Acadia Stock Falls 13% as Alzheimer's Psychosis Study Misses Primary Goal

Key Facts

1Acadia stock fell 13% after its Phase II Alzheimer's psychosis study narrowly missed its primary goal.

2Results from the 60 mg dose support continued Phase III development despite the primary miss.

Acadia Pharmaceuticals stock fell 13% after its Phase II Alzheimer's psychosis study narrowly missed its primary goal. Zacks reported that the clinical trial's failure to meet the primary endpoint triggered a significant sell-off as investors reassessed the drug's path to regulatory approval.

Results from the 60 mg dose provided enough support for the company to continue into Phase III development despite the initial primary miss. While specific closing price levels were not established on September 25, 2026, the qualitative downward pressure reflects market skepticism regarding the clinical trial outcomes.