An Open-Label Study to Explore the Clinical Efficacy of GS 7977 With Ribavirin Administered Pre-Transplant in Preventing Hepatitis C Virus (HCV) Recurrence Post-Transplant

Inclusion Criteria:

1. Willing and able to provide written informed consent

2. Males or females, age > 18 years old

3. Male subjects must agree to consistently and correctly use a condom while their
female partner agrees to use an approved form of birth control from the date of
Screening until 7 months after their last dose of ribavirin.

4. Confirmation of chronic HCV infection documented by at least one measurement of serum
HCV RNA above the LLoQ measured at Screening, and at least one of the following:

- a positive anti-HCV antibody test, HCV RNA or HCV genotyping test at least 6
months prior to the Baseline/Day 1 visit together with positive HCV RNA test and
anti-HCV antibody at the time of screening, or

- a positive HCV RNA test and anti-HCV antibody test at the time of screening
together with either a liver biopsy consistent with chronic HCV infection (or a
liver biopsy performed before enrollment with evidence of CHC disease, such as
the presence of fibrosis)

5. HCV RNA > 10e4 IU/mL at Screening

6. Patients meeting the MILAN criteria undergoing liver transplant for HCC secondary to
HCV with a MELD of < 22 and a HCC weighted MELD of ≥ 22.

7. Child-Pugh Score (CPT) ≤ 7

8. Planned management of the subject to meet UNOS criteria, with imaging studies made
available for review if required.

9. Subject has not been treated with any investigational drug or device within 30 days
of the Screening visit.

Exclusion Criteria:

1. A female of child-bearing potential who is pregnant or nursing

2. Prior exposure to a direct-acting antiviral targeting the HCV NS5b polymerase

3. Any transplant patient who has agreed to a liver transplant from a live donor.

4. Subjects requiring planned induction therapy with biologics post-transplantation or
with a post-transplantation immunosuppressive regimen not consistent with the
following within the first 12 weeks post-transplant:

- Solumedrol/Prednisone (tapering over approximately 7 days)

- Tacrolimus (maintaining a serum level of 5 12 ng/mL)

- Mycophenolate mofetil (up to 2 g/day)

- Introduction of new maintenance immunosuppressants different from the above list
is disallowed except in consultation during the first 12 weeks post-transplant

5. Current, uncontrolled ascites, variceal hemorrhage, hepatic encephalopathy,
hepatorenal syndrome and hepatopulmonary syndrome, among other signs of decompensated
cirrhosis.

6. Chronic liver disease of a non-HCV etiology (e.g., hemochromatosis, Wilson's disease,
alpha-1 antitrypsin deficiency, cholangitis)

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

8. Contraindications to RBV therapy

9. Chronic use of systemically administered immunosuppressive agents (e.g., prednisone
equivalent > 10 mg/day) in the Pre-transplant treatment period.

10. History of previous solid organ transplantation

11. Evidence of renal impairment (CrCl < 60 mL/min) calculated by the Cockroft-Gault
equation.

12. History or current evidence of psychiatric illness, immunologic disorder,
hemoglobinopathy, pulmonary or cardiac disease, porphyria, or poorly controlled
diabetes, cancer other than HCC, or a history of malignancy that in the opinion of
the investigator makes the patient unsuitable for the study. Patients with clinical
signs or symptoms of acute pancreatitis with elevated lipase (at Screening or during
the Screening period)

13. Known hypersensitivity to RBV, the study investigational medicinal product, the
metabolites, or formulation excipients

14. History of having received any systemic antineoplastic (including sorafenib) or
immunomodulatory treatment (including radiation) within 6 months prior to the first
dose of study drug or the expectation that such treatment will be needed at any time
during the study (excluding a local regional therapy such as TACE).

15. Treatment with Transcatheter arterial chemoembolization (TACE) or radio frequency
ablation (RFA) within 30 days prior to the first dose.

16. Participation in a clinical study with an investigational drug, biologic, or device
within 3 months prior to first dose administration at the Baseline/Day 1 Visit.