Description: Vicriviroc (aformerly SCH-417690; SCH-D) is an orally bioavailable and CNS penetrant CCR5 antagonist and entry inhibitor of HIV-1 with a Ki of 2.5 nM. It also inhibits HIV-1 in PBMC cells, with IC90s of 3.3 nM (JrFL), 2.8 nM (ADA-M), 1.8 nM (301657), 4.9 nM (JV1083) and 10 nM (RU 570). Vicriviroc can be administered once daily. Vicriviroc binds to a small hydrophobic pocket between the transmembrane helices near the extracellular surface of the CCR5 receptor. Binding to this pocket induces a conformational change of the extracellular segment of CCR5 and prevents binding of gp120 to the target cell, consequently preventing the virus from entering the target cell at all.