- Virological failure following a previous treatment of at least 12 weeks by peginterferon alpha-2a ≥ 135 µg once weekly or peginterferon alpha-2b ≥ 1.0 µg per kg once weekly + ribavirin ≥ 600 mg once daily. Virological failure defined by persistence of a detectable HCV-RNA, with the same genotype than before. Null responder patient, with less than 2 Log10 HCV-RNA decline at week 12 with cirrhosis are excluded from the study. Null responder patients without cirrhosis (equal or below METAVIR F3) are limited to less than 30 % of all patients included