Abstract

Background and Aims: Two types of peginterferon, alpha-2a (PEG-IFN-alpha 2a) and 2b (PEG-IFN-alpha 2b), are approved for the treatment of hepatitis C infection. Several high-quality studies have compared the efficacy of these two types of interferon, but it seems that any of these trials had inadequate statistical power on their own to find even a tiny difference between these two medicines. We pooled the available data in the literature to find any small difference between these two medicines. Methods: In a systematic review of the literature, randomized controlled trials comparing the use of PEG-alpha 2a vs. 2b were assessed. The DerSimonian and Laird method was employed to run meta-analysis. The end points were virological responses. Results: In 7 randomized controlled trials, 3518 patients were randomized to receive PEG-IFN-alpha 2a + ribavirin (n=1762) or PEG-IFN-alpha 2b + ribavirin (n=1756). Early virological response (EVR), early treatment response (ETR), and sustained virological response (SVR) were greater for patients treated with PEG-IFN-alpha 2a. Odds Ratios (ORs) were 1.38 (95 confidence interval CI 1.11-1.71), 1.67 (95% CI 1.24-2.24), and 1.38 (95% CI 1.02-1.88) respectively. In the subset of naive patients with genotype 1/4 and 2, OFts of SVR were 1.38 (95% CI 1.02-1.88) and 4.06 (950/0 CI 1.67-9.86) respectively. PEG-IFN-alpha 2a had significantly higher rate of neutropenia OR=1.50 (95% CI 1.25-1.79) but pooled OR for withdrawal rates was not significant OR=0.78 (95% CI 0.47-1.29). Conclusions: PEG-IFN-alpha 2a with similar safety is more effective than PEG-IFN-alpha 2b. A longer duration of maximum serum concentration compared with PEG-IFN-alpha 2b (168 vs. 48-72 h.) yields a greater SVR and higher neutropenia in PEG-IFN-alpha 2a recipients.