IDX136

IDX136 is a potent, macrocyclic, second-generation inhibitor of the Hepatitis C Virus (HCV) NS3/4A serine protease. Developed by Idenix Pharmaceuticals, it was designed to provide high antiviral potency and an improved resistance profile against common NS3 mutations compared to first-generation inhibitors like telaprevir. The molecule works by binding to the active site of the NS3/4A protease complex, which is responsible for the essential cleavage of the HCV polyprotein into mature non-structural proteins (NS4A, NS4B, NS5A, and NS5B) required for viral RNA replication. Clinical development reached Phase 1/2, demonstrating significant reductions in viral load in patients with HCV genotype 1. However, development was discontinued as the therapeutic landscape shifted toward multi-drug direct-acting antiviral (DAA) regimens and following the acquisition of Idenix by Merck in 2014.