Vicriviroc, a CCR5 receptor antagonist for the potential treatment of HIV infection

Highly active antiretroviral therapy has revolutionized the care of patients with HIV infection, but treatment is often complicated by the development of antiretroviral resistance. CCR5 inhibitors are a novel class of antiretroviral agents that block the CCR5 receptor, thereby preventing HIV-1 recognition and entry into CD4+ macrophages and T-cells. Schering-Plough Corp is developing vicriviroc, a CCR5 inhibitor that has demonstrated good oral bioavailability, has a long half-life that allows once daily dosing, and is primarily metabolized by cytochrome P450 CYP3A4. In vitro and clinical data suggest that vicriviroc has excellent antiviral potency with minimal toxicity. Phase I and II clinical trials demonstrated promising efficacy results when vicriviroc is administered to patients infected with CCR5-tropic HIV-1. At the time of publication, phase III trials were ongoing or planned to investigate the efficacy and safety of vicriviroc in antiretroviral-naïve and -experienced patients infected with HIV-1.