Do you or a loved one experience dyskinesias as part of Parkinson’s disease (PD)? The Parkinson’s Disease Foundation (PDF) has exciting news that may affect those of you who experience levodopa-induced dyskinesias (LIDs), the twisting and writhing movements that occur when people take levodopa.
A few months ago, the Food and Drug Administration (FDA) granted orphan drug status to an experimental PD medication called eltoprazine, which is designed to ease LIDs. This status acknowledges that the drug fills an important unmet need (if approved, it would be the first drug available to treat LIDs) and may allow the drug to become available more quickly.
Not only that, the drug was identified for treatment of LIDs in Parkinson’s because of basic science funded by PDF 10 years ago. In this installment of Back to Basics (see installment one here), we give you the story on this drug — how basic science from 2006 might help the PD community in 2016.
The Back Story of Basic Science
Eltoprazine works by helping to regulate brain cells that release serotonin. Back in 2006, the PD community wasn’t thinking too much about serotonin (dopamine is the main chemical messenger involved in Parkinson’s). But Manolo Carta, Ph.D., of Lund University was thinking about it, and was awarded PDF funding to explore its role in Parkinson’s disease.
He was interested in a discovery by other scientists, who had found that when dopamine neurons die in Parkinson’s, serotonin neurons pitch in to help produce dopamine. (Have you ever heard the saying, “it takes a village?” As it turns out, this proves true for the brain.) But when serotonin neurons try to help, they make the mistake of releasing too much dopamine into the brain. Dr. Carta suggested that this might cause dyskinesias in Parkinson’s.
In his first year of PDF funding, he studied animals. His experiments showed that damaging serotonin neurons in mice with PD-like symptoms stopped their dyskinesias. But he wondered, was there a drug that could mimic this effect in people? If yes, would that stop dyskinesias in people with Parkinson’s?
From Idea to Solution
In 2007, Dr. Carta received a second year of PDF funding to study possible treatments — molecules that would help serotonin neurons release less dopamine. He studied two drugs that targeted the helper neurons at different spots (known as 5-HT1A and 5-HT1B receptors). He found that when low doses of both drugs were combined, he could ease LIDs in animals with PD. Not only that, the drug combo prevented LIDs when it was given with levodopa right away. Based on this finding— that targeting brain cells at two spots rather than just one can help ease LIDs — the drug eltoprazine (originally indicated for treatment of aggression) was identified as a good candidate for treating LIDs in Parkinson’s.
Fast forward several years, after thorough testing in animal models, in 2015, the first clinical trial of eltoprazine was conducted in Sweden in a group of 22 people with Parkinson’s. The researchers found that the drug significantly reduced LIDs in people with Parkinson’s, while maintaining the benefits of levodopa that eased Parkinson’s movement symptoms.
The results so far are promising, as is the FDA’s “orphan status” but more trials are needed to understand the long-term effects of eltoprazine, and whether it works well at all stages of PD.
Eltoprazine, if approved by the FDA, could bring relief to people suffering from LIDs. This is exciting, because currently dyskinesias are treated either by lowering the dose of levodopa (which can worsen symptoms) or through deep brain stimulation (which is not for everyone).
This novel therapeutic area could bring so much help to the PD community, and it all started with basic science experiments ten years ago. The path from basic science to approved treatments for PD can be long and winding. Sometimes there can be roadblocks. But when it works, the journey is worth the wait.
As part of its mission to end Parkinson’s, PDF funds $4 million a year in basic science. In ‘Back to Basics,” Dr. Vernaleo traces how basic science is helping PDF come closer to solving, treating and ending Parkinson’s disease.