['hepatitis c virus infection']
['ldv/sof', 'rbv']

        Key Inclusion Criteria:

          -  Willing and able to provide written informed consent

          -  Chronic HCV infection (≥ 6 months) documented by medical history or liver biopsy

          -  HCV genotype 4 at screening

          -  HCV treatment naive or prior participation in this study or study GS-US-334-0138
             (Cohorts 1 and 2 only)

          -  Cohort 3 only: HCV treatment-experienced (previously received therapy for HCV
             infection with an interferon (IFN)-containing regimen, with or without RBV and/or an
             HCV NS3/NS4A protease inhibitor (PI)

          -  Body mass index (BMI) ≥ 18 kg/m^2

          -  Screening laboratory values within defined thresholds

          -  Use of effective protocol-approved contraception methods

        Key Exclusion Criteria:

          -  History of clinically-significant illness or any other major medical disorder that may
             interfere with treatment, assessment or compliance with the protocol

          -  Infection with hepatitis B virus (HBV) or human immunodeficiency virus (HIV)

          -  Pregnant or nursing females or male with pregnant female partner

          -  Clinically-relevant drug or alcohol abuse within 12 months of screening

        Note: Other protocol defined Inclusion/Exclusion criteria may apply.
      