Hepatitis C: therapeutic perspectives

Continuous efforts are vital to develop new treatment strategies to improve sustained response rates, especially for difficult to treat patients infected with the hepatitis C virus. Despite the introduction of ribavirin, more than 50% of the patients do not eliminate the virus with the current standard therapy of interferon-a (IFN) and ribavirin. Options to further enhance response rates include modification of the IFN-dosing schedule with daily dosing of IFN, new IFN such as consensus interferon or modified IFN with longer half-life and more favourable pharmacokinetics such as pegylated IFN (PEG-IFN). Clinical trials with new IFN showed that consensus IFN may improve response rates in unsuccessfully pre-treated patients and patients with HCV-genotype-1. Treatments with PEG-IFN will double response rates achieved with standard IFN monotherapy. The combination of PEG-IFN and ribavirin improves the virological response to more than 50% and even to more than 80% in patients with genotype 2 or 3. By now, standard therapy of chronic hepatitis C has been changed to the combination of PEG-IFN plus ribavirin. Future anti-viral drugs may comprise molecules that directly inhibit HCV proteins and interfere with viral replication. NS3/4A serine protease, ribonucleic acid (RNA) helicase, RNA-dependent RNA polymerase may be potential targets for new drugs. Furthermore antisense oligonucleotides or ribozymes may become new treatment options to inhibit HCV replication. Finally, immunotherapies to enhance HCV-specific immune responses are also attractive strategies to control HCV infection and to prevent chronic liver disease.