Dose comparison study of pegylated interferon-alpha-2b plus ribavirin in naïve Japanese patients with hepatitis C virus genotype 2: a randomized clinical trial.

To compare the efficacy and safety of pegylated interferon (PEG-I) at 1 and 1.5 mu g/kg, and in combination with ribavirin (RBV) for 24 weeks in naive Japanese patients infected with hepatitis C virus genotype 2. The present study was an open-label, randomized trial of 55 patients receiving PEG-I (1 or 1.5 mu g/kg body weight [BW], subcutaneously, once a week) and RBV for 24 weeks. The patients were followed up for 24 weeks without treatment. The intention-to-treat analyses showed that the proportion of patients with a sustained virological response (SVR) in the 1-mu g/kg PEG-I-RBV group (38.5%, 10/26) was lower than that of the 1.5-mu g/kg PEG-I-RBV group (74.1%, 20/27; P = 0.013). The PEG-I dose was reduced in two of the 26 patients of the 1-mu g/kg PEG-I-RBV group (one because of thrombocytopenia at 2 weeks, and one because of generalized fatigue at 20 weeks), and four of the 27 patients of the 1.5-mu g/kg PEG-I-RBV group (one because of neutropenia at 20 weeks, and three because of generalized fatigue at 1, 5, and 8 weeks). The multivariate analysis identified age (< 60 years) and dose of PEG-I (1.5 mu g/kg) as significant determinants of SVR. The dose of PEG-I to be used at the start of therapy should be 1.5-mu g/kg BW in naive Japanese patients infected with hepatitis C virus genotype 2.