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Acadia Drug Shows Early Promise in Treating Alzheimer’s Psychosis

Xconomy San Diego — 

An Acadia Pharmaceuticals drug developed to treat hallucinations and delusions experienced by Parkinson’s disease patients is now showing signs it could also treat similar psychoses associated with Alzheimer’s disease.

San Diego-based Acadia (NASDAQ: ACAD) reported that patients treated in an exploratory study with its drug pimavanserin showed a statistically significant reduction in psychosis compared against a group given a placebo. Investors cheered the news, boosting Acadia’s stock price 13.6 percent to $28.88 in trading Tuesday morning.

Antipsychotics that are currently available work by blocking receptors for dopamine. Acadia says pimavanserin, a selective serotonin inverse agonist (SSIA), works in a different way. The Acadia drug targets 5-HT2A receptors, which the company says are thought to play a role in Alzheimer’s disease psychosis. In April, the FDA approved pimavanserin (Nuplazid) to treat to treat psychosis associated with Parkinson’s disease, the first drug approved to treat that condition. No FDA-approved treatments are available to treat psychosis in Alzheimer’s patients.

Of the approximately 2.7 million people in the United States diagnosed with Alzheimer’s disease, the Alzheimer’s Association says studies suggest between 25 and 50 percent of those patients may develop psychosis. Acadia studied 181 patients in its Phase 2 trial, randomized to receive 34 milligrams of pimavanserin or placebo once daily. The mean age of patients in the study was 86.

The main goal of Acadia’s trial was a change in the psychosis score using the Neuropsychiatric Inventory-Nursing Home Psychosis, a rating scale for evaluating patients in an institutional setting. After six weeks, Acadia says, patients who received pimavanserin scored a 3.76 point improvement on that scale, compared against a 1.93 point improvement in the placebo group. But that effect appeared to weaken. On the secondary endpoint of the trial measuring the drug’s effect after 12 weeks, Acadia said that its drug maintained the improvement on psychosis that was seen at the six-week mark but that those results were not statistically significant compared against the placebo group.

Acadia says that it is continuing to analyze the results of the Phase 2 trial and that it plans to present more information at a future medical conference.

Image by Flickr user _DJ _ under a Creative Commons license.