Purpose / DescriptionThis multicenter, phase 3, randomized, double-blind trial used a 2 x 2 factorial design to examine the efficacy of 24 versus 48 weeks of peginterferon alfa-2a plus ribavirin, as well as the difference between fixed low dose (800 mg/day) versus weight-based (1000 or 1200 mg/day) dosing of ribavirin in patients with chronic HCV infection. Investigators enrolled 1311 patients, among whom 740 had genotype 1 infection. In patients with genotype 1, significantly higher SVR24 rates were observed with weight-based ribavirin dosing (compared with fixed low dose ribavirin) and with 48 versus 24 weeks of therapy. Among patients with genotypes 2 or 3 infection, ribavirin dosing and duration of therapy did not significantly affect SVR rates. This study clearly demonstrated that treatment of genotype 1 HCV with peginterferon alfa-2a plus ribavirin generates significantly higher SVR24 rates when higher doses of ribavirin are used and patients receive a longer treatment duration.