Acadia Pharma Parkinson's Drug Slows Psychosis

SAN DIEGO (TheStreet) -- Acadia Pharmaceuticals' (ACAD) experimental drug pimavanserin reduced psychotic episodes in patients with Parkinson's disease compared to a placebo, achieving the primary endpoint of a phase III study, the company said Tuesday.

Shares of Acadia were UP 145% to $5.64 in early Tuesday trading.

Acadia needs to conduct another phase III study of pimavanserin in Parkinson's patients in order to confirm Tuesday's results. Two previous late-stage studies of the drug failed to demonstrate a significant reduction in psychotic episodes.

Treatment with a 40 mg dose of pimavanserin resulted in a 5.79-point reduction in psychotic behavior compared to a 2.73-point reduction in patients treated with a placebo. The 3.06-point difference in the two arms of the phase III study was statistically significant.

Reduction in psychotic behavior focused mostly on hallucinations and delusions and was assessed using a 9-item scale adapted from the Scale for the Assessment of Positive Symptoms (SAPS).

Pimavanserin achieved its antipsychotic effects without worsening motor function in Parkinson's patients, meeting a key secondary endpoint of the trial.

The pimavanserin data are "better than I expected," said Zacks analyst Jason Napodano, in a twitter post reacting to the Acadia study results. The U.S. market opportunity for pimavanserin in Parkinson's disease psychosis is $300-400 million, he adds.

-- Reported by Adam Feuerstein in Boston.

Follow @AdamFeuerstein

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.