Gilead Sciences Inc. said Tuesday that it is beginning an open-labeltrial of GS 504 for the treatment of cytomegalovirus (CMV) retinitis inAIDS patients, its third ongoing trial of the agent for that indication.The Foster City, Calif., company is using the open-label trial as asupplement to two pivotal Phase II/III trials in which patients still arebeing enrolled.The trial will enroll up to 100 patients with relapsing CMV retinitis, acondition in which retinal lesions have progressed despiteadministration of an approved therapeutic. The study will be held at sixcenters in the U.S. and one in the U.K. Patients will be randomized intotwo treatment groups, each receiving one intravenous dose level of GS504 once per week for two weeks, followed by one of two dose levelsevery other week."This study will be examining the potential effectiveness of GS 504 totreat patients whose retinitis is no longer responding to current therapyand/or a patient who may be intolerant of an approved therapeutic,"Lana Lauher, manager of corporate communications and investorrelations for Gilead, told BioWorld."To conduct this third clinical trial has been part of our strategy allalong," Lauher said. "It will expand and increase our level ofinformation regarding use of the compound in this patient population."Lauher said there currently are no additional CMV retinitis trialsplanned for GS 504, which inhibits viral replication.Last month, Gilead said it would begin enrolling the second 24 patientsin a 48-patient pivotal study. That action came after an interim analysisof the trial by an independent safety monitoring board, as called for inthe protocol. The induction phase of that study calls for intravenousadministration of 5 mg/kg of the nucleotide analog once a week for twoweeks, then 5 mg/kg or 3 mg/kg every other week. There also is adeferred treatment group.The clinical endpoint in that trial is the progression of CMV retinitis asmeasured by retinal photographs, which quantifies changes in retinallesions.A third study of the GS 504 (also known as HPMPC) is beingconducted by the Studies of the Ocular Complication of AIDS (SOCA)research group. It is designed to enroll 90 patients at the 11-SOCAaffiliated clinical centers in the U.S.In addition to the intravenous formulation of GS 504 for CMV retinitis,the agent is being studied in a Phase I/II trial in bone marrow transplantpatients at risk for CMV lung infection (pneumonitis).A topical formulation of GS 504 is in two Phase I/II studies in AIDSpatients, one for herpes simplex virus and another for genital wartscaused by human papillomavirus.GS 393 (also called PMEA) is in Phase I/II studies for the treatment ofHIV, and GS 840, an oral pro-drug of GS 393, is in a Phase I study fortreatment of HIV.Gilead (NASDAQ:GILD) stock was down 25 cents Tuesday, closing at$8 per share. n
-- Jim Shrine
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