We evaluated the safety and efficacy of an escalating dose regimen of pegylated interferon alpha-2a (PEG-IFN(alpha-2a)) and ribavirin in the early phase of recurrent hepatitis C after orthotopic liver transplantation (OLT). In this prospective study, 26 patients transplanted for hepatitis C virus cirrhosis with recurrent hepatitis C were treated 3.4 +/- 3.6 months after OLT and compared with an untreated historical control. PEG-IFN(alpha-2a) was initiated as monotherapy, following stepwise dose escalation up to 180 mug/week and the addition of ribavirin up to 1200 mg/day or maximally tolerated doses for 48 weeks. In the intent-to-treat analysis, 38% showed an early virological response (EVR), 35% an end of treatment response (ETR) and 19% a sustained virological response (SVR). SVR was associated with EVR (P = 0.0001) and cumulative PEG-IFN(alpha-2a) dose (P = 0.04). There was no significant histological improvement compared with untreated patients. There were no treatment-related serious adverse events. Adverse events included leucopenia (77%) and thrombocytopenia (46%). Three patients discontinued therapy due to side effects, fourteen were nonresponders and four relapsers. Treatment with PEG-IFN(alpha-2a) and ribavirin in the acute phase of post-transplant recurrent hepatitis C yielded an EVR of 38% and an SVR of 19%. The combination was safe and well tolerated.