Lilly's triple-hormone drug retatrutide yields deep, lasting weight loss in Phase 3 obesity study

Eli Lilly announced topline TRIUMPH-1 results for retatrutide, a first-in-class GIP/GLP-1/glucagon triple agonist, in adults with obesity or overweight and comorbidities. Across 4 mg, 9 mg, and 12 mg doses, participants achieved meaningful weight loss at 80 weeks (4 mg: 19.0%, 9 mg: 25.9%, 12 mg: 28.3%), with the 12 mg group averaging 70.3 lb and 45.3% reaching ≥30% weight loss; BMI ≤22 was achieved by 65.3% at Week 80. Some participants with higher BMI continued losing weight in extensions, reaching about 30% total body weight loss over roughly two years. All arms met primary and key secondary endpoints, and the follow-on extension data covered up to 104 weeks. Safety disclosures mirror warnings associated with Lilly's obesity medicines.