Hyporesponsiveness to PegIFNα2B plus ribavirin in patients with hepatitis C-related advanced fibrosis.
BACKGROUND & AIMS
The success of pegylated-interferon (PegIFN)/ribavirin (Rbv) therapy of chronic hepatitis C is compromised by liver fibrosis. Whether fibrosis equally affects the two PegIFNα-based therapies is unknown. To assess the response to the two PegIFN regimens in patients with different degree of liver fibrosis.


METHODS
A sub-analysis of the MIST study: 431 consecutive naïve patients randomly assigned, based on HCV genotype, to receive either (A) PegIFNα2a 180 μg/wk plus daily Rbv 800-1200 mg or (B) PegIFNα2b 1.5 μg/kg/week plus daily Rbv 800-1200 mg, were stratified according to Ishak staging (S) into mild (S0-S2) or moderate (S3, S4) fibrosis and cirrhosis (S5, S6).


RESULTS
In A the sustained virological response (SVR) rates were not significantly influenced by fibrosis stage (71% in S0-S2, 66% in S3, S4, 53% in S5, S6, p=0.12), compared to B where the SVR rates differed according to fibrosis stage (65%, 46%, and 38%, p=0.004, respectively). This was even more so in HCV-1/4 patients treated with PegIFNα2b where the SVR rates were twice as many in S0-S2 vs. S≥3 (44% vs. 22%, p=0.02), while in A the SVR rates were similar between the two fibrosis subgroups (S0-S2: 47% vs. S≥3: 48%, p=0.8). By logistic regression analysis genotype 1/4 and lack of rapid virological response were independent predictors of treatment failure in both treatment groups, while S≥3 fibrosis was associated to PegIFNα2b treatment failure, only (OR 2.83, 95% CI 1.4-5.68, p=0.004).


CONCLUSIONS
Liver fibrosis was an independent moderator of treatment outcome in patients receiving PegIFNα2b, not in those receiving PegIFNα2a.