Retatrutide improves knee osteoarthritis symptoms in two late-stage trials
Eli Lilly reported that investigational retatrutide improved knee pain, physical function and body weight versus placebo in the TRIUMPH-4 and TRIUMPH-1-OA phase 3 studies. TRIUMPH-4 followed 445 participants for 68 weeks, while TRIUMPH-1-OA randomized 574 people and assessed outcomes at 80 weeks. The findings were disclosed during the American College of Rheumatology's 2026 meeting and appeared in the New England Journal of Medicine on November 8, 2026.
Why it matters
The results add potential osteoarthritis benefits to retatrutide's obesity-development program, but the medicine remains unapproved by U.S. regulators. Lilly said seven more phase 3 readouts were expected in 2026, creating additional clinical and regulatory milestones for investors.
Key facts
- 1TRIUMPH-4 assigned 445 people to weekly retatrutide or placebo for 68 weeks, while TRIUMPH-1-OA included 574 randomized participants and evaluated them for 80 weeks. medscape.com
- 2Using the efficacy estimand in TRIUMPH-4, WOMAC pain scores fell 4.48 points with 9-mg retatrutide and 4.41 points with 12-mg retatrutide, compared with 2.43 points for placebo. medscape.com
- 3In TRIUMPH-4, mean weight loss was 26.4% with 9-mg retatrutide and 28.7% with 12-mg retatrutide, versus 2.1% with placebo. medscape.com
- 4TRIUMPH-1-OA showed WOMAC pain-score reductions of 3.66, 4.19 and 4.30 points for the 4-mg, 9-mg and 12-mg doses, respectively, compared with 2.24 points for placebo at 80 weeks. medscape.com
- 5The drug has not received approval from U.S. regulators. ibtimes.com.au
Open questions
- TRIUMPH-4 figures differ between the materials because material 1 reports efficacy-estimand results, while material 2 reports topline results using another statistical approach: material 2 gives WOMAC pain changes of −3.96 and −3.74 for the 9-mg and 12-mg doses versus −2.12 for placebo, and weight changes of 20.0% and 23.7% versus 4.6%.
- The materials do not establish whether U.S. regulators will approve retatrutide or when any approval decision will occur.
Summary written by AlphAI AI Desk from 2 of 2 sources. Not investment advice. Figures are as stated by the linked sources.