Why Is Acadia Pharmaceuticals (ACAD) Stock Down 18% Today?

Core Insights - Acadia Pharmaceuticals' stock is declining following the failure of its Phase 3 clinical trial for pimavanserin, a drug aimed at treating negative symptoms of schizophrenia [1][2] - The trial did not meet its primary endpoint, leading the company to halt further development of pimavanserin [1] - As a result of the trial's failure, ACAD stock has dropped by 17.6% [2] Company Overview - Acadia Pharmaceuticals is focused on developing treatments for central nervous system disorders, with pimavanserin being a key candidate for schizophrenia [1] - The CEO expressed disappointment over the trial results, highlighting the significant unmet need in the patient population [1] Market Reaction - The failure of the Phase 3 trial has resulted in negative sentiment among shareholders, as the company cannot seek commercialization approval for pimavanserin [2] - The stock market response reflects investor concerns regarding wasted resources in drug development that will not yield a marketable product [2]