Background/aims: The aim of the present, open-labelled, controlled study was to determine whether 5 MU of interferon (IFN) alpha 2b combined with a standard dose of ribavirin might increase the rate of viral clearance in all patients with chronic HCV hepatitis or at least in those with an unfavourable genotype.
Methods: A total of 298 previously untreated patients with chronic hepatitis C were randomized to 5 or 3 MU of interferon alpha 2b 3 times per week with 1000-1200 mg of ribavirin daily (148 and 150 patients, respectively). Patients were treated for 12 months and observed for 6 months posttreatment.
Results: In patients infected with HCV genotype 1, the sustained virologic response was 37.8% (95% CI 27.3-48.1) with IFN 5 MU and 19.2% (95% CI 10.1-28.2) with IFN 3 MU (P=0.008). Out of 45 sustained responders with genotype 1, 31 (69%) had received 5 MU and 14 (31.1%) the standard 3 MU dose of IFN in combination with ribavirin (P=0.01). Of the 86 responders infected with genotype non-1, 39 (45.3%) were from the 5 MU IFN group and 47 (54.6%) were from the 3 MU IFN group; these figures were not significant. At the multivariate analysis of baseline features for all patients, the variables with an independent effect for a sustained response were genotype non-1 (odds ratio (OR) 3.98, 95% CI 2.36-6.40), and the histological grading (score 0-2) (OR 2.48, 95% CI 1.12-5.51) and staging (score 0-1) (OR 1.73, 95% CI 1.02-2.95). For patients with genotype 1 only the high regimen of IFN entered the model (OR 2.39, 95% CI 1.13-5.05), whereas for patients with genotype non-1 an age of <40 years (OR 2.64, 95% CI 1.23-5.70) and staging (score 0-1) (OR 2.38, 95% CI 1.07-5.28) were independent predictors of a sustained response.
Conclusions: Our study suggests that when treating naive patients with genotype 1, there is a significant increase in the rate of sustained virologic clearance by increasing the dose of IFN given in combination with ribavirin.