Currently known as BMS-663068, the drug was shown to be safe and to work against the virus.
HIV cell entry is a three-step process. The virus must first attach to the CD4 receptor on the surface of a cell, then bind to a co-receptor (either CCR5 or CXCR4) and, finally, fuse with the cell membrane, releasing viral components into the cell. Of other drugs that target cell entry, the CCR5 antagonist maraviroc (Celsentri in Europe and Selzentry in the US) targets the second step and the fusion inhibitor T-20 (enfuvirtide, Fuzeon) acts at the third step.
BMS-663068 would be the first drug to target the initial step. The active form of the drug has the laboratory name BMS-626529.
They were divided into five arms, and treated with various doses of the drug, once or twice daily, with or without a ritonavir (Norvir) booster. The study lasted eight days.
Viral load fell substantially, and there were good increases in CD4 cell count.
Both once- and twice-daily dosing were effective, but boosting with ritonavir only marginally increased the potency of the drug.
The drug will be examined in further studies starting later this year.