Lundbeck, Otsuka to seek new FDA approval for Rexulti after it reduced agitation in Alzheimer's patents

Less than two weeks after an independent FDA panel shot down one potential treatment for patients with Alzheimer's disease, another has emerged with positive trial results.

On Monday, Lundbeck of Denmark and Otsuka of Japan revealed that a phase 3 study of brexpiprazole in Alzheimer’s patients showed that the drug for major depressive disorder reduced agitation (AAD) at a statistically significant rate when pitted against placebo. 

The drug, known commercially as Rexulti, won FDA approval in 2015 for schizophrenia and major depressive disorder. It nabbed fast-track status for Alzheimer’s patients in 2016. Rexulti garnered sales of 2.85 billion Danish Krone ($405 million) for Lundbeck last year.

Gaining an indication for AAD could boost Rexulti's peak sales by $500 million, SVB Securities estimated in a note to clients. With the news, Lundbeck's shares jumped by 9% on Monday.

Full study results of the trial of 345 Alzheimer’s patients aged 55 to 90 from the United States, Spain and several countries in Eastern Europe have yet to be compiled. The patients were observed over a 12-week period and were assessed by caregivers using the Cohen-Mansfield Agitation Inventory scoring system.

The results pooled two treatment groups—one that received a 2 mg daily dose, while the other got 3 mg per day. Notably, no new safety signals were observed with the inclusion of the higher dose treatment group, which "suggests a wide tolerability index for Rexulti in this frail patient population," SVB wrote.

SVB also points out that Rexulti carries a black-box warning of increased mortality in the elderly.

"It will be interesting to see how the favorable safety and tolerability of Rexulti demonstrated thus far in Alzheimer's patients could impact the label despite the relatively short-duration (12 weeks) of all the trials in AAD," analyst Marc Goodman wrote.

Based on this outcome, the companies plan to file an FDA application for approval before the end of this year, they said.

Further analysis of the data will be conducted to determine the full potential of brexpiprazole in the treatment of agitation in Alzheimer’s patients, the companies added. There are no FDA-approved treatments for AAD.

In a statement, the companies said AAD is a "very prevalent clinical manifestation" of Alzheimer's disease, and that it's "one of the most complex and stressful aspects of care" for patients. It's associated with more caregiver burden, earlier nursing home placement, increased morbidity and mortality and more, the companies added.

The trial results come on the heels of an FDA advisory committee voting 9 to 3 to turn down a bid by Acadia to expand its antipsychotic drug Nuplazid to Alzheimer's patients.

The company hoped to show that Parkinson's drug Nuplazid could reduce hallucinations and delusions in Alzheimer's disease psychosis.