A diabetes drug may be able to slow the progression of Parkinson's disease, representing a "significant step forward" in the future management of the condition, a new study suggests. The progression of motor symptoms, like tremors and slowness of movement, was slowed in patients who took the treatment called lixisenatide, the research found. However, the research also found that nausea occurred in 46% of people receiving lixisenatide, and vomiting occurred in 13%. Professors Wassilios Meissner and Olivier Rascol, principal investigators of the study, jointly said: "For 30 years, we have been trying to understand how to slow the decline associated with Parkinson's disease over time. In this context, the positive results of the Lixipark phase 2 trial showing less progression of motor symptoms of Parkinson's disease over a year constitute a significant step forward in the future management of the disease. We look forward to confirming these encouraging results in the future, in order to translate such findings into clinical practice." The drug belongs to a group of medicines called glucagon-like peptide 1 receptor agonists (or GLP-1R agonists) that work by mimicking the action of a natural gut hormone that is produced after eating food. The hormone stimulates insulin release from the pancreas, which helps cells in the body to absorb glucose that is eventually turned into energy. There is a known link between Parkinson's and type 2 diabetes, with research suggesting people with diabetes have a higher risk of developing Parkinson's. People with Parkinson's who are type 2 diabetic often experience a more rapid progression of their symptoms, research has suggested. It has also been reported that people with diabetes who are treated with the medicines have a reduced risk of developing Parkinson's. Dr Richard Wyse, director of clinical development at Cure Parkinson's, said: "I am thrilled to see the extremely positive, groundbreaking clinical outcome of the lixisenatide trial, which could have real meaning for people living with Parkinson's." The LixiPark study involved 156 people who had been recently diagnosed with Parkinson's. They were treated with either lixisenatide, which is licensed for diabetes in the UK, or a dummy drug together with their usual Parkinson's medication. The progression of motor symptoms in those receiving the lixisenatide treatment slowed, while motor symptoms in people in the other group continued to progress. The findings were consistent at the end of the 12-month study and two months after treatment stopped, and researchers say longer and larger studies are now needed. Led by Professors Olivier Rascol and Wassilios Meissner at the University Hospital of Toulouse and University Hospital of Bordeaux, respectively, the LixiPark trial involved 21 different research centres of the NS-Park Network across
France. The study, sponsored by the Toulouse University Hospital, was co-funded by
UK charity Cure Parkinson's, with Van Andel Institute, and the French Ministry of Health, with drug and placebo support from pharmaceutical company Sanofi. Masud Husain, professor of neurology, University of Oxford, said: "The results of this trial are really encouraging for people with Parkinson's disease. After a year, patients who were on the drug were significantly better off in their movements than those who weren't on the medication. "However, the findings do not provide conclusive evidence that the drug has a protective effect on the brain to effectively slow down disease progression. We also have to bear in mind the side effects. Nausea occurred in nearly half and vomiting in 13% of people on the medication." Professor Michele Vendruscolo, co-director, Centre for Misfolding Diseases, University of Cambridge, said: "GLP-1 agonists are widely used to treat type 2 diabetes, and are among the leading repurposed drugs being tested for disease-modifying effects in Parkinson's disease. In addition to prompting longer and larger clinical trials, these results show that a more quantitative understanding of the mechanism of action of GLP-1 agonists may reveal one or more therapeutic targets for the development of more potent drugs to treat Parkinson's disease."