UPDATE 1-Acadia antipsychotic for Parkinson's succeeds in trial

Tue Nov 27, 2012 11:20am EST

* Significantly reduces psychotic symptoms vs placebo

* Achieves antipsychotic effect without loss of motor function

* Drugs appears to be tolerable, safe in Phase III study

* Company planning second confirmatory Phase III trial

* Shares rise 150 percent (Adds stock price, analyst comment)

By Bill Berkrot

Nov 27 (Reuters) - An antipsychotic drug for Parkinson's disease patients being developed by Acadia Pharmaceuticals Inc succeeded in meeting the primary goal and key secondary goals of a pivotal late stage clinical trial, the company said on Tuesday.

Acadia shares more than doubled after the company released initial, or top line, results from the 199-patient Phase III trial of pimavanserin that showed the drug was significantly better than placebo at reducing psychotic effects of Parkinson's disease psychosis.

Pimavanserin also met a secondary goal of the study by demonstrating that it could achieve an antipsychotic effect without worsening of motor function, the company said.

Acadia shares jumped 150 percent to $5.75 on Nasdaq.

"These data represent an unprecedented advance for Parkinson's patients who suffer from the psychosis frequently associated with this disease," Dr. Jeffrey Cummings, director of the Cleveland Clinic Lou Ruvo Center for Brain Health, said in a statement.

"Among Parkinson's patients, psychosis is the leading cause of institutionalization and dramatically increases the risk of mortality," Cummings said.

On a nine-item scale measuring psychosis symptoms, such as hallucinations and delusions, from the start of the trial to day 43, pimavanserin led to a 5.79 point improvement compared with a 2.73 point improvement for placebo patients. The result was deemed to be highly statistically significant, the company said.

"The data certainly look positive," said Brian Lian, an analyst with Suntrust Robinson Humphrey. "Across the board it appeared to show improvement on multiple measures and certainly across all the primary and secondary endpoints.

The company is planning a second, similar Phase III study to confirm the results before seeking approval from U.S. health regulators, Acadia Chief Executive Uli Hacksell said.

"Once you have those trial results, assuming they're positive, it sure seems like you have demonstrated efficacy and the safety profile is also very promising," said Lian, who estimates $220 million in sales for Parkinson's psychosis by 2020 and significantly more if the drug is also used to treat psychosis associated Alzheimer's disease.

The Acadia drug in 2009 failed to meet the goals of a previous Phase III study due to what the company said was an unusually large placebo effect. Much of that effect came from patients in Eastern Europe and India, where they were exposed during the trial to much better healthcare standards than is typical for such patients in those countries, possibly contributing to the placebo effect, Hacksell explained.

The latest trial was conducted only with North American patients.

"We are very excited about the top line results that successfully met all the objectives of this pivotal Phase III study," Hacksell told Reuters by telephone. "This is an important advance in a very complicated and difficult disease."

Parkinson's disease psychosis, or PDP, is a debilitating disorder that develops in up to 60 percent of patients as their Parkinson's disease progresses.

Most current antipsychotic drugs cannot be used in Parkinson's disease patients because those drugs block dopamine in the brain, which is the primary target for Parkinson's therapy and can lead to worsening of motor function for such patients. "So they cannot be used at effective doses," Hacksell said of available antipsychotics.

Pimavanserin selectively blocks certain serotonin receptors in the brain but has no effect on dopamine.

"The results of this study suggest that a selective, non-dopaminergic-based therapy has the potential to transform the treatment landscape for patients with this debilitating disorder," Cleveland Clinic's Cummings said.

The Acadia drug also led to improvements in nighttime sleep, daytime wakefulness and caregiver burden in the late stage trial, in which patients were also taking their regular Parkinson's medication, the company said.

The drug was well tolerated with the most common adverse side effect being urinary tract infections.

"When you look at clinical trials in general they have some gray aspects of them. We don't see any gray in the outcome of this study," the Acadia CEO said. "It's all super strong." (Reporting by Bill Berkrot; Editing by Tim Dobbyn and Marguerita Choy)