Efficacy and Safety of MK-1167 in Participants With Alzheimer's Disease Dementia Taking Stable Donepezil Treatment (MK-1167-007)

Inclusion Criteria:

• Reports a history of cognitive and functional decline with gradual onset and slowprogression for at least 1 year before Screening, that is either corroborated by aninformant who knows the subject well or is documented in medical records

• Meets the criteria for a diagnosis of probable Alzheimer's disease (AD) based on theNational Institute of Neurological and Communicative Disorders - Stroke and theAlzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria forprobable AD

• Is receiving donepezil 10 mg daily for symptomatic treatment of cognitive impairmentassociated with AD. The dose level must be stable for at least 2 months prior toScreening. If receiving donepezil via a transdermal system (ie, patch), it should bea 10-mg/day dose and should switch prescription to a 10-mg oral daily dose, beforeenrollment

• Has a reliable and competent trial partner/caregiver who has a close relationshipwith the participant, has face-to-face contact at least 3 days a week for a minimumof 6 waking hours a week, and is willing to accompany the participant, if desired,to study visits

Exclusion Criteria:

• History of clinically significant endocrine, gastrointestinal, cardiovascular,hematological, hepatic, immunological, renal, respiratory, genitourinary, or majorneurological (including stroke and chronic seizures) abnormalities or diseases thatare not under medical control over the past 2 months.

• Has evidence of a clinically relevant or unstable psychiatric disorder, based onDSM-5 criteria, or has a history of clinically significant psychiatric disorder inthe last 5 years. Generalized anxiety disorder, and/or insomnia under good controlfor ≥ 2 months on stable medical therapy may not be exclusionary.

• History of cancer (malignancy). Participants with adequately treated disease deemedas "cured," or who, in the opinion of the study investigator, are highly unlikely tosustain a recurrence for the duration of the study, may be enrolled at thediscretion of the investigator and Sponsor.

• History of significant multiple and/or severe allergies (eg, food, drug, latexallergy), or has had an anaphylactic reaction or significant intolerability (ie,systemic allergic reaction) to prescription or nonprescription drugs or food.

• Had a major surgery and/or donated or lost 1 unit of blood (approximately 500 mL)within 4 weeks prior to the prestudy (screening) visit.

• Unable to refrain from or anticipates the use of any medication, includingprescription and nonprescription drugs or herbal remedies beginning approximately 2weeks (or 5 half-lives) prior to administration of the initial dose of studyintervention, throughout the study, until the poststudy visit. There may be certainprotocol-specified medications that are permitted.

• The participant is a smoker and/or has used nicotine or nicotine-containing products (eg, nicotine patch and electronic cigarette) within 3 months of screening.

• Consumes greater than 3 servings of alcoholic beverages per day. Participants whoconsume 4 servings of alcoholic beverages per day may be enrolled at the discretionof the investigator.

• The participant is a regular user of cannabis, any illicit drugs or has a history ofdrug (including alcohol) abuse within approximately 2 years.