Schering-Plough initiates Phase II study of HIV drug

This randomized, controlled, open-label study is projected to enroll approximately 200 treatment-naive HIV-infected adult patients at more than 20 sites in North America, Central America, Europe and South Africa. Patients coinfected with hepatitis B or C may be included in the study.

The primary efficacy endpoint of the study is the mean change from baseline in viral load (log10 HIV RNA) at week 48 of treatment. A key secondary efficacy endpoint is the proportion of patients with plasma HIV RNA less than 50 copies/mL at week 48 of treatment.

The study will be conducted in two stages. In the first stage, 80 patients will be randomized (40 per treatment arm) into the study. When the 80 subjects from the first stage have completed 24 weeks of treatment, a formal interim analysis will be conducted and the results presented to an independent data safety monitoring board to assure the safety of the study participants. The study will be extended to stage 2 based on the results of the 24-week interim analysis; at which time an additional 120 patients (60 per treatment arm) will be enrolled. The final analysis will be conducted at week 48 of treatment for all patients.

The study in treatment-naive patients evaluates the virologic benefit of vicriviroc, administered once-daily as a single 30mg tablet, in combination with ritonavir-boosted atazanavir, compared to a control group receiving Truvada (emtricitabine and tenofovir disoproxil fumarate) plus ritonavir- boosted atazanavir, which is a currently recommended option for first-line therapy. Vicriviroc is a next-generation HIV entry inhibitor designed to prevent the virus from infecting CD4 cells by blocking its predominant entry route, the CCR5 co-receptor.