Acadia’s Remlifanserin Shows Mixed Phase 2 Results in Alzheimer’s Psychosis Trial — Acadia Pharmaceuticals Inc.

Event summary

Acadia’s 60 mg dose of remlifanserin showed a -12.6 change in SAPS-H+D vs. -10.4 for placebo (p=0.0603) in Phase 2 RADIANT trial.
Key secondary endpoint (CGI-S-ADP) met with a -1.3 change vs. -0.9 for placebo (p=0.0077).
30 mg dose showed minimal improvement; Acadia will remove it from Phase 3 trials.
No safety concerns identified; no QT prolongation or negative cognitive/motor impacts observed.
Phase 3 trials will continue with protocol amendments; detailed results to be presented at CTAD in November 2026.

The big picture

Acadia’s remlifanserin is one of the few drugs in development for Alzheimer’s disease psychosis, a condition with no approved therapies. The Phase 2 results suggest potential efficacy at the higher dose, but the lack of statistical significance on the primary endpoint raises questions about the regulatory path forward. The favorable safety profile is a positive, but the company will need to demonstrate stronger efficacy in Phase 3 to gain approval.

What we're watching

Regulatory Pathway: Whether the Phase 2 data will be sufficient to support regulatory approval given the mixed primary endpoint result.
Execution Risk: The pace at which Acadia can amend and complete Phase 3 trials while maintaining data integrity.
Competitive Landscape: How Acadia’s progress compares to other companies developing treatments for Alzheimer’s disease psychosis.