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

        Inclusion Criteria:

          -  Willing and able to provide written informed consent

          -  HCV RNA > 10^4 IU/mL at screening

          -  Chronic HCV infection (≥ 6 months)

          -  Confirmed CPT class B (7-9) at screening

        Exclusion Criteria:

          -  Current or prior history of solid organ transplantation, significant pulmonary
             disease, significant cardiac disease, or porphyria

          -  Inability to exclude hepatocellular carcinoma (HCC) by imaging within 6 months of
             baseline/Day 1

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

          -  Screening ECG with clinically significant abnormalities

          -  Prior exposure to SOF or any other nucleotide analogue HCV nonstructural protein 5B
             (NS5B) inhibitor or any HCV NS5A inhibitor

          -  Laboratory results outside of acceptable ranges at screening
      