Aim: The optimal ribavirin dose in the treatment of patients infected with hepatitis C virus (HCV) genotype 2 remains to be elucidated. We aimed to seek the optimal ribavirin dose required for this genotype in a randomized trial.
Methods: We compared the efficacy and tolerability of the 24-week peginterferon α-2b (1.5 µg/kg/week) therapy in combination with a weight-based higher dose (600-1000 mg) and lower dose (400-800 mg) of ribavirin for genotype 2 patients. Noninferior margin was set at 10%.
Results: A total of 120 patients were randomized to a higher-dose or a lower-dose group. Sustained virological response (SVR) by intention-to-treat analysis was achieved in 47/58 (81.0%, 90% confidential interval [CI]: 72.6-89.5) patients in the higher-dose group and 41/60 (68.3%, 90% CI: 58.5-78.2) patients in the lower-dose group (difference, -12.7%; 90% CI, -25.7 to 0.3). Relapse rates were 10% and 21.6% in the higher-dose and the lower-dose groups, respectively. Multiple logistic regression analysis showed that ribavirin dose/kg body weight was the only significant predictor of SVR (≥9.5 mg/kg per day vs <9.5 mg/kg per day; odds ratio = 3.34; 95% CI, 1.41-7.92; P = 0.006). Twenty-one (36.2%) in the higher-dose group required ribavirin dose reduction because of anemia, whereas seven patients (11.7%) did in the lower-dose group (P < 0.01). Three of the higher-dose group and two of the lower-dose group required premature termination of therapy.
Conclusions: Weight-based lower-dose ribavirin regimen was not equivalent to the higher-dose counterpart in the treatment of HCV genotype 2. We discourage treating these patients with low-dose ribavirin regimens. The peginterferon therapy in combination with ribavirin at a weight-based higher dose (600-1000 mg) remains the standard-of-care treatment for this genotype.
© 2011 The Japan Society of Hepatology.