000087504512/312021Q1false150,554,7500.0010.0010.00050.000513231528418Indefinite until commercializationIndefinite0002.9003.6254.0505.2002.2503.1503.2500.831.18000008750452021-01-012021-03-31xbrli:shares00008750452021-04-21iso4217:USD0000875045us-gaap:ProductMember2021-01-012021-03-310000875045us-gaap:ProductMember2020-01-012020-03-310000875045biib:Revenuesfromanticd20therapeuticprogramsMember2021-01-012021-03-310000875045biib:Revenuesfromanticd20therapeuticprogramsMember2020-01-012020-03-310000875045us-gaap:ProductAndServiceOtherMember2021-01-012021-03-310000875045us-gaap:ProductAndServiceOtherMember2020-01-012020-03-3100008750452020-01-012020-03-31iso4217:USDxbrli:shares00008750452021-03-3100008750452020-12-3100008750452019-12-3100008750452020-03-310000875045us-gaap:PreferredStockMember2020-12-310000875045us-gaap:CommonStockMember2020-12-310000875045us-gaap:AdditionalPaidInCapitalMember2020-12-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeMember2020-12-310000875045us-gaap:RetainedEarningsMember2020-12-310000875045us-gaap:TreasuryStockMember2020-12-310000875045us-gaap:ParentMember2020-12-310000875045us-gaap:NoncontrollingInterestMember2020-12-310000875045us-gaap:RetainedEarningsMember2021-01-012021-03-310000875045us-gaap:ParentMember2021-01-012021-03-310000875045us-gaap:NoncontrollingInterestMember2021-01-012021-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-01-012021-03-310000875045us-gaap:CommonStockMember2021-01-012021-03-310000875045biib:December2019ShareRepurchaseProgramMemberus-gaap:TreasuryStockMember2021-01-012021-03-310000875045biib:December2019ShareRepurchaseProgramMemberus-gaap:ParentMember2021-01-012021-03-310000875045biib:December2019ShareRepurchaseProgramMember2021-01-012021-03-310000875045biib:December2019ShareRepurchaseProgramMemberus-gaap:CommonStockMember2021-01-012021-03-310000875045biib:December2019ShareRepurchaseProgramMemberus-gaap:AdditionalPaidInCapitalMember2021-01-012021-03-310000875045biib:December2019ShareRepurchaseProgramMemberus-gaap:RetainedEarningsMember2021-01-012021-03-310000875045us-gaap:AdditionalPaidInCapitalMember2021-01-012021-03-310000875045us-gaap:PreferredStockMember2021-03-310000875045us-gaap:CommonStockMember2021-03-310000875045us-gaap:AdditionalPaidInCapitalMember2021-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeMember2021-03-310000875045us-gaap:RetainedEarningsMember2021-03-310000875045us-gaap:TreasuryStockMember2021-03-310000875045us-gaap:ParentMember2021-03-310000875045us-gaap:NoncontrollingInterestMember2021-03-310000875045us-gaap:PreferredStockMember2019-12-310000875045us-gaap:CommonStockMember2019-12-310000875045us-gaap:AdditionalPaidInCapitalMember2019-12-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeMember2019-12-310000875045us-gaap:RetainedEarningsMember2019-12-310000875045us-gaap:TreasuryStockMember2019-12-310000875045us-gaap:ParentMember2019-12-310000875045us-gaap:NoncontrollingInterestMember2019-12-310000875045us-gaap:RetainedEarningsMember2020-01-012020-03-310000875045us-gaap:ParentMember2020-01-012020-03-310000875045us-gaap:NoncontrollingInterestMember2020-01-012020-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeMember2020-01-012020-03-310000875045us-gaap:TreasuryStockMemberbiib:March2019ShareRepurchaseProgramMember2020-01-012020-03-310000875045biib:March2019ShareRepurchaseProgramMemberus-gaap:ParentMember2020-01-012020-03-310000875045biib:March2019ShareRepurchaseProgramMember2020-01-012020-03-310000875045biib:March2019ShareRepurchaseProgramMemberus-gaap:CommonStockMember2020-01-012020-03-310000875045biib:March2019ShareRepurchaseProgramMemberus-gaap:AdditionalPaidInCapitalMember2020-01-012020-03-310000875045us-gaap:RetainedEarningsMemberbiib:March2019ShareRepurchaseProgramMember2020-01-012020-03-310000875045us-gaap:TreasuryStockMemberbiib:A2018ShareRepurchaseProgramMember2020-01-012020-03-310000875045us-gaap:ParentMemberbiib:A2018ShareRepurchaseProgramMember2020-01-012020-03-310000875045biib:A2018ShareRepurchaseProgramMember2020-01-012020-03-310000875045us-gaap:CommonStockMemberbiib:A2018ShareRepurchaseProgramMember2020-01-012020-03-310000875045biib:A2018ShareRepurchaseProgramMemberus-gaap:AdditionalPaidInCapitalMember2020-01-012020-03-310000875045us-gaap:RetainedEarningsMemberbiib:A2018ShareRepurchaseProgramMember2020-01-012020-03-310000875045us-gaap:CommonStockMember2020-01-012020-03-310000875045us-gaap:AdditionalPaidInCapitalMember2020-01-012020-03-310000875045us-gaap:PreferredStockMember2020-03-310000875045us-gaap:CommonStockMember2020-03-310000875045us-gaap:AdditionalPaidInCapitalMember2020-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeMember2020-03-310000875045us-gaap:RetainedEarningsMember2020-03-310000875045us-gaap:TreasuryStockMember2020-03-310000875045us-gaap:ParentMember2020-03-310000875045us-gaap:NoncontrollingInterestMember2020-03-31biib:productbiib:segmentxbrli:pure0000875045biib:BIIB118Member2020-03-012020-03-310000875045country:USbiib:FumarateMember2021-01-012021-03-310000875045biib:FumarateMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:FumarateMember2021-01-012021-03-310000875045country:USbiib:FumarateMember2020-01-012020-03-310000875045biib:FumarateMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:FumarateMember2020-01-012020-03-310000875045country:USbiib:InterferonMember2021-01-012021-03-310000875045biib:InterferonMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:InterferonMember2021-01-012021-03-310000875045country:USbiib:InterferonMember2020-01-012020-03-310000875045biib:InterferonMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:InterferonMember2020-01-012020-03-310000875045country:USbiib:TysabriProductMember2021-01-012021-03-310000875045biib:TysabriProductMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:TysabriProductMember2021-01-012021-03-310000875045country:USbiib:TysabriProductMember2020-01-012020-03-310000875045biib:TysabriProductMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:TysabriProductMember2020-01-012020-03-310000875045country:USbiib:FAMPYRAMember2021-01-012021-03-310000875045biib:FAMPYRAMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:FAMPYRAMember2021-01-012021-03-310000875045country:USbiib:FAMPYRAMember2020-01-012020-03-310000875045biib:FAMPYRAMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:FAMPYRAMember2020-01-012020-03-310000875045country:USbiib:MSProductRevenuesMember2021-01-012021-03-310000875045biib:MSProductRevenuesMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:MSProductRevenuesMember2021-01-012021-03-310000875045country:USbiib:MSProductRevenuesMember2020-01-012020-03-310000875045biib:MSProductRevenuesMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:MSProductRevenuesMember2020-01-012020-03-310000875045country:USbiib:SPINRAZAMember2021-01-012021-03-310000875045biib:SPINRAZAMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:SPINRAZAMember2021-01-012021-03-310000875045country:USbiib:SPINRAZAMember2020-01-012020-03-310000875045biib:SPINRAZAMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:SPINRAZAMember2020-01-012020-03-310000875045country:USbiib:BENEPALIMember2021-01-012021-03-310000875045us-gaap:NonUsMemberbiib:BENEPALIMember2021-01-012021-03-310000875045biib:BENEPALIMember2021-01-012021-03-310000875045country:USbiib:BENEPALIMember2020-01-012020-03-310000875045us-gaap:NonUsMemberbiib:BENEPALIMember2020-01-012020-03-310000875045biib:BENEPALIMember2020-01-012020-03-310000875045country:USbiib:IMRALDIMember2021-01-012021-03-310000875045biib:IMRALDIMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:IMRALDIMember2021-01-012021-03-310000875045country:USbiib:IMRALDIMember2020-01-012020-03-310000875045biib:IMRALDIMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:IMRALDIMember2020-01-012020-03-310000875045country:USbiib:FLIXABIMember2021-01-012021-03-310000875045biib:FLIXABIMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:FLIXABIMember2021-01-012021-03-310000875045country:USbiib:FLIXABIMember2020-01-012020-03-310000875045biib:FLIXABIMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:FLIXABIMember2020-01-012020-03-310000875045country:USbiib:BiosimilarsMember2021-01-012021-03-310000875045biib:BiosimilarsMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:BiosimilarsMember2021-01-012021-03-310000875045country:USbiib:BiosimilarsMember2020-01-012020-03-310000875045biib:BiosimilarsMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:BiosimilarsMember2020-01-012020-03-310000875045country:USbiib:FUMADERMMember2021-01-012021-03-310000875045biib:FUMADERMMemberus-gaap:NonUsMember2021-01-012021-03-310000875045biib:FUMADERMMember2021-01-012021-03-310000875045country:USbiib:FUMADERMMember2020-01-012020-03-310000875045biib:FUMADERMMemberus-gaap:NonUsMember2020-01-012020-03-310000875045biib:FUMADERMMember2020-01-012020-03-310000875045country:USus-gaap:ProductMember2021-01-012021-03-310000875045us-gaap:ProductMemberus-gaap:NonUsMember2021-01-012021-03-310000875045country:USus-gaap:ProductMember2020-01-012020-03-310000875045us-gaap:ProductMemberus-gaap:NonUsMember2020-01-012020-03-31biib:wholesaler0000875045biib:DistributorOneMember2021-01-012021-03-310000875045biib:DistributorTwoMember2021-01-012021-03-310000875045biib:DistributorOneMember2020-01-012020-03-310000875045biib:DistributorTwoMember2020-01-012020-03-310000875045biib:ReserveforCashDiscountsMember2020-12-310000875045biib:ContractualAdjustmentsMember2020-12-310000875045us-gaap:SalesReturnsAndAllowancesMember2020-12-310000875045biib:ReserveforCashDiscountsMember2021-01-012021-03-310000875045biib:ContractualAdjustmentsMember2021-01-012021-03-310000875045us-gaap:SalesReturnsAndAllowancesMember2021-01-012021-03-310000875045biib:ReserveforCashDiscountsMember2021-03-310000875045biib:ContractualAdjustmentsMember2021-03-310000875045us-gaap:SalesReturnsAndAllowancesMember2021-03-310000875045us-gaap:AccountsReceivableMember2021-03-310000875045us-gaap:AccountsReceivableMember2020-12-310000875045us-gaap:OtherCurrentLiabilitiesMember2021-03-310000875045us-gaap:OtherCurrentLiabilitiesMember2020-12-310000875045biib:RocheGroupGenentechMember2021-01-012021-03-310000875045biib:RocheGroupGenentechMember2020-01-012020-03-310000875045biib:ZINBRYTAMemberus-gaap:CollaborativeArrangementMember2021-01-012021-03-310000875045biib:ZINBRYTAMemberus-gaap:CollaborativeArrangementMember2020-01-012020-03-310000875045us-gaap:CollaborativeArrangementMemberbiib:SamsungBiosimilarAgreementMember2021-01-012021-03-310000875045us-gaap:CollaborativeArrangementMemberbiib:SamsungBiosimilarAgreementMember2020-01-012020-03-310000875045us-gaap:RoyaltyMember2021-01-012021-03-310000875045us-gaap:RoyaltyMember2020-01-012020-03-310000875045biib:OthercorporaterevenuesMember2021-01-012021-03-310000875045biib:OthercorporaterevenuesMember2020-01-012020-03-310000875045biib:OutLicensedPatentsMember2021-03-310000875045biib:OutLicensedPatentsMember2020-12-310000875045us-gaap:InProcessResearchAndDevelopmentMember2021-03-310000875045us-gaap:InProcessResearchAndDevelopmentMember2020-12-310000875045us-gaap:TrademarksAndTradeNamesMember2021-03-310000875045us-gaap:TrademarksAndTradeNamesMember2020-12-310000875045biib:VixotrigineMember2021-01-012021-03-310000875045biib:VixotrigineMember2020-01-012020-03-310000875045biib:TGNMemberus-gaap:InProcessResearchAndDevelopmentMember2021-03-310000875045biib:BIIB111Memberbiib:NightstarMember2020-10-012020-12-310000875045srt:MinimumMemberbiib:OutLicensedPatentsMember2021-01-012021-03-310000875045srt:MaximumMemberbiib:OutLicensedPatentsMember2021-01-012021-03-310000875045us-gaap:DevelopedTechnologyRightsMembersrt:MinimumMember2021-01-012021-03-310000875045us-gaap:DevelopedTechnologyRightsMembersrt:MaximumMember2021-01-012021-03-310000875045biib:InLicensedPatentsMembersrt:MinimumMember2021-01-012021-03-310000875045srt:MaximumMemberbiib:InLicensedPatentsMember2021-01-012021-03-310000875045us-gaap:InProcessResearchAndDevelopmentMember2021-01-012021-03-310000875045us-gaap:TrademarksAndTradeNamesMember2021-01-012021-03-310000875045us-gaap:FairValueMeasurementsRecurringMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2021-03-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMember2021-03-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2021-03-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2021-03-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:USTreasuryAndGovernmentMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:USTreasuryAndGovernmentMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:USTreasuryAndGovernmentMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:USTreasuryAndGovernmentMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:AssetBackedSecuritiesMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:AssetBackedSecuritiesMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:AssetBackedSecuritiesMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:AssetBackedSecuritiesMember2021-03-310000875045us-gaap:FairValueMeasurementsRecurringMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2020-12-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMember2020-12-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Member2020-12-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Member2020-12-310000875045us-gaap:CorporateDebtSecuritiesMemberus-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Member2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:USTreasuryAndGovernmentMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:USTreasuryAndGovernmentMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:USTreasuryAndGovernmentMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:USTreasuryAndGovernmentMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:AssetBackedSecuritiesMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel1Memberus-gaap:AssetBackedSecuritiesMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel2Memberus-gaap:AssetBackedSecuritiesMember2020-12-310000875045us-gaap:FairValueMeasurementsRecurringMemberus-gaap:FairValueInputsLevel3Memberus-gaap:AssetBackedSecuritiesMember2020-12-310000875045us-gaap:MeasurementInputDiscountRateMember2021-03-310000875045us-gaap:MeasurementInputDiscountRateMembersrt:WeightedAverageMember2021-03-310000875045us-gaap:MeasurementInputDiscountRateMember2020-12-310000875045us-gaap:MeasurementInputDiscountRateMembersrt:WeightedAverageMember2020-12-310000875045biib:SeniorNotesThreePointSixTwoFivePercentDueTwentyTwentyTwoMember2021-03-310000875045biib:SeniorNotesThreePointSixTwoFivePercentDueTwentyTwentyTwoMember2020-12-310000875045biib:SeniorNotesFourPointZeroFivePercentDueTwentyTwentyFiveMember2021-03-310000875045biib:SeniorNotesFourPointZeroFivePercentDueTwentyTwentyFiveMember2020-12-310000875045biib:A2.25SeniorNotesdueMay12030Member2021-03-310000875045biib:A2.25SeniorNotesdueMay12030Member2020-12-310000875045biib:SeniorNotesFivePointTwoPercentDueTwentyFortyFiveMember2021-03-310000875045biib:SeniorNotesFivePointTwoPercentDueTwentyFortyFiveMember2020-12-310000875045biib:A3.15SeniorNotesdueMay12050Member2021-03-310000875045biib:A3.15SeniorNotesdueMay12050Member2020-12-310000875045biib:A3250SeniorNotesDueFebruary152051Member2021-03-310000875045biib:A3250SeniorNotesDueFebruary152051Member2020-12-310000875045biib:SeniorNotesFivePointTwoPercentDueTwentyFortyFiveMember2021-02-012021-02-280000875045biib:A3250SeniorNotesDueFebruary152051Member2021-02-012021-02-280000875045us-gaap:FairValueMeasurementsRecurringMember2019-12-310000875045us-gaap:FairValueMeasurementsRecurringMember2020-03-310000875045biib:SeniorNotesTwoPointNinePercentDueTwentyTwentyMember2021-03-310000875045us-gaap:MeasurementInputDiscountRateMembersrt:MinimumMember2021-03-310000875045us-gaap:MeasurementInputDiscountRateMembersrt:MaximumMember2021-03-310000875045us-gaap:CommercialPaperMember2021-03-310000875045us-gaap:CommercialPaperMember2020-12-310000875045us-gaap:RepurchaseAgreementsMember2021-03-310000875045us-gaap:RepurchaseAgreementsMember2020-12-310000875045us-gaap:MoneyMarketFundsMember2021-03-310000875045us-gaap:MoneyMarketFundsMember2020-12-310000875045us-gaap:DebtSecuritiesMember2021-03-310000875045us-gaap:DebtSecuritiesMember2020-12-310000875045biib:CorporateDebtSecuritiesCurrentMember2021-03-310000875045biib:CorporateDebtSecuritiesNonCurrentMember2021-03-310000875045biib:GovernmentSecuritiesCurrentMember2021-03-310000875045biib:GovernmentSecuritiesNonCurrentMember2021-03-310000875045biib:MortgageAndOtherAssetBackedSecuritiesCurrentMember2021-03-310000875045biib:MortgageAndOtherAssetBackedSecuritiesNonCurrentMember2021-03-310000875045biib:EquitySecuritiesCurrentMember2021-03-310000875045biib:EquitySecuritiesNonCurrentMember2021-03-310000875045biib:CorporateDebtSecuritiesCurrentMember2020-12-310000875045biib:CorporateDebtSecuritiesNonCurrentMember2020-12-310000875045biib:GovernmentSecuritiesCurrentMember2020-12-310000875045biib:GovernmentSecuritiesNonCurrentMember2020-12-310000875045biib:MortgageAndOtherAssetBackedSecuritiesCurrentMember2020-12-310000875045biib:MortgageAndOtherAssetBackedSecuritiesNonCurrentMember2020-12-310000875045biib:EquitySecuritiesCurrentMember2020-12-310000875045biib:EquitySecuritiesNonCurrentMember2020-12-3100008750452020-01-012020-06-300000875045biib:StrategicInvestmentsMember2021-03-310000875045us-gaap:OtherNoncurrentAssetsMemberbiib:StrategicInvestmentsMember2020-12-310000875045biib:SageTherapeuticsIncMember2020-11-012020-11-300000875045biib:SageTherapeuticsIncMember2021-01-012021-03-310000875045biib:DenaliTherapeuticsIncMember2021-01-012021-03-310000875045biib:DenaliTherapeuticsIncMember2021-03-310000875045biib:DenaliTherapeuticsIncMember2021-01-012021-03-310000875045biib:SangamoTherapeuticsInc.AgreementMember2020-02-012020-02-290000875045biib:SangamoCommonStockMember2020-04-012020-04-300000875045srt:MinimumMember2021-01-012021-03-310000875045srt:MaximumMember2021-01-012021-03-310000875045srt:MinimumMember2020-01-012020-06-300000875045srt:MaximumMember2020-01-012020-06-300000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMembercurrency:EUR2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMembercurrency:EUR2020-12-310000875045currency:CHFus-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMember2021-03-310000875045currency:CHFus-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMember2020-12-310000875045us-gaap:ForeignExchangeContractMembercurrency:CADus-gaap:DesignatedAsHedgingInstrumentMember2021-03-310000875045us-gaap:ForeignExchangeContractMembercurrency:CADus-gaap:DesignatedAsHedgingInstrumentMember2020-12-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMembercurrency:GBP2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMembercurrency:GBP2020-12-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMembercurrency:JPY2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMembercurrency:JPY2020-12-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMember2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:DesignatedAsHedgingInstrumentMember2020-12-310000875045biib:ShorttermderivativeMember2021-03-310000875045biib:ShorttermderivativeMember2021-01-012021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:SalesMember2021-01-012021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:SalesMember2020-01-012020-03-310000875045us-gaap:ForeignExchangeContractMemberbiib:CashflowsrevenueMemberus-gaap:SalesMember2021-01-012021-03-310000875045us-gaap:ForeignExchangeContractMemberbiib:CashflowsrevenueMemberus-gaap:SalesMember2020-01-012020-03-310000875045us-gaap:OperatingExpenseMemberus-gaap:ForeignExchangeContractMember2021-01-012021-03-310000875045us-gaap:OperatingExpenseMemberus-gaap:ForeignExchangeContractMember2020-01-012020-03-310000875045us-gaap:OperatingExpenseMemberus-gaap:ForeignExchangeContractMemberbiib:CashflowsoperatingexpensesMember2021-01-012021-03-310000875045us-gaap:OperatingExpenseMemberus-gaap:ForeignExchangeContractMemberbiib:CashflowsoperatingexpensesMember2020-01-012020-03-310000875045us-gaap:InterestRateSwapMemberus-gaap:DesignatedAsHedgingInstrumentMember2021-03-310000875045us-gaap:InterestRateSwapMemberus-gaap:FairValueHedgingMemberus-gaap:AccruedLiabilitiesMember2020-12-310000875045us-gaap:InterestRateSwapMemberus-gaap:InterestExpenseMember2021-01-012021-03-310000875045biib:SamsungBiosimilarAgreementMember2020-03-310000875045biib:SamsungBiosimilarAgreementMember2021-03-31iso4217:KRW0000875045biib:SamsungBiosimilarAgreementMember2018-11-012018-11-300000875045us-gaap:NetInvestmentHedgingMember2021-01-012021-03-310000875045us-gaap:NetInvestmentHedgingMember2020-01-012020-09-300000875045us-gaap:NetInvestmentHedgingMember2021-03-310000875045us-gaap:NetInvestmentHedgingMember2020-12-310000875045us-gaap:NetInvestmentHedgingMember2020-01-012020-03-310000875045us-gaap:OtherNonoperatingIncomeExpenseMemberus-gaap:NetInvestmentHedgingMember2021-01-012021-03-310000875045us-gaap:OtherNonoperatingIncomeExpenseMemberus-gaap:NetInvestmentHedgingMember2020-01-012020-03-310000875045us-gaap:NondesignatedMember2021