The primary purpose of this study is to evaluate the safety, tolerability, pharmacokinetics and activity of escalating, multiple, oral doses of GS-5885 in subjects with chronic genotype 1 Hepatitis C Virus (HCV) infection. Each participant in the study will be sequestered in the clinic for the initial 5 days of the study.

Inclusion Criteria:

• Chronically infected with HCV genotype 1
• HCV treatment-naïve
• Not co-infected with HIV or HBV
• HCV RNA viral load of at least 100,000 IU/mL
• BMI 19 to 35 kg/m2
• Subject agrees to use highly effective contraception methods if female of childbearing potential or sexually active male.

Exclusion Criteria:

• History of clinically-significant illness or any other major medical disorder that may interfere with subject treatment, assessment or compliance with the protocol
• Decompensated liver disease or cirrhosis or evidence of hepatocellular carcinoma
• Serological evidence of co-infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or another HCV genotype
• Subjects with known, current use of amphetamines and/or cocaine; subjects taking methadone or buprenorphine (opioid replacement therapy) or ongoing alcohol abuse