Danoprevir (ITMN-191) is an orally active NS3/4A protease inhibitor for hepatitis C virus (HCV) with an IC50 of 0.29 nM and is selective for NS3/4A over a panel of 53 proteases (IC50 higher than 10 μM). Danoprevir (ITMN-191) inhibits HCV genotypes 1a, 1b, 4, 5, and 6 (IC50s=0.2-0.4 nM) as well as 2b and 3a (IC50s=1.6, 3.5 nM). Danoprevir is also a SARS-CoV 3CLpro inhibitor with an IC50 of 0.05 μM