Recent advances in hepatitis C virus treatment: review of HCV protease inhibitor clinical trials.

Hepatitis C virus (HCV) infection affects millions of people world-wide, and chronic infection can result in end-stage liver disease and hepatocellular carcinoma. Conventional therapy to date has involved combination antiviral therapy including alpha-interferon and ribavirin; response rates with these drugs are variable based on both viral and host factors, such as HCV viral load, HCV genotype, HIV co-infection, host genetic polymorphisms (such as those in the IL28B region), and other factors. Recent advances in HCV treatment have included pegylated forms of alpha-interferon and, more recently, the development of specifically targeted antiviral therapy for HCV (STAT-C) with novel HCV protease inhibitors (PIs) for genotype 1 HCV. Although unlikely to be administered as monotherapy due to the potential for development of HCV PI drug resistance mutations, results of phase II trials of two PIs in development have recently been reported, demonstrating promising therapeutic efficacy of HCV PIs in combination with established conventional treatment. This review outlines the advances and the challenges in the development of these HCV PIs as effective HCV antiviral agents and their role in clinical practice.