Merck says that its HIV drug vicriviroc failed two late-stage trials, scuttling any immediate plans to file for an approval at the FDA. Merck acquired the drug through its acquisition of Schering-Plough, which had expected an approval by the end of this year and peak sales of $500 million to $750 million. Analysts, though, had expected a much smaller peak, saying that the experience of Selzentry--another CCR5 co-receptor antagonist--indicated a limited demand for the drug. Merck plans to continue studying the drug in a treatment naïve population. Report