Schering discontinues phase 2 studies of vicriviroc in treatment naive patients

On 27 October 2005, Schering-Plough issued a press release that it has discontinued a phase 2 study with its investigational CCR5 receptor antagonist, vicriviroc, used in combination with AZT and 3TC (Combivir) in treatment-naive HIV patients. This decision was due to a return of detectable virus in some patients late in therapy compared to the standard-of-care control regimen of AZT/3TC/efavirenz.

The company noted that this decision was not based on hepatotoxicity or other significant safety issues in patients receiving vicriviroc in the study or in a second phase 2 study in treatment-experienced HIV patients, which is continuing. The Phase II study in U.S. treatment-experienced patients is being conducted by the NIH-sponsored AIDS Clinical Trials Group (ACTG) and is fully enrolled.

Schering-Plough said that it discontinued its phase 2 treatment-naive study following a recommendation from the independent Data Safety Monitoring Board (DSMB), which has been meeting regularly to conduct reviews of the safety and efficacy data. The increased incidence of detectable virus was only seen in some patients after several weeks of treatment. The study had been under way since spring 2004 in 23 centers in Europe and Canada, with 92 patients enrolled. Patients already enrolled in the treatment-naive study will continue to receive vicriviroc until they can be switched to an alternative regimen in consultation with their physician. Clinical trial investigators for the study, their Ethics Committees and Health Authorities are being notified.

Press release from Schering Plough: Schering Plough discontinues Phase II study of vicriviroc in treatment-naive HIV patients, continues Phase II study in treatment-experienced patients. 27 October 2005.
http://www.schering-plough.com