A drug to treat hallucinations and delusions in patients with Parkinson’s disease is being made available in the United States.
Pimavanserin (Nuplazid) has been granted a fast-track marketing authorisation by the US Food and Drug Administration (FDA) and was approved on the grounds that it has the potential to address a serious clinical condition, despite only preliminary clinical evidence supporting it.
Some 50% of all Parkinson’s disease patients have delusions and hallucinations, which can be “profoundly disturbing and disabling”, according to Mitchell Mathis, director of the division of psychiatry products in the FDA’s Center for Drug Evaluation and Research. The drug “represents an important treatment for people with Parkinson’s disease who experience these symptoms”, he says.
The drug’s approval follows the results of a six-week clinical trial involving 199 patients in which pimavanserin was shown to be superior to placebo in decreasing the frequency and severity of hallucinations and delusions without worsening the primary motor symptoms of Parkinson’s disease.
The most common side effects reported were swelling, usually of the ankles, legs and feet, nausea and confusion.
As with similar atypical antipsychotic drugs, pimavanserin comes with a ‘boxed warning’ because of its increased risk of death if used to treat older people with dementia-related psychosis and is not approved to treat this group of patients.
The National Parkinson Foundation, a US organisation that promotes research and supports patients with the disease, describes the drug as a “breakthrough treatment”.
“[Pimavanserin] represents a major paradigm shift in the treatment of Parkinson’s disease psychosis,” says Michael Okun, the foundation’s national medical director. “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.”
Janine Barnes, neurology specialist pharmacist for Dudley clinical commissioning group in the West Midlands, also recognises pimavanserin’s potential.
“If the drug does not block dopamine sites, which presumably it does not if motor function is not impaired, I would agree that this is a significant breakthrough as hallucinations and delusions can be very difficult to manage in Parkinson’s disease,” she says. “If this is the case, it is definitely a drug which we would want available in the UK to manage our Parkinson’s patients.”
The European Medicines Agency, which evaluates drugs for use across the European Union, confirmed it has not received a marketing authorisation application for pimavanserin and as a result it is not reviewing the drug at present.
Pimavanserin is marketed in the United States by Acadia Pharmaceuticals.