Acadia Plans Phase 3 After Alzheimer’s Drug Endpoint Miss

Acadia Pharmaceuticals announced topline Phase 2 results from the RADIANT trial on September 24, 2026, for remlifanserin in Alzheimer’s disease psychosis. At Week 6 the 60 mg dose produced a 12.6-point reduction on SAPS-H+D versus 10.4 points for placebo, a standardized effect size of 0.26 and a p-value of 0.0603 that narrowly missed statistical significance. On the key secondary endpoint CGI-S-ADP, 60 mg showed a 1.3-point reduction versus 0.9 for placebo, effect size 0.37 and nominal p-value 0.0077. The 30 mg dose showed minimal improvement. Safety findings matched placebo on adverse events, serious adverse events and discontinuations; no QT interval prolongation signal was observed and there were no deaths in remlifanserin groups. CONTESTED: None found. Rated coverage was a single center outlet; no left- or right-rated headlines were recorded (single-source story, no split found). Jeffrey Cummings said the findings provide encouraging evidence for 60 mg remlifanserin. Acadia plans to continue two ongoing Phase 3 studies and has amended the Phase 3 program to remove the 30 mg dose arm.