Pune, India | September 19, 2025
Weight loss often brings health improvements, especially when fat levels drop. But it can also have a hidden cost-muscle loss. Losing lean mass weakens the body, lowers metabolism, and reduces mobility. Regeneron’s Phase 2 COURAGE trial offers a new path. It shows patients may lose fat without losing as much muscle.
The COURAGE trial tested a new treatment plan. Instead of using semaglutide alone—a GLP-1 receptor agonist already approved for obesity—the researchers added experimental antibodies to improve results. The study included adults with a BMI of 30 or more and lasted 26 weeks.
Researchers divided participants into four groups. One group took semaglutide only. The other three used semaglutide with trevogrumab, either in low or high doses, or with both trevogrumab and garetosmab. Trevogrumab blocks myostatin (GDF8), a protein that slows muscle growth. Garetosmab blocks activin A, which also affects muscle regulation.
The results showed clear differences. In the semaglutide-only group, about 33–35% of the lost weight came from muscle. Those who took antibody combinations lost far less muscle. The group using all three therapies kept nearly 80% of the lean mass they would have lost. This group also burned more fat—up to 27% more than those on semaglutide alone.
This trial signals a new approach to obesity care. It focuses not just on weight loss but on what kind of weight is lost. Muscle matters. It supports strength, balance, movement, and a healthy metabolism. Protecting it can lead to better health outcomes in the long run.
The study also raised safety flags. As treatments got more complex, side effects increased. The group receiving all three drugs had more severe reactions and a higher dropout rate. Two participants in that group died. While investigators have not directly linked the deaths to the drugs, the events stress the need for caution.
Now, the trial moves into its second phase—another 26 weeks. This phase will examine whether patients can maintain their results and handle the treatment over time.
If future results stay positive, this method could change how obesity is treated. Patients might lose fat while keeping strength and mobility. This could mean a better quality of life, even after major weight loss.
Regeneron’s approach is about more than the number on the scale. It aims to help people lose the right kind of weight—fat, not muscle. That shift could lead to smarter, safer treatments and a more balanced view of health.
Although early findings look good, researchers need more data. Larger trials will confirm if the benefits last and if the side effects can be managed. These studies will also help define the best dosages and combinations for different types of patients.
In summary, the COURAGE trial opens new possibilities. It shows that losing fat doesn’t mean giving up muscle. With the right combination of therapies, patients can achieve healthier, more complete weight loss. If future phases confirm these results, this strategy could redefine obesity care—focusing on preserving strength, function, and long-term well-being.
