Acadia Remlifanserin Phase 2 Results Narrowly Miss
Acadia remlifanserin Phase 2 results narrowly missed the primary endpoint; a key secondary was nominally significant and the company will advance 60 mg into Phase 3.
KEY TAKEAWAYS
- 60 mg narrowly missed the prespecified primary endpoint (SAPS-H+D; effect size 0.26; p=0.0603).
- Key secondary CGI-S-ADP was nominally significant versus placebo (effect size 0.37; p=0.0077).
- Acadia will advance 60 mg into Phase 3 and remove the 30 mg arm.
HIGH POTENTIAL TRADES SENT DIRECTLY TO YOUR INBOX
Add your email to receive our free daily newsletter. No spam, unsubscribe anytime.
Acadia Pharmaceuticals on September 24, 2026, reported Phase 2 results for remlifanserin in Alzheimer’s disease psychosis that narrowly missed the prespecified primary endpoint. The 60-mg once-daily dose produced a nominally significant key secondary outcome and a favorable safety profile. The company said it will advance the 60-mg dose into Phase 3.
Efficacy Results and Safety
The data came from the Phase 2 portion of the ongoing RADIANT clinical program evaluating remlifanserin for hallucinations and delusions associated with Alzheimer’s disease psychosis. At week six, the 60-mg dose reduced symptoms by 12.6 points on the Scale for the Assessment of Positive Symptoms—Hallucinations and Delusions (SAPS-H+D), compared with a 10.4-point reduction for placebo. The standardized effect size was 0.26 with a p-value of 0.0603, narrowly missing conventional statistical significance.
On the Clinical Global Impression–Severity scale for Alzheimer’s disease psychosis (CGI-S-ADP), the 60-mg dose showed a 1.3-point improvement versus 0.9 for placebo, with a standardized effect size of 0.37 and nominal p=0.0077. Acadia reported that the difference between the 60-mg group and placebo increased over the six-week treatment period on both measures. The 30-mg dose showed minimal improvement compared with placebo across endpoints.
Efficacy analyses used the prespecified modified full analysis set (mFAS) population. Across both doses, rates of adverse events, serious adverse events, and discontinuations due to adverse events were similar to placebo. The company reported no QT-prolongation signal, no apparent negative impact on motor symptoms or cognition, and no deaths in the remlifanserin treatment arms.
Phase 3 Plans and Timing
Acadia described the topline results as "Phase 3 enabling" and said it will advance the 60-mg once-daily dose into Phase 3. The company plans to amend the ongoing RADIANT protocols to remove the 30-mg arm while continuing enrollment in its two Phase 3 studies.
Remlifanserin remains investigational for Alzheimer’s disease psychosis. The company did not report any FDA approval or regulatory filing in the announcement. Market reports described a negative reaction to the mixed efficacy data.
Acadia said it will present detailed Phase 2 efficacy and safety results at the Clinical Trials on Alzheimer’s Disease conference in November 2026.
