Merck’s HIV Drug Fails to Meet Phase III Endpoint

Merck’s HIV treatment vicriviroc did not meet the primary efficacy endpoint in two Phase III studies involving patients previously treated with other HIV medicines. Based on these studies, according to a company statement, Merck does not plan to seek approval for the drug at this time. Merck plans to continue Phase II studies of the drug among treatment-naïve HIV patients.

Vicriviroc is a new class of HIV treatments designed to block receptors to CCR5, a protein that gives HIV an entryway into human immune system cells. Merck had acquired the drug through its recent $41 billion purchase of Schering-Plough Corp. Previous studies of the drug among treatment-experienced patients suggested it was able to suppress the virus, and was generally well tolerated, during two years of therapy.