Drug manufacturer Pfizer has announced that it will halt development of its NNRTI Capravirine. According to Pfizer, the decision was made based on recent data that failed to show Capravirine was any more effective than existing therapies. That combined with the problem of drug interactions with existing therapies prompted Pfizer to make the move. Pfizer says that resources will now be used to develop its other new HIV medications including its Phase III drug Maraviroc, the first in a class of CCR5 inhibitors that inhibit HIV's ability to enter the cell.