This is a research study to evaluate the safety, tolerability and anti-viral activity of GS-9669 in patients with Hepatitis C infection.

Inclusion Criteria:

• Adult subjects 18-65 years of old, inclusive
• Documented chronic HCV infection to be of at least 6 months duration and plasma HCV RNA ≥ 5 log10 IU/mL at screening.
• HCV treatment naïve or PEG-IFN, IFN, and/or RBV experienced (treatment must have ceased at least 3 months prior to screening). Treatment experienced subjects should not exceed 40% of the subjects enrolled in each cohort
• Mono-infection with HCV genotype 1a for Cohorts 1, 2, 3, 4, and 5 and mono-infection with HCV genotype 1b for Cohort 6 and 7.
• Estimated creatinine clearance ≥ 70 mL/min,
• QTcF interval ≤ 450 msec for males and ≤ 470 msec for females, QRS duration < 120 msec, PR interval < 220 msec,
• Body mass index (BMI) of 19.0 to 34.0 kg/m^2, inclusive.

Exclusion Criteria:

• Urine drug screen positive for illicit/illegal drugs
• ALT and AST levels > 5 times the upper limit of the normal range (ULN)
• Direct bilirubin > ULN, clinical or other laboratory evidence of hepatic decompensation (i.e., platelets < 90,000/mm^3, prothrombin time ≥ 1.5 × ULN and albumin < 3.5 g/dL) are not eligible for study participation.
• Subjects with an absolute neutrophil count (ANC) < 1,000 cells/mm^3 (< 750 cells/mm^3 for black or African-American subjects), hemoglobin (Hb) < 11 g/dL,
• Coinfected with hepatitis B virus (HBV), human immunodeficiency virus (HIV), or another HCV genotype other than genotype 1a/b are not eligible for study participation.
• Evidence of hepatocellular carcinoma (e.g., a-fetoprotein > 50 ng/mL or as indicated by recent ultrasound or other standard of care measure)
• History of significant cardiac disease. The following ECG abnormalities at screening are exclusionary: QTcF (QT corrected using Fridericia's formula=QT/RR^0.333) > 450 msec for males and > 470 for females; QRS > 120 msec (left or right hemiblock is not exclusionary); PR interval > 220 msec; bradycardia (< 45 beats per minute); second or third degree heart block.
• History of clinically-significant illness or any other major medical disorder that may interfere with subject treatment, assessment or compliance with the protocol
• History of a primary gastrointestinal disorder that could interfere with the absorption of the study drug or that could interfere with normal gastrointestinal anatomy or motility