Schering-Plough Reports Vicriviroc Data For Phase II VICTOR-E1 Study

Schering-Plough has reported long-term data with vicriviroc, its investigational CCR5 receptor antagonist, from an ongoing, open-label extension of the phase II VICTOR-E1 study in treatment-experienced HIV-infected patients.

The results showed that vicriviroc plus optimised background therapy achieved durable virologic suppression and increased CD4 cell counts, and was generally well tolerated over two years of therapy.

Reportedly, the study involved 85 treatment-experienced HIV-infected patients who received 48 weeks of open-label vicriviroc (30mg once daily) plus an optimised antiretroviral regimen containing a ritonavir-boosted protease inhibitor after completion of 48 weeks of treatment in the double-blind phase of the VICTOR-E1 study.

More than half of these patients began open-label treatment with undetectable virus, ie an HIV-1 RNA level of less than 50 copies/ml, and about two-thirds had less than 400 copies/ml. 70 patients remained on therapy at the time of the 96-week analysis.

However, the virologic effect seen during the double-blind phase of the study was sustained in these patients during open-label vicriviroc treatment, with the percentage of patients achieving undetectable virus increasing over the course of therapy.

Additionally, further improvements in CD4 counts were observed with longer vicriviroc therapy, with a mean increase of 50 cells/mm3 from week 48 of the double-blind study to the end of the 96-week period.

Jihad Slim, an investigator for the vicriviroc clinical program, said: “These long-term results with vicriviroc added to optimised background therapy are encouraging and show potential for durable viral suppression and sustained elevated CD4 counts in treatment-experienced HIV-infected patients. Importantly, vicriviroc was generally well tolerated, with most patients continuing on treatment for as long as two years.”