Description: The purpose of the study is to evaluate the effectiveness and safety of MK-8931 compared with placebo in patients with mild to moderate stage Alzheimer's disease. MK-8931 is a potent inhibitor of an enzyme that regulates amyloid accumulation in the brain. Toxic amyloid arises from the cleavage of the amyloid precursor protein (APP) by the action of beta-secretase and gamma-secretase. Blocking or inhibiting the action of BACE1 (beta-site APP cleaving enzyme 1) may decrease the amount of amyloid-beta peptides produced and may slow progression of disease. Two different dosages of MK-8931 will be compared with placebo in this study so participants will have a two in three chance of receiving the active medication.

Eligibility: Men and women between 55 to 85 years of age in general good health with mild to moderate stage Alzheimer's disease. They may be on medical treatment for Alzheimer's disease providing their medications have been stable for three months. Each participant must have a reliable partner or caregiver who will accompany them to all trial visits and oversee the administration of study medication. This study is planned to last approximately 20 months.

For more information contact Munir H. Chowdhury at (713) 798-5328 or email