaults">
        <link:definition>99900 - Disclosure - Standard And Custom Axis Domain Defaults</link:definition>
        <link:usedOn>link:presentationLink</link:usedOn>
        <link:usedOn>link:calculationLink</link:usedOn>
        <link:usedOn>link:definitionLink</link:usedOn>
      </link:roleType>
    </xsd:appinfo>
  </xsd:annotation>
  <xsd:import namespace="https://xbrl.org/2023/calculation-1.1" schemaLocation="https://www.xbrl.org/2023/calculation-1.1.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/ecd/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-2025.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <xsd:import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <xsd:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd" />
  <xsd:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd" />
  <xsd:import namespace="http://fasb.org/us-roles/2025" schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd" />
  <xsd:import namespace="http://fasb.org/us-gaap/2025" schemaLocation="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd" />
  <xsd:import namespace="http://fasb.org/srt/2025" schemaLocation="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/country/2025" schemaLocation="https://xbrl.sec.gov/country/2025/country-2025.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/dei/2025" schemaLocation="https://xbrl.sec.gov/dei/2025/dei-2025.xsd" />
  <xsd:import namespace="http://xbrl.sec.gov/ecd-sub/2025" schemaLocation="https://xbrl.sec.gov/ecd/2025/ecd-sub-2025.xsd" />
  <xsd:element name="DebtDiscountLoanTerminationExpenses" id="xoma_DebtDiscountLoanTerminationExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AdditionalPaidInCapitalShareBasedCompensationReclassificationFromLiability" id="xoma_AdditionalPaidInCapitalShareBasedCompensationReclassificationFromLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="StockPriceHurdlesOfDollar33Member" id="xoma_StockPriceHurdlesOfDollar33Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockPriceHurdlesOfDollar38Member" id="xoma_StockPriceHurdlesOfDollar38Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockPriceHurdlesOfDollar43Member" id="xoma_StockPriceHurdlesOfDollar43Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockPriceHurdlesOfDollar48Member" id="xoma_StockPriceHurdlesOfDollar48Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber" id="xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingNumber" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingWeighted" id="xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedAndExpectedToVestOutstandingWeighted" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="TaxReserveContingentConsiderationMember" id="xoma_TaxReserveContingentConsiderationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TaxCvrContingentConsiderationMember" id="xoma_TaxCvrContingentConsiderationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LeaseSecurityDepositContingentConsiderationMember" id="xoma_LeaseSecurityDepositContingentConsiderationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AdditionalClosingNetCashContingentConsiderationMember" id="xoma_AdditionalClosingNetCashContingentConsiderationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledInYearOneThroughTwo" id="xoma_PercentageShareOfNetProceedsEntitledInYearOneThroughTwo" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledInYearThreeThroughFour" id="xoma_PercentageShareOfNetProceedsEntitledInYearThreeThroughFour" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledInYearFiveThroughSix" id="xoma_PercentageShareOfNetProceedsEntitledInYearFiveThroughSix" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledInYearSevenThroughTen" id="xoma_PercentageShareOfNetProceedsEntitledInYearSevenThroughTen" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearOneThroughThree" id="xoma_PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearOneThroughThree" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearFourThroughFive" id="xoma_PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearFourThroughFive" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearSixThroughSeven" id="xoma_PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearSixThroughSeven" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearEightThroughTen" id="xoma_PercentageShareOfNetProceedsEntitledRelatedToCollaborationAndLicenseAgreementInYearEightThroughTen" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="AssetAcquisitionContingentValueRightsLeaseSecurityDeposit" id="xoma_AssetAcquisitionContingentValueRightsLeaseSecurityDeposit" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="DifferenceBetweenContingentValueRightsLiabilityAccruedAndActualAmountPaid" id="xoma_DifferenceBetweenContingentValueRightsLiabilityAccruedAndActualAmountPaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AdditionalExpenseAccrued" id="xoma_AdditionalExpenseAccrued" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="O2025Q4DividendsMember" id="xoma_O2025Q4DividendsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AccruedAndOtherLiabilitiesCurrent" id="xoma_AccruedAndOtherLiabilitiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DefinedContributionPlanIssuanceOfCommonStockForServicesOrClaims" id="xoma_DefinedContributionPlanIssuanceOfCommonStockForServicesOrClaims" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ConsolidatedFinancialStatementDetailAbstract" id="xoma_ConsolidatedFinancialStatementDetailAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyPurchaseAgreementTextBlock" id="xoma_RoyaltyPurchaseAgreementTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquitySecuritiesPolicy" id="xoma_EquitySecuritiesPolicy" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RezoluteIncMember" id="xoma_RezoluteIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ProceedsFromUpfrontPayment" id="xoma_ProceedsFromUpfrontPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LicenseAgreementMember" id="xoma_LicenseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EligiblePotentialAdditionalPaymentsReceivableUponAchievementOfSpecifiedFutureNetSalesMilestones" id="xoma_EligiblePotentialAdditionalPaymentsReceivableUponAchievementOfSpecifiedFutureNetSalesMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="RoyaltyPurchaseAgreementMember" id="xoma_RoyaltyPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyReceivablePercentageOnNetSales" id="xoma_RoyaltyReceivablePercentageOnNetSales" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TwoThousandFifteenEmployeeStockPurchasePlanMember" id="xoma_TwoThousandFifteenEmployeeStockPurchasePlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TwoThousandTenLongTermIncentiveAndStockAwardPlanMember" id="xoma_TwoThousandTenLongTermIncentiveAndStockAwardPlanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="BiotechnologyValueFundLPMember" id="xoma_BiotechnologyValueFundLPMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentageOfGrossProceedsPaidToAgentForSaleOfCommonShares" id="xoma_PercentageOfGrossProceedsPaidToAgentForSaleOfCommonShares" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TenYearWarrantsIssuedThirdRangeMember" id="xoma_TenYearWarrantsIssuedThirdRangeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContractualObligationEstimatedMilestonePayments" id="xoma_ContractualObligationEstimatedMilestonePayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="Partner1Member" id="xoma_Partner1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Partner2Member" id="xoma_Partner2Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Partner3Member" id="xoma_Partner3Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NumberOfMajorPartners" id="xoma_NumberOfMajorPartners" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LicenseAgreementAndCommonStockPurchaseAgreementMember" id="xoma_LicenseAgreementAndCommonStockPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="OperatingLeasePaymentsNonCash" id="xoma_OperatingLeasePaymentsNonCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="CommonStockWarrantDisclosureTextBlock" id="xoma_CommonStockWarrantDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PalobiofarmaSLMember" id="xoma_PalobiofarmaSLMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyInterestAcquisitionAgreementsMember" id="xoma_RoyaltyInterestAcquisitionAgreementsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FirstRoyaltyInterestAcquisitionAgreementMember" id="xoma_FirstRoyaltyInterestAcquisitionAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SecondRoyaltyInterestAcquisitionAgreementMember" id="xoma_SecondRoyaltyInterestAcquisitionAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="HealthCareRoyaltyPartnersTwoLimitedPartnersMember" id="xoma_HealthCareRoyaltyPartnersTwoLimitedPartnersMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MilestonePeriodsNumber" id="xoma_MilestonePeriodsNumber" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="AgreementDrugCandidatesNumber" id="xoma_AgreementDrugCandidatesNumber" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="EmployeeMember" id="xoma_EmployeeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CommonStockWarrantExercisePrice14.71Member" id="xoma_CommonStockWarrantExercisePrice14.71Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="XomaCorporationMember" id="xoma_XomaCorporationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NoncontrollingInterestOwnershipPercentageByParentIfSharesConverted" id="xoma_NoncontrollingInterestOwnershipPercentageByParentIfSharesConverted" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ContractualObligationEstimatedMilestonePaymentsNumberOfProducts" id="xoma_ContractualObligationEstimatedMilestonePaymentsNumberOfProducts" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="LeaseDisclosureTextBlock" id="xoma_LeaseDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LesseeOperatingLeaseSupplementalCashFlowInformationTableTextBlock" id="xoma_LesseeOperatingLeaseSupplementalCashFlowInformationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LesseeOperatingLeaseSupplementalInformationTableTextBlock" id="xoma_LesseeOperatingLeaseSupplementalInformationTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ViractaTherapeuticsInc.Member" id="xoma_ViractaTherapeuticsInc.Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AccruedPreferredStockDividendCurrent" id="xoma_AccruedPreferredStockDividendCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="MilestonesReceivableExcludingConsiderationRetainedMaximum" id="xoma_MilestonesReceivableExcludingConsiderationRetainedMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="MaximumConsiderationRetained" id="xoma_MaximumConsiderationRetained" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="RegulatoryAndCommercialMilestonesReceivableMaximum" id="xoma_RegulatoryAndCommercialMilestonesReceivableMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="KurosBiosciencesAgKurosUsLlcAndKurosRoyaltyFundUsLlcMember" id="xoma_KurosBiosciencesAgKurosUsLlcAndKurosRoyaltyFundUsLlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EligibleMilestonePaymentsReceivableUponAchievementOfPreCommercialMilestones" id="xoma_EligibleMilestonePaymentsReceivableUponAchievementOfPreCommercialMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MaximumValueOfStockToBeIssued" id="xoma_MaximumValueOfStockToBeIssued" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="TakedaPharmaceuticalCompanyLimitedMember" id="xoma_TakedaPharmaceuticalCompanyLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CommercialPaymentPurchaseAgreementMember" id="xoma_CommercialPaymentPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CommercialSalesReceivablePercentageOnNetSales" id="xoma_CommercialSalesReceivablePercentageOnNetSales" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AffitechResearchAsMember" id="xoma_AffitechResearchAsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FutureMilestonesRoyaltiesPurchaseRightsAndCommercialPaymentsPolicyPolicyTextBlock" id="xoma_FutureMilestonesRoyaltiesPurchaseRightsAndCommercialPaymentsPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CommercialPaymentReceivableTerm" id="xoma_CommercialPaymentReceivableTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MaximumPayableOnSalesMilestone" id="xoma_MaximumPayableOnSalesMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PercentageOfGrossProceedsPaidToAgentForSaleOfShares" id="xoma_PercentageOfGrossProceedsPaidToAgentForSaleOfShares" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AccruedSalariesAndEmployeeBenefitsCurrent" id="xoma_AccruedSalariesAndEmployeeBenefitsCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ContingentConsiderationUnderPurchaseAgreements" id="xoma_ContingentConsiderationUnderPurchaseAgreements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ContingentConsiderationSalesMilestonesMember" id="xoma_ContingentConsiderationSalesMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyAndCommercialPaymentPurchaseAgreementsAbstract" id="xoma_RoyaltyAndCommercialPaymentPurchaseAgreementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MilestonePaymentReceivedCounterparty" id="xoma_MilestonePaymentReceivedCounterparty" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MilestonePaymentReceivablePercentage" id="xoma_MilestonePaymentReceivablePercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinancialAssetsFairValueDisclosure" id="xoma_FinancialAssetsFairValueDisclosure" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfRoyaltyAndCommercialPaymentReceivablesActivityTableTextBlock" id="xoma_ScheduleOfRoyaltyAndCommercialPaymentReceivablesActivityTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionsPolicyPolicyTextBlock" id="xoma_AssetAcquisitionsPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AptevoMember" id="xoma_AptevoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CreditLossContractWithCustomerAssetPolicyTextBlock" id="xoma_CreditLossContractWithCustomerAssetPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LadrxMember" id="xoma_LadrxMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfHurdles." id="xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfHurdles." type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfCalendarDays" id="xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfCalendarDays" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="StockPriceHurdlesOfDollar30Member" id="xoma_StockPriceHurdlesOfDollar30Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockPriceHurdlesOfDollar35Member" id="xoma_StockPriceHurdlesOfDollar35Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockPriceHurdlesOfDollar40Member" id="xoma_StockPriceHurdlesOfDollar40Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="StockPriceHurdlesOfDollar45Member" id="xoma_StockPriceHurdlesOfDollar45Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceAbstract" id="xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageExercisePriceAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AssignmentAndAssumptionAgreementAndRoyaltyPurchaseAgreementMember" id="xoma_AssignmentAndAssumptionAgreementAndRoyaltyPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PaymentOfConsiderationUnderAgreementsInvestingActivities" id="xoma_PaymentOfConsiderationUnderAgreementsInvestingActivities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ReceiptsUnderAgreementsInvestingActivities" id="xoma_ReceiptsUnderAgreementsInvestingActivities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="LeasedFacilitiesTwoEmeryvilleCaliforniaMember" id="xoma_LeasedFacilitiesTwoEmeryvilleCaliforniaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PerformanceStockUnitsMember" id="xoma_PerformanceStockUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="EligibleMilestonePaymentsReceivableUponAchievementOfMilestones" id="xoma_EligibleMilestonePaymentsReceivableUponAchievementOfMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AgreementsNumber" id="xoma_AgreementsNumber" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="CommonStockWarrantIssuedDecemberTwentyTwentyThreeMember" id="xoma_CommonStockWarrantIssuedDecemberTwentyTwentyThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="WarrantsPolicyTextBlock" id="xoma_WarrantsPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ScheduleOfAccretionOfDebtDiscountsAndIssuanceCostsIncludedInInterestExpenseTableTextBlock" id="xoma_ScheduleOfAccretionOfDebtDiscountsAndIssuanceCostsIncludedInInterestExpenseTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BlueOwlCommercialPaymentBackedLoanAgreementMember" id="xoma_BlueOwlCommercialPaymentBackedLoanAