This is a Phase 2 Randomized, Double-Blind, Placebo-Controlled Study of GS-5885, GS-9451, Tegobuvir and Ribavirin; GS-5885, GS-9451 and Tegobuvir; GS-5885, GS-9451 and Ribavirin in Interferon Ineligible or Intolerant Subjects with Chronic Genotype 1a or 1b HCV Infection.

Inclusion Criteria:

• Adult subjects 18 and older with chronic HCV infection
• Liver biopsy results (performed no more than 3 years prior to Screening) indicating the absence of cirrhosis
• Monoinfection with HCV genotype 1a or 1b
• Interferon ineligible or intolerant
• Body mass index (BMI) between 18 and 40 kg/m2
• Use of highly effective contraception methods if female of childbearing potential or sexually active male
• Screening laboratory values within defined thresholds
• Has not been exposed to any investigational drug or device within 30 days of the Screening visit
• Able to comply with the dosing instructions for study drug administration and able to complete the study schedule of assessments

Exclusion Criteria:

• Prior treatment of HCV with any direct-acting antiviral (whether approved or experimental)
• Decompensated liver disease or cirrhosis
• Co-infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or another HCV genotype
• History of difficulty with blood collection and/or poor venous access
• Pregnant or nursing female or male with pregnant female partner
• Chronic liver disease of a non-HCV etiology
• Suspicion of hepatocellular carcinoma
• Clinically-relevant drug abuse