Boceprevir (trade name Victrelis) is first-generation, selective, small molecule inhibitor of the non-structural serine protease (NS3) and NS4A polypeptide complex (NS3/NS4A) and is a direct acting antiviral drug against the hepatitis C virus. It is indicated the treatment of chronic hepatitis C (CHC) genotype 1 infection, in combination with peginterferon alfa and ribavirin, in adult patients (18 years of age and older) with compensated liver disease, including cirrhosis, who are previously untreated or who have failed previous interferon and ribavirin therapy. Boceprevir is not approved as a monotherapy. Upon administration, boceprevir reversibly binds to the active center of the HCV NS3/NS4A and prevents NS3/NS4A protease-mediated polyprotein maturation. This disrupts the processing of viral proteins and the formation of a viral replication complex, which inhibits viral replication in HCV genotrype 1-infected host cells. NS3, a serine protease, is essential for the proteolytic cleavages within the HCV polyprotein and plays a key role during HCV viral RNA replication. NS4A is an activating factor for NS3.