Differences in virological response to peginterferon-α plus ribavirin in HIV-positive patients coinfected with HCV subtypes 1a or 1b.

BACKGROUND: Both viral and host factors influence response to peginterferon-α plus ribavirin (pegIFNα/RBV) in patients with chronic hepatitis C. The impact of these variables is more pronounced in HIV/Hepatitis C virus (HCV)-coinfected individuals, in whom treatment response rates are lower.

METHODS: Virological responses at multiple time points were assessed in all HIV/HCV-coinfected patients that completed a first course of pegIFNα/RBV. Viral responses were stratified by HCV geno/subtypes and IL28B rs12979860 variants.

RESULTS: A total of 331 HIV/HCV-coinfected patients were analyzed. HCV geno/subtype distribution was as follows: HCV-1a in 97, HCV-1b in 62, HCV-3 in 122, and HCV-4 in 50. Age, gender, CD4 counts, plasma HIV RNA and liver fibrosis stage did not differ significantly across HCV geno/subtypes. In contrast, mean serum HCV RNA was greater in HCV-1a compared with the rest (P < 0.0001). The proportion of IL28B CC variants was higher in HCV-3 compared with the rest (P = 0.001). Virological responses were better in HCV-1b than HCV-1a at any given time point during therapy. IL28B variants significantly influenced virological responses across all HCV-1 subtypes, with the strongest effect seen in HCV-1a. In a multivariate linear regression analysis, both HCV-1b and IL28B CC variants were significantly associated with greater HCV RNA drops at weeks 4 (R = 0.52, p < 0.0001) and 12 (R = 0.49, P < 0.0001) of therapy.

CONCLUSIONS: The response to pegIFNα/RBV therapy is lower in HCV-1a than HCV-1b in HIV/HCV-coinfected patients. The strongest influence of IL28B variants is seen in HCV-1a. This information may be relevant when using most directly acting antivirals in coinfected patients along with pegIFNα/RBV, given that selection of drug resistance occurs more frequently in HCV-1a than HCV-1b.