Study Comparing the Tolerability and Viral Reduction of the Combination of IFN a-2b XL + Ribavirin Versus Peg IFN a-2b + Ribavirin in Patients With Chronic Hepatitis C, Genotype 1 or 4

Inclusion Criteria: * Patient having voluntarily signed the Informed Consent Form prior to any study specific procedure being performed * Male or female HCV genotype 1 or 4 infected patients (positive serum HCV RNA), aged between 18 and 65 years inclusive, with a body mass within the range over or equal of 45Kg and below or equal to 100 Kg * Patient being either naïve to therapy, either non-responder to previous standard Peg-interferon α + ribavirin therapy, * With no absolute contra-indication to interferon α or ribavirin * Female patients must be non-lactating and of non-childbearing potential, or have a negative pregnancy test results to enter the study * No evidence of acute or advanced liver disease, uncontrolled diabetes, cardiovascular, immunological, or thyroid disease, and no recently diagnosed malignancy * Vital signs within normal ranges, or if outside the normal ranges, not deemed clinically significant in the opinion of the Investigator. An ECG with no clinically significant abnormalities Exclusion Criteria: * History of solid organ transplantation * Severe systemic infection, uncontrolled diabetes, cancers, associated liver disease * General anesthesia or recent blood transfusion