Weight loss and diabetes medications may slow progression of Alzheimer's disease, preliminary study suggests

A drug used to treat weight loss and diabetes may slow cognitive decline in people with mild Alzheimer's disease, according to a mid-stage study presented at the Alzheimer's Association's International Conference in late July. The results have not yet been published in a peer-reviewed journal.

“This looks promising,” Alberto Espay, a neurologist at the University of Cincinnati, tells NBC News' Berkeley Lovelace Jr. “If this is reproduced in a Phase 3 trial, it could become the first truly disease-modifying treatment for Alzheimer's disease.”

Experts say larger studies are needed to confirm the findings, but the results are part of a growing body of research examining whether diabetes and weight loss drugs can be used to treat Alzheimer's disease.

“It makes us really think about the potential of these new drugs for Alzheimer's or other forms of dementia,” Rebecca Edelmayer, senior director of scientific engagement at the Alzheimer's Association, told USA Today's Ken Alltucker.

Drugs called glucagon-like peptide-1 (GLP-1) agonists, including Ozempic and Mounjaro, are used to help people lose weight, control their diabetes and reduce their risk of heart disease, stroke and kidney disease, a statement from the conference said. Animal studies have shown that these drugs can also reduce levels of amyloid protein in the brain, which is linked to Alzheimer's disease.

Researchers tested one of these GLP-1 agonists called liraglutide, which is sold as the weight-loss drug Saxenda and the diabetes drug Victoza. Liraglutide is not approved to treat Alzheimer's disease.

For the new study, the team recruited 204 people with mild Alzheimer's disease from 24 different clinics in the UK. Half received a daily injection of liraglutide for a year, while the other half received a placebo. The patients underwent memory tests and MRIs to measure their brain structure and volume, as well as PET scans to measure glucose metabolism, which is linked to Alzheimer's.

“This is the first study that has actually looked at a relatively large number of patients to see if there is a neuroprotective effect in Alzheimer's disease,” Paul Edison, who led the research and is a neuroscientist at Imperial College London, told CNN's Meg Tirrell.

Many regions of the brain shrink in Alzheimer's patients. However, participants who received liraglutide experienced 50 percent less shrinkage in several parts of the brain related to memory, learning, language and decision-making than the control group. Patients who received the drug also had 18 percent less cognitive decline, as shown by various tests of memory, comprehension, language and spatial orientation.

However, the treatment did not appear to significantly affect glucose metabolism in the brains of those affected.

Espay tells NBC News that it makes sense that GLP-1 appears to help protect the brain, since Alzheimer's is a “syndrome of many diseases caused by different biological, toxic or infectious influences.”

In the treatment group, 79 people completed the one-year treatment, and in the placebo group, 87 people completed the treatment. The most common side effect was gastrointestinal problems such as nausea.

“Having a drug that has a very good safety profile and can be used widely – that will be a game changer,” Edison tells CNBC's Annika Kim Constantino.

According to CNBC, Novo Nordisk, the company that sells the drug, partially funded the new research.

“The study was conducted on a small group of people,” Sheona Scales, research director at Alzheimer's Research UK, told Guardian'S Andrew Gregory. “Larger trials are currently underway to test whether drugs such as liraglutide can slow the progression of Alzheimer's disease.”

A three-year clinical trial testing the GLP-1 agonist semaglutide – sold under the names Ozempic diabetes drug and Wegovy weight-loss drug – in 1,800 people with early-stage Alzheimer's disease is currently underway, the statement said.