Acadia’s Remlifanserin Misses Phase 2 Primary Endpoint but Advances in Alzheimer’s Psychosis

Acadia Pharmaceuticals said remlifanserin, its experimental treatment for hallucinations and delusions associated with Alzheimer’s disease psychosis, narrowly missed the primary endpoint in the Phase 2 portion of its RADIANT program.

At six weeks, the 60-mg once-daily dose improved SAPS-H+D scores by 12.6 points versus 10.4 points with placebo; the result was not statistically significant (p=0.0603). The 30-mg dose showed minimal benefit.

The 60-mg dose did achieve a nominally significant key secondary endpoint:
clinician-rated overall psychosis severity improved by 1.3 points versus 0.9 with placebo (p=0.0077).

Acadia will keep enrolling two ongoing Phase 3 studies, but plans to drop the ineffective 30-mg arm and focus on 60 mg. It is also considering modest changes to patient-selection criteria, potentially emphasizing patients with more severe baseline psychosis.

Safety was broadly comparable with placebo, with no apparent signal of QT prolongation, motor worsening, or cognitive harm reported in the topline disclosure.

Investors reacted negatively:
Acadia shares fell roughly 11% following the announcement, reflecting concern over the missed primary endpoint despite the company’s decision to continue the program.