RIBAVIRN DOSAGE IN HCV GENOTYPES 2 AND 3 PATIENTS COMPLETING SHORT THERAPY WITH PEG-INTERFERON ALFA-2B AND RIBAVIRIN

Background. Optimal dose of ribavirin to be used in combination with Peg-IFN in HCV genotype 2/3 patients undergoing short treatment has not been established. Aim. To explore relationship between starting ribavirin doses and rapid [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 trials was performed. Multiple regression analyses 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 dichotomized by using a recursive partitioning and amalgamation method. Results. A non-linear relationship was ascertained between ribavirin dose and RVR but not SVR. Once selected 15.2 mg/kg as the best value for discriminating RVR versus non RVR, low baseline viremia, genotype 2, and high ribavirin dose were independent predictors of RVR. The likelihood of an SVR was not correlated with baseline ribavirin dose, but independently predicted by adherence to the full dose throughout treatment and normal platelet counts. Conclusions. High starting ribavirin doses increases rate of RVR in genotype 2/3 patients undergoing short treatment. Maintenance of full planned dose was essential for optimal SVR rates.