Study to Investigate the Influence of Hepatic Insufficiency on the Pharmacokinetics of Grazoprevir (MK-5172-013)

Inclusion Criteria:

• If female, must be of non-childbearing potential or willing to use at least 2 acceptable methods of contraception from enrollment to 2 weeks after the last dose of study drug
• No clinically significant abnormality on electrocardiogram

Hepatic Insufficiency Participants Only:

• Other than hepatic insufficiency with features of cirrhosis, is otherwise in good health based on medical history, physical examination, vital signs, and laboratory safety tests
• Chronic (>6 months), stable (no acute episodes of illness within the previous 2 months due to deterioration in hepatic function) hepatic insufficiency with features of cirrhosis due to any etiology
• Score on the Child-Pugh scale must range from 5 to 6 (mild hepatic insufficiency) to from 7 to 9 (moderate hepatic insufficiency) to from 10 to 15 (severe hepatic insufficiency)

Matched Healthy Participants Only:

- In good health based on medical history, physical examination, vital signs, and laboratory safety tests

Exclusion Criteria:

• History of any illness that might confound the results of the study or poses an additional risk to the participant
• History of clinically significant endocrine, gastrointestinal (other than related to their hepatic impairment), cardiovascular, hematological, immunological, renal, respiratory, or genitourinary abnormalities or diseases
• Pregnancy
• Estimated creatinine clearance of ≤60 mL/min
• History of stroke, chronic seizures, or major neurological disorder
• History of neoplastic disease (including leukemia, lymphoma, malignant melanoma), or myeloproliferative disease, regardless of the time since treatment
• Unable to refrain from or anticipates the use of any medication, including prescription and non-prescription drugs or herbal remedies (such as St. John's Wort, green tea, gingko, coenzyme Q, ginseng, echinacea, etc.) or nutritional supplements (e.g., garlic supplements), beginning approximately 2 weeks (or 5 half-lives) prior to administration of the initial dose of study drug, throughout the study, until the poststudy visit
• Participated in another investigational study within 4 weeks
• History of significant multiple and/or severe allergies or has had an anaphylactic reaction or significant intolerability to prescription or non-prescription drugs or food

Hepatic Insufficiency Participants Only:

- Has a history of hepatitis C infection by serology, regardless of most recent viral load status.

Matched Healthy Participants Only:

• History of any chronic and/or active hepatic disease including elevations of serum transaminases, hepatitis, biliary tract disease, or a history of any significant gastrointestinal surgery.
• History of hepatitis C. Participants with a history of self-limited hepatitis A with complete resolution documented at least 6 months prior to entry will be eligible for inclusion