-03-310000875045us-gaap:NondesignatedMember2020-12-310000875045us-gaap:DesignatedAsHedgingInstrumentMemberus-gaap:OtherCurrentAssetsMember2021-03-310000875045us-gaap:DesignatedAsHedgingInstrumentMemberus-gaap:OtherCurrentAssetsMember2020-12-310000875045us-gaap:OtherNoncurrentAssetsMemberus-gaap:DesignatedAsHedgingInstrumentMember2021-03-310000875045us-gaap:OtherNoncurrentAssetsMemberus-gaap:DesignatedAsHedgingInstrumentMember2020-12-310000875045us-gaap:DesignatedAsHedgingInstrumentMemberus-gaap:AccruedLiabilitiesMember2021-03-310000875045us-gaap:DesignatedAsHedgingInstrumentMemberus-gaap:AccruedLiabilitiesMember2020-12-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:CashFlowHedgingMemberus-gaap:OtherNoncurrentLiabilitiesMember2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:CashFlowHedgingMemberus-gaap:OtherNoncurrentLiabilitiesMember2020-12-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:NetInvestmentHedgingMemberus-gaap:OtherCurrentAssetsMember2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:NetInvestmentHedgingMemberus-gaap:OtherCurrentAssetsMember2020-12-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:NetInvestmentHedgingMemberus-gaap:AccruedLiabilitiesMember2021-03-310000875045us-gaap:ForeignExchangeContractMemberus-gaap:NetInvestmentHedgingMemberus-gaap:AccruedLiabilitiesMember2020-12-310000875045us-gaap:NondesignatedMemberus-gaap:OtherCurrentAssetsMember2021-03-310000875045us-gaap:NondesignatedMemberus-gaap:OtherCurrentAssetsMember2020-12-310000875045us-gaap:NondesignatedMemberus-gaap:AccruedLiabilitiesMember2021-03-310000875045us-gaap:NondesignatedMemberus-gaap:AccruedLiabilitiesMember2020-12-31utr:sqft0000875045biib:BiologicsManufacturingMember2021-01-012021-03-310000875045biib:WarehouseUtilitiesAndSupportSpaceMember2021-01-012021-03-310000875045biib:AdministrativeSpaceMember2021-01-012021-03-310000875045biib:SolothurnSwitzerlandMember2021-03-310000875045biib:SolothurnSwitzerlandMember2020-12-3100008750452021-02-012021-02-280000875045biib:SeniorNotesFivePointTwoPercentDueTwentyFortyFiveMember2021-01-012021-03-310000875045us-gaap:SeniorNotesMember2020-04-300000875045us-gaap:SeniorNotesMemberbiib:A2.25SeniorNotesdueMay12030Member2020-04-300000875045us-gaap:SeniorNotesMemberbiib:A3.15SeniorNotesdueMay12050Member2020-04-300000875045us-gaap:SeniorNotesMemberbiib:A2.90SeniorNotesDueSept152020Member2015-09-150000875045us-gaap:SeniorNotesMemberbiib:A2.90SeniorNotesDueSept152020Memberus-gaap:InterestExpenseMember2021-01-012021-03-310000875045us-gaap:SeniorNotesMemberbiib:A2.90SeniorNotesDueSept152020Member2021-01-012021-03-310000875045biib:October2020ShareRepurchaseProgramMember2020-10-310000875045biib:October2020ShareRepurchaseProgramMember2021-01-012021-03-310000875045biib:October2020ShareRepurchaseProgramMember2021-03-310000875045biib:December2019ShareRepurchaseProgramMember2020-12-310000875045biib:December2019ShareRepurchaseProgramMember2020-01-012020-03-310000875045biib:March2019ShareRepurchaseProgramMember2020-03-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember2020-12-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember2020-12-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMember2020-12-310000875045us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember2020-12-310000875045us-gaap:AccumulatedTranslationAdjustmentMember2020-12-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember2021-01-012021-03-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember2021-01-012021-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMember2021-01-012021-03-310000875045us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember2021-01-012021-03-310000875045us-gaap:AccumulatedTranslationAdjustmentMember2021-01-012021-03-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember2021-03-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember2021-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMember2021-03-310000875045us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember2021-03-310000875045us-gaap:AccumulatedTranslationAdjustmentMember2021-03-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember2019-12-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember2019-12-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMember2019-12-310000875045us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember2019-12-310000875045us-gaap:AccumulatedTranslationAdjustmentMember2019-12-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember2020-01-012020-03-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember2020-01-012020-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMember2020-01-012020-03-310000875045us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember2020-01-012020-03-310000875045us-gaap:AccumulatedTranslationAdjustmentMember2020-01-012020-03-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMember2020-03-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMember2020-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMember2020-03-310000875045us-gaap:AccumulatedDefinedBenefitPlansAdjustmentMember2020-03-310000875045us-gaap:AccumulatedTranslationAdjustmentMember2020-03-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMemberus-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2021-01-012021-03-310000875045us-gaap:AccumulatedNetUnrealizedInvestmentGainLossMemberus-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2020-01-012020-03-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMemberus-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2021-01-012021-03-310000875045us-gaap:AccumulatedGainLossNetCashFlowHedgeParentMemberus-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2020-01-012020-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMemberus-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2021-01-012021-03-310000875045us-gaap:AccumulatedOtherComprehensiveIncomeLossDerivativeQualifyingAsHedgeExcludedComponentIncludingPortionAttributableToNoncontrollingInterestMemberus-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2020-01-012020-03-310000875045us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2021-01-012021-03-310000875045us-gaap:ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember2020-01-012020-03-310000875045biib:TimeVestedRestrictedStockUnitsMember2021-01-012021-03-310000875045biib:TimeVestedRestrictedStockUnitsMember2020-01-012020-03-310000875045biib:MarketStockUnitsMember2021-01-012021-03-310000875045biib:MarketStockUnitsMember2020-01-012020-03-310000875045biib:PerformanceStockUnitsSettledinStockMember2021-01-012021-03-310000875045biib:PerformanceStockUnitsSettledinStockMember2020-01-012020-03-310000875045us-gaap:ResearchAndDevelopmentExpenseMember2021-01-012021-03-310000875045us-gaap:ResearchAndDevelopmentExpenseMember2020-01-012020-03-310000875045us-gaap:SellingGeneralAndAdministrativeExpensesMember2021-01-012021-03-310000875045us-gaap:SellingGeneralAndAdministrativeExpensesMember2020-01-012020-03-310000875045us-gaap:ParentMember2021-01-012021-03-310000875045us-gaap:ParentMember2020-01-012020-03-310000875045biib:MarketStockUnitsMember2021-01-012021-03-310000875045biib:MarketStockUnitsMember2020-01-012020-03-310000875045biib:TimeVestedRestrictedStockUnitsMember2021-01-012021-03-310000875045biib:TimeVestedRestrictedStockUnitsMember2020-01-012020-03-310000875045biib:CashSettledPerformanceSharesMember2021-01-012021-03-310000875045biib:CashSettledPerformanceSharesMember2020-01-012020-03-310000875045us-gaap:PerformanceSharesMember2021-01-012021-03-310000875045us-gaap:PerformanceSharesMember2020-01-012020-03-310000875045biib:PerformanceStockUnitsSettledinStockMember2021-01-012021-03-310000875045biib:PerformanceStockUnitsSettledinStockMember2020-01-012020-03-310000875045biib:PerformanceStockUnitsSettledinCashMember2021-01-012021-03-310000875045biib:PerformanceStockUnitsSettledinCashMember2020-01-012020-03-310000875045biib:EmployeeStockPurchasePlanMember2021-01-012021-03-310000875045biib:EmployeeStockPurchasePlanMember2020-01-012020-03-310000875045biib:TECFIDERAMember2021-03-310000875045biib:IonisSangamoDenaliAndSageMember2021-01-012021-03-310000875045biib:EisaiMember2021-01-012021-03-310000875045biib:EisaiMember2020-01-012020-03-310000875045biib:EisaiMemberbiib:E2609andBAN2401Memberus-gaap:SellingGeneralAndAdministrativeExpensesMember2021-01-012021-03-310000875045biib:EisaiMemberbiib:E2609andBAN2401Memberus-gaap:SellingGeneralAndAdministrativeExpensesMember2020-01-012020-03-310000875045biib:EisaiMember2019-10-012019-12-310000875045biib:EisaiMemberus-gaap:ResearchAndDevelopmentExpenseMemberbiib:AducanumabMember2021-01-012021-03-310000875045biib:EisaiMemberus-gaap:ResearchAndDevelopmentExpenseMemberbiib:AducanumabMember2020-01-012020-03-310000875045biib:EisaiMemberbiib:AducanumabMemberus-gaap:SellingGeneralAndAdministrativeExpensesMember2021-01-012021-03-310000875045biib:EisaiMemberbiib:AducanumabMemberus-gaap:SellingGeneralAndAdministrativeExpensesMember2020-01-012020-03-310000875045biib:UCBPharmaS.A.Memberus-gaap:ResearchAndDevelopmentExpenseMember2021-01-012021-03-310000875045biib:UCBPharmaS.A.Memberus-gaap:ResearchAndDevelopmentExpenseMember2020-01-012020-03-310000875045biib:SangamoTherapeuticsInc.AgreementMember2021-01-012021-03-310000875045biib:SamsungBiosimilarAgreementMember2019-07-012019-09-300000875045biib:SamsungBiosimilarAgreementMember2018-11-070000875045biib:SamsungBiosimilarAgreementMemberus-gaap:InventoriesMember2021-01-012021-03-310000875045us-gaap:DevelopedTechnologyRightsMemberbiib:SamsungBiosimilarAgreementMember2021-01-012021-03-310000875045biib:SamsungBiosimilarAgreementMember2021-01-012021-03-310000875045biib:SamsungBiosimilarAgreementMember2020-01-012020-03-310000875045biib:SamsungBiosimilarAgreementMember2020-12-310000875045biib:SamsungBiosimilarAgreementMember2020-01-012020-03-310000875045biib:SamsungBiosimilarAgreementMember2020-01-310000875045biib:SamsungBiosimilarAgreementMember2021-01-012021-03-310000875045biib:SamsungBiosimilarAgreementMember2021-03-310000875045biib:SamsungBiosimilarAgreementMember2020-12-310000875045biib:NeurimmuneMember2021-01-012021-03-310000875045biib:NeurimmuneMember2017-10-012017-10-310000875045biib:NeurimmuneMember2018-05-012018-05-310000875045biib:NeurimmuneMemberbiib:RegulatoryMilestonesMember2020-12-310000875045biib:TwelvemonthsMember2021-03-310000875045biib:NeurimmuneMemberbiib:RegulatoryMilestonesMember2021-03-310000875045country:JPbiib:AducanumabMemberbiib:RegulatoryMilestonesMember2021-03-31

