Ensitrelvir (fumarate)

An inhibitor of SARS-CoV-2 Mpro (IC50 = 0.013 µM); selective for Mpro over HIV-1 protease and the human proteases caspase-2, chymotrypsin, thrombin, and cathepsin B, -D, -G, and -L (IC50s = >100 µM for all); reduces the cytopathic effects of SARS-CoV-2 clinical isolates, including Alpha, Beta, Gamma, Delta, and Omicron strains, SARS-CoV, and MERS-CoV, in Vero E6 cells expressing human TMPRSS2 (EC50s = 0.29-1.4 µM); decreases lung viral titers in a mouse model of SARS-CoV-2 Gamma variant infection when administered at the time of, and 12 hours after, infection from 2-32 mg/kg, p.o.