Schering-Plough Expands Vicriviroc Phase II Study in Treatment-Naive Patient...( ...),Health

KENILWORTH, N.J., July 15 /PRNewswire-FirstCall/ -- Schering-Plough Corporation (NYSE: SGP) today announced that it has extended to stage two an ongoing Phase II clinical study with vicriviroc, its investigational CCR5 antagonist, for use in first-line therapy of adult treatment-naive HIV-infected patients with R5-type virus only. In this study, vicriviroc is being evaluated in a novel nucleoside-sparing regimen that is designed to provide additional options for treatment-naive patients in a once daily regimen, while preserving other drug classes for subsequent lines of treatment.

The study is being conducted in two stages, with the first stage initiated in January 2008 and having enrolled 95 patients (47-48 per treatment arm). Following 24 weeks of treatment, a formal interim analysis was conducted and the safety results were reviewed by an independent Data Safety Monitoring Board. Based on these results, the study has been extended to stage two, in which the enrollment target is an additional 105 patients.

Unlike other classes of HIV drugs that work to inhibit viral replication within human CD4+ cells, most of which are part of the immune system, vicriviroc is an HIV entry inhibitor designed to prevent the virus from infecting healthy CD4 cells by blocking its predominant entry route, the CCR5 co-receptor. Approximately 80-90 percent of treatment-naive patients have virus that uses the CCR5 co-receptor.(1)

"CCR5 antagonists, such as vicriviroc, have a novel mechanism of action and may play a unique role as physicians seek to construct new HIV regimens to meet the specific needs of their patients," said Joseph C. Gathe, Jr., M.D., F.A.C.P., clinical instructor, department of internal medicine, Baylor College of Medicine, Houston, and lead inve
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