Ulonivirine (MK-8507) in Participants With Mild or Moderate Hepatic Impairment (MK-8507-014)

Inclusion criteria

Mild and Moderate HI (Panels A and B):

• Has a diagnosis of chronic (>6 months), stable HI with features of cirrhosis due to any etiology (stability of hepatic disease should correspond to no acute episodes of illness within the previous 2 months due to deterioration in hepatic function)

Healthy Controls (Panel C):

• Is in good health

All Participants (Panels A to C):

• Has a body mass index (BMI) ≥18.5 and ≤40 kg/m^2, inclusive
• If male, uses contraception in accordance with local regulations
• If female, is not pregnant or breastfeeding and one of the following applies: 1) is not a woman of childbearing potential (WOCBP), or 2) is a WOCBP and is abstinent/uses acceptable contraception, has a negative highly sensitive pregnancy test within 24 hours of receiving study intervention, and provides medical/menstrual/recent sexual history for review by the investigator

Exclusion criteria

Mild and Moderate HI (Panels A and B):

• Has a history of any illness that, in the opinion of the investigator, might confound the results of the study or poses an additional risk to the participant by their participation in the study
• Is not in sufficient health
• Is institutionalized/mentally or legally incapacitated
• Is positive for human immunodeficiency virus (HIV)-1 or HIV-2
• Has received antiviral and/or immune modulating therapy for hepatitis B virus (HBV) or hepatitis C virus (HCV) within 90 days prior to study start
• Is taking medication for a chronic condition and has not been on a stable regimen for ≥ 1 month

Healthy Controls (Panel C):

• Has a history of clinically significant endocrine, gastrointestinal, cardiovascular, hematological, hepatic, immunological, renal, respiratory, genitourinary, or major neurological (including stroke and chronic seizures) abnormalities or diseases
• Is mentally or legally incapacitated
• Is positive for hepatitis B virus surface antigen (HBsAg), hepatitis C antibodies, HIV-1, or HIV-2
• Is unable to refrain from or anticipates the use of any medication, including prescription and nonprescription drugs or herbal remedies beginning approximately 2 weeks (or 5 half-lives) prior to first dose of study drug

All Participants (Panel A to C):

• Has a history of cancer (malignancy)
• Has a history of significant multiple and/or severe allergies
• Has known hypersensitivity to the active substance or any of the excipients of the study drug
• Has participated in another investigational study within 4 weeks (or 5 half-lives, whichever is greater) prior to Screening