Gilead Sciences Inc. announced Tuesday that GS 504, its agentfor the treatment of peripheral retinitis due to cytomegalovirus(CMV), has entered Phase II/III human clinicals.

The drug will be compared with placebo in a group of 24patients to determine its impact on the progression of CMVretinitis in AIDS patients as measured by retinal photographs.

Phase I/II trial results on GS 504 presented at the NationalInstitutes of Health in December 1992 indicated that the agentwas able to retard the progress of CMV in patients with activeviral infection or at risk of developing CMV retinitis, but itserved principally as a dose-refinement study.

The current Phase II/III trial, being conducted at seven sites inthe U.S. and one in Great Britain, will measure the effects of 5mg/Kg of GS 504 given once a week for two weeks, thenadministered every other week.

The company said the infrequent dosing and topical applicationof GS 504 gives it an advantage in convenience and safety overtreatments for CMV that require intravenous administrationthrough an indwelling catheter.

Gilead (NASDAQ:GILD) of Foster City, Calif., is also developing GS504 for treating herpes simplex virus in AIDS patients who areunresponsive to acyclovir. The drug entered Phase I/II trialsfor that indication in December. --Karl Thiel

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