A new clinical trial found that taking a popular diabetes and weight-loss drug once weekly significantly improves blood sugar and leads to substantial weight loss in adults with type 1 diabetes who use automated insulin delivery systems.

The results are published today in the journal NEJM Evidence.

Semaglutide is a medication that belongs to a class of drugs known as glucagon-like peptide-1, or GLP-1, receptor agonists. Sold under the trade names such as Ozempic, Wegovy and Rybelsus, the drug was initially developed for the treatment of type 2 diabetes, helping to manage blood sugar levels.

The 26-week, double-blind study involved 72 participants across four medical centers, including Oregon Health & Science University. Researchers found that 36% of patients taking semaglutide met all three key health goals—improved blood glucose levels, reduced time spent in low blood sugar and at least 5% weight loss—compared to none in the placebo group.

“Semaglutide helped more people reach their blood sugar and weight goals without decreasing blood sugar,” said Andrew Ahmann, M.D., emeritus professor of medicine at Oregon Health & Science University’s School of Medicine, and a co-author on the study.

Those on semaglutide lost an average of about 18.5 pounds over six months in the study and saw modest improvements in average blood sugar levels (A1C) and the amount of time blood sugar stays in a healthy range, without a higher risk of dangerous low blood sugar or serious complications like diabetic ketoacidosis.

While semaglutide is already approved for type 2 diabetes and obesity, its use in type 1 diabetes remains investigational. This is the first randomized clinical trial to show that the medication may also be effective in type 1 diabetes in patients already using automated insulin delivery.

Viral Shah, M.D., of the Indiana University School of Medicine, is senior author on the study. In addition to Shah and Ahmann, other co-authors include Halis Akturk, M.D. and Janet Snell-Bergeon, Ph.D., of University of Colorado Anschutz Medical Campus, Davida Kruger, D.N.P., M.D., of Henry Ford Health, Anuj Bhargava, M.D., of Iowa Diabetes Research, Giorgos Bakoyannis, Ph.D., of Indiana University School of Medicine, and Laura Pyle, Ph.D., of the University of Washington.