Retatrutide heads toward FDA filing after positive phase 3 obesity trial results

Clinical takeaway: Retatrutide remains investigational, but if approved, the first triple hormone receptor agonist could expand treatment options for patients with obesity complicated by type 2 diabetes, cardiovascular disease, and other obesity-related conditions.

Obesity treatment continues to evolve rapidly, with newer therapies delivering progressively greater weight loss and broader cardiometabolic effects. Positive phase 3 results from the TRIUMPH program have positioned retatrutide for a planned FDA submission in early 2027, potentially making it the first GIP, GLP-1, and glucagon triple hormone receptor agonist approved for obesity.

The planned submission is supported by positive topline results from the TRIUMPH-2 and TRIUMPH-3 phase 3 trials, which evaluated retatrutide in two clinically challenging populations. In adults with obesity or overweight and type 2 diabetes, participants lost up to an average of 20.8% of body weight (49.6 lb) over 80 weeks, while A1c decreased by as much as 1.6 percentage points.

In adults with severe obesity and established cardiovascular disease, with or without type 2 diabetes, weight loss reached 22.6% (55.8 lb) at 80 weeks. Retatrutide also improved several cardiometabolic risk factors, including triglycerides, non-HDL cholesterol, systolic blood pressure, waist circumference, and high-sensitivity C-reactive protein. Although fewer major adverse cardiovascular events occurred with retatrutide than placebo, the study was not designed to determine whether the drug reduces cardiovascular events.

The safety profile was consistent with other incretin-based therapies. Gastrointestinal adverse events, including diarrhea, nausea, constipation, decreased appetite, and vomiting, were the most common side effects and were generally mild to moderate.

If approved, retatrutide could offer clinicians another option for patients who require substantial weight reduction, particularly those with obesity complicated by diabetes or cardiovascular disease. Lilly also stated that the phase 3 program supports planned regulatory submissions for obesity associated with knee osteoarthritis pain and obstructive sleep apnea, potentially broadening the drug's future clinical role.

Source: Eli Lilly and Company. (2026 Jul 23). Lilly's triple agonist, retatrutide, successful in two additional Phase 3 obesity trials, delivering significant improvements in weight and A1C