A Study of Response-Guided Duration of Combination Therapy With GS-9190, GS-9256, Pegasys® and Copegus® in Previously Untreated Subjects With Genotype 1 Chronic Hepatitis C

Inclusion Criteria: * Adult subjects 18 to 70 years of age * Chronic HCV infection for at least 6 months prior to Baseline (Day 1) * Liver biopsy results (performed no more than 2 years prior to Screening) indicating the absence of cirrhosis * Monoinfection with HCV genotype 1a or 1b * HCV treatment-naïve * Body mass index (BMI) between 18 and 36 kg/m2 * Creatinine clearance \>/= 50 mL/min * Subject agrees to use highly effective contraception methods if female of childbearing potential or sexually active male. * Screening laboratory values within defined thresholds for ALT, AST, leukopenia, neutropenia, anemia, thrombocytopenia, thyroid stimulating hormone (TSH), potassium, magnesium Exclusion Criteria: * Autoimmune disease * Decompensated liver disease or cirrhosis * Poorly controlled diabetes mellitus * Severe psychiatric illness * Severe chronic obstructive pulmonary disease (COPD) * Serological evidence of co-infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or another HCV genotype * Suspicion of hepatocellular carcinoma or other malignancy (with exception of certain skin cancers) * History of hemoglobinopathy * Known retinal disease * Subjects who are immunosuppressed * Subjects with known, current use of amphetamines, cocaine, opiates (i.e., morphine, heroin), methadone, or ongoing alcohol abuse * Subjects who are on or are expected to be on a potent cytochrome P450 (CYP) 3A4 or Pgp inhibitor, or a QT prolonging medication within 2 weeks of Baseline (Day 1) or during the study * Subjects must have no history of clinically significant cardiac disease, including a family history of Long QT syndrome, and no relevant electrocardiogram (ECG) abnormalities at screening