The IL28B effect on hepatitis C virus kinetics among HIV patients after the first weeks of pegylated-interferon/ribavirin treatment varies according to hepatitis C virus-1 subtype.

Objective: To evaluate the IL28B effect on hepatitis C virus (HCV) decline during first weeks of treatment according to HCV-1 subtypes.

Methods: Patients coinfected with HIV/HCV genotype 1 and naive to peginterferon-alpha-2a and ribavirin (Peg-IFN-alpha-2a/RBV) were included. Plasma HCV-RNA was measured at baseline, and then at weeks 1, 2, and 4. HCV-1 subtype (1a or 1b) was determined. HCV viral decline was analyzed according to HCV-1 subtype between baseline and week 1, week 2 and week 4 of treatment. Additionally, we analyzed the effect of the IL28B (rs12979860) genotype on HCV viral decline with HCV-1a and HCV-1b genotype patients (CC versus non-CC).

Results: Two hundred and six patients were included in the study, of whom 113 (54.8%) and 93 (45.2%) were infected by HCV-1a and 1b genotypes, respectively. No differences were found between HCV-1 subtypes in terms of HCV viral decline or rapid virological response rate. The effect of the IL28B-CC genotype on HCV viral decline was observed only among patients infected with HCV-1b at all time points analyzed (week 1: CC 1.53 ± 0.33, non-CC 0.27 ± 0.24, P <0.001; week 2: CC 1.81 ± 0.39, non-CC 0.74 ± 0.39, P = 0.002; week 4: CC 2.97 ± 0.53, non-CC 1.2 ± 0.61, P < 0.001).

Conclusion: Our study suggests that the effect associated with the impact of the IL28B-CC genotype on HCV decline during the first weeks of treatment with Peg-IFN-alpha-2a/RBV differs according to HCV-1 subtype and may be limited to HCV-1b patients.