Different impact of IL28B polymorphisms on response to peginterferon-α plus ribavirin in HIV-positive patients infected with HCV subtypes 1a or 1b

Background: HCV subtype 1a has emerged as a predictor of poor response to triple hepatitis C therapy including boceprevir or telaprevir, which largely has been attributed to a lower resistance barrier in HCV-1a compared to -1b. Objectives: We examined whether a lower efficacy of pegIFN/RBV on HCV-1a than HCV-1b could alternatively contribute to explain it. Study design: All chronic hepatitis C patients who had completed a course of pegIFN/RBV therapy at our institution were examined. For this study we selected individuals that were IFN-naive and had been successfully subtyped as 1a or 1b. Moreover, only HIV-coinfected patients were included as they represented a more uniform population in terms of demographics and treatment exposure at our institution. The IL28B rs12979860 alleles were typed using the 5' nuclease assay. Results: A total of 96 individuals were examined, 58 of whom harbored HCV-1a and 38 HCV-1b. IL28B allele distribution was as follows: 33 CC and 63 CT/TT. SVR was achieved by 64% of CC vs 30% of CT/TT patients (p = 0.001). On the other hand, SVR was 53% in HCV-1b vs 34% in HCV-1a (p = 0.08). Interestingly, the effect of IL28B variants on SVR was mainly recognized in HCV-1a (63% in CC vs 20% in CT/TT; p = 0.001), being marginal on HCV-1b (64% in CC vs 46% in CT/TT; p = 0.27). Conclusions: The rate of SVR to pegIFN/RBV therapy tends to be lower in HIV-infected patients with chronic hepatitis C due to HCV-1a than HCV-1b; being the impact of IL28B variants significantly stronger on HCV-1a than HCV-1b. (C) 2012 Elsevier B. V. All rights reserved.