A NS3/4A protease inhibitor (Ki = 14 nM) that prevents HCV viral replication; inhibits the NS3/4A protease in an in vitro HCV replicon system (EC50 = 200 nM) and blocks the activity of recombinant HCV genotype 1a and 1b NS3/4A protease enzymes in vitro (Kis = 14 nM for each subtype)