Early virologic response and IL28B polymorphisms in patients with chronic hepatitis C genotype 3 treated with peginterferon alfa-2a and ribavirin.

ABSTRACT

BACKGROUND & AIMS: Polymorphisms of the IL28B gene (rs12979860 and rs8099917) are associated with high sustained virological response (SVR) rates in HCV genotype 1 patients. This study analyzes the impact of these IL28B polymorphisms on early treatment response (weeks 2 and 4) and SVR in HCV genotype 3 patients. METHODS: rs12979860 and rs8099917 were analyzed by the Step-OnePlus Real-time PCR system in 71 out of 72 Caucasian HCV genotype 3 patients participating, at our center, in a randomized study comparing 400mg with 800 mg ribavirin/day. HCV RNA was determined at weeks 2 and 4 of 180 µg/week peginterferon alfa-2a/ribavirin treatment. Sixty-nine patients completed the treatment and follow-up. RESULTS: rs12979860 genotyping revealed that 27 (37.5%) patients had C/C, 39 (54.2%) T/C, and 5 (6.9%) T/T. Thirteen patients (18.1%) became HCV RNA negative at week 2 and an additional 30 (41.7%) at week 4 (rapid virologic response; RVR); thus a total of 43 had a RVR (C/C 77.8%; T/C or T/T 50.0%). Irrespective of the ribavirin dose, the viral load decline was larger than in those with the T allele (T/C or T/T) (week 2 4.46; [0.36-6.02] median; [range] vs. 3.50; [0.14-5.62]; log IU HCV-RNA/ml; p<0.001; week 4 4.97; [1.21-6.20] vs. 4.49; [1.16-6.23]; p=0.003). Despite the faster initial viral response in C/C carriers, SVR rates were not different compared to T-allele carriers. Results of the SNP in the rs8099917 region were similar. CONCLUSIONS: IL28B polymorphisms modulate early virologic response to peginterferon/ribavirin treatment. In contrast to HCV genotype 1 patients, no effect on SVR rates was observed in genotype 3 patients. The clinical relevance of an earlier viral decline in C/C patients needs to be determined.