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CommonStockWarrantsAtExercisePriceOf35.00PerShareMember" id="xoma_CommonStockWarrantsAtExercisePriceOf35.00PerShareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CommonStockWarrantsAtExercisePriceOf42.50PerShareMember" id="xoma_CommonStockWarrantsAtExercisePriceOf42.50PerShareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CommonStockWarrantsAtExercisePriceOf50.00PerShareMember" id="xoma_CommonStockWarrantsAtExercisePriceOf50.00PerShareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SecurityInterestInPercentageOfEquity" id="xoma_SecurityInterestInPercentageOfEquity" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="AmountDepositedIntoReserveAccountsToPayInterestAdministrativeFeesAndOperatingExpenses" id="xoma_AmountDepositedIntoReserveAccountsToPayInterestAdministrativeFeesAndOperatingExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RestrictedCashAdditionalToBeFunded" id="xoma_RestrictedCashAdditionalToBeFunded" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="BlueOwlCommercialPaymentBackedLoanAgreementInitialTermLoanMember" id="xoma_BlueOwlCommercialPaymentBackedLoanAgreementInitialTermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="BlueOwlCommercialPaymentBackedLoanAgreementDelayedDrawTermLoanMember" id="xoma_BlueOwlCommercialPaymentBackedLoanAgreementDelayedDrawTermLoanMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CashReserveAccountsInterestAndAdministrativeFeesAndOperatingExpensesMember" id="xoma_CashReserveAccountsInterestAndAdministrativeFeesAndOperatingExpensesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CashReserveAccountsInterestAndAdministrativeFeesMember" id="xoma_CashReserveAccountsInterestAndAdministrativeFeesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CashReserveAccountsOperatingExpensesMember" id="xoma_CashReserveAccountsOperatingExpensesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PaymentsOfFinancingCostsFeesAndLenderExpenses" id="xoma_PaymentsOfFinancingCostsFeesAndLenderExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ProceedsFromIssuanceOfLongTermDebtNet" id="xoma_ProceedsFromIssuanceOfLongTermDebtNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="DebtInstrumentUnamortizedDiscountAllocatedFeesAndLenderExpenses" id="xoma_DebtInstrumentUnamortizedDiscountAllocatedFeesAndLenderExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="KinnateMember" id="xoma_KinnateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AcquisitionNumberOfContingentValueRights" id="xoma_AcquisitionNumberOfContingentValueRights" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="CommercialPaymentPeriodDue" id="xoma_CommercialPaymentPeriodDue" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="LongTermRightsReceivableNonCurrentCreditLossExpenseAndImpairmentOfIntangibleAssetsFiniteLived" id="xoma_LongTermRightsReceivableNonCurrentCreditLossExpenseAndImpairmentOfIntangibleAssetsFiniteLived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFour" id="xoma_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RepaymentsOfLongTermDebtAndInterestPaid" id="xoma_RepaymentsOfLongTermDebtAndInterestPaid" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RoyaltyPercentageApplicableUnderAgreement" id="xoma_RoyaltyPercentageApplicableUnderAgreement" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="DareMember" id="xoma_DareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ScenarioOneMember" id="xoma_ScenarioOneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OvapreneMember" id="xoma_OvapreneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SildenafilCreamMember" id="xoma_SildenafilCreamMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OvapreneAndSildenafilCreamMember" id="xoma_OvapreneAndSildenafilCreamMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentValueRightsAgreementMember" id="xoma_ContingentValueRightsAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentConsiderationSalesMilestonesThreeMember" id="xoma_ContingentConsiderationSalesMilestonesThreeMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="VariableLeaseCostNet" id="xoma_VariableLeaseCostNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="MilestoneAssetsNoncurrent" id="xoma_MilestoneAssetsNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="GainLossOnAssetAcquisition" id="xoma_GainLossOnAssetAcquisition" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RevenueNotFromContractWithCustomerUnitsOfRevenueMethod" id="xoma_RevenueNotFromContractWithCustomerUnitsOfRevenueMethod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AssetAcquisitionSharePrice" id="xoma_AssetAcquisitionSharePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="LeasedFacilitiesSanFranciscoCaliforniaMember" id="xoma_LeasedFacilitiesSanFranciscoCaliforniaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PayableOnMilestone" id="xoma_PayableOnMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PayableOnMilestoneSpecifiedAmountOfEachSuccessiveReceipt" id="xoma_PayableOnMilestoneSpecifiedAmountOfEachSuccessiveReceipt" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PayableOnMilestoneReturnThreshold" id="xoma_PayableOnMilestoneReturnThreshold" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AssetAcquisitionsLicensingAndOtherArrangementsAbstract" id="xoma_AssetAcquisitionsLicensingAndOtherArrangementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AssetAcquisitionNumberOfSharesTendered" id="xoma_AssetAcquisitionNumberOfSharesTendered" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="TovorafenibMember" id="xoma_TovorafenibMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeNotFromContractWithCustomerCostRecoveryMethod" id="xoma_IncomeNotFromContractWithCustomerCostRecoveryMethod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RevenueRevenueNotFromContractWithCustomerUnitsOfRevenueMethodPolicyTextBlock" id="xoma_RevenueRevenueNotFromContractWithCustomerUnitsOfRevenueMethodPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PurchasedReceivablesCostRecoveryMethodNetCurrent" id="xoma_PurchasedReceivablesCostRecoveryMethodNetCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PurchasedReceivablesEffectiveInterestRateMethodNetCurrent" id="xoma_PurchasedReceivablesEffectiveInterestRateMethodNetCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RightsReceivableCostRecoveryMethod" id="xoma_RightsReceivableCostRecoveryMethod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RightsReceivableCostRecoveryMethodAcquisitionOfPaymentReceivable" id="xoma_RightsReceivableCostRecoveryMethodAcquisitionOfPaymentReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RestrictedCashReleasedToUnrestrictedCash" id="xoma_RestrictedCashReleasedToUnrestrictedCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RightsReceivableCostRecoveryMethodReceiptOfPayments" id="xoma_RightsReceivableCostRecoveryMethodReceiptOfPayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="MilestoneAssetsIncreaseDecrease" id="xoma_MilestoneAssetsIncreaseDecrease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AssetAcquisitionContingentConsiderationLiabilityChangeInAmount" id="xoma_AssetAcquisitionContingentConsiderationLiabilityChangeInAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="TwistBioscienceCorporationMember" id="xoma_TwistBioscienceCorporationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="NumberOfPartners" id="xoma_NumberOfPartners" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="KinnateCvrHoldersMember" id="xoma_KinnateCvrHoldersMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ChangeInFairValueOfAvailableForSaleDebtSecuritiesCashEquivalents" id="xoma_ChangeInFairValueOfAvailableForSaleDebtSecuritiesCashEquivalents" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RightsReceivableEirMethod" id="xoma_RightsReceivableEirMethod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RightsReceivableEirMethodReceiptOfPayments" id="xoma_RightsReceivableEirMethodReceiptOfPayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RightsReceivableEirMethodReclassificationOfPaymentReceivablesFromCostRecoveryToEirMethod" id="xoma_RightsReceivableEirMethodReclassificationOfPaymentReceivablesFromCostRecoveryToEirMethod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PulmokineMember" id="xoma_PulmokineMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ScheduleOfIncomeFromPurchasedReceivablesTableTextBlock" id="xoma_ScheduleOfIncomeFromPurchasedReceivablesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RoyaltyAndCommercialPaymentReceivablesCostRecoveryMethodShortTerm" id="xoma_RoyaltyAndCommercialPaymentReceivablesCostRecoveryMethodShortTerm" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RoyaltyAndCommercialPaymentReceivablesCostRecoveryMethodLongTerm" id="xoma_RoyaltyAndCommercialPaymentReceivablesCostRecoveryMethodLongTerm" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RoyaltyAndCommercialPaymentReceivablesEffectiveInterestRateMethodShortTerm" id="xoma_RoyaltyAndCommercialPaymentReceivablesEffectiveInterestRateMethodShortTerm" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RoyaltyAndCommercialPaymentReceivablesEffectiveInterestRateMethodLongTerm" id="xoma_RoyaltyAndCommercialPaymentReceivablesEffectiveInterestRateMethodLongTerm" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="IncomeNotFromContractWithCustomerEffectiveInterestRateMethod" id="xoma_IncomeNotFromContractWithCustomerEffectiveInterestRateMethod" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RoyaltyAndCommercialPaymentReceivableActivitiesUnderCostRecoveryMethodAbstract" id="xoma_RoyaltyAndCommercialPaymentReceivableActivitiesUnderCostRecoveryMethodAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RoyaltyAndCommercialPaymentReceivableActivitiesUnderEirMethodAbstract" id="xoma_RoyaltyAndCommercialPaymentReceivableActivitiesUnderEirMethodAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentPaymentsAcquiredPercentage" id="xoma_ContingentPaymentsAcquiredPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="NumberOfEarlyStagePrograms" id="xoma_NumberOfEarlyStagePrograms" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="StockIssuedDuringPeriodValuePerformanceStockUnitsNetOfForfeituresTotal" id="xoma_StockIssuedDuringPeriodValuePerformanceStockUnitsNetOfForfeituresTotal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="StockIssuedDuringPeriodSharesPerformanceStockUnitsNetOfForfeituresTotal" id="xoma_StockIssuedDuringPeriodSharesPerformanceStockUnitsNetOfForfeituresTotal" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="BusinessDevelopmentAndDealCosts" id="xoma_BusinessDevelopmentAndDealCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="CastleCreekBiosciencesIncMember" id="xoma_CastleCreekBiosciencesIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IntellectualPropertySeralutinibMember" id="xoma_IntellectualPropertySeralutinibMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AssetAcquisitionClassOfWarrantOrRightNumberReceived" id="xoma_AssetAcquisitionClassOfWarrantOrRightNumberReceived" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="AssetAcquisitionClassOfWarrantOrRightPricePerShare" id="xoma_AssetAcquisitionClassOfWarrantOrRightPricePerShare" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
