3. (For Cohort 1 only) Therapy-naïve to interferon, pegylated interferon, and ribavirin (For Cohort 2 only) Confirmed prior virological failure (null response, partial response, breakthrough or relapse) with an approved dose of PegIFN alfa/RBV or IFN beta/RBV for at least 12 weeks and with an 8-week washout period before screening