Data from a small clinical trial published on Tuesday showed that a drug from the GLP-1 receptor agonist class known for weight loss slowed the loss of brain volume in people with mild Alzheimer's disease.

The trial results, published at the Alzheimer's Association International Conference, provided the first glimpse of how GLP-1 drugs may act on hard-to-treat brain disorders.

The trial studied just 204 patients in Britain, half of whom received Novo Nordisk's earlier-generation GLP-1 drug liraglutide, and the other half a placebo.

The trial did not meet its primary endpoint, or main goal, which was change in the cerebral glucose metabolic rate, an assessment of brain function.

It did meet the secondary endpoints. It showed liraglutide appeared to reduce shrinking in the parts of the brain that control memory, learning, language and decision-making by nearly 50% compared to placebo.

The trial was not sponsored by Novo. However, the Danish drugmaker is testing its new-generation, more effective GLP-1 drug semaglutide — sold as diabetes drug Ozempic and obesity drug Wegovy — in thousands of patients with early Alzheimer's. Its two trials began in 2021 and results are expected in 2025.

Rebecca Edelmeyer, senior director of scientific engagement at the Alzheimer's Association, told Reuters in an interview that the results published on Tuesday were "really intriguing."

"This is our first time really seeing this type of intervention readout in a clinical trial," she said.

Researchers told Reuters last year that diabetes regimens, from Ozempic to insulin and metformin, appear to address several different aspects of the metabolic system implicated in Alzheimer's, including a protein called amyloid and inflammation.

The hope is that improving glucose utilization and reducing inflammation in the body - including the brain - could slow progression of Alzheimer's.

Still, the trial published on Tuesday was not designed to measure cognitive benefits, and some scientists urged caution.

"The repurposing of drugs is an important avenue of research but there is a lot of uncertainty here," said Stephen Evans, emeritus professor at the London School of Hygiene and Tropical Medicine.

He said the shrinking in the memory and learning parts of the brain observed in the small trial "may not translate to important cognitive benefits" and the results did not demonstrate that liraglutide could protect against dementia, though pursuing a larger trial would be worthwhile.