Schering-Plough Initiates Phase II Study With Vicriviroc in Treatment-Naive HIV-Infecte...( Novel Nucleoside-Sparing Regimen ...),Health

Novel Nucleoside-Sparing Regimen Designed to Avoid Risk of Toxicity

Associated with Nucleoside Class of HIV Drugs

KENILWORTH, N.J., April 15 /PRNewswire-FirstCall/ -- Schering-Plough Corporation (NYSE: SGP) today announced that it has initiated a 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. 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. Approximately 80-90 percent of treatment-naive patients have virus that uses the CCR5 co-receptor.(1) Vicriviroc also is being studied in two large Phase III clinical studies in treatment-experienced HIV patients, which are ongoing and currently enrolling patients.

The study in treatment-naive patients evaluates the virologic benefit of vicriviroc, administered once-daily as a single 30 mg tablet, in combination with ritonavir-boosted atazanavir,(2) compared to a control group receiving Truvada (emtricitabine and tenofovir disoproxil fumarate)(3) plus ritonavir- boosted atazanavir, which is a currently recommended option for first-line therapy. Atazanavir is a product in the protease inhibitor (PI) class of HIV medications. Truvada is a combination product in the nucleoside reverse transcriptase inhibitor (NRTI) class.

"A nucleoside-sparing vicriviroc regimen for initial treatment may have the added strategic benefit of preserving most products used to create a highly active antiretroviral therapy "cocktail" for later use in patients, while also avoiding the risk of toxicity known to be associated with the nucleoside
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