Side effects of combination therapy of peginterferon and ribavirin for chronic hepatitis-C.

Objective: The aim of this study was to elucidate the side effects after combination therapy of peginterferon and ribavirin for Japanese patients with chronic hepatitis C.
Methods: Inclusion criteria were HCV-genotype 1b and serum HCV RNA level of > 100 KIU/ml. Six hundred and twelve patients were received combination therapy and enrolled in this non-randomized prospective cohort study. Patients were monitored until the discontinuation of combination therapy based on treatment-related side effects. The percentage of each medication actually taken during treatment was calculated.
Results: Sixty-eight patients were stopped the combination therapy due to side effects. The cumulative discontinuation rate due to side effects of therapy was 8.4% at 0.5 year and 14.9% at one year. Discontinuation rate due to side effects was high with statistically significant in the following cases: 1) patients > or = 65 years, 2) patients who had diabetes. Sustained viral response (SVR) was 17.6% (12/68) in the discontinuation group. In the discontinuation group, when the percentage of both peginterferon and ribavirin actually taken during treatment was > or = 60%, SVR was 31% (9/29). On the other hand, when the percentage of each medication actually taken during treatment was < 60%, SVR was 7.7% (3/39). In the discontinuation group, patients with adherence of > 60% to the total of scheduled dose tended to have a high SVR compared to those with < or = 60% adherence to the total of scheduled dose.
Conclusion: In combination therapy, patient age and complications of patient are important factors contributing to the safety. In the discontinuation group, patients with adherence of > 60% to the total of scheduled dose tend to have a high SVR.