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 int...