Randomized trial of peginterferon α-2a plus ribavirin versus peginterferon α-2b plus ribavirin for chronic hepatitis C in Japanese patients

Pegylated interferon (PegIFN) plus ribavirin is the standard therapy for patients with chronic hepatitis C genotype 1. Although several randomized clinical trials have compared PegIFN alpha-2a with PegIFN alpha-2b, these 2 regimens have not been directly compared in Asian patients. We, therefore, compared the safety and antiviral efficacy of these agents in Japanese patients. A total of 201 PegIFN-na < ve, chronic hepatitis C patients were randomly assigned to once-weekly PegIFN alpha-2a (180 mu g) or PegIFN alpha-2b (60-150 mu g) plus ribavirin. We compared the sustained virological response (SVR) rates between the 2 regimens and analyzed their effects in relation to baseline characteristics, including single nucleotide polymorphisms (SNPs) near the interleukin-28B (IL28B) gene (rs8099917). PegIFN alpha-2a was associated with a higher SVR rate than PegIFN alpha-2b (65.3 vs. 51.0%, P = 0.039). PegIFN alpha-2a and SNPs near IL28B independently predicted SVR (odds ratio 2.36; 95% confidence interval [CI] 1.19-15.50, and odds ratio 7.31; 95% CI 3.45-4.68, respectively) in logistic regression analysis. PegIFN alpha-2a was more effective than PegIFN alpha-2b (81.8 vs. 62.7%, P = 0.014) in IL28B TT genotype patients, despite similarly low SVR rates in patients with TG or GG genotypes (36.4 vs. 35.9%). Patients weighing < 60 kg, women, and patients aged > 60 years had significantly higher SVR rates with PegIFN alpha-2a than with PegIFN alpha-2b (63.9, 61.3, and 67.3% vs. 43.8, 43.3,and 39.2%, respectively). PegIFN alpha-2a plus ribavirin resulted in higher SVR rates than PegIFN alpha-2b plus ribavirin in Japanese patients. PegIFN alpha-2a-based treatment should therefore be the preferred choice for women, older or low-weight patients, and those with the IL28B TT genotype.