Ask the doctors: GLP-1 medications my slow progression of Parkinson’s symptoms

Dear Doctors: I have Parkinson’s disease. I was diagnosed 10 months ago, and it is already affecting my ability to walk and to use my hands. My husband recently read that there’s a diabetes drug that can slow down the symptoms. Do you know anything about that?

Dear Reader: Your husband is referring to the results of a clinical trial that were published earlier this year in the New England Journal of Medicine. The researchers found that an older diabetes drug, which is a precursor to Ozempic, may have a protective effect on the nervous system in people living with early-stage Parkinson’s disease. This recent study builds on previous research that was conducted in mice. Those studies found the drug could slow the progression of some of the physical symptoms of the disease.

For those who are unfamiliar, Parkinson’s disease is a progressive neurological disorder in which changes to certain tissues in the brain have an adverse effect on movement. Symptoms are progressive and vary from person to person. The most common include tremor, impaired balance, rigid muscles, slowed movement, changes to speech, disordered sleep and changes to memory and cognition. The causes of the disease are not yet understood, and there is no known cure at this time.

The clinical trial you are asking about included 156 adults who ranged in age from 40 to 75. Each was in the earlier stages of the disease, with symptoms ranging from mild to moderate. Half of the participants received a diabetes drug called lixisenatide. This is a class of drug known as glucagon-like peptide-1 (GLP-1) and is similar to Ozempic. The other participants were given a placebo. Everyone in the study continued to take their usual Parkinson’s medications.

Throughout the course of the study, the motor symptoms of the group receiving the diabetes drug did not progress, which suggests a neuroprotective effect. This contrasted with the control group, who received a placebo. Those participants saw a progressive worsening of their symptoms, which is a hallmark of Parkinson’s. Some people taking the diabetes medication experienced side effects associated with that class of drug, including nausea and vomiting.

As for why this class of diabetes drug may slow the progression of Parkinson’s motor symptoms, the answers are not yet clear. Previous research has found that people living with diabetes are up to 40% more likely to develop Parkinson’s disease. The link to diabetes doesn’t end there. The data show that when someone has diabetes and Parkinson’s disease, they are at risk of a more rapid progression of motor symptoms.

As with many chronic and progressive diseases, inflammation also plays a role. Clinicians suspect the anti-inflammatory properties of this class of diabetes drugs may help protect the neurons in the brain that produce dopamine, and which become progressively damaged in Parkinson’s patients.

While the results of the study are encouraging, the researchers caution that the research is in the early stages. The results of a two-year clinical trial, which will be available later this year, are expected to shed more light on the topic.

Send your questions to askthedoctors@mednet.ucla.edu.