  <xsd:element name="AssetAcquisitionClassOfWarrantOrRightTerm" id="xoma_AssetAcquisitionClassOfWarrantOrRightTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RightsReceivablePercentageOnNetSalesAndProceeds" id="xoma_RightsReceivablePercentageOnNetSalesAndProceeds" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="MilestonePaymentsNumber" id="xoma_MilestonePaymentsNumber" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RoyaltyFinancingAgreementMember" id="xoma_RoyaltyFinancingAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RightsReceivableSpecifiedPercentageOfNetSalesDomestic" id="xoma_RightsReceivableSpecifiedPercentageOfNetSalesDomestic" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RightsReceivableSpecifiedPercentageOfNetSalesInternational" id="xoma_RightsReceivableSpecifiedPercentageOfNetSalesInternational" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="RightsReceivableSpecifiedPercentageOfProceeds" id="xoma_RightsReceivableSpecifiedPercentageOfProceeds" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="InvestmentsWarrantAssetsPolicyPolicyTextBlock" id="xoma_InvestmentsWarrantAssetsPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="DebtInstrumentPrincipalPayments" id="xoma_DebtInstrumentPrincipalPayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="IncomeNotFromContractWithCustomerCostRecoveryMethodMilestone" id="xoma_IncomeNotFromContractWithCustomerCostRecoveryMethodMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="IncomeNotFromContractWithCustomerCostRecoveryMethodRoyalties" id="xoma_IncomeNotFromContractWithCustomerCostRecoveryMethodRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="XaciatoMember" id="xoma_XaciatoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MiplyffaMember" id="xoma_MiplyffaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="VabysmoMember" id="xoma_VabysmoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IxinityMember" id="xoma_IxinityMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SingleReportableSegmentMember" id="xoma_SingleReportableSegmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IncomeNotFromContractWithCustomerEffectiveInterestRateMethodCashFlowImpact" id="xoma_IncomeNotFromContractWithCustomerEffectiveInterestRateMethodCashFlowImpact" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="RightsReceivableEirMethodPaymentOfSalesBasedMilestones" id="xoma_RightsReceivableEirMethodPaymentOfSalesBasedMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ContingentConsiderationSalesMilestonesFourMember" id="xoma_ContingentConsiderationSalesMilestonesFourMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="InvestmentWarrantsNoncurrent" id="xoma_InvestmentWarrantsNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour" id="xoma_FiniteLivedIntangibleAssetExpectedAmortizationAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="BioinventInternationalAbMember" id="xoma_BioinventInternationalAbMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AcquisitionServiceArrangerFeeReceivable" id="xoma_AcquisitionServiceArrangerFeeReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="PercentageShareOfPotentialMilestoneProceeds" id="xoma_PercentageShareOfPotentialMilestoneProceeds" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ProceedsFromMilestoneNet" id="xoma_ProceedsFromMilestoneNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="InvestmentWarrantTerm" id="xoma_InvestmentWarrantTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="TemporaryEquityPolicyPolicyTextBlock" id="xoma_TemporaryEquityPolicyPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ContractBasedIntangibleAssetsBioinventMember" id="xoma_ContractBasedIntangibleAssetsBioinventMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LavaTherapeuticsNvMember" id="xoma_LavaTherapeuticsNvMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TurnstoneBiologicsCorpMember" id="xoma_TurnstoneBiologicsCorpMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="HillevaxIncMember" id="xoma_HillevaxIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="AssetAcquisitionContingentValueRightsLiabilityNoncurrent" id="xoma_AssetAcquisitionContingentValueRightsLiabilityNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AssetAcquisitionContingentValueRightsLiabilityCurrent" id="xoma_AssetAcquisitionContingentValueRightsLiabilityCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAssetAcquisitionAccrualOfContingentValueRightsLiability" id="xoma_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAssetAcquisitionAccrualOfContingentValueRightsLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ThomasBurnsMember" id="xoma_ThomasBurnsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedCashHeldForBlueOwlLoanAgreementMember" id="xoma_RestrictedCashHeldForBlueOwlLoanAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedCashHeldForBostonLeasePaymentsMember" id="xoma_RestrictedCashHeldForBostonLeasePaymentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedCashHeldForAcquisitionOfMuralMember" id="xoma_RestrictedCashHeldForAcquisitionOfMuralMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LicenseCollaborationAndOtherArrangementsAbstract" id="xoma_LicenseCollaborationAndOtherArrangementsAbstract" type="xbrli:stringItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LicenseCollaborationAndOtherArrangementsTextBlock" id="xoma_LicenseCollaborationAndOtherArrangementsTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="MuralOncologyPlcMember" id="xoma_MuralOncologyPlcMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CommonStockAtMarketAgreementMember" id="xoma_CommonStockAtMarketAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SeriesBPreferredStockAtMarketAgreementMember" id="xoma_SeriesBPreferredStockAtMarketAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="XenotherapeuticsIncMember" id="xoma_XenotherapeuticsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SubleasedFacilityKinnateAcquisitionMember" id="xoma_SubleasedFacilityKinnateAcquisitionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LeasedFacilityBostonMember" id="xoma_LeasedFacilityBostonMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LeasedFacilitySwitzerlandMember" id="xoma_LeasedFacilitySwitzerlandMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="SubleasedFacilityBostonMember" id="xoma_SubleasedFacilityBostonMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LesseeOperatingSubleaseExpiryTerm" id="xoma_LesseeOperatingSubleaseExpiryTerm" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" id="xoma_LesseeOperatingLeaseLiabilityToBePaidAfterYearFour" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PercentageShareOfProceedsFromSpecifiedAssets" id="xoma_PercentageShareOfProceedsFromSpecifiedAssets" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="AssetAcquisitionContingentValueRightsConsiderationAdjustment" id="xoma_AssetAcquisitionContingentValueRightsConsiderationAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PercentageShareOfNetProceedsFromDisposition" id="xoma_PercentageShareOfNetProceedsFromDisposition" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfUnusedFunds" id="xoma_PercentageShareOfUnusedFunds" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="AssetAcquisitionContingentValueRightsLiability" id="xoma_AssetAcquisitionContingentValueRightsLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RestrictedCashHeldForBostonLeaseSecurityDepositMember" id="xoma_RestrictedCashHeldForBostonLeaseSecurityDepositMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentValueRightAgreementContingentConsiderationProbable" id="xoma_ContingentValueRightAgreementContingentConsiderationProbable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="CashAcquiredFromAssetAcquisition" id="xoma_CashAcquiredFromAssetAcquisition" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ScenarioIfLeaseTerminatedAssignedOrSubleasedAfterTwelveMonthsOfClosingDateMember" id="xoma_ScenarioIfLeaseTerminatedAssignedOrSubleasedAfterTwelveMonthsOfClosingDateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ScenarioIfLeaseTerminatedAssignedOrSubleasedWithinTwelveMonthsOfClosingDateMember" id="xoma_ScenarioIfLeaseTerminatedAssignedOrSubleasedWithinTwelveMonthsOfClosingDateMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="OtherMiscellaneousExpenseIncomeNet" id="xoma_OtherMiscellaneousExpenseIncomeNet" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PercentageShareOfSecurityDeposit" id="xoma_PercentageShareOfSecurityDeposit" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfSublease" id="xoma_PercentageShareOfSublease" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ShareBasedPaymentArrangementEquityClassifiedAwardsMember" id="xoma_ShareBasedPaymentArrangementEquityClassifiedAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ShareBasedPaymentArrangementLiabilityClassifiedAwardsMember" id="xoma_ShareBasedPaymentArrangementLiabilityClassifiedAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentValueRightsLiabilityWorkingCapitalAdjustment" id="xoma_ContingentValueRightsLiabilityWorkingCapitalAdjustment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="GenerationBioCoMember" id="xoma_GenerationBioCoMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RepareTherapeuticsIncMember" id="xoma_RepareTherapeuticsIncMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IntellectualPropertyLava1266Member" id="xoma_IntellectualPropertyLava1266Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="IntellectualPropertyLavaPartneredProgramMember" id="xoma_IntellectualPropertyLavaPartneredProgramMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ArrangerFeeReceived" id="xoma_ArrangerFeeReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ShareholderMember" id="xoma_ShareholderMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="CollaborationAgreementAndRevenueShareAgreementMember" id="xoma_CollaborationAgreementAndRevenueShareAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="MaximumRemainingMilestonePayments" id="xoma_MaximumRemainingMilestonePayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="debit" />
