ADA26: retatrutide delivers unprecedented weight loss in Phase III TRIUMPH-1

Results from the Phase III TRIUMPH-1 trial of retatrutide by Eli Lilly were presented at the 86th Scientific Sessions of the American Diabetes Association. Retatrutide is an experimental triple hormone receptor agonist administered once weekly that targets glucose-dependent insulinotropic peptide, GLP-1, and glucagon receptors. The study included 2,339 participants randomized to doses of 4 mg, 9 mg, 12 mg, or placebo. At the highest dose of 12 mg, participants achieved a mean body weight reduction of 28.3% (70.3 pounds), with over 25% of participants achieving weight loss ≥35%, approaching the efficacy of bariatric surgery. Over 65% of participants on the 12 mg dose achieved a BMI <30 kg/m² and 33.3% achieved a BMI <25 kg/m². Adverse events were consistent with incretin therapies, with gastrointestinal events predominating. The drug is expected for regulatory submission in late 2026 or early 2027.