<?xml version="1.0" encoding="us-ascii"?>
<!--XBRL document created with Merrill Bridge  6.0.103.0 -->
<!--Based on XBRL 2.1-->
<!--Created on: 11/9/2015 3:32:12 PM-->
<!--Modified on: 11/9/2015 3:32:12 PM-->
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  <element id="bpmc_AccruedSeveranceCosts" name="AccruedSeveranceCosts" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_LoanAndSecurityAgreementMember" name="LoanAndSecurityAgreementMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" name="LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_PercentageFeePayableOnTotalLoanAdvancesAtEndOfLoan" name="PercentageFeePayableOnTotalLoanAdvancesAtEndOfLoan" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_PercentageFeePayableOnOutstandingPrincipalInEventOfPrepaymentOfLoanAdvancesOption1" name="PercentageFeePayableOnOutstandingPrincipalInEventOfPrepaymentOfLoanAdvancesOption1" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_PercentageFeePayableOnOutstandingPrincipalInEventOfPrepaymentOfLoanAdvancesOption2" name="PercentageFeePayableOnOutstandingPrincipalInEventOfPrepaymentOfLoanAdvancesOption2" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_NonemployeePerformanceBasedRestrictedStockMember" name="NonemployeePerformanceBasedRestrictedStockMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEmployeeShareholderMinimumOwnershipPercentageForExercisePriceFairValueRestrictions" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEmployeeShareholderMinimumOwnershipPercentageForExercisePriceFairValueRestrictions" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardCliffVestingPeriodForNewEmployees" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardCliffVestingPeriodForNewEmployees" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasedInPeriod" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasedInPeriod" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasedInPeriodWeightedAverageGrantDateFairValue" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasedInPeriodWeightedAverageGrantDateFairValue" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_SharesForWhichPerformaceConditionConsideredProbableOfAchievement" name="SharesForWhichPerformaceConditionConsideredProbableOfAchievement" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEmployeeShareholderExercisePriceMinimumPercentageFairValueRestriction" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEmployeeShareholderExercisePriceMinimumPercentageFairValueRestriction" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_MilestoneAxis" name="MilestoneAxis" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_MilestoneDomain" name="MilestoneDomain" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_PreclinicalMilestoneFirstLicensedProductMember" name="PreclinicalMilestoneFirstLicensedProductMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_DevelopmentMilestoneFirstLicensedProductMember" name="DevelopmentMilestoneFirstLicensedProductMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_DevelopmentMilestoneSecondLicensedProductMember" name="DevelopmentMilestoneSecondLicensedProductMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_CommercialMilestoneMember" name="CommercialMilestoneMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ResearchAndDevelopmentCostsIncurredUnderResearchPlanCollaborativePartnerFundingPercentagePerAgreement" name="ResearchAndDevelopmentCostsIncurredUnderResearchPlanCollaborativePartnerFundingPercentagePerAgreement" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_NonrefundableUpfrontPaymentReceived" name="NonrefundableUpfrontPaymentReceived" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_Milestoneachivementpaymentsreceivable" name="Milestoneachivementpaymentsreceivable" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_LicensedProductRoyaltyTermFromFirstCommericalSaleOption1" name="LicensedProductRoyaltyTermFromFirstCommericalSaleOption1" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_LicensedProductRoyaltyTermFromFirstCommericalSaleOption2" name="LicensedProductRoyaltyTermFromFirstCommericalSaleOption2" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_CollaborativeArrangementPeriodOfPriorNoticeToTerminateAgreement" name="CollaborativeArrangementPeriodOfPriorNoticeToTerminateAgreement" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_CollaborativeAgreementNumberOfDeliverables" name="CollaborativeAgreementNumberOfDeliverables" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_EmployeeStockPurchasePlan2015Member" name="EmployeeStockPurchasePlan2015Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_SeriesaWarrantsMember" name="SeriesaWarrantsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_SeriesBWarrantsMember" name="SeriesBWarrantsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_WarrantTerm" name="WarrantTerm" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_PaymentOfOfferingCosts" name="PaymentOfOfferingCosts" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_StockIssuedDuringPeriodSharesNewIssuesUnderwriters" name="StockIssuedDuringPeriodSharesNewIssuesUnderwriters" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_TermLoan2014Member" name="TermLoan2014Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_SeriesAndSeriesBWarrantsMember" name="SeriesAndSeriesBWarrantsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_NumberOfCommonSharesExercisableFromWarrants" name="NumberOfCommonSharesExercisableFromWarrants" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_NumberOfWarrantsForCommonStockCancelled" name="NumberOfWarrantsForCommonStockCancelled" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_WarrantsDisclosureTextBlock" name="WarrantsDisclosureTextBlock" nillable="true" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_LeaseIncentivePayableNoncurrent" name="LeaseIncentivePayableNoncurrent" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ReclassificationOfWarrantLiabilityToAdditionalPaidInCapital" name="ReclassificationOfWarrantLiabilityToAdditionalPaidInCapital" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfAdditionalSharesAuthorized" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfAdditionalSharesAuthorized" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_StockOptionAndIncentivePlan2015Member" name="StockOptionAndIncentivePlan2015Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_OfficeAndLaboratorySpaceInCambridgeMassachusettsMember" name="OfficeAndLaboratorySpaceInCambridgeMassachusettsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_OperatingLeasesBaseAnnualRentInitial" name="OperatingLeasesBaseAnnualRentInitial" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_OperatingLeasesBaseAnnualRentMaximum" name="OperatingLeasesBaseAnnualRentMaximum" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_OperatingLeasesAllowanceForLeaseholdImprovements" name="OperatingLeasesAllowanceForLeaseholdImprovements" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_AccruedLeaseholdImprovementExpenses" name="AccruedLeaseholdImprovementExpenses" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ConsultingFeesPayableCurrent" name="ConsultingFeesPayableCurrent" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="bpmc_ShareBasedCompensationArrangementByShareBasedPaymentAwardForfeitureRate" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardForfeitureRate" nillable="true" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
</xsd:schema>
