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

        Key Inclusion Criteria:

          -  Willing and able to provide written informed consent or for those individuals where
             hepatic encephalopathy affects their ability to provide initial or ongoing consent,
             has an appropriate and legally-authorized representative (LAR) willing and able to
             provide consent on behalf of the individual.

          -  HCV RNA infection with quantifiable virus at screening

          -  Must have chronic genotype 1 or 4 HCV infection for ≥ 6 months by medical history or
             liver biopsy

          -  Currently on the liver transplantation wait list

          -  Screening electrocardiogram (ECG) without clinically significant abnormalities.

          -  A negative serum pregnancy test result is required for females

        Key Exclusion Criteria:

          -  Any previous solid organ transplant

          -  Any serious or active medical or psychiatric illness which, in the opinion of the
             investigator, would interfere with participant's treatment, assessment, or compliance

          -  HIV infection or a positive hepatitis B virus surface antigen result

          -  History of malignancy (with exception of hepatocellular carcinoma within Milan
             criteria, certain resolved skin cancers or other early cancer for which surgical
             resection is considered to be completely curative)

          -  Treatment with any approved or experimental medication with known anti-HCV activity
             within 1 month prior to screening date

          -  Prior exposure to an HCV non-structural protein (NS)5A inhibitor

          -  Patients on hemodialysis prior to or at the time of transplantation will be excluded

          -  Creatinine clearance (CLcr) < 40 mL/min at screening or < 40 mL/min on day of
             transplant

          -  Participation in a clinical study with an investigational drug or biologic within 28
             days prior to screening visit

          -  Receipt or planned receipt of an organ from an HCV positive donor

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