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.