The new drug pimavanserin may help people with Parkinson’s disease experience less severe or frequent symptoms of psychosis.
As of now, the only treatment options for those who experience psychosis—a common symptom for many people with Parkinson's—are dopamine antagonist antipsychotic drugs, such as clozapine and quetiapine. The problem is that they can make motor symptoms worse, accelerate cognitive decline, increase a person’s risk of stroke, and even cause death.
Psychosis is characterized by delusions or hallucinations and is a major reason why people with Parkinson's are often admitted to nursing homes. The new findings offer hope that more patients with Parkinson’s will be able to receive care at home.
Drug Yields Fewer Psychosis Symptoms
Clive Ballard, a professor at King’s College London, lead the research on 199 Parkinson's patients who experienced psychosis and were over the age of 40. Some received 40 mg of pimavanserin once daily; others took a placebo pill.
A nine-item Parkinson's disease scale, known as a SAPS-PD, was used to evaluate their psychosis symptoms throughout the 43-day study.
The researchers found that patients on pimavanserin had better SAPS-PD scores compared to those who took the placebo. Thirty-seven precent of patients taking the drug saw improved scores, compared to just 14 percent of participants on the placebo.
The scientists also noted that patients taking the drug slept better at night, were more wakeful during the day, and were easier for caregivers to treat. And importantly, the patients on pimavanserin did not experience worsening motor symptoms.
How Pimavanserin Works
Pimavanserin blocks serotonin 5-HT2A receptors in the neocortex, the area of the brain that controls sensory perceptions, language, and conscious thought. The neocortex is also linked to visual hallucinations and delusions—both aspects of psychosis.
Among patients taking it, pimavanserin was well tolerated. Researchers said the most common side effect was a slightly elevated risk of urinary tract infections. During the study, 10 patients stopped taking the drug, compared to four on the placebo.
The researchers say that the drug could perhaps be used to treat symptoms of psychosis in those with Alzheimer’s and other dementia-related conditions as well.
Bringing the Drug to Market
How close is pimavanserin to being available for use?
Dr. Anne Corbett, co-author of the paper and a psychosis researcher at King’s College, said the U.S. Food and Drug Administration is looking to license the drug. If they approve the medication, it's more likely that the National Institute for Health and Care Excellence in the U.K. will do the same.
She says the drug could have a “considerable” impact on Parkinson’s treatment, giving doctors a valuable option to treat disturbing symptoms.
Pimavanserin is beneficial for caregivers, too, she said. They may not have to put their loved ones in treatment centers, which is often a difficult decision and lifestyle change.
“Since psychosis is often a reason for people moving into residential care, this could mean that people can stay living at home for longer,” Corbett said.