An Efficacy and Safety Study of Simeprevir and Sofosbuvir With and Without Ribavirin in Participants With Recurrent Genotype 1 Hepatitis C Post-Orthotopic Liver Transplant (GALAXY)

Inclusion Criteria:

• Participant must be infected with Hepatitis C virus (HCV) Genotype 1 (1a or 1b) with Baseline HCV ribonucleic acid (RNA) greater than (>) 10,000 international unit per milliliter (IU/mL). Retesting of HCV RNA to assess eligibility will be allowed once, using an unscheduled visit during the Screening period
• Participant must have had an orthotopic liver transplant greater than or equal to (>=) 6 months to 15 years prior to enrollment
• Participant must have had primary liver transplant
• Participant must be on a stable immunosuppressive regimen for at least 3 months prior to the Screening visit. Immunosuppression regimens may include calcineurin inhibitors (for example, tacrolimus), mammalian target of rapamycin (mTOR) inhibitor, mycophenolate mofetil, prednisone, prednisolone less than or equal to (<=) 5 milligram per day (mg/day), other corticosteroids (except systemic dexamethasone), sirolimus, everolimus, or azathioprine. Stable immunosuppression includes normal adjustment of immunosuppressant dose but excludes changes in immunosuppressant medication and/or treatment of rejection.
• Participant's renal function as measured by the Cockcroft Gault formula must be >30 milliliter per minute (mL/min)

Exclusion Criteria:

• Participants received prior treatment with an investigational or Food and Drug Administration (FDA) approved direct-acting antiviral drug for the treatment of hepatitis C. Prior HCV treatment with interferon or peginterferon with or without ribavirin (RBV) is allowed but must have been completed at least 3 months prior to Screening
• Participants with hepatic decompensation defined by any of the following: 1) Any post-liver transplant clinical signs including ascites, hepatic encephalopathy, and/or evidence of varices with or without variceal bleeding, and 2) Child-Turcotte-Pugh (CTP) score >=7
• Participant has (post-transplant) any underlying serious or life-threatening condition, such as severe uncontrolled cardiopulmonary disease, vascular disease, rheumatologic condition, renal failure, dialysis, ongoing systemic infection, uncontrolled malignancy, or other serious illness that would compromise adherence to medications and ability to comply with all aspects of the study protocol
• Any other active, clinically significant disease or clinically significant findings during the Screening period of medical history, physical examination, laboratory testing, or electrocardiogram (ECG) recording that, in the investigator's opinion, would compromise the participant's safety or could interfere with the participant participating in and completing the study. Retesting of laboratory results that lead to exclusion will be allowed once using an unscheduled visit during the Screening period to assess eligibility
• Participant is a woman who is pregnant, breast-feeding, or planning to become pregnant while enrolled in this study or within 6 months after the last dose of ribavirin (or longer when dictated by local regulations)