Diabetes drug may slow progression of Parkinson’s, say researchers

A drug similar to those used in “skinny jabs” could help to slow the progression of symptoms of Parkinson’s disease, research suggests.

According to the Parkinson’s Foundation, more than 10 million people around the world are living with Parkinson’s – a condition in which nerve cells in the brain are lost over time causing problems with movement, balance and memory, among other effects.

Although treatments are available to help manage symptoms, there is no cure.

However, in recent years glucagon-like peptide 1 receptor agonists (or GLP-1R agonists) have caused excitement, with one such drug, a type 2 diabetes medication called exenatide, found to help slow the progression of motor symptoms in a small group of people with Parkinson’s.

Now researchers say another such drug, a type 2 diabetes medication called lixisenatide, appears to do the same, supporting the theory that Parkinson’s could be associated with insulin resistance in the brain.

Prof Wassilios Meissner, of University hospital of Bordeaux, a principal investigator of the study, said the results were exciting.

“We have to stay cautious about all the interpretation and about applicability at the current stage, but it is really a very, very clear and strong signal we have never seen except [in the] exenatide trial,” he said.

GLP-1R agonists shot to fame for their use in managing type 2 diabetes and aiding weight loss, with semaglutide and liraglutide among the best-known drugs.

However, unlike exenatide and lixisenatide, these do not easily cross into the brain, making them less likely candidates for use in treating Parkinson’s.

Writing in the New England Journal of Medicine, researchers in France report how they randomly split 156 people who had recently been diagnosed with Parkinson’s into two equal-sized groups.

While both groups took their usual Parkinson’s medication, one group was given an additional daily injection of lixisenatide, while the other was given a placebo.

Before, during and after the study, participants underwent an examination of their motor symptoms and were given a score on a disease-severity scale.

The results reveal that after 12 months, those given lixisenatide showed essentially no progression of motor problems, while those given the placebo showed worsening symptoms, dropping around three points on the 132-point assessment scale – a modest difference, yet thought to be clinically meaningful.

The difference remained two months after the trial stopped and other Parkinson’s medications were halted overnight.

That, the researchers say, suggests lixisenatide does not just reduce symptoms but protects the brain against the loss of neurons.

However, there was a drawback, with about half of the participants receiving lixisenatide reporting nausea and 13% reporting vomiting.

The researchers add that further work is now needed to unpick whether lixisenatide does indeed slow disease progression itself, whether the benefits persist over time or even increase if the drugs are given for longer, the best dose and whether the drug would offer benefits to people at other stages of Parkinson’s.

Heather Mortiboys, a professor of cellular neuroscience and metabolism at the University of Sheffield, who was not involved in the work, said the findings paved the way for larger phase 3 clinical trials.

“The new clinical trial results for lixisenatide showing a significant reduction in motor symptom progression compared with placebo group represent a really promising and very exciting step forward in our research fight to get new drugs to the clinic for Parkinson’s,” she said.

“The study provides more weight to all of the current results showing this class of drug, GLP-1R agonists, have real potential for Parkinson’s.”