MK-639 data

Merck presented preliminary results of ongoing Phase II trials, showing that MK-639 initially reduces the level of viral RNA in some AIDS patients by up to 99 percent. However, as a result of viral resistance, viral load in many patients begins to rebound toward baseline within several months.

After six months of treatment, MK-639 increases median CD4 counts by more than 100 over baseline, according to data presented at the National Task Force on AIDS Drug Development meeting in Bethesda. In most patients, CD4 counts remain above baseline for more than six months, even with viral resistance. Patients improved on other parameters, including body weight, hemoglobin, neutrophil and platelet counts. There was no significant toxicity at doses up to 2.4 g/day. ...