Psychosis, a condition of the mind associated with a loss of contact with reality, can be a problem for many living with Parkinson’s disease (PD), as it’s often a side effect from the medications taken to treat the motor symptoms of the disease.  Psychosis is more common among older Parkinson’s patients and those who experience cognitive impairment.     

Currently, doctors may prescribe certain anti-schizophrenic drugs to treat psychosis, which can manifest itself in the form of hallucinations (seeing things that aren’t there) and delusions (fixed, false and generally paranoid beliefs).  But serious side effects and safety concerns make these drugs less than optimal, says Michael F. Fox Foundation (MJFF) Scientific Advisory Board member Irene Hegeman Richard, MD.    

For these reasons, an effective treatment for psychosis remains a major unmet need for the Parkinson’s community, including for caregivers who are exposed to the frightening realities of their partners’ altered states of mind. 

But today, encouraging news on this front, as clinical study results suggest such a therapy, called pimavanserin, is getting closer to pharmacy shelves. 

The phase 3 trial, from San Diego-based biotech Acadia Pharmaceuticals, found that, in addition to being safe, pimavanserin was effective against psychosis. The drug was also found to improve upon the nighttime sleep and daytime wakefulness that is often disrupted in those who experience psychosis, while lessening the burden experienced by caregivers of the study’s subjects.  The fact that the drug showed strong positive data on each of these outcomes is reason for optimism, says Richard. 

Still, there is time to wait until people with PD might be able to take pimavanserin: Acadia says that a second phase 3 trial will be conducted prior to any potential regulatory approval from the FDA.

“While these results are certainly encouraging,” adds Richard,” it will be important to see if there are any longer term effects or rare side effects which may not have been evident during the course of this relatively brief clinical trial.  

“If pimavanserin does turn out to be an effective and well-tolerated medication to treat psychosis in PD, that would have a major impact on patients and their caregivers.”

Note: In unrelated work, Acadia has received funding from MJFF for pre-clinical studies into a novel target for PD called Nurr1.  Nurr1 is a receptor in the brain thought to play a critical role in the growth, maintenance and survival of the dopaminergic neurons that are depleted in PD. Acadia is investigating potential drug compounds that activate Nurr1 to see if doing so might maintain the health of these dopamine-containing neurons, in turn restoring motor function.