Pharmacokinetics of Suvorexant in Participants With Hepatic Insufficiency (MK-4305-017)

This study will determine whether the plasma concentration-time profile and pharmacokinetics (PK) of suvorexant (MK-4305) in participants with moderate and mild hepatic insufficiency are similar to those observed in healthy participants.

Study Design:

This study plans to enroll 16 participants in Part I (8 participants with moderate hepatic insufficiency and 8 healthy participants) and 16 participants in Part II (8 participants with mild hepatic insufficiency and 8 healthy participants).

Part II will be conducted only if the primary hypothesis is not met and there is a significant difference in the PK of suvorexant between healthy participants and moderate hepatic insufficiency participants in Part I.

Eligibility Criteria:
Inclusion Criteria for Hepatic Insufficiency Participants:

* Females of reproductive potential must have a negative pregnancy test and agree to use (and/or have their partner use) two acceptable methods of birth control
* Body Mass Index (BMI) ≤35 kg/m\^2 prior to start of study
* Diagnosis of stable hepatic insufficiency
* Smoking is restricted to ≤10 cigarettes per day

Inclusion Criteria for Healthy Matched Participants:

* Females of reproductive potential must have a negative pregnancy test and agree to use (and/or have their partner use) two acceptable methods of birth control
* BMI within approximately 20% of that of his/her hepatic participant
* Participant is healthy
* Participant is matched by race, gender, age (+/- 5 yrs) to his/her hepatic participant enrolled in the study
* Smoking is restricted to ≤10 cigarettes per day

Exclusion Criteria for Hepatic Insufficiency Participants:

* Participant is mentally or legally incapacitated
* History of a clinically significant psychiatric disorder over the last 5 to 10 years
* Participant has a history of any illness not related to his/her hepatic insufficiency
* History of a persistent sleep abnormality occurring for at least three (3)

months

* Participant has a history of stroke, chronic seizures, or major neurological disorder
* History of clinically significant hematological, immunological, renal,

respiratory, or genitourinary abnormalities, uncomplicated kidney stones or childhood asthma

* History of cancer
* History of cataplexy
* Participant is a nursing mother
* Participant consumes \>3 servings of alcohol a day
* Participant consumes \>6 caffeine servings a day
* History of multiple and/or severe allergies
* Participant is currently using or has history of illegal drug use
* Participant has traveled across 3 or more time zones within 2 weeks of study participation
* Participant works a night shift and is not able to avoid night shift work within 1 week before each treatment visit

Exclusion Criteria for Healthy Matched Participants:

* Participant is mentally or legally incapacitated. History of a clinically significant psychiatric disorder over the last 5 to 10 years.
* Participant has a history of any illness
* History of a persistent sleep abnormality occurring for at least three (3) months
* Participant has a history of stroke, chronic seizures, or major neurological disorder
* History of clinically significant endocrine, gastrointestinal,

cardiovascular, hematological, immunological, renal, respiratory, or genitourinary abnormalities, uncomplicated kidney stones or childhood asthma

* History of cancer
* History of cataplexy
* Participant is a nursing mother
* Participant consumes \>3 servings of alcohol a day
* Participant consumes \>6 caffeine servings a day
* History of multiple and/or severe allergies
* Participant is currently using or has history of illegal drug use
* Participant has a history of any chronic and/or active hepatic disease
* Participant has traveled across 3 or more time zones within 2 weeks of study participation
* Participant works a night shift and is not able to avoid night shift work within 1 week before each treatment visit