Danoprevir is an orally bioavailable inhibitor of hepatitis C virus (HCV) nonstructural protein 3/4A (NS3/4A; IC50 = 1 nM), a serine protease essential for HCV replication. It is selective for NS3/4A over a panel of 53 proteases at a concentration of 10 μM. Danoprevir inhibits replication of the HCV genotypes 1a, 1b, 4, 5, and 6 (IC50s = 0.2-0.4 nM) as well as 2b and 3a (IC50s = 1.6 and 3.5 nM, respectively) in vitro. It also reduces the number of HCV genotype 1b replicons in Huh-7 cells (EC50 = 1.8 nM).