  <xsd:element name="EmployeeStockOptionLiabilityClassifiedAwardsMember" id="xoma_EmployeeStockOptionLiabilityClassifiedAwardsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PercentageShareOfNetProceedsFromOngoingAndFutureCollaborations" id="xoma_PercentageShareOfNetProceedsFromOngoingAndFutureCollaborations" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="ThresholdPeriodDuringWhichHoldersAreEntitledToReceiveNetProceeds" id="xoma_ThresholdPeriodDuringWhichHoldersAreEntitledToReceiveNetProceeds" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfNetProceedsFromSaleTransferLicenseOrOtherDivestitureOfIntellectualProperty" id="xoma_PercentageShareOfNetProceedsFromSaleTransferLicenseOrOtherDivestitureOfIntellectualProperty" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfExcessClosingCash" id="xoma_PercentageShareOfExcessClosingCash" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PercentageShareOfTaxReserve" id="xoma_PercentageShareOfTaxReserve" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="PaymentForInMoneyOptions" id="xoma_PaymentForInMoneyOptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="NumberOfSharesIssuedRelatingToInMoneyOptions" id="xoma_NumberOfSharesIssuedRelatingToInMoneyOptions" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="EstimatedAdditionalClosingNetCashContingentConsideration" id="xoma_EstimatedAdditionalClosingNetCashContingentConsideration" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PaymentOfDebtIssuanceCostsAndLoanFees" id="xoma_PaymentOfDebtIssuanceCostsAndLoanFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="StockRepurchaseProgramJanuary2024Member" id="xoma_StockRepurchaseProgramJanuary2024Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="LesseeOperatingLeaseLiabilityToBePaidReversedFromRestrictedCash" id="xoma_LesseeOperatingLeaseLiabilityToBePaidReversedFromRestrictedCash" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AdjustmentsToAdditionalPaidInCapitalReclassificationsOfLiabilityToEquityClassifiedAwards" id="xoma_AdjustmentsToAdditionalPaidInCapitalReclassificationsOfLiabilityToEquityClassifiedAwards" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="PaymentsForContingentConsiderationInvestingActivities" id="xoma_PaymentsForContingentConsiderationInvestingActivities" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="TransactionCostsIncludedInAccountsPayableAndAccruedExpenses" id="xoma_TransactionCostsIncludedInAccountsPayableAndAccruedExpenses" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ReclassificationOfLiabilityClassifiedAwardsToEquity" id="xoma_ReclassificationOfLiabilityClassifiedAwardsToEquity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="AdjustmentToContingentValueRightsLiabilitySoonAfterAcquisitions" id="xoma_AdjustmentToContingentValueRightsLiabilitySoonAfterAcquisitions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="LigandPharmaceuticalsIncorporatedMember" id="xoma_LigandPharmaceuticalsIncorporatedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="PercentageShareOfNetProceedsThatMayResultFromOngoingLitigation" id="xoma_PercentageShareOfNetProceedsThatMayResultFromOngoingLitigation" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" />
  <xsd:element name="O2026Q1DividendsMember" id="xoma_O2026Q1DividendsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="TerminationFeeForLease" id="xoma_TerminationFeeForLease" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="LicenseAgreementUpfrontPaymentReceived" id="xoma_LicenseAgreementUpfrontPaymentReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="LicenseAgreementPrepaidResearchFundingReceived" id="xoma_LicenseAgreementPrepaidResearchFundingReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="LicenseAgreementMilestoneReceivable" id="xoma_LicenseAgreementMilestoneReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="AssetAcquisitionExcessNetCashReceivedInTransactionAmountDistributed" id="xoma_AssetAcquisitionExcessNetCashReceivedInTransactionAmountDistributed" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="RestrictedCashHeldForBinneyLeaseSecurityDepositMember" id="xoma_RestrictedCashHeldForBinneyLeaseSecurityDepositMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedCashHeldForGenerationBioPostClosingExpensesMember" id="xoma_RestrictedCashHeldForGenerationBioPostClosingExpensesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="RestrictedCashHeldForLavaContingentValueRightPaymentsMember" id="xoma_RestrictedCashHeldForLavaContingentValueRightPaymentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="true" />
  <xsd:element name="ContingentValueRightsAgreementContingentValueRightsAdjustment2025SeptemberAgreement" id="xoma_ContingentValueRightsAgreementContingentValueRightsAdjustment2025SeptemberAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ContingentValueRightsAgreementContingentValueRightsAdjustment2025NovemberAgreement" id="xoma_ContingentValueRightsAgreementContingentValueRightsAdjustment2025NovemberAgreement" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ContingentValueRightsAgreementContingentValueRightsAdjustmentLiabilityIncreaseForInterestEarnedOnReserveAccount" id="xoma_ContingentValueRightsAgreementContingentValueRightsAdjustmentLiabilityIncreaseForInterestEarnedOnReserveAccount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" abstract="false" xbrli:balance="debit" />
  <xsd:element name="ContingentValueRightsAgreementContingentValueRightsPaymentLiability" id="xoma_ContingentValueRightsAgreementContingentValueRightsPaymentLiability" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ContingentValueRightsAgreementContingentValueRightsPaymentLiabilityTaxReserve" id="xoma_ContingentValueRightsAgreementContingentValueRightsPaymentLiabilityTaxReserve" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="ContingentValueRightsAgreementContingentValueRightsPaymentLiabilityReceiptsAfterExcessNetCashDistribution" id="xoma_ContingentValueRightsAgreementContingentValueRightsPaymentLiabilityReceiptsAfterExcessNetCashDistribution" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" xbrli:balance="credit" />
  <xsd:element name="BusinessCombinationContingentValueRightsPerShare" id="xoma_BusinessCombinationContingentValueRightsPerShare" type="xbrli:pureItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" abstract="false" />
</xsd:schema>
