Global pharma powerhouse Eli Lilly has announced that its investigational drug retatrutide achieved striking results in the Phase 3 TRIUMPH-4 trial, showing major weight loss and pain reduction for adults with obesity or overweight and knee osteoarthritis—without diabetes.

 

In the global trial, 84% of participants had a BMI of 35 kg/m² or higher. Retatrutide, tested at 9 mg and 12 mg doses alongside diet and exercise, met all primary and key secondary endpoints. Participants lost an average of up to 28.7% of body weight (71.2 lbs) and saw pain reductions of up to 4.5 points (75.8%) on the WOMAC pain scale after 68 weeks.

 

"People with obesity and knee osteoarthritis often live with pain and restricted mobility, and may eventually require total joint replacement," said Kenneth Custer, 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."

 

The trial marks a potential turning point for people battling obesity-related joint pain, suggesting retatrutide may offer a non-surgical path to significant weight loss and improved mobility.