Entecavir

Entecavir (SQ 34676; BMS 200475) is a potent and selective inhibitor of HBV, with an EC₅₀ of 3.75 nM in HepG2 cell. IC50 & Target:EC50: 3.75 nM (anti-HBV, HepG2 cell)^[2] In Vitro: BMS-200475 has a EC₅₀ of 3.75 nM against HBV. It is incorporated into the protein primer of HBV and subsequently inhibits the priming step of the reverse transcriptase. The antiviral activity of BMS-200475 is significantly less against the other RNA and DNA viruses^[1]. Entecavir is more readily phosphorylated to its active metabolites than other deoxyguanosine analogs (penciclovir, ganciclovir, lobucavir, and aciclovir) or lamivudine. The intracellular half-life of entecavir is 15 h^[2]. In Vivo: Daily oral treatment with BMS-200475 at doses ranging from 0.02 to 0.5 mg/kg of body weight for 1 to 3 months effectively reduces the level of woodchuck hepatitis virus (WHV) viremia in chronically infected woodchucks^[3].