The TRIUMPH-4 trial — part of Eli Lilly’s Phase 3 TRIUMPH program — reached its primary completion date in November 2025. This trial tested retatrutide in adults with obesity or overweight and knee osteoarthritis, a common and disabling comorbidity of excess weight.
Why knee OA?
Obesity is the strongest modifiable risk factor for knee osteoarthritis. Mechanical stress from excess weight damages joint cartilage over time, and obesity-related systemic inflammation may accelerate the process. Weight loss is a first-line recommendation in OA management guidelines, but achieving and maintaining clinically meaningful weight loss is difficult.
TRIUMPH-4 tested whether retatrutide — already shown to produce substantial weight loss — could improve both weight and OA-specific outcomes:
- Primary endpoints: Change in knee pain (WOMAC pain subscale) and physical function (WOMAC physical function subscale), plus percent change in body weight
- Population: Adults with BMI ≥30 (or ≥27 with a weight-related comorbidity) and symptomatic knee OA
- Design: Randomized, double-blind, placebo-controlled
Canadian participation
TRIUMPH-4 included 10 Canadian trial sites, reflecting strong Canadian investigator interest in obesity-related OA research. Canada has a high prevalence of both obesity and osteoarthritis, with OA affecting approximately 1 in 7 Canadian adults.
What to expect
Results from TRIUMPH-4 have not yet been published or presented. If positive, they could:
- Support a separate indication for obesity-related knee OA, potentially broadening the patient population eligible for treatment
- Provide evidence for OA-specific outcomes (pain, function) beyond weight loss alone
- Influence clinical guidelines that currently recommend weight loss for OA but lack effective pharmacologic tools to achieve it
The detailed results timeline is unknown, but data from completed Phase 3 trials in the TRIUMPH program are typically presented at major medical conferences within 6–12 months of study completion. We will update this page when results are available.
Sources
- ClinicalTrials.gov — TRIUMPH-4 (NCT05931367)
- TRIUMPH trial design paper — Diabetes, Obesity and Metabolism | DOI: 10.1111/dom.70209
This article reports on clinical trial milestones using publicly available registry data. It does not speculate on unconfirmed trial results.