Acadia Pharma Plunges 19% as Remlifanserin Misses Primary Endpoint
Acadia Pharmaceuticals fell 19% after remlifanserin narrowly missed the primary endpoint in a Phase 2 trial for Alzheimer's disease psychosis. The 60mg dose improved scores but the p-value was 0.0603, just above significance. Management plans to continue with the 60mg dose in Phase 3, citing a favorable safety profile and secondary endpoint success.
The RADIANT trial enrolled 326 patients and tested two doses of remlifanserin against placebo. The 60mg arm produced a 12.6-point improvement on the SAPS H+D scale versus 10.4 for placebo, yielding a p-value of 0.0603 that fell just short of the 0.05 significance threshold. Secondary measures of overall psychosis severity showed stronger results, with an effect size of 0.37 and a nominal p-value of 0.0077.
Acadia plans to advance only the 60mg dose into Phase 3, eliminating the weaker 30mg arm. Management noted that applying modestly higher baseline psychosis criteria would preserve roughly 80% of patients while improving the primary effect size to 0.33. Analysts responded with mixed adjustments: BMO lowered its target to $34 with an Outperform rating, Citigroup cut to $33, and TD Cowen maintained a Buy with a $37 target. The company's commercial portfolio, including DAYBUE and NUPLAZID, generated combined second-quarter sales of approximately $308 million.
Alzheimer's disease psychosis affects a substantial patient population with no FDA-approved therapy specifically targeting hallucinations and delusions. If remlifanserin fails to demonstrate clearer efficacy in Phase 3, patients and caregivers could face continued reliance on off-label treatments. However, Bristol Myers Squibb's competing ADEPT program may offer an alternative path forward. The trial outcome also shapes investor confidence in Acadia's pipeline, potentially influencing the company's ability to fund future research and development efforts across its other programs.