A Single-Dose Study of the Pharmacokinetics of Vibegron (MK-4618) in Adults With Hepatic Insufficiency (MK-4618-013)

This study is planned to be conducted in two parts. Part 1 of the study will include participants with moderate hepatic insufficiency and healthy participants. If Part 2 is conducted, Part 2 of the study will include participants with mild hepatic insufficiency.

Inclusion criteria

For both healthy participants and participants with hepatic insufficiency:

• Continuous non-smokers who haven't used nicotine-containing products for at least 3 months prior to study drug administration
• Body mass index (BMI) ≤39 kg/m^2
• Good health based on medical history, physical examination, vital signs, laboratory safety tests, and electrocardiogram (ECG)
• Females of childbearing potential must be sexually inactive for 14 days prior to study drug administration and throughout study or use acceptable birth control method
• Females of non-childbearing potential must have undergone an acceptable sterilization procedure at least 6 months prior to Day 1 of study or be postmenopausal with amenorrhea for at least 1 year prior to Day 1
• Non-vasectomized males must agree to use a condom with spermicide or abstain from sexual intercourse during the trial and for 3 months after study drug administration

For participants with hepatic insufficiency only:

• Diagnosis of chronic, stable, hepatic insufficiency
• For Part 1 Participants: Child-Pugh scale range from 7 to 9
• For Part 2 Participants: Child-Pugh scale range from 5 to 6