This study is designed to assess the safety and tolerability of boceprevir dosed 800 mg three times daily (TID) orally (PO) in combination with Peginterferon alfa-2b (PEG2b) 1.5 mcg/kg once a week (QW) administered subcutaneously (SC) plus ribavirin (RBV) (800 to 1400 mg/day) PO in Response Guided Therapy (RGT) in adult Vietnamese subjects with Chronic Hepatitis C, Genotype 1 (CHC GT1) who failed prior treatment with any interferon and ribavirin in Vietnam.

Each participant will participate in the trial for a maximum of 80 weeks from the time the participant signs the Informed Consent Form (ICF) through the final contact. After a Screening phase of approximately 4 to 8 weeks, each participant will receive treatment for approximately 36-48 weeks depending on response at Treatment Week 8.

A 4-week lead-in period with PEG2b plus RBV will be followed by 32 weeks boceprevir plus PEG2b/RBV. At treatment Week 36 participants will be assigned to the following treatments depending on the virologic response at Week 8 and cirrhotic status:

1. For non-cirrhotic participants with undetectable hepatitis C virus (HCV)-RNA on Week 8, all treatment will be discontinued at Week 36.
2. For non-cirrhotic participants with detectable HCV-RNA on Week 8, only boceprevir treatment will be discontinued at Week 36 and PEG2b and RBV treatment will continue to Week 48.
3. For cirrhotic participants, the boceprevir plus PEG2b/RBV treatment will continue to Week 48.

The study has a futility rule at Week 12 at which point all subjects with detectable HCV-RNA levels will be discontinued. All participants will have a post-treatment follow-up period of at least 24 weeks.

Inclusion Criteria:

• Weight ≥ 40 kg to ≤ 125 kg
• Sexually active male participants and female participants of child-bearing potential must agree to use a medically acceptable form of contraception
• Must have documented Chronic Hepatitis C Genotype 1 infection
• Must have failed prior treatment with interferon plus ribavirin
• Must have completed treatment with interferon plus ribavirin for at least 12 weeks
• Must have had a liver biopsy or Fibroscan to determine status as cirrhotic or non-cirrhotic
• Participants with cirrhosis must have had an ultrasound or imaging study within 6 months of the Screening visit

Exclusion Criteria:

• Known co-infection with the human immunodeficiency virus (HIV) or the hepatitis B virus
• Prior discontinuation of treatment with interferon or ribavirin due to the occurrence of an adverse event(s) considered by the investigator to be possibly or probably related to the treatment
• Treatment with ribavirin within 90 days and any interferon within 1 month of the Screening visit
• Treatment with any investigational drug within 30 days prior to the Screening visit
• Treatment with midazolam, pimozide, amiodarone, flecainide, propafenone, quinidine, or ergot derivatives within 2 weeks prior to the Day 1 visit
• Participation in any investigational trial within 30 days of the Screening visit
• Evidence of decompensated liver disease
• Child Pugh score > 6 (Class B and C)
• Diabetic and/or hypertensive participants with clinically significant ocular examination findings
• Pre-existing psychiatric conditions
• Clinical diagnosis of substance abuse
• Active or suspected malignancy
• Pregnant or nursing