Mixed data from S-P's vicriviroc in HIV study

US health care company Schering-Plough says that studies of its antiviral drug vicriviroc, a CCR5 receptor antagonist, show the compound's efficacy when given to HIV-infected patients. The findings were presented at the 13th Conference on Retroviruses and Opportunistic Infections, in Denver, Colorado, USA.

In this trial, CCR5 tropic patients with HIV were randomized to receive one of three doses of the drug or placebo, once-a-day for 14 days, before combivir was added to all regimens for a further 34 weeks. Patients assigned placebo were given efavirenz in addition to combivir. Initial analysis revealed that patients on vicriviroc experienced a dose-related drop in viral load during the first two weeks. The proportion of patients who experienced virologic breakthrough was 4% in the placebo group and 56%, 41% and 17% in the 25mg, 50mg and 7mg, cohorts respectively. Additionally, the compound caused no liver toxicity.

The firm commented that the results would aid further development of the drug in terms of future safety assessments, and the identification of potential drug interactions.