Pimavanserin (Nuplazid, Acadia Pharmaceuticals) has received FDA approval for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. In 2014, the FDA designated pimavanserin as a breakthrough therapy for this condition.
“Today’s approval of Nuplazid represents a major paradigm shift in the treatment of Parkinson’s disease psychosis,” said Michael S. Okun, MD, Medical Director of the National Parkinson Foundation. “Through its novel and selective mechanism of action, Nuplazid is a breakthrough treatment that works in a whole new way, treating hallucinations and delusions without blocking dopamine receptors and, therefore, not impairing motor function in Parkinson’s psychosis patients.”
Pimavanserin is the first medication to be approved by the FDA for this indication. It is also the only drug approved by the FDA that preferentially targets 5-HT2A receptors. These receptors are thought to play an important role in Parkinson’s disease psychosis. The pharmacology of pimavanserin establishes a new class of drug—selective serotonin inverse agonists (SSIA)—by not only preferentially targeting 5-HT2A receptors, but also avoiding activity at dopamine and other receptors commonly targeted by antipsychotics. Typical Parkinson’s disease therapy consists of drugs that stimulate dopamine to treat patients’ motor symptoms such as tremor, muscle rigidity, and difficulty walking. Pimavanserin does not interfere with patients’ dopaminergic therapy and therefore does not impair their motor function.
According to the National Parkinson Foundation, about one million people in the United States and four to six million people worldwide suffer from Parkinson’s disease. An estimated 40% of these patients have Parkinson’s disease psychosis, which is characterized by hallucinations and delusions, is associated with significant caregiver burden, and is a major reason for nursing home placement among Parkinson’s patients.
“Parkinson’s disease psychosis is a debilitating condition that adds a tremendous burden on the lives of patients already contending with motor issues such as slow movement, loss of balance, and muscle rigidity,” said Todd Sherer, PhD, Chief Executive Officer of the Michael J. Fox Foundation. “It also places an increased burden on caregivers and can lead to loss of independence and nursing home admittance for patients. A therapy to treat the hallucinations and delusions associated with Parkinson’s disease psychosis without worsening motor symptoms can significantly impact the lives of Parkinson’s patients and their loved ones.”
The FDA approval of pimavanserin was based on data from the pivotal phase 3 Study-020 and other supportive studies, representing the largest research and development program in Parkinson’s disease psychosis to date. In Study-020, pimavanserin significantly reduced the frequency and severity of psychotic symptoms compared with placebo on the Scale for Assessment of Positive Symptoms–Parkinson’s Disease. This benefit was achieved without impairing motor function. The most common adverse reactions (5% or more and twice the rate of placebo) in this study were peripheral edema (7% pimavanserin versus 3% placebo) and confusional state (6% pimavanserin versus 3% placebo). Results of Study-020 were published in The Lancet.
Acadia plans to make Nuplazid commercially available in the U.S. in June 2016.
Source: Acadia Pharmaceuticals; April 29, 2016.