['chronic hepatitis c', 'hepatitis c virus', 'hcv', 'direct-acting antiviral agent (daa)-experienced']
['abt-493, abt-530', 'ribavirin (rbv)', 'abt-493/abt-530']

        Inclusion Criteria:

          1. Patients from 18 to 70 years in Arms A, B, and C; patients 18 years of age or older in
             Arms D and E.

          2. Previous treatment with DAA-containing regimen for chronic hepatitis C virus (HCV)
             infection resulting in either on-treatment virologic failure or post-treatment relapse

          3. Chronic HCV genotype (GT) 1, 4, 5, or 6-infection (GT4-6 in Arms D and E)

        Exclusion Criteria:

          1. History of severe, life-threatening or other significant sensitivity to any drug

          2. Female who is pregnant, planning to become pregnant during the study or breastfeeding;
             or male whose partner is pregnant or planning to become pregnant during the study

          3. Recent (within 6 months prior to study drug administration) history of drug or alcohol
             abuse that could preclude adherence to the protocol

          4. Positive for hepatitis B surface antigen (HBsAg) or anti-human immunodeficiency virus
             antibody (HIV Ab)

          5. Co-infection with more than one HCV genotype
      