FDA批准吸入性炭疽治疗新药Anthrasil，应对炭疽生化袭击

2015年3月26日讯/生物谷BIOON/--美国食品和药物管理局（FDA）近日批准一款新药Anthrasil（炭疽病免疫球蛋白静脉注射液）联合适当的抗生素用于吸入性炭疽（inhalationanthrax）的治疗。
吸入性炭疽是一种罕见的疾病，由吸入炭疽杆菌的孢子所致，当人体接触到受感染的动物、或受污染的动物产品或人为蓄意释放（生化袭击）的炭疽孢子后便可能感染；吸入孢子后，炭疽杆菌会在体内增殖并产生毒素，引发严重的不可逆的组织损伤和死亡。
为支持美国对可能发生的炭疽袭击事件的准备，美国卫生和人类服务部(HHS)下属生物医学高级研究及发展管理局（BARDA）于2011年在BioShield计划下买进Anthrasil，作为一种实验性药物用于美国国家战略储备。在获批之前，Anthrasil的使用需要得到FDA的紧急使用授权。此次Anthrasil获批，将为其他FDA已批准的药物提供一个重要的补充。
Anthrasil采用接种炭疽疫苗免疫的个体的血浆制成，含有能中和炭疽毒素的抗体。Anthrasil的获批，是基于动物研究的疗效数据及人体安全性研究数据。Anthrasil的疗效研究在动物中开展，因为在人类中开展充分控制疗效研究不可行或不道德。动物研究中，兔子和猴子被暴露于一个致死剂量的炭疽孢子，然后采用Anthrasil或安慰剂治疗，评价存活率。经Anthrasil治疗的猴感染组存活率在36-70%，安慰剂组存活率为0，同时更高剂量Anthrasil治疗表现出升高的存活率。兔子研究中，兔子感染炭疽后采用中等剂量Anthrasil治疗取得的存活率为26%，安慰剂组为2%。另一项兔子研究显示，Anthrasil联合抗生素治疗存活率为71%，安慰剂联合抗生素治疗的存活率为25%。
这些动物研究结果提供了充分的证据，表明Anthrasil有合理很可能使吸入性炭疽患者受益。在药品审查中，当在人体中开展临床试验不可行或不道德时，FDA的动物条令允许来自充分且良好对照的动物研究数据，用于支持药物的审查。
Anthrasil安全性研究在74名健康人类志愿者中进行测试，最常见的副作用包括头痛、背痛、恶心、注射部位的疼痛和肿胀。
Anthrasil由加拿大Cangene公司研发，由美国生物医学高级研究发展局(BARDA)提供资金支持，该机构负责储备疫苗、药品及医疗设备，应对传染病及其他突发公共卫生事件。
英文原文：FDAapprovestreatmentforinhalationanthrax
TheU.S.FoodandDrugAdministrationyesterdayapprovedAnthrasil,AnthraxImmuneGlobulinIntravenous(Human),totreatpatientswithinhalationalanthraxincombinationwithappropriateantibacterialdrugs.
Inhalationalanthraxisararediseasethatcanoccurafterexposuretoinfectedanimalsorcontaminatedanimalproducts,orasaresultofanintentionalreleaseofanthraxspores.ItiscausedbybreathinginthesporesofthebacteriumBacillusanthracis.Wheninhaled,theanthraxbacteriareplicateinthebodyandproducetoxinsthatcancausemassiveandirreversibletissueinjuryanddeath.Tosupportthenation’spreparednessagainstapossibleanthraxattack,theU.S.DepartmentofHealthandHumanServices’BiomedicalAdvancedResearchandDevelopmentAuthority(BARDA)purchasedAnthrasilunderProjectBioShieldin2011asanexperimentaldrugfortheU.S.StrategicNationalStockpile.BecauseAnthrasilwasnotapproved,itsusepriortotoday’sapprovalwouldhaverequiredanemergencyuseauthorizationfromtheFDA.
Anthrasilismanufacturedfromtheplasmaofindividualsvaccinatedagainstanthrax.Theplasmacontainsantibodiesthatneutralizetoxinsproducedbytheanthraxbacteria.
“Today’sapprovalprovidesanimportantadditionaltreatmenttootherFDA-approvedtherapiesforinhalationalanthrax,alife-threateningdisease,”saidKarenMidthun,M.D.,directoroftheFDA’sCenterforBiologicsEvaluationandResearch.“ThisproductwillbestoredinU.S.StrategicNationalStockpiletofacilitateitsavailabilityinresponsetoananthraxemergency.”
TheefficacyofAnthrasilwasstudiedinanimalsbecauseitwasnotfeasibleorethicaltoconductadequatelycontrolledefficacystudiesinhumans.RabbitsandmonkeyswereexposedtoalethalaerosolizeddoseofB.anthracisspores,thentreatedwithAnthrasiloraplacebo,andevaluatedforsurvival.Survivalinanthrax-infectedmonkeystreatedwithAnthrasilrangedfrom36to70percentcomparedto0percentsurvivalintheplacebogroupwithatrendtowardincreasedsurvivalathigherdosesofAnthrasil.RabbitstreatedwithamoderatedoseofAnthrasilafterinfectionexhibited26percentsurvivalcomparedto2percentsurvivalintheplacebogroup.AnotherstudyinrabbitsshowedthatacombinationofAnthrasilandantibioticsresultedin71percentsurvivalcomparedto25percentsurvivalinanimalstreatedwithantibioticsalone.
TheresultsofstudiesinresearchanimalsprovidedsufficientevidencethatAnthrasilisreasonablylikelytobenefithumanswithinhalationalanthrax.TheFDA’sAnimalRuleallowsefficacyfindingsfromadequateandwell-controlledanimalstudiestosupportFDAapprovalwhenitisnotfeasibleorethicaltoconducttrialsinhumans.
Thesafetyoftheproductwastestedin74healthyhumanvolunteers.Themostcommonlyobservedsideeffectswereheadache,backpain,nauseaandinfusionsitepainandswelling.
TheproductismanufacturedbyCangeneCorporation,basedinWinnipeg,Canada.ItwasdevelopedwithsupportfromBARDAwithinHHS’OfficeoftheAssistantSecretaryforPreparednessandResponse.
TheFDA,anagencywithintheU.S.DepartmentofHealthandHumanServices,protectsthepublichealthbyassuringthesafety,effectiveness,andsecurityofhumanandveterinarydrugs,vaccinesandotherbiologicalproductsforhumanuse,andmedicaldevices.Theagencyalsoisresponsibleforthesafetyandsecurityofournation’sfoodsupply,cosmetics,dietarysupplements,productsthatgiveoffelectronicradiation,andforregulatingtobaccoproducts.
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