Semaglutide, the drug used in Ozempic, has been linked to lowering the risk of Alzheimer's disease in the past. So, it was natural for the scientists to be hopeful when they tested the possibility of an Ozempic-like drug to improve Parkinson's disease symptoms, in a trial. However, the results were far from what they expected.
The new study has cast doubt on the potential of GLP-1 drugs, like Ozempic and Wegovy, to treat neurodegenerative diseases such as Parkinson’s.
Researchers had hoped that exenatide, a drug in the same class, could slow the disease’s progression. However, a rigorous 96-week clinical trial involving 194 patients found no benefit. No improvement in symptoms, no changes in brain scans, and no slowed progression of the disease was found.
The disappointing findings, published in The Lancet, suggest that while GLP-1 drugs have been revolutionary for weight loss and diabetes, their effectiveness in treating Parkinson’s remains unproven.
“It’s hugely disappointing,” said Dr. Thomas Foltynie of University College London, who led the trial. “We were expecting we would come through and we would get a positive result.”
What is Parkinson's disease
It is a movement disorder of the nervous system that keeps getting worse. The first symptoms are barely noticeable - like a tremor in just one hand or sometimes a foot or the jaw. While tremor is a telltale sign of Parkinson's disease, in some cases it could be absent. Stiffness, slowing of movement and trouble with balance that raises the risk of falls are other signs of the neurodegenerative disease.
Parkinson's disease could also steal expressions from your face and it is noticed that the arms of the patients may not swing upon walking. Speech changes are also noticed and over time it can become soft or slurred.
What really happens in Parkinson's disease is that nerve cells in the brain called neurons slowly die. The symptoms occur as a result of loss of neurons that produce a chemical messenger - dopamine - in the brain.
Low dopamine levels could lead to irregular brain activity which could cause movement issues and other symptoms of Parkinson's disease.
“This is a sobering moment,” Dr. Michael S. Okun, a Parkinson’s disease expert at the University of Florida and the national medical adviser for the Parkinson’s Foundation told New York Times. “This is a really well done study and it came up empty-handed.”
A study published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association had earlier found that semaglutide, the active ingredient in diabetes medications Ozempic, Rybelsus, and Wegovy, may help lower Alzheimer’s disease risk in people with type 2 diabetes, when compared to seven other drugs used to treat diabetes.
How the study was conducted
The 194 people with Parkinson’s disease involved in the study from the six research hospitals in the U.K were randomly assigned to inject themselves once a week for 96 weeks with exenatide, a type 2 diabetes treatment made by AstraZeneca and available under the brand name Byetta, or with a placebo.
While it is one of the GLP-1 receptor agonists, Exenatide is not as powerful weight loss drug as the newer drugs in the market. However, experts stated that there is no evidence suggesting newer GLP-1 drugs would yield different results in studies on brain diseases.
Why researchers tagged the results as disappointing
Researchers were hoping for a positive result as there were suggestions that GLP-1 drugs might help Parkinson’s patients.
GLP-1 drugs showed neuroprotective effects in laboratory studies and in research on rats with brain injuries similar to those seen in Parkinson’s disease. This raised hopes that similar benefits might extend to patients.
Earlier, two small studies suggested that exenatide may slow the progression of some Parkinson’s symptoms over a year’s time.
When a GLP-1 drug similar to Ozempic helped slow Parkinson's symptoms
A recent New England Journal of Medicine study tested lixisenatide, a GLP-1 drug, as a potential treatment for early-stage Parkinson’s. The phase 2 trial involved 156 participants who took either lixisenatide or a placebo for 12 months while continuing their usual Parkinson’s medications.
Results showed that those on lixisenatide maintained stable movement symptoms, while the placebo group worsened. Even after a two-month break from treatment, the lixisenatide group still showed better movement function, suggesting a possible slowing of disease progression.
Lixisenatide also demonstrated the ability to cross the blood-brain barrier better than other GLP-1 drugs. However, side effects were common—46% experienced nausea, 13% had vomiting, and some participants reduced their dose due to discomfort.
(Picture courtesy: iStock)
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