Japanese Pegylated Interferon (PegIFN) Alfa-2b/Ribavirin (RBV) Combination Trial

Inclusion criteria: 1. Chronic hepatitis C infection, diagnosed by positive anti-HCV antibodies and detected HCV RNA at screening in addition to: * positive anti-HCV antibodies or detected HCV RNA at least 6 months before screening; or, * liver biopsy consistent with chronic HCV infection. 2. HCV genotype 1 infection confirmed by genotypic testing at screening 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 4. HCV RNA = 100,000 IU/mL at screening 5. Documentation of a liver biopsy within 3 years or fibroscan within 6 months before randomization (Visit 2) 6. Age 20 to 70 years 7. Female patients who are infertile or who are of childbearing potential with a negative pregnancy test and agreeing to use one accepted method of birth control in addition to the use of a condom by their male partners. or Male patients who are infertile, who are without pregnant female partners or who consistently and correctly use condoms. 8. Signed informed consent form before trial participation Exclusion criteria: 1. HCV infection of mixed genotype (1/2, 1/3, and 1/4) diagnosed by genotypic testing at screening, 2. Evidence of acute or chronic liver disease due to causes other than chronic HCV infection. Steatosis diagnosed incidentally (e.g. by biopsy) without clinical relevance is not an exclusion criterion. 3. HIV co-infection, 4. Hepatitis B virus (HBV) infection based on presence of hepatitis B surface antigen (HBsAg), 5. Active malignancy, or history of malignancy within the last 5 years prior to screening (with an exception of appropriately treated basal cell carcinoma of the skin or in situ carcinoma of the uterine cervix), 6. Active or, history of alcohol or illicit drug abuse within the past 12 months, 7. A condition that is defined as one which in the opinion of investigator may put the patient at risk because of participation in this study, may influence the results of this study, or limit the patient's ability to participate in this study, 8. Usage of any investigational drugs within 30 days prior to screening, or planned usage of an investigational drug during the course of this study, 9. Received concomitant systemic antiviral, hematopoietic growth factor, or immunomodulatory treatment within 30 days prior to screening. Patients being treated with oral antivirals such as acyclovir, famciclovir or valacyclovir for recurrent herpes simplex infection; or with oseltamivir or zanamivir for influenza A infection, may be screened, 10. Received silymarin (milk thistle), glycyrrhizin (Stronger Neo-Minophagen C; SNMC), or Sho-saiko-to (SST) within 28 days prior to randomization (Visit 2) and throughout the treatment phase of this trial, 11. (For Cohort 2 only) Patients who have been previously treated with at least one dose of any antiviral or immunomodulatory drug other than (pegylated) interferon alfa, interferon beta or ribavirin for acute or chronic HCV infection including and not restricted to protease or polymerase inhibitors, 12. Known hypersensitivity to any ingredient of the study drugs, 13. Alpha fetoprotein value \>100 ng/mL at screening; if \>20 ng/mL and =100 ng/mL, patients may be included if there is no evidence of liver cancer in an appropriate imaging study (e.g., ultrasound, CT scan, or MRI) within last 6 months prior to randomization (Visit 2), Other exclusion criteria related to pegylated interferon and/or ribavirin restrictions are not listed here.