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Form 10-Q
QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the quarterly period ended March 31, 2021
OR
TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
Commission File Number 0-19311
BIOGEN INC.
(Exact name of registrant as specified in its charter)
Delaware 33-0112644
(State or other jurisdiction of
incorporation or organization)
 (I.R.S. Employer
Identification No.)
225 Binney Street, Cambridge, MA 02142
(617679-2000
(Address, including zip code, and telephone number, including
area code, of registrant’s principal executive offices)
Securities registered pursuant to Section 12(b) of the Act:
Title of each classTrading Symbol(s)Name of each exchange on which registered
Common Stock, $0.0005 par valueBIIBThe Nasdaq Global Select Market
Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days:    Yes  x    No  o
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files):    Yes  x    No  o
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and "emerging growth company" in Rule 12b-2 of the Exchange Act:
Large accelerated filerxAccelerated filer
Non-accelerated filerSmaller reporting company
Emerging growth company
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes      No  x
The number of shares of the issuer’s Common Stock, $0.0005 par value, outstanding as of April 21, 2021, was 150,554,750 shares.


Table of Contents
BIOGEN INC.
FORM 10-Q — Quarterly Report
For the Quarterly Period Ended March 31, 2021
TABLE OF CONTENTS
 
  Page
Item 1.
Item 2.
Item 3.
Item 4.
PART II — OTHER INFORMATION
Item 1.
Item 1A.
Item 2.
Item 6.

