Sofosbuvir plus ribavirin for the treatment of hepatitis C virus genotype 2 in Korea: What's the optimal dosage of ribavirin in real-world setting?

Objective This study aimed to investigate the efficacy and safety of sofosbuvir plus ribavirin for the treatment of hepatitis C virus (HCV) genotype 2 infection and to determine the optimal ribavirin dosage. Methods From May 2016 to March 2017, 199 patients received sofosbuvir plus ribavirin treatment for HCV genotype 2 infection at four centers in Jeollanam-do Province, Korea. After excluding patients lost to follow-up and those with insufficient data, we retrospectively assessed the data for 194 patients. The treatment efficacy and safety of sofosbuvir plus ribavirin were evaluated. Results A sustained virological response was achieved in 189 patients (intention-to-treat [ITT] 97.4%; per protocol [PP]: 99.5%, both at 12 and 24 weeks) whose average ribavirin dosage was 937.1 mg/day. The most frequent adverse event was anemia (17.5%), and its incidence significantly increased (P < 0.001) with a higher ribavirin dosage per body weight. Discontinuation of ribavirin or dosage reduction occurred in 27 (14.2%). The ribavirin dosage reduction rate increased at a dosage of >15 mg/kg (area under the receiver operating characteristic curve 0.652, 95% confidence interval [CI] 0.54-0.76, P = 0.01). Multivariate analysis showed that age >= 70 years, with liver cirrhosis, and female gender were associated with ribavirin dosage reduction. Conclusions Remarkable outcomes were attained in patients with HCV genotype 2 infection treated with sofosbuvir plus ribavirin. Age >= 70 years, with liver cirrhosis, and female gender were associated with ribavirin dosage reduction. Thus, sustained virological response can be achieved with <1000 mg of ribavirin, with an optimal dosage of 15 mg/kg.