The purpose of this study is, to assess whether EDP239 can reduce the HCV viral load in HCV gentotype-1 in chronically infected subjects and to further evaluate the safety profile of EDP239.

Inclusion Criteria:

• Subjects must have chronic genotype-1 hepatitis C virus infection and plasma HCV-RNA ≥ 105 IU/mL at the time of screening.
• Subjects must have chronic HCV infection as determined by any of the following:
• be anti-HCV (+) for at least 6 months per subject history or medical records
• an anti-HCV test, viral load, or genotype > 6 months ago
• In the setting of a recent positive anti-HCV test (< 6 months), liver biopsy demonstrating chronicity
• Subjects must have IL-28b genotype "CC"
• Subjects must weigh at least 50 kg to participate in the study, and must have a body mass index (BMI) within the range of 18 - 36 kg/m2. BMI = Body weight (kg) / [Height (m)]2

Exclusion Criteria:

• Use of other investigational drugs at the time of enrollment, or within 5 half-lives of enrollment, or within 30 days (for small molecules) whichever is longer; or longer if required by local regulations.
• Previous treatment, including the use of any investigational agents, for the treatment of HCV infection.
• Women of child bearing potential.
• Subjects with IL-28b genotype "CT or TT".
• ALT γ-GT, and AST must be below 5 x the upper limit of normal (ULN).
• Serum bilirubin must not exceed ULN.
• The PT (INR) must be within normal limits.
• If necessary, laboratory testing may be repeated on one occasion (as soon as possible) prior to randomization, to rule out any laboratory error.
• Use of drugs that inhibit or induce CYP3A4.