Acadia Pharmaceuticals announced Monday that experimental schizophrenia drug ACP-104 did not meet any primary or secondary endpoints in a mid-stage trial, and that further studies of the compound are not expected. The company's shares plummeted as much as 56 percent on the news.

In the study involving 247 patients with schizophrenia who were experiencing an acute psychotic episode, participants were randomised to receive one of two doses of the drug twice daily or placebo over a six-week period. The company revealed that neither dose was successful at improving efficacy compared with placebo.

Acadia CEO Uli Hacksell called the results "disappointing" and said the company would further analyse the findings. The CEO also noted that the drugmaker will continue its Phase III programme for a separate product, pimavanserin, for the treatment of Parkinson's disease psychosis.

Reference Articles

Acadia Pharmaceuticals announces results from ACP-104 Phase IIb schizophrenia trial - (Acadia)

Acadia schizophrenia drug fails mid-stage trial - (CNN Money)

Acadia Pharma: ACP-104 Phase IIb schizophrenia trail missed primary endpoint - (Forbes)

Acadia shares hit new low on failed study - (MSN Money)

Acadia shares sink on failed study - (TheStreet.com)