Popular diabetes and weight-loss drug semaglutide’s older brother may help slow the progression of Alzheimer’s disease. In clinical trial data released this week, British scientists found evidence that liraglutide can reduce brain shrinkage and cognitive decline in Alzheimer’s patients. Semaglutide has been tested in larger phase III trials in neurodegenerative diseases.
Liraglutide and similar drugs mimic the hormone GLP-1, which helps regulate our blood sugar and appetite. It was approved in 2010 to treat type 2 diabetes; in 2014, it was approved to treat obesity. It is known that people with poorly controlled diabetes are at higher risk for Alzheimer’s disease and other forms of dementia, and some animal studies suggest that liraglutide may prevent the damaging brain changes that occur in Alzheimer’s disease. Therefore, scientists at Imperial College London decided to conduct a double-blind, randomized, placebo-controlled trial of liraglutide in the treatment of Alzheimer’s disease.
The trial involved 204 patients diagnosed with early-stage Alzheimer’s, half of whom were given liraglutide. The drug did not appear to significantly alter glucose metabolism in people’s brains, which was the study’s main metric. But the researchers did find that people who took liraglutide experienced nearly 50% slower decline in brain volume loss over the next year than those who took a placebo. People taking the drug also experienced an 18% slowdown in cognitive decline during this period. The team’s findings were presented this week at the Alzheimer’s Association International Conference.
This research is preliminary; it has not yet gone through the peer review process. Assuming the results are valid, it’s unclear exactly how liraglutide improves people’s brains. But the researchers do have several possible explanations.
“We believe that liraglutide may protect the brain by reducing inflammation, reducing the toxic effects of insulin resistance and Alzheimer’s biomarkers, or improving the way nerve cells in the brain communicate,” said study researcher, Department of Neuroscience, Imperial College Professor Paul Edison said.
Perhaps the most exciting part of this study is that since this study began, more effective GLP-1 drugs have become available, such as semaglutide. Semaglutide (sold as Ozempic and Wegovy) and the newer tilsiparatide (Mounjaro and Zepbound) have been shown to be more effective than older GLP-1 drugs (such as liraglutide) in treating diabetes and obesity. A study published last month has found evidence that semaglutide can boost brain health in people with type 2 diabetes.
Novo Nordisk, the maker of liraglutide and semaglutide, is currently conducting two large, placebo-controlled trials to see whether semaglutide can improve the trajectory of patients with early-stage Alzheimer’s disease. If these results, expected in the next few years, are positive, semaglutide and other GLP-1 drugs will become the latest tools in a growing arsenal of anti-Alzheimer’s drugs.
