Semaglutide for Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a rare, genetic disease that leads to muscle weakness, breathing difficulties, heart disease, and early death. Approximately half of individuals with DMD have elevated body mass indices (BMIs) in the overweight or obesity range. High BMI is due to a combination of factors including limited mobility and steroid medications, which are used to treat DMD.

There are new medications, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) that promote weight loss in the general population. GLP-1 RAs are approved for weight loss in children and adults and have beneficial effects on the heart. There is a concern that these medications could have unwanted side effects in individuals with DMD, specifically decreasing their muscle mass. While it is important to consider the use weight-loss medications in DMD, the investigators want to ensure that they are safe and well-tolerated. Therefore, this study will systematically evaluate whether the use of GLP-1 RAs in adolescents and young adults with DMD affects muscle mass.

The overall goal of this study is to assess the safety and tolerability of GLP1-RAs in individuals with both DMD and obesity. The primary focus will be on muscle health, but the study will also evaluate activity levels, mood, gastrointestinal symptoms, and quality of life. Secondary goals will be to understand the impact of GLP1-RAs on weight, fat mass, glucose and insulin levels, and heart and lung function in individuals with DMD. The investigators hypothesize that GLP1-RAs will be well-tolerated and will decrease fat mass, without a large decrease in muscle mass.

Participants will:

* Take oral semaglutide or a placebo every day for 24 weeks (randomized controlled trial)

* Then take oral semaglutide every day for 40 weeks (open label extension)

* Complete in-person study visits at 3 timepoints

* Study visits may include: an MRI of the body to evaluate muscle and fat tissue, laboratory testing, a mixed meal tolerance test, questionnaires, an MRI of the heart, pulmonary function tests, and additional measures

* Calls with the study team between visits (monthly or every other month)