Current and Future Therapy for Chronic Hepatitis C Virus Liver Disease

Therapy with recombinant human interferon alpha remains pivotal to the treatment for chronic hepatitis C virus liver disease. Semi-synthetic protein-polymer conjugates of interferon with polyethylene glycol have also been recently developed. These conjugates protect the protein from degradation; reduce the immunogenicity; and prolong exposure to drug by a sustained absorption, restricted volume of distribution and sustained high serum concentration. Therapy with pegylated interferons is associated with significantly greater sustained virological response rates (SVR) compared to the non-pegylated formulation. Ribavirin is a guanosine analog with minimal antiviral activity against HCV. It demonstrates significant clinical synergism when administered in combination with interferon. Amantadine blocks entry of influenza A virus into cells. Used in combination with ribavirin and interferon as triple therapy, it may have some benefit compared to dual or monotherapy. Current treatment with pegylated interferons combined with weight-based ribavirin, provides the highest sustained virological response rates. In the absence of suitable animal models, HCV dynamic studies in man have been helpful in defining the mechanisms of action of interferon in chronic HCV liver disease. Novel therapeutic agents are being developed as the replication cycle of HCV is being understood. However, their safety and efficacy remain to be established and availability for clinical use is unlikely within the next 3 to 5 years. This review describes current antiviral therapy in chronic HCV liver disease, addresses the potential role of viral dynamics in elucidating the mechanisms of action of the drugs and discusses future potential therapeutics agents.