A Study of Seltorexant in Participants With Probable Alzheimer's Disease

A Multicenter, Randomized, Placebo-Controlled, Double-Blind Study to Investigate the Safety, Tolerability, and Clinical Efficacy of Seltorexant (JNJ-42847922) on Behavioral and Psychological Symptoms of Dementia in Patients With Probable Alzheimer's Disease

The purpose of this study is to investigate the effect of seltorexant versus placebo on the sum of Agitation and Aggression domain scores (A plus A) of the Neuropsychiatric Inventory-Clinician rating (NPI-C) in participants with probable Alzheimer's Disease (AD) with clinically significant agitation/aggression.

Inclusion Criteria:

• Participant has received a diagnosis of probable Alzheimer Disease (AD) (Diagnostic and Statistical Manual of Mental Disorders-5 [DSM-5]) with the following characteristics at screening: Clinical Dementia Rating (CDR) global score greater than or equal to (>=) 1; Mini-Mental State Examination (MMSE) total score of 10 to 24 (inclusive)
• Participant meets the criteria of a syndrome diagnosis of agitation based on International Psychogeriatric Association (IPA) consensus clinical and research definition of agitation in cognitive disorders for at least 2 weeks before screening
• Participant meets the criteria of Neuropsychiatric Inventory (NPI-12) Agitation/Aggression (A/A) domain score >= 4 with frequency score >= 2 at screening and baseline with no more than 35 percent (%) of improvement in NPI-12 A/A domain score from the screening to baseline assessments
• Female participants must be postmenopausal before study entry (amenorrhea for at least 12 months)
• Body Mass Index (BMI) within the range 18-40 kilograms per square meter (kg/m^2) (inclusive)

Exclusion Criteria:

• Participant fulfils diagnostic criteria for non-Alzheimer's Dementia: example, Frontotemporal Dementia (FTD), Diffuse Lewy Body Dementia (DLBD), and post-stroke dementia, based on clinical history. (Participants may be included with mixed AD/vascular dementia)
• Participant has a clinically significant acute illness within 7 days prior to study intervention administration
• Participants with a history of delirium within 30 days prior to or during screening
• Participant with a cause of agitation that is not secondary to dementia (such as pain) or significant history of aggression prior to dementia based on investigator judgment
• Participants who are not stable on concomitant medications or take prohibited medications