Remlifanserin for the Treatment of Alzheimer Disease Psychosis Receives FDA Fast Track Designation

Acadia Pharmaceuticals today announced that the US Food and Drug Administration (FDA) has granted Fast Track designation to remlifanserin, which is an investigational, highly selective, 5-HT2A receptor inverse agonist for the treatment of hallucinations and delusions associated with Alzheimer disease psychosis (ADP).¹

Remlifanserin is thought to reduce hallucinations and delusions through selective 5-HT2A receptor inverse agonism, potentially restoring excitatory/inhibitory balance without direct dopamine blockade and avoiding the common safety and tolerability issues associated with atypical antipsychotics.

“FDA Fast Track designation for remlifanserin underscores the significant unmet need for new treatment options for people living with Alzheimer disease psychosis, a serious condition for which there are currently no FDA-approved therapies,” said Catherine Owen Adams, the chief executive officer of Acadia. “This is an important milestone for the remlifanserin program, and we look forward to sharing upcoming topline data from the RADIANT phase 2 trial as we continue to advance remlifanserin as a potential new treatment option for patients and families impacted by this devastating condition.”

Acadia also provided an update on RADIANT, the development program evaluating remlifanserin for the treatment of hallucinations and delusions associated with ADP. Enrollment in the phase 2 portion of the program has been completed. Acadia anticipates reporting topline results in September/October 2026. Following the blueprint of RADIANT’s design, investigators have begun screening and enrollment for the upcoming phase 3 studies.

Approximately 20% to 70% of patients may experience dementia-related psychosis, dependent on the type of dementia and the stage of the disease progression,² demonstrating the large unmet need in this space.

References

1. Acadia Pharmaceuticals receives FDA Fast Track Designation for remlifanserin in Alzheimer's disease psychosis. News release. July 20, 2026. Accessed July 20, 2026. https://www.businesswire.com/news/home/20260720458854/en/Acadia-Pharmaceuticals-Receives-FDA-Fast-Track-Designation-for-Remlifanserin-in-Alzheimers-Disease-Psychosis

2. Cummings J, Ballard C, Tariot P, et al. Pimavanserin: potential treatment for dementia-related psychosis. J Prev Alzheimers Dis. 2018;5(4):253-258.