Further evidence on the benefits of pimavanserin

The treatment is currently available in the USA, after being licensed by the FDA in May, but is still unavailable in the UK.

Results from King's College London and the University of Exeter, published earlier this year in the scientific journal Nature Reviews Neurology, have featured in the headlines today. You can read the research on the Nature Reviews Neurology website.

What is psychosis?

Around 80% of people with Parkinson's develop dementia as the condition progresses. Many people with dementia will experience symptoms such as delusions and hallucinations (sometimes called psychosis).

This means that they may see, hear, smell or taste things that aren't there, or have thoughts and beliefs that aren't based on reality. And these symptoms are often particularly intense in Parkinson's. 

Commonly-prescribed medications only have a marginal benefit in reducing these symptoms in Parkinson's. They also quadruple the risk of stroke, and can worsen motor symptoms - causing tremor, slow movements and resulting in problems with walking and falls.

A new type of antipsychotic

In the UK, drugs that are available to treat hallucinations and delusions target a receptor for a chemical messenger on brain cells called dopamine.

These drugs work well in Schizophrenia, but Parkinson's and dementia with Lewy bodies cause the dopamine producing brain cells to be lost. This means the drugs are less effective and can have significant side effects.

Pimavanserin has been specifically designed to treat hallucinations and delusions without worsening the motor symptoms of Parkinson's. It works by targeting 5HT2A receptors that respond to serotonin in the brain.

Pimavanserin should be licenced

Claire Bale, Head of Research Communications and Engagement at Parkinson's UK, said: 

"This new analysis suggests that pimavanserin is even more effective for treating psychotic symptoms – like hallucinations and delusions – in people with Parkinson's dementia than in those with Parkinson's without dementia.

"This is extremely promising because psychotic symptoms are a very common and distressing feature of Parkinson's dementia and current treatment options are extremely limited.

"Pimavanserin has been approved for use by the Food and Drug Administration (FDA) in the US but has not yet been submitted for approval to the European equivalent, the European Medicines Agency.

"It is now imperative that pimavanserin goes through the European approval process to be made available to people who would benefit hugely from the drug. People with Parkinson's can't wait any longer for better treatments."