An Efficacy and Safety Trial of Verubecestat (MK-8931) in Mild to Moderate Alzheimer's Disease (P07738)

Inclusion Criteria: * Diagnosis of probable AD based on both a) the National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria and b) the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria for AD * AD is of mild to moderate severity * Clear history of cognitive and functional decline over at least one year that is either a) documented in medical records or b) documented by history from an informant who knows the subject well * Able to read at a 6th grade level or equivalent, and must have a history of academic achievement and/or employment sufficient to exclude mental retardation * If a participant is receiving an acetylcholinesterase inhibitor, memantine, medical food/supplement (e.g., vitamin E) and/or herbal medications for AD, the dose must have been stable for at least three months before Screening, and the participant must be willing to remain on the same dose for the duration of the trial. Participants may need to be on AD treatments in accordance with local requirements * Participant must have a reliable and competent trial partner/caregiver who must have a close relationship with the subject Inclusion Criteria for Extension Period (Part II): * Tolerated study drug and completed the initial 78-week period of the trial (Part I) * Participant must have a reliable and competent trial partner who must have a close relationship …