Phase 3 Randomized Placebo Controlled Clinical Trial of Donepezil

Randomized, double-blind, placebo-controlled study with 24 weeks of exposure to drug or placebo followed by a 12 week wash-out period. Patients who meet the eligibility criteria will be stratified by age (\<50, 50-59, 60-69, ≥70) and randomized to donepezil or placebo with equal probability. A total of 276 patients will be enrolled (138 per arm). We expect an accrual rate of 7-10 participants per month based on our prior feasibility study. We expect the study to be complete within 40 months. Participants will be asked to take one 5mg tablet of donepezil or one tablet of matching placebo orally once a day for 6 weeks followed by two 5mg tablets (10mg total) of donepezil or two placebo tablets orally once a day for 18 weeks. After 24 weeks, participants will begin a 12 week wash-out period. Time points for performing study assessments. Participants will be administered the cognitive battery of tests and questionnaires at baseline, week 12, week 24 and week 36. In addition, a single vial of blood will be drawn at baseline for apolipoprotein E (APOE) genotyping and subsequent bioassays (pending supplemental funding).