2

Table of Contents
NOTE REGARDING FORWARD-LOOKING STATEMENTS
This report contains forward-looking statements that are being made pursuant to the provisions of the Private Securities Litigation Reform Act of 1995 (the Act) with the intention of obtaining the benefits of the “Safe Harbor” provisions of the Act. These forward-looking statements may be accompanied by such words as “aim,” “anticipate,” “believe,” “could,” “estimate,” “expect,” “forecast,” "goal," “intend,” “may,” “plan,” “potential,” “possible,” “will,” “would” and other words and terms of similar meaning. Reference is made in particular to forward-looking statements regarding:
the anticipated amount, timing and accounting of revenue; contingent, milestone, royalty and other payments under licensing, collaboration, acquisition or divestiture agreements; tax positions and contingencies; collectability of receivables; pre-approval inventory; cost of sales; research and development costs; compensation and other selling, general and administrative expense; amortization of intangible assets; foreign currency exchange risk; estimated fair value of assets and liabilities; and impairment assessments;
expectations, plans and prospects relating to sales, pricing, growth and launch of our marketed and pipeline products;
the potential impact of increased product competition in the markets in which we compete, including increased competition from new originator therapies, generics, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways, including generic or biosimilar versions of our products;
patent terms, patent term extensions, patent office actions and expected availability and period of regulatory exclusivity;
our plans and investments in our core and emerging growth areas as well as implementation of our corporate strategy;
the drivers for growing our business, including our plans and intention to commit resources relating to discovery, research and development programs and business development opportunities as well as the potential benefits and results of certain business development transactions;
the expectations, development plans and anticipated timelines, including costs and timing of potential clinical trials, filings and approvals, of our products, drug candidates and pipeline programs, including collaborations with third-parties, as well as the potential therapeutic scope of the development and commercialization of our and our collaborators’ pipeline products;
the timing, outcome and impact of administrative, regulatory, legal and other proceedings related to our patents and other proprietary and intellectual property rights, tax audits, assessments and settlements, pricing matters, sales and promotional practices, product liability and other matters;
our ability to finance our operations and business initiatives and obtain funding for such activities;
adverse safety events involving our marketed products, generic or biosimilar versions of our marketed products or any other products from the same class as one of our products;
the direct and indirect impact of the COVID-19 pandemic on our business and operations, including sales, expense, supply chain, manufacturing, cyber-attacks or other privacy or data security incidents, research and development costs, clinical trials and employees;
the potential impact of healthcare reform in the United States (U.S.) and measures being taken worldwide designed to reduce healthcare costs and limit the overall level of government expenditures, including the impact of pricing actions and reduced reimbursement for our products;
our manufacturing capacity, use of third-party contract manufacturing organizations, plans and timing relating to changes in our manufacturing capabilities, activities in new or existing manufacturing facilities and the expected timeline for the Solothurn manufacturing facility to be partially operational and for the gene therapy manufacturing facility in Research Triangle Park, North Carolina to be operational;
the impact of the continued uncertainty of the credit and economic conditions in certain countries and our collection of accounts receivable in such countries;
lease commitments, purchase obligations and the timing and satisfaction of other contractual obligations; and
the impact of new laws (including tax), regulatory requirements, judicial decisions and accounting standards.
3

Table of Contents
These forward-looking statements involve risks and uncertainties, including those that are described in Item 1A. Risk Factors included in this report and elsewhere in this report, that could cause actual results to differ materially from those reflected in such statements. You should not place undue reliance on these statements. Forward-looking statements speak only as of the date of this report. Except as required by law, we do not undertake any obligation to publicly update any forward-looking statements, whether as a result of new information, future developments or otherwise.
NOTE REGARDING COMPANY AND PRODUCT REFERENCES
References in this report to:
“Biogen,” the “company,” “we,” “us” and “our” refer to Biogen Inc. and its consolidated subsidiaries; and
“RITUXAN” refers to both RITUXAN (the trade name for rituximab in the U.S., Canada and Japan) and MabThera (the trade name for rituximab outside the U.S., Canada and Japan).
NOTE REGARDING TRADEMARKS
AVONEX®, PLEGRIDY®, RITUXAN®, RITUXAN HYCELA®, SPINRAZA®, TECFIDERA®, TYSABRI® and VUMERITY® are registered trademarks of Biogen.
BENEPALI™, FLIXABI™, FUMADERM™ and IMRALDI™ are trademarks of Biogen.
ENBREL®, EYLEA®, FAMPYRATM, GAZYVA®, HUMIRA®, LUCENTIS®, OCREVUS®, REMICADE® and other trademarks referenced in this report are the property of their respective owners.
4

Table of Contents
PART I FINANCIAL INFORMATION

BIOGEN INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
(unaudited, in millions, except per share amounts)
 
 For the Three Months Ended March 31,
 20212020
Revenue:
Product, net$2,211.7 $2,904.6 
Revenue from anti-CD20 therapeutic programs389.0 520.4 
Other93.3 109.3 
Total revenue2,694.0 3,534.3 
Cost and expense:
Cost of sales, excluding amortization and impairment of acquired intangible assets478.1 454.3 
Research and development514.2 476.3 
Selling, general and administrative595.0 570.1 
Amortization and impairment of acquired intangible assets98.1 71.5 
Collaboration profit (loss) sharing68.5 71.8 
(Gain) loss on fair value remeasurement of contingent consideration(33.8)(4.6)
Acquired in-process research and development 75.0 
Total cost and expense1,720.1 1,714.4 
Income from operations973.9 1,819.9 
Other income (expense), net(506.9)(120.5)
Income before income tax expense and equity in loss of investee, net of tax467.0 1,699.4 
Income tax expense44.2 292.0 
Equity in (income) loss of investee, net of tax18.2 14.8 
Net income404.6 1,392.6 
Net income (loss) attributable to noncontrolling interests, net of tax(5.6)(6.5)
Net income attributable to Biogen Inc.$410.2 $1,399.1 
Net income per share:
Basic earnings per share attributable to Biogen Inc.$2.70 $8.10 
Diluted earnings per share attributable to Biogen Inc.$2.69 $8.08 
Weighted-average shares used in calculating:
Basic earnings per share attributable to Biogen Inc.151.9 172.8 
Diluted earnings per share attributable to Biogen Inc.152.3 173.1 





