The purpose of this study is to determine if 48 weeks of therapy with Pegylated Interferon Lambda plus Ribavirin is effective and safe for a treatment of chronic hepatitis C (CHC) compared to therapy with Pegylated Interferon Alfa-2a plus Ribavirin.

Inclusion Criteria:

• Chronic hepatitis C, Genotype 1 or 4
• HCV Ribonucleic acid (RNA) ≥ 100,000 IU/mL at screening
• Liver biopsy documenting no cirrhosis (within prior 2 years) or cirrhosis (from any time prior to randomization). Where approved for staging of liver disease, non-invasive imaging may be used to assess the extent of liver disease. Subjects with compensated cirrhosis can enroll and will be capped at 10%
• Naive to prior anti-HCV therapy

Exclusion Criteria:

• Infected with HCV other than Genotype 1 or 4
• Positive Hepatitis B surface antigen (HBsAg), or Human immunodeficiency virus-1 (HIV-1)/HIV-2 antibody or hepatitis D virus (HDV) at screening
• Evidence of liver disease other than HCV
• Active substance abuse
• Use of hematologic growth factors within 90 days prior to study randomization
• Evidence of decompensated cirrhosis based on radiologic criteria or biopsy results and clinical criteria