Acadia advances remlifanserin program after Phase 2 Alzheimer’s trial results

• Acadia Pharmaceuticals (NASDAQ:ACAD) reported topline Phase 2 results from the RADIANT trial evaluating remlifanserin in Alzheimer’s disease psychosis (ADP).
• The 60 mg once-daily dose showed improvement versus placebo on hallucinations and delusions measures, supporting continuation into Phase 3 trials.
• Acadia plans to continue its Phase 3 program while removing the 30 mg dose arm based on Phase 2 findings.

Acadia Pharmaceuticals (NASDAQ:ACAD) announced Phase 3-enabling topline results from the Phase 2 portion of its ongoing RADIANT clinical trial program evaluating remlifanserin for hallucinations and delusions associated with Alzheimer’s disease psychosis (ADP).

The company reported that the once-daily 60 mg dose showed improvements compared with placebo on key measures of psychosis symptoms after six weeks of treatment.

For the primary endpoint, the change from baseline in the Scale for the Assessment of Positive Symptoms-Hallucinations and Delusions (SAPS-H+D) subscales, the 60 mg remlifanserin group showed a change of -12.6 compared with -10.4 for placebo at week six.

The difference produced a standardized effect size of 0.26 with a p-value of 0.0603.

For the key secondary endpoint, Clinical Global Impression–Severity for Alzheimer’s disease psychosis (CGI-S-ADP), the 60 mg dose showed a change from baseline of -1.3 compared with -0.9 for placebo, producing a standardized effect size of 0.37 with a nominal p-value of 0.0077.

Acadia said the treatment difference between remlifanserin 60 mg and placebo increased throughout the six-week treatment period.

The 30 mg dose showed limited improvement compared with placebo.

The company reported a favorable safety profile, with adverse events, serious adverse events, and treatment discontinuations occurring at rates similar to placebo.

No QT prolongation signal was observed, and the company reported no deaths in remlifanserin treatment groups.

Acadia plans to continue enrollment in two ongoing Phase 3 studies evaluating remlifanserin in ADP while modifying the program to remove the 30 mg dosage arm.

Detailed safety and efficacy results from the RADIANT Phase 2 study are expected to be presented at the Clinical Trials on Alzheimer’s Disease (CTAD) conference in Boston in November 2026.

Remlifanserin is also being studied in a separate Phase 2 trial evaluating its potential use in psychosis associated with Lewy body dementia.