Gilead Sciences Inc. was given the go-ahead to continue a Phase II/IIIpivotal study of its agent, GS 504, for the treatment of retinitis causedby cytomegalovirus (CMV) infection in AIDS patients, the Foster City,Calif., company said Tuesday.The original protocol called for an interim analysis of the trial, after the24th patient was enrolled for a month, by an independent data andsafety monitoring board. One reason for the analysis was to make surethere were no adverse side effects, Lana Lauher, manager of corporatecommunications and investor relations for Gilead, told BioWorld."We're pleased to have received notification that the study will beongoing, and we will continue patient enrollment as planned," Lauhersaid. Twenty-four more patients now will be enrolled, bringing thestudy up to 48 patients, who will be treated at seven centers in the U.S.and one in London.The induction phase of the study calls for intravenous administration of5 mg/kg of GS 504 once a week for two weeks, then 5 mg/kg or 3mg/kg every other week. There also is a deferred treatment group in therandomized study, which stared in January.The clinical endpoint is the progression of CMV retinitis as measuredby retinal photographs, which quantifies changes in retinal lesions.A second pivotal study of GS 504, with the same indication in asimilarly designed trial, is being conducted by the Studies of the OcularComplications of AIDS (SOCA) research group, a clinical trialsnetwork affiliated with the National Institutes of Health. That study isdesigned to enroll 90 patients through the 11 SOCA-affiliated centersin the U.S.Phase I/II trial results of GS 504 presented in December 1992 indicatedthe agent was able to slow the progression of CMV in patients withactive viral infection or at risk of developing CMV retinitis. But thattrial served primarily as a dose-refinement study of the small moleculenucleotide analog, which also is known as HPMPC.GS 504 also is being tested in a Phase I/II trial in organ transplantpatients who are at risk for CMV lung infection, and a topicalformulation of the agent is in a Phase I/II study as a treatment forherpes simplex virus in AIDS patients. The same topical formulation isbeing studied in a Phase I/II trial for treatment of genital warts causedby human papilloma virus in AIDS patients.Gilead has GS 393, also known as PMEA, in a Phase I/II trial fortreatment of HIV, and GS 840, an oral pro-drug of GS 393, in Phase Ifor HIV.Gilead (NASDAQ:GILD) stock was up 25 cents Tuesday, closing at$8.50 a share. n

-- Jim Shrine

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