A Phase 2 Randomized, Placebo-Controlled, Double-Blind, Parallel-group Study to Evaluate the Efficacy and Safety of MK-1167 as Adjunctive Therapy in Participants With Mild to Moderate Alzheimer's Disease Dementia

Researchers want to learn if giving MK-1167 (the study medicine) along with acetylcholinesterase inhibitor (AChEI) therapy can improve symptoms of Alzheimer's disease dementia (AD dementia), such as memory and mental activity. AD dementia is the most common type of dementia. AChEI therapy is the standard treatment for AD dementia. The goals of this study are to learn: * If at least one dose level (amount) of MK-1167 works to improve a person's memory and thinking compared to a placebo * About the safety of MK-1167 and if people tolerate it