题目内容：
根据以下材料，回答题AFoodandDrugAdministration(FDA)advisorycommitteehasconcludedthatanovelnewtreatmentcangreatlyhelprheumatoidarthritispatients.
ThepanelrecommendedapprovingEnbrelforusealoneinpatientswhohaven'trespondedtootherdrugsorincombinationwithmethotrexate,acancerdrugthathasbeenthemaintreatmentfor
rheumatoidarthritiS.
TheFDAmustmakeafinaldecisionbyearlyNovember,andthedrug'smakersaysitcouldbeonthemarketbyyear'send.
Inrheumatoidarthritis,whichaffects2.1millionAmericans,theimmunesystemattackshealthyjoints.Amajorwrongdoerinthisprocessisaproteincalled"tumorkillingfactor",orTNF,which
interactswithaspecialmolecule,orTNFreceptor,oncells'surfaces.
tokeepinflammationincheck,cellsnormallyreleasesomereceptorstomopupexcessTNF,renderingitinactive.Apparently,rheumatoidarthritispatientsdon'thaveenoughfree-floatingTNFreceptors.
EnbrelconsistsofgeneticallyengineeredTNFreceptors.Inasix-monthstudy,234patientswithadvancedrheumatoidarthritisreceivedoneoftwodosesofEnbreloraplacebo(harmlesssubstancegivenasifitweremedicine)intwice-a-weekinjections.Theytookinjectionsforsixmonths.Bytheend,40%ofpatientsonthelargerEnbreldosesawsymptoms,suchas.swellingandjointpain,cutinhalf.Only5%ontheplacebodidthat
well.Themainsideeffectwasminorirritationattheinjectionsite.
BecausesomeTNFisneededforanormalimmuneresponse,thereisatleastatheoreticalriskofinfectionsorevencancerinpatientswhotakeEnbrel,sotheFDApanelurgedlong-termsafetystudies.
Lastweek,theFDAapprovedArava,anoraltreatmentforrheumatoidarthritisthatissimilartomethotrexate.WhilecallingbothEnbrelandArava"potentiallyveryimportant",BrianButcher,vice
presidentforresearchattheArthritisFoundation,notestheyhavebeentestedinrelativelyfewpatients.
Butchersaystheirsafetyshouldbecloselymonitoredoncethey'rewidelyavailable.
EnbrelasrecommendedbyFDAadvisorycommittee A．couldbeasubstituteformethotrexateinthenearfuture.
B．mightbringhopetorheumatoidarthritispatients.
C．shouldbeadministeredtoallrheumatoidarthritispatientsalike.
D．woulddistinguishitselfforitscancer—killingeffect.
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