Effect of treatment with interferon alpha-2b and ribavirin in patients infected with genotype 2 hepatitis C virus.

Aim: Nearly 20% of chronic hepatitis C (CHC) patients with genotype 2 hepatitis C virus (HCV) infection are not curable, even by interferon (IFN)-ribavirin combination therapy. The aim of this study is to investigate the factors that determine the efficacy of combination therapy in patients with genotype 2 HCV infection. Methods: Fifty patients with CHC who underwent a treatment of 6 MU IFN alpha-2b with ribavirin for 24 weeks were retrospectively analyzed. Results: All the patients showed no serum HCV-RNA within 12 weeks after starting the therapy. Forty-one of the 50 patients (82%) achieved a sustained virological response (SVR). The age, sex, genotype (2a vs. 2b) and grade/stage of the liver by histopathology and pretreatment viral load werenot different between the sustained responders and relapsers. Univariate analysis showed that an earlier viral clearance from blood and a larger number of amino acid substitutions in the interferon sensitivity determining region (ISDR) were predictors of SVR. Multivariate analysis showed that a large number of amino acid substitutions in the ISDR was a predictor of SVR. Conclusion: The characterization of the amino acid sequences of ISDR may be helpful for predicting a relapse after combination therapy in patients with genotype 2 HCV infection.