Lilly's triple agonist, retatrutide, delivered weight loss of up to an average of 71.2 lbs along with substantial relief from osteoarthritis pain in first successful Phase 3 trial

In TRIUMPH-4, participants with obesity and knee osteoarthritis taking retatrutide 12 mg lost an average of 28.7% of their body weight at 68 weeks

Retatrutide reduced WOMAC pain scores by up to an average of 4.5 points (75.8%) and significantly improved measures of physical function, with more than 1 out of 8 retatrutide-treated patients completely free from knee pain at the end of the trial 

Seven additional Phase 3 trials evaluating the investigational once-weekly treatment in obesity and type 2 diabetes are expected to complete in 2026

INDIANAPOLIS, Dec. 11, 2025 /PRNewswire/ — Eli Lilly and Company (NYSE: LLY) today announced positive topline results from the Phase 3 TRIUMPH-4 clinical trial evaluating the safety and efficacy of the two highest investigational doses of retatrutide, a first-in-class GIP, GLP-1 and glucagon triple hormone receptor agonist, in adults with obesity or overweight and knee osteoarthritis, and without diabetes, as an adjunct to healthy diet and physical activity. In this global registration trial, where 84.0% of participants had a baseline BMI of ≥35 kg/m², each dose of retatrutide (9 mg and 12 mg) met all primary and key secondary endpoints, delivering significant weight loss and improvements in pain and physical function at 68 weeks using both the efficacy and treatment-regimen estimands.1,2 For the co-primary endpoints, retatrutide lowered weight by up to an average of 28.7% (71.2 lbs) and reduced pain by up to an average of 4.5 points (75.8%) using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score.3

“People with obesity and knee osteoarthritis often live with pain and restricted mobility, and may eventually require total joint replacement,” said Kenneth Custer, Ph.D., executive vice president and president, Lilly Cardiometabolic Health. “We are encouraged by the results of TRIUMPH-4, which highlight the powerful effect of retatrutide, a first-in-class triple agonist, on body weight, pain and physical function. With seven additional Phase 3 readouts expected in 2026, we believe retatrutide could become an important option for patients with significant weight loss needs and certain complications, including knee osteoarthritis.”