The optimal ribavirin dose for patients infected with hepatitis C virus genotype 3: should we utilize more?

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.

Randomized study of peginterferon-alpha2a plus ribavirin vs peginterferon-alpha2b plus ribavirin in chronic hepatitis C

BACKGROUND & AIMS

Ribavirin (RBV) combined with either pegylated interferon (PegIFN) alpha2a or PegIFNalpha2b is the standard of care for chronic hepatitis C virus (HCV) infection. Due to the lack of head-to-head studies, the 2 PegIFNs have not been directly compared. The endpoints of our study were safety and antiviral efficacy of the 2 regimens.

METHODS

Treatment-naïve patients with chronic hepatitis C were randomly (1:1) assigned after stratification for HCV genotype to receive either 1.5 mcg/Kg/week PegIFNalpha2b plus RBV 800-1200 mg/day or 180 mcg/week PegIFNalpha2a plus RBV 800-1200 mg/day for 24 or 48 weeks according to HCV genotype. The study was powered to detect a difference of at least 10% in safety and efficacy of the 2 regimens.

RESULTS

The 212 patients on PegIFNalpha2a and the 219 patients on PegIFNalpha2b had similar baseline characteristics, including cirrhosis (20% vs 18%, respectively). By intention to treat, the 2 groups showed similar rates of treatment-related serious adverse events (1% vs 1%, respectively) and drop out rates for adverse effects (7% vs 6%, respectively). Overall, sustained virologic response (SVR) rate was higher in PegIFNalpha2a than in PegIFNalpha2b patients (66% vs 54%, respectively, P = .02), being 48% vs 32% in the 222 HCV-1 and -4 patients (P = .04), and 96% vs 82%, respectively, in the 143 HCV-2 patients (P = .01). PegIFNalpha2a independently predicted SVR in the logistic regression analysis (odds ratio, 1.88; 95% confidence interval: 1.20-2.96).

CONCLUSIONS

Although the 2 regimens showed a similar safety profile, the PegIFNalpha2a-based treatment yielded significantly more SVR than PegIFNalpha2b.