See accompanying notes to these unaudited condensed consolidated financial statements.
5

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
(unaudited, in millions)
 
 For the Three Months Ended March 31,
 20212020
Net income attributable to Biogen Inc.$410.2 $1,399.1 
Other comprehensive income:
Unrealized gains (losses) on securities available for sale, net of tax
(0.8)(7.8)
Unrealized gains (losses) on cash flow hedges, net of tax
149.6 33.8 
Gains (losses) on net investment hedges
22.4 23.0 
Unrealized gains (losses) on pension benefit obligation, net of tax
2.0 0.8 
Currency translation adjustment
(48.5)(63.9)
Total other comprehensive income (loss), net of tax124.7 (14.1)
Comprehensive income attributable to Biogen Inc.534.9 1,385.0 
Comprehensive income (loss) attributable to noncontrolling interests, net of tax(4.9)(5.9)
Comprehensive income$530.0 $1,379.1 

































See accompanying notes to these unaudited condensed consolidated financial statements.
6

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED BALANCE SHEETS
(unaudited, in millions, except per share amounts)
 
As of March 31, 2021As of December 31, 2020
ASSETS
Current assets:
Cash and cash equivalents$1,217.5 $1,331.2 
Marketable securities1,320.0 1,278.9 
Accounts receivable, net1,854.3 1,913.8 
Due from anti-CD20 therapeutic programs369.8 413.5 
Inventory1,171.8 1,068.6 
Other current assets786.1 881.1 
Total current assets6,719.5 6,887.1 
Marketable securities821.9 772.1 
Property, plant and equipment, net3,438.3 3,411.5 
Operating lease assets414.5 433.3 
Intangible assets, net2,988.1 3,084.3 
Goodwill5,763.1 5,762.1 
Deferred tax asset1,286.3 1,369.5 
Investments and other assets2,423.0 2,899.0 
Total assets$23,854.7 $24,618.9 
LIABILITIES AND EQUITY
Current liabilities:
Taxes payable$143.1 $142.0 
Accounts payable430.4 454.9 
Accrued expense and other2,592.3 3,145.3 
Total current liabilities3,165.8 3,742.2 
Notes payable7,267.2 7,426.2 
Deferred tax liability966.7 1,032.8 
Long-term operating lease liabilities380.0 402.0 
Other long-term liabilities1,411.8 1,329.6 
Total liabilities13,191.5 13,932.8 
Commitments and contingencies
Equity:
Biogen Inc. shareholders’ equity:
Preferred stock, par value $0.001 per share  
Common stock, par value $0.0005 per share0.1 0.1 
Additional paid-in capital  
Accumulated other comprehensive loss(174.3)(299.0)
Retained earnings13,833.5 13,976.3 
Treasury stock, at cost(2,977.1)(2,977.1)
Total Biogen Inc. shareholders’ equity10,682.2 10,700.3 
Noncontrolling interests(19.0)(14.2)
Total equity10,663.2 10,686.1 
Total liabilities and equity$23,854.7 $24,618.9 
See accompanying notes to these unaudited condensed consolidated financial statements.
7

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOW
(unaudited, in millions)
 For the Three Months Ended March 31,
 20212020
Cash flow from operating activities:
Net income$404.6 $1,392.6 
Adjustments to reconcile net income to net cash flow from operating activities:
Depreciation, amortization and impairments146.9 119.9 
Acquired in-process research and development 75.0 
Share-based compensation70.0 67.7 
Contingent consideration(33.8)(4.6)
Deferred income taxes(15.0)36.9 
(Gain) loss on strategic investments437.6 62.0 
Loss on equity method investment18.2 16.8 
Other71.7 28.9 
Changes in operating assets and liabilities, net:
Accounts receivable37.2 (238.4)
Due from anti-CD20 therapeutic programs43.8 78.6 
Inventory(112.5)(62.2)
Accrued expense and other current liabilities(283.6)(347.4)
Income tax assets and liabilities64.8 223.0 
Other changes in operating assets and liabilities, net(80.9)18.5 
Net cash flow provided by operating activities769.0 1,467.3 
Cash flow from investing activities:
Proceeds from sales and maturities of marketable securities819.2 2,389.3 
Purchases of marketable securities(913.3)(1,684.7)
Proceeds from divestiture of Hillerød, Denmark manufacturing operations28.1  
Purchases of property, plant and equipment(92.6)(149.7)
Acquired in-process research and development (75.0)
Acquisitions of intangible assets (37.0)
Proceeds from sales of strategic investments91.2 0.5 
Other2.7 (0.5)
Net cash flow (used in) provided by investing activities(64.7)442.9 
Cash flow from financing activities:
Purchases of treasury stock(600.0)(2,220.2)
Payments related to issuance of stock for share-based compensation arrangements, net(27.1)(29.6)
Repayment of borrowings and premiums paid on debt exchange(169.3) 
Other11.4 4.5 
Net cash flow used in financing activities(785.0)(2,245.3)
Net increase (decrease) in cash and cash equivalents(80.7)(335.1)
Effect of exchange rate changes on cash and cash equivalents(33.0)12.7 
Cash and cash equivalents, beginning of the period1,331.2 2,913.7 
Cash and cash equivalents, end of the period$1,217.5 $2,591.3 








See accompanying notes to these unaudited condensed consolidated financial statements.
8

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF EQUITY
(unaudited, in millions)
 Preferred stockCommon stockAdditional
paid-in
capital
Accumulated
other
comprehensive
loss
Retained
earnings
Treasury stockTotal
Biogen Inc.
shareholders’
equity
Noncontrolling
interests
Total
equity
 SharesAmountSharesAmountSharesAmount
Balance, December 31, 2020 $ 176.2 $0.1 $ $(299.0)$13,976.3 (23.8)$(2,977.1)$10,700.3 $(14.2)$10,686.1 
Net income— — — — — — 410.2 — — 410.2 (5.6)404.6 
Other comprehensive income (loss), net of tax— — — — — 124.7 — — — 124.7 0.7 125.4 
Capital contribution by noncontrolling interest— — — — — — — — —  0.1 0.1 
Repurchase of common stock pursuant to the 2020 Share Repurchase Program, at cost— —  — — — — (2.2)(600.0)(600.0)— (600.0)
Retirement of common stock pursuant to the 2020 Share Repurchase Program, at cost— — (2.2) (93.8)— (506.2)2.2 600.0  —  
Issuance of common stock under stock option and stock purchase plans— — 0.1  19.7 — — — — 19.7 — 19.7 
Issuance of common stock under stock award plan— — 0.3   — (46.8)— — (46.8)— (46.8)
Compensation related to share-based payments— — — — 72.6 — — — — 72.6 — 72.6 
Other— — — — 1.5 —  — — 1.5 — 1.5 
Balance, March 31, 2021 $ 174.4 $0.1 $ $(174.3)$13,833.5 (23.8)$(2,977.1)$10,682.2 $(19.0)$10,663.2 













See accompanying notes to these unaudited condensed consolidated financial statements.

9

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - (Continued)
(unaudited, in millions)
 Preferred stockCommon stockAdditional
paid-in
capital
Accumulated
other
comprehensive
loss
Retained
earnings
Treasury stockTotal
Biogen Inc.
shareholders’
equity
Noncontrolling
interests
Total
equity
SharesAmountSharesAmountSharesAmount
Balance, December 31, 2019 $ 198.0 $0.1 $ $(135.2)$16,455.4 (23.8)$(2,977.1)$13,343.2 $(4.1)$13,339.1 
Net income— — — — — — 1,399.1 — — 1,399.1 (6.5)1,392.6 
Other comprehensive income (loss), net of tax— — — — — (14.1)— — — (14.1)0.6 (13.5)
Repurchase of common stock pursuant to the March 2019 Share Repurchase Program, at cost— — — — — — — (4.1)(1,279.1)(1,279.1)— (1,279.1)
Retirement of common stock pursuant to the March 2019 Share Repurchase Program, at cost— — (4.1)— (71.0)— (1,208.1)4.1 1,279.1 — — — 
Repurchase of common stock pursuant to the December 2019 Share Repurchase Program, at cost— — — — — — — (3.2)(941.1)(941.1)— (941.1)
Retirement of common stock pursuant to the December 2019 Share Repurchase Program, at cost— — (3.2) (15.6)— (925.5)3.2 941.1  —  
Issuance of common stock under stock option and stock purchase plans— — 0.1  18.1 — — — — 18.1 — 18.1 
Issuance of common stock under stock award plan— — 0.3   — (47.8)— — (47.8)— (47.8)
Compensation related to share-based payments— — — — 69.2 —  — — 69.2 — 69.2 
Other— — — — (0.6)— — — — (0.6)— (0.6)
Balance, March 31, 2020 $ 191.1 $0.1 $0.1 $(149.3)$15,673.1 (23.8)$(2,977.1)$12,546.9 $(10.0)$12,536.9 












See accompanying notes to these unaudited condensed consolidated financial statements.

