Ribavirin dosage in patients with HCV genotypes 2 and 3 who completed short therapy with peg-interferon alpha-2b and ribavirin.

BACKGROUND: The optimal dose of ribavirin to be used in combination with Peg-IFN in patients with HCV genotypes 2 and 3 undergoing short treatment has not been established. AIM: To explore the relationship between starting ribavirin doses, expressed as mg/kg body weight and both rapid viral response at treatment week 4 (RVR) and sustained virological response (SVR) in patients treated for 12-14 weeks with peg-interferon alpha-2b and ribavirin. METHODS: A post hoc analysis of data collected from two multicenter clinical trials was performed. Multiple regression analyses were employed to identify independent baseline and on-treatment predictors of RVR and SVR. For each dose of ribavirin, the empirical estimated probability of response was computed and the continuous exposure index was dichotomized by using a recursive partitioning and amalgamation method. RESULTS: A nonlinear relationship was ascertained between ribavirin dose and RVR, but not SVR. A dose of 15.2 mg/kg was selected as the best splitting value for discriminating RVR vs. non-RVR. Regression analysis identified low baseline viraemia, genotype 2 and high ribavirin dose as independent prognostic factors for RVR. The likelihood of an SVR was not correlated with baseline ribavirin dose, but was independently predicted by adherence to the full dose throughout treatment and normal platelet counts. CONCLUSIONS: Starting high ribavirin doses appears capable of increasing the rate of RVR in patients with HCV genotypes 2 and 3 undergoing short treatment. Maintenance of the full planned dose throughout treatment is essential for achieving optimal SVR rates.

A randomized controlled trial of pegylated interferon alpha-2a (40 KD) or interferon alpha-2a plus ribavirin and amantadine vs interferon alpha-2a and ribavirin in treatment-naïve patients with chronic hepatitis C.

We determined whether triple therapy comprising amantadine (AMA), ribavirin (RBV) and either peginterferon (PEG-IFN) alpha-2a or conventional IFN alpha-2a would improve sustained virological response (SVR) rates over dual therapy with IFN alpha-2a and RBV in patients with chronic HCV infection. A total of 362 treatment-naïve patients were randomized to 48 weeks of treatment with: PEG-IFN alpha-2a 180 microg/week (group A) or IFN alpha-2a 3 MU tiw (groups B and C). All patients received RBV 1000 or 1200 mg/day and those in groups A and B received AMA 200 mg/day. SVR was defined as an undetectable HCV RNA after 24 weeks of untreated follow-up. At the end of therapy, 74.4% (95% CI 0.66-0.82) of patients in group A were HCV RNA-negative compared with 42.5% (95% CI 0.33-0.50) of those in group B (P = 0.0001) and 48.8% (95% CI 0.40-0.56) of those in group C. SVR was achieved in a significantly greater proportion of patients in group A compared with groups B and C: 65.3% (95% CI 0.53-0.56), 33.3% (95% CI 0.25-0.41) and 44.6% (95% CI 0.36-0.53; P = 0.0001) respectively. In patients with genotype 1, SVR rates were 55.2, 22.8 and 28.8% with the three regimens respectively. Factors independently associated with SVR were HCV genotype 2 or 3, therapy with PEG-IFN, female gender and age. In treatment-naive patients with chronic hepatitis C, triple therapy with PEG-IFN alpha-2a, RBV and AMA produces higher SVR than dual or triple therapy with conventional IFN alpha-2a.

Efficacy of 5 MU of interferon in combination with ribavirin for naïve patients with chronic hepatitis C virus: a randomized controlled trial.

BACKGROUND: In chronic hepatitis C the schedule of interferon (IFN), 3 MU thrice weekly (tiw) plus ribavirin (1000-1200 mg/daily) needs further evaluation, as IFN dosages >3 MU achieve better responses. AIMS: To compare the efficacy of 5 MU tiw of IFN with (96 patients) or without ribavirin (96 patients) for 12 months in naïve patients, to evaluate the effect of baseline features on the response to therapy, and to determine a reliable point in time during treatment to predict non-response. RESULTS: Sustained virologic response was 20.8% (95% CI 13-29) with IFN monotherapy and 54.2% (95% CI 44-64) with combination (P = 0.0001), the relapse rate 39.4% (95% CI 23-56) and 9% (95% CI 1-16) (P = 0.0007), and the combined rate of sustained biochemical and virologic response 22.7% (95% CI 14-31) and 60.5% (95% CI 50-71) (P = 0.0001), respectively. Patients given combination therapy were more likely to respond regardless of baseline features. Apart from genotype non-1, predictive factors for IFN monotherapy were ineffective in predicting response to combination therapy. Using logistic regression analysis, IFN-ribavirin was the strongest predictor of response (X2 = 21.3; P = 0.0001). Viral persistence at month 3 of therapy was a more accurate predictor than aminotransferase values for non-response to IFN monotherapy but not to combination therapy (positive predictive values of 98 and 82%, respectively). CONCLUSION: In this study, 5 MU of IFN combined with a standard dose of ribavirin has yielded the highest rate of sustained response reported to date. Further dose finding studies are warranted.

A randomized trial of amantadine and interferon versus interferon alone as initial treatment for chronic hepatitis C.

The aim of this study was to compare, in an open-label study, the efficacy and safety of a combination of interferon (IFN) and amantadine (AMA) with that of IFN alone in previously untreated patients with chronic hepatitis C. A total of 200 patients were randomized to 6 MU of IFN-alpha2a 3 times per week, with 200 mg of AMA daily (n = 99) or to an identical dose of interferon alpha2a (n = 101). Patients were treated for 12 months and observed for 6 months' posttreatment. At the completion of treatment, 28.7% of patients in the monotherapy group and 45.5% in the combination group had a virologic response (P =.014). At 6 months' posttreatment, a sustained virologic response was observed in 16.8% (95% CI: 9-23) of patients with IFN alone versus 29.3% (95% CI: 19-37) of patients who were treated with combination therapy (P =.036). In each of the 2 treatments, genotype was the only predictive parameter for a sustained response. At the logistic regression analysis, therapy and genotype were the only 2 parameters with an independent predictive value. In the combination group, at examination of month 3, hepatitis C virus (HCV)-RNA status had a 97.6% (95% CI: 93-102) positive predictive value and a 50% (95% CI: 37-63) negative predictive value for a sustained virologic clearance. A substantial proportion of naïve patients with chronic hepatitis C have an end-of-treatment and end-of-follow-up virologic and biochemical response to a combination of IFN and AMA. This new treatment appears safe and well tolerated.