The approval, granted to the medicine developers Otsuka Pharmaceutical and Lundbeck, is the first FDA-approved treatment option for this indication. In 2015, the agency had approved Rexulti to treat schizophrenia and major depressive disorder.

"Agitation is one of the most common and challenging aspects of care among patients with dementia due to Alzheimer's disease. 'Agitation' can include symptoms ranging from pacing or restlessness to verbal and physical aggression," Dr. Tiffany Farchione, director of the division of psychiatry in the FDA's Center for Drug Evaluation and Research, said in a statement. "These symptoms are leading causes of assisted living or nursing home placement and have been associated with accelerated disease progression."

Agitation is among the most persistent, complex, stressful, and costly aspects of care among patients with behavioral and psychological symptoms of dementia, the agency noted.

The effectiveness of Rexulti for the treatment of agitation associated with dementia due to Alzheimer's disease was determined through two 12-week, randomized, double-blind, placebo-controlled, fixed-dose studies. In these studies, patients were required to have a probable diagnosis of Alzheimer's dementia; have a score between five and 22 on the Mini-Mental State Examination, a test that detects whether a person is experiencing cognitive impairment; and exhibit the type, frequency, and severity of agitation behaviors that require medication. Trial participants were between the ages of 51 to 90.

In the first study, patients received 1 or 2 milligrams (mg) of Rexulti, while in the second study patients received 2 or 3 mg of Rexulti.

The primary efficacy endpoint in these two studies was the change from baseline in the Cohen-Mansfield Agitation Inventory total (CMAI) score at week 12. CMAI is a survey tool that uses input from caregivers to rate the frequency of certain agitative behaviors in dementia patients on a scale from one to 7. In both studies, patients who received 2 mg or 3 mg of Rexulti showed statistically significant and clinically meaningful improvements in total CMAI scores compared to patients in the placebo group at week 12, the FDA said.

The agency granted this application under its Fast Track designation, a pathway to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need.