AIDSDrugWorksonMonkeysFosterCityfirmrecordsafirst

November17,1995

ByBARRYKAYETimesStaffWriter

FOSTERCITY–ResearchersataFosterCitybiotechnologycompanyreportedtodaythat,forthefirsttime,adrugthatinhibitstheabilityoftheAIDSvirustoreplicateitselfachieveda100percentsuccessrateinmonkeys.

Theearly,preclinicalstudiesindicatethatarevolutionarycompounddevelopedbyGileadSciencesprovidedprotectionagainstthedevelopmentofsimianimmunodeficiencyvirus(SIV)inprimatesupto24hoursaftertheyweregivenlargedosesofthedisease.

GileadconductedthestudyinconjunctionwithscientistsattheNationalInstitutesofHealthandresearchersattheUniversityofWashingtonPrimateCenterinSeattle.Theresultsappearinthismonth’sissueoftheprestigiousSciencemagazine.

“Nootherdrughasevershownthiskindofactivity.Itisreallyunbelievable,”saidRobertaBlack,amicrobiologistwiththeNationalInstituteofAllergyandInfectiousDiseases,adivisionofNIH.

FindingacureforAIDShasbeenespeciallydifficultbecausethevirusthatcausesitisconstantlychangingandmutating.Scientistsalsoknowverylittleabouthowthediseaseitselfactuallyworks.

[PhotoCaption:MICHAELRIORDAN:GileadCEOsays,“Itturnsofftheenzymethevirususestoreplicateitself.”]

Gilead’sworkinvolvessomethingknowninbiotechnologycirclesasanucleotideanalog,amoleculethatbindstoasubstancecalledreversetranscriptase.

“Itturnsofftheenzymethatthevirususestoreplicateitself,”saidMichaelRiordan,chiefexecutiveofficeratGilead.

Riordancautionedthatthedrug,calledPMPA,hasnotyetbeentestedinhumans,althoughhesaidthediseaseinmonkeysisverysimilartotheHIVvirus.

ThereisnoknowncureforAIDS,whichattacksthehumanimmunesystemandisalmostalwaysfatal.

ResearchersattheNationalInstituteofAllergyandInfectiousDiseases,whichhelpedfundthestudy,saidearlytestsshowthattheGileaddrugblockedalltracesofthediseasein25macaquemonkeysmorethanoneyearaftertheexperimentbegan.

“Itsoundsalmosttoogoodtobetrue,”saidDr.MartaMarthas,avirologistattheUniversityofCaliforniaatDavis’RegionalPrimateResearchCenter.Butsheadded,“Youcan’targuewiththatresult.”

Dr.AshleyHaase,anexpertonlentiviruses,thevirusfamilythatincludesHIVandSIV(simian),saidhewas“surprisedandpleased”bythefinding.

Headdedthatthestudywascarefullydoneandthatitwas“ifanything,moredifficult”toprotectagainstSIVthanitwastoprotectagainstHIVinfections.

NIH’sBlack,whowasonworkfurloughbecauseofthefederalbudgetimpasse,saidatremendousamountofadditionalresearchstillneedstobecompleted.

Furthertestsareneeded,forexample,todeterminehowwellmonkeystoleratehighdosesofthedrug.

“Monkeysarenothumanbeings,”shesaid.“Althoughitisanexcellentmodelforevaluatingdrugs,itisstillamodel.”

ButamongtheencouragingbenefitsoftheGileadcompoundisthat,inachievinga100percentsuccessrate,therewerenoadditionalcomplications.

“SuchcompleteprotectionwithnotoxicityisunprecedentedinthemonkeymodelofAIDS,”saidAnthonyS.Fauci,directorofinfectiousdiseasesatNIH.

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