10

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
(unaudited)

1.    Summary of Significant Accounting Policies
References in these notes to "Biogen," the "company," "we," "us" and "our" refer to Biogen Inc. and its consolidated subsidiaries.
Business Overview
Biogen is a global biopharmaceutical company focused on discovering, developing and delivering worldwide innovative therapies for people living with serious neurological and neurodegenerative diseases as well as related therapeutic adjacencies. Our core growth areas include multiple sclerosis (MS) and neuroimmunology; Alzheimer’s disease and dementia; neuromuscular disorders, including spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS); movement disorders, including Parkinson's disease; ophthalmology; and neuropsychiatry. We are also focused on discovering, developing and delivering worldwide innovative therapies in our emerging growth areas of immunology; acute neurology; and neuropathic pain. In addition, we commercialize biosimilars of advanced biologics. We support our drug discovery and development efforts through the commitment of significant resources to discovery, research and development programs and business development opportunities.
Our marketed products include TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, TYSABRI and FAMPYRA for the treatment of MS; SPINRAZA for the treatment of SMA; and FUMADERM for the treatment of severe plaque psoriasis. We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, chronic lymphocytic leukemia (CLL) and other conditions; RITUXAN HYCELA for the treatment of non-Hodgkin's lymphoma and CLL; GAZYVA for the treatment of CLL and follicular lymphoma; OCREVUS for the treatment of primary progressive MS and relapsing MS; and other potential anti-CD20 therapies pursuant to our collaboration arrangements with Genentech, Inc. (Genentech), a wholly-owned member of the Roche Group. For additional information on our collaboration arrangements with Genentech, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2020 (2020 Form 10-K).
Our innovative drug development and commercialization activities are complemented by our biosimilar business that expands access to medicines and reduces the cost burden for healthcare systems. Through our agreements with Samsung Bioepis Co., Ltd. (Samsung Bioepis), our joint venture with Samsung BioLogics Co., Ltd. (Samsung BioLogics), we market and sell BENEPALI, an etanercept biosimilar referencing ENBREL, IMRALDI, an adalimumab biosimilar referencing HUMIRA, and FLIXABI, an infliximab biosimilar referencing REMICADE, in certain countries in Europe and have an option to acquire exclusive rights to commercialize these products in China. Additionally, we have exclusive rights to commercialize two potential ophthalmology biosimilar products, SB11, a proposed ranibizumab biosimilar referencing LUCENTIS, and SB15, a proposed aflibercept biosimilar referencing EYLEA, in major markets worldwide, including the United States (U.S.), Canada, Europe, Japan and Australia. For additional information on our collaboration arrangements with Samsung Bioepis, please read Note 16, Collaborative and Other Relationships, to these unaudited condensed consolidated financial statements (condensed consolidated financial statements).
Basis of Presentation
In the opinion of management, our condensed consolidated financial statements include all adjustments, consisting of normal recurring accruals, necessary for a fair statement of our financial statements for interim periods in accordance with accounting principles generally accepted in the United States (U.S. GAAP). The information included in this quarterly report on Form 10-Q should be read in conjunction with our audited consolidated financial statements and the accompanying notes included in our 2020 Form 10-K. Our accounting policies are described in the Notes to Consolidated Financial Statements in our 2020 Form 10-K and updated, as necessary, in this report. The year-end condensed consolidated balance sheet data presented for comparative purposes was derived from our audited financial statements, but does not include all disclosures required by U.S. GAAP. The results of operations for the three months ended March 31, 2021, are not necessarily indicative of the operating results for the full year or for any other subsequent interim period.
We operate as one operating segment, focused on discovering, developing and delivering worldwide innovative therapies for people living with serious neurological and neurodegenerative diseases as well as related therapeutic adjacencies.
11

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
(unaudited, continued)
Consolidation
Our condensed consolidated financial statements reflect our financial statements, those of our wholly-owned subsidiaries and those of certain variable interest entities where we are the primary beneficiary. For consolidated entities where we own or are exposed to less than 100.0% of the economics, we record net income (loss) attributable to noncontrolling interests in our condensed consolidated statements of income equal to the percentage of the economic or ownership interest retained in such entities by the respective noncontrolling parties. Intercompany balances and transactions are eliminated in consolidation.
In determining whether we are the primary beneficiary of a variable interest entity, we apply a qualitative approach that determines whether we have both (1) the power to direct the economically significant activities of the entity and (2) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. These considerations impact the way we account for our existing collaborative relationships and other arrangements. We continuously assess whether we are the primary beneficiary of a variable interest entity as changes to existing relationships or future transactions may result in us consolidating or deconsolidating one or more of our collaborators or partners.
Use of Estimates
The preparation of our condensed consolidated financial statements requires us to make estimates, judgments and assumptions that may affect the reported amounts of assets, liabilities, equity, revenue and expense and related disclosure of contingent assets and liabilities. On an ongoing basis we evaluate our estimates, judgments and methodologies. We base our estimates on historical experience and on various other assumptions that we believe are reasonable, the results of which form the basis for making judgments about the carrying values of assets, liabilities and equity and the amount of revenue and expense. Actual results may differ from these estimates.
The length of time and full extent to which the COVID-19 pandemic directly or indirectly impacts our business, results of operations and financial condition, including sales, expense, reserves and allowances, manufacturing, clinical trials, research and development costs and employee-related amounts, depends on future developments that are highly uncertain, subject to change and are difficult to predict, including as a result of new information that may emerge concerning COVID-19 and the actions taken to contain or treat COVID-19 as well as the economic impact on local, regional, national and international customers and markets. We have made estimates of the impact of the COVID-19 pandemic within our condensed consolidated financial statements and there may be changes to those estimates in future periods.
New Accounting Pronouncements
From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (FASB) or other standard setting bodies that we adopt as of the specified effective date. Unless otherwise discussed below, we do not believe that the adoption of recently issued standards have or may have a material impact on our condensed consolidated financial statements or disclosures.
Income Taxes
In December 2019 the FASB issued Accounting Standards Update No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This standard removes certain exceptions to the general principles in Topic 740 and simplifies certain other aspects of the accounting for income taxes. This standard became effective for us on January 1, 2021, and did not have a material impact on our condensed consolidated financial statements and related disclosures.
2.    Acquisitions
BIIB118 Acquisition
In March 2020 we acquired BIIB118 (CK1 inhibitor) for the potential treatment of patients with behavioral and neurological symptoms across various psychiatric and neurological diseases from Pfizer Inc. (Pfizer). We are developing BIIB118 for the potential treatment of irregular sleep wake rhythm disorder in Parkinson's disease and plan to develop BIIB118 for the potential treatment of sundowning in Alzheimer's disease.
12

