Treatment with Nuplazid (pimavanserin) does not lead to a different mortality risk compared to the antipsychotic medication Seroquel (quetiapine), or to combination treatment with both medications, in patients with Parkinson’s psychosis, according to results from a large study.
The study, “Mortality in patients with Parkinson disease psychosis receiving pimavanserin and quetiapine” was published in the journal Neurology.
In April 2016, Acadia Pharmaceuticals’ Nuplazid became the first therapy approved by the U.S. Food and Drug Administration (FDA) for hallucinations and delusions associated with Parkinson’s psychosis.
However, two years later, a CNN report cited an analysis by the nonprofit Institute for Safe Medication Practices, which found a total of 700 deaths in the FDA’s Adverse Event Reporting System — including 500 among Parkinson’s patients in which Nuplazid was the only therapy likely involved — in the nine months following Nuplazid’s arrival on the market in June 2016.
Now, researchers at University of California San Diego School of Medicine explored the medication’s safety further. “We wanted to better understand and assess the risks of using pimavanserin (Nuplazid) within our own patient community, either alone or in combination with other commonly prescribed medications,” Fatta B. Nahab, MD, the study’s senior author, said in a press release.
Besides Nuplazid, the team focused on Seroquel, a second-generation antipsychotic (SGA), which is often used to treat Parkinson’s psychosis. Results were mixed. Use of Seroquel and other SGAs led to concerns about increased morbidity and mortality in patients with dementia or those with Parkinson’s, prompting an FDA black box warning.
Unlike Seroquel, Nuplazid does not affect dopamine receptors, so it does not interfere with the effectiveness of Parkinson’s treatments for motor symptoms.
The team conducted a retrospective analysis of 4,478 UC San Diego Health patients with Parkinson’s, of whom 676 were being prescribed Nuplazid, Seroquel, or both, between April 29, 2016 and April 29, 2018.
Results showed that patients treated with Nuplazid alone (113 patients, mean age 75.9 years) had a lower mortality percentage when compared to those treated with quetiapine only (505 patients, mean age 75.2 years), or with both compounds (58 patients, mean age 74.1 years ). However, the differences were not statistically significant.
When compared to 784 Parkinson’s patients not on these medications (mean age 80 years), the results revealed a significantly greater risk (74%) of mortality in the Seroquel-only group and a trend toward increased risk in the combination treatment group.
“It’s reasonable to assume, however, that individuals requiring these medications have greater disease severity and are at a higher risk of complications and death,” Nahab noted.
A subset of the patients receiving both medications exhibited the highest rate of mortality, although not statistically different. Importantly, the team noted that the combination therapy’s safety is not yet established, as the pivotal Phase 3 trial of Nuplazid (NCT01174004) excluded individuals on antipsychotics.
“Our findings provide the largest comparative report of mortality risk in [Parkinson’s psychosis],” researchers wrote.
However, Nahab noted limitations on the study’s design and nature, which precluded the determination of cause of death or duration of antipsychotic treatment.
“While the results pertaining to [Nuplazid] provide some reassurance for clinicians, patients, and families, future studies are needed to evaluate factors such as disease severity and cause of death,” they added.
Earlier this week, Nuplazid’s benefits were further supported after a recent FDA review did not find any new or unexpected safety concerns, concluding that its benefits outweigh its risks for patients with Parkinson’s disease psychosis.