A Study of Pegasys (Peginterferon Alfa-2a) Administered Alone or in Combination With Copegus (Ribavirin) in Patients With Chronic Hepatitis C Who Have Participated in Previous Pegasys Trials

Inclusion Criteria: * Adult patients, ≥ 18 years of age. * Chronic hepatitis C. * Compensated liver disease (Child-Pugh Class A). * Previous participation in a donor protocol in which treatment or re-treatment with Pegasys alone or in combination with Copegus was recommended or deemed appropriate after study completion. * Have completed safety and efficacy assessments as defined in the donor protocol without violation or any major deviation. * Have not received any other anti-hepatitis C virus treatment after the completion of the donor protocol. * For females of childbearing potential, a negative pregnancy test within 24 hours prior to first dose of study drug. * Fertile patients (male and female) must use 2 reliable forms of contraception (combined) for the duration of the study (treatment and follow-up) in accordance with the locally approved label for Copegus. Exclusion Criteria: * Pregnant or breastfeeding women. * Male partners of women who are pregnant. * Patients with hemoglobinopathies. * Hepatic decompensation (Child-Pugh Class B or C) before or during treatment. * Non-responder patients (defined as patients previously treated with Pegasys and Copegus combination therapy at standard doses for at least 12 weeks who did not achieve at least a 2-log drop from their baseline viral load). * Liver disease other than chronic hepatitis C, including hepatic carcinoma.