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
(unaudited, continued)
In connection with this acquisition, we made an upfront payment of $75.0 million to Pfizer, which was accounted for as an asset acquisition and recorded as acquired in-process research and development (IPR&D) in our condensed consolidated statements of income as BIIB118 has not yet reached technological feasibility. We may also pay Pfizer up to $635.0 million in potential additional development and commercialization milestone payments as well as tiered royalties in the high single digits to sub-teens.
3.    Revenue
Product Revenue
Revenue by product is summarized as follows:
 For the Three Months Ended March 31,
20212020
(In millions)United
States
Rest of
World
TotalUnited
States
Rest of
World
Total
Multiple Sclerosis (MS):
Fumarate*$236.0 $316.9 $552.9 $777.5 $323.3 $1,100.8 
Interferon**241.8 158.7 400.5 292.6 173.4 466.0 
TYSABRI273.3 230.0 503.3 277.7 244.7 522.4 
FAMPYRA 26.6 26.6  28.3 28.3 
Subtotal: MS product revenue751.1 732.2 1,483.3 1,347.8 769.7 2,117.5 
Spinal Muscular Atrophy:
SPINRAZA148.7 371.8 520.5 235.4 329.6 565.0 
Biosimilars:
BENEPALI 121.7 121.7  133.5 133.5 
IMRALDI 57.9 57.9  61.6 61.6 
FLIXABI 25.5 25.5  23.7 23.7 
Subtotal: Biosimilar product revenue 205.1 205.1  218.8 218.8 
Other:
FUMADERM 2.8 2.8  3.3 3.3 
Total product revenue$899.8 $1,311.9 $2,211.7 $1,583.2 $1,321.4 $2,904.6 
*Fumarate includes TECFIDERA and VUMERITY. VUMERITY became commercially available in the U.S. in November 2019.
**Interferon includes AVONEX and PLEGRIDY.
We recognized revenue from two wholesalers accounting for 30.0% and 9.3% of gross product revenue for the three months ended March 31, 2021, and 30.0% and 14.6% for the three months ended March 31, 2020.
An analysis of the change in reserves for discounts and allowances is summarized as follows:
(In millions)DiscountsContractual
Adjustments
ReturnsTotal
Balance, December 31, 2020$141.4 $1,093.0 $41.6 $1,276.0 
Current provisions relating to sales in current year185.1 775.7 3.8 964.6 
Adjustments relating to prior years0.9 (32.1)1.0 (30.2)
Payments/credits relating to sales in current year(111.8)(284.8) (396.6)
Payments/credits relating to sales in prior years(82.8)(562.9)(1.7)(647.4)
Balance, March 31, 2021$132.8 $988.9 $44.7 $1,166.4 
13

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
(unaudited, continued)
The total reserves above, which are included in our condensed consolidated balance sheets, are summarized as follows:
(In millions)As of March 31, 2021As of December 31, 2020
Reduction of accounts receivable$173.4 $195.4 
Component of accrued expense and other993.0 1,080.6 
Total revenue-related reserves$1,166.4 $1,276.0 
Revenue from Anti-CD20 Therapeutic Programs
Revenue from anti-CD20 therapeutic programs are summarized in the table below. For the purposes of this footnote, we refer to RITUXAN and RITUXAN HYCELA collectively as RITUXAN.
 For the Three Months Ended March 31,
(In millions)20212020
Biogen’s share of pre-tax profits in the U.S. for RITUXAN and GAZYVA$174.1 $341.3 
Other revenue from anti-CD20 therapeutic programs214.9 179.1 
Total revenue from anti-CD20 therapeutic programs$389.0 $520.4 
For additional information on our collaboration arrangements with Genentech, please read Note 18, Collaborative and Other Relationships, to our consolidated financial statements included in our 2020 Form 10-K.
Other Revenue
Other revenue is summarized as follows:
 For the Three Months Ended March 31,
(In millions)20212020
Revenue from collaborative and other relationships:
Revenue earned under our technical development agreement, manufacturing services agreements and royalty revenue on biosimilar products with Samsung Bioepis$3.9 $3.7 
Other revenue from collaborative and other relationships 0.2 
Other royalty and corporate revenue:
Royalty6.2 11.4 
Other corporate83.2 94.0 
Total other revenue$93.3 $109.3 
We receive royalties from net sales on products related to patents that we have out-licensed and we record other corporate revenue primarily from amounts earned under contract manufacturing agreements.
4.    Inventory
The components of inventory are summarized as follows:
(In millions)As of March 31, 2021As of December 31, 2020
Raw materials$331.3 $314.9 
Work in process634.8 544.5 
Finished goods205.7 209.2 
Total inventory$1,171.8 $1,068.6 
14

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
(unaudited, continued)
5.    Intangible Assets and Goodwill
Intangible Assets
Intangible assets, net of accumulated amortization, impairment charges and adjustments are summarized as follows:
  As of March 31, 2021As of December 31, 2020
(In millions)Estimated LifeCostAccumulated
Amortization
NetCostAccumulated
Amortization
Net
Completed technology4-28 years$7,394.3 $(5,190.3)$2,204.0 $7,394.3 $(5,136.5)$2,257.8 
In-process research and developmentIndefinite until commercialization720.1  720.1 762.5  762.5 
Trademarks and trade namesIndefinite64.0  64.0 64.0  64.0 
Total intangible assets$8,178.4 $(5,190.3)$2,988.1 $8,220.8 $(5,136.5)$3,084.3 
For the three months ended March 31, 2021, amortization and impairment of acquired intangible assets totaled $98.1 million, compared to $71.5 million in the prior year comparative period. For the three months ended March 31, 2021, amortization and impairment of acquired intangible assets reflects a $44.3 million impairment charge related to vixotrigine (BIIB074) for the potential treatment of trigeminal neuralgia (TGN). For the three months ended March 31, 2020, we had no impairment charges.
Completed Technology
Completed technology primarily relates to our acquisition of all remaining rights to TYSABRI as well as other amounts related to our other marketed products and programs acquired through business combinations.
IPR&D Related to Business Combinations
IPR&D represents the fair value assigned to research and development assets that we acquired as part of a business combination and had not yet reached technological feasibility at the date of acquisition. Included in IPR&D balances are adjustments related to foreign currency exchange rate fluctuations. We review amounts capitalized as acquired IPR&D for impairment annually, as of October 31, and whenever events or changes in circumstances indicate to us that the carrying value of the assets might not be recoverable. The carrying value associated with our IPR&D assets as of March 31, 2021, relates to the various IPR&D programs we acquired in connection with our acquisitions of Nightstar Therapeutics plc (NST) and Convergence Pharmaceuticals Holdings Ltd. (Convergence). The majority of the balance relates to our acquisition of NST in June 2019. For additional information on our acquisition of NST, please read Note 2, Acquisitions, to our consolidated financial statements included in our 2020 Form 10-K.
Vixotrigine
In the periods since we acquired vixotrigine, there have been numerous delays in the initiation of Phase 3 studies for the potential treatment of TGN and for the potential treatment of diabetic painful neuropathy (DPN), another form of neuropathic pain. We have engaged with the U.S. Food and Drug Administration (FDA) regarding the design of the Phase 3 studies of vixotrigine for TGN and DPN and now plan to perform an additional clinical trial of vixotrigine before initiating a Phase 3 study of DPN.
The performance of this additional clinical trial has delayed the initiation of the Phase 3 studies of vixotrigine for the potential treatment of TGN, and, as a result, we recognized an impairment charge of $44.3 million related to vixotrigine for the potential treatment of TGN during the first quarter of 2021. As of March 31, 2021, the carrying value associated with our remaining vixotrigine IPR&D assets was $135.1 million, all of which is related to DPN.
BIIB111 and BIIB112
During the fourth quarter of 2020 we recognized an impairment charge of $115.0 million related to BIIB111 (timrepigene emparvovec) for the potential treatment of choroideremia, a rare, degenerative, X-linked inherited retinal disorder that leads to blindness and currently has no approved treatments, as a result of third-party manufacturing delays that may impact our timeline for a potential filing of a Biologics License Application (BLA) for regulatory approval by up to one year, and increase the costs associated with advancing BIIB111 through Phase 3 development.
15

Table of Contents
BIOGEN INC. AND SUBSIDIARIES
NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
(unaudited, continued)
We are continuing to monitor the manufacturing issues encountered with BIIB111 and their potential impact on that program's timing. As of March 31, 2021, we have no indication that BIIB111 or BIIB112 (cotoretigene toliparvovec) for the potential treatment of X-linked retinitis pigmentosa, which is a rare inherited retinal disease with no currently approved treatments, were impaired; however, we will continue to monitor the capabilities of our manufacturing partners and how any additional new manufacturing issues might affect the planned timing of such gene therapy programs.
Estimated Future Amortization of Intangible Assets
The estimated future amortization of finite-lived intangible assets for the next five years is expected to be as follows:
(In millions)As of March 31, 2021
2021 (remaining nine months)$165.0 
2022215.0 
2023215.0 
2024225.0 
2025220.0 
2026200.0 
Goodwill
The following table provides a roll forward of the changes in our goodwill balance:
(In millions)As of March 31, 2021
Goodwill, beginning of period$5,762.1