Eli Lilly’s Retatrutide Trial Links Obesity Treatment With Knee Osteoarthritis Relief Potential

Eli Lilly And Company (LLY) announced an update on their ongoing clinical study.

Eli Lilly’s Knee Osteoarthritis Obesity Trial Reaches Key Milestone

Study Overview: Eli Lilly and Company has completed a Phase 3 trial titled “A Phase 3 Study to Investigate the Efficacy and Safety of LY3437943 Once Weekly in Participants Who Have Obesity or Overweight and Osteoarthritis of the Knee: A Randomized, Double-Blind, Placebo-Controlled Trial.” The study tested whether once-weekly treatment with retatrutide can safely reduce weight and improve symptoms in people who are obese or overweight and also have knee osteoarthritis, a group with high unmet medical need and rising healthcare costs.

Intervention/Treatment: The trial evaluated retatrutide (LY3437943), a once-weekly injectable drug given under the skin, in two dose levels, compared with a placebo injection. The goal was to see if retatrutide can drive meaningful weight loss and potentially ease knee pain and function, offering a single treatment that targets both obesity and joint disease.

Study Design: This was an interventional Phase 3 study with participants randomly assigned to one of three groups: retatrutide dose 1, retatrutide dose 2, or placebo. The design was parallel, meaning each group stayed on its assigned treatment throughout the trial. It was double-blind, so neither patients nor study doctors knew who received the active drug. The main aim was treatment-focused: to test how well retatrutide works and how safe it is versus placebo.

Study Timeline: The study was first submitted on June 27, 2023, signaling the start of formal registration and setup for this late-stage program. The treatment period lasted about 77 weeks, reflecting a long follow-up suitable for tracking sustained weight and joint outcomes. The trial is now listed as completed, and the record was last updated on January 20, 2026, indicating a fresh data status and movement toward analysis and possible disclosure of results.

Market Implications: Completion of this Phase 3 study is important for Eli Lilly’s obesity pipeline and adds a new angle: potential benefits in knee osteoarthritis. For investors, this update supports the view that Lilly is pushing beyond pure weight loss into related conditions tied to obesity, which could widen the addressable market. Positive data, if confirmed, may strengthen Lilly’s competitive position against other obesity players, including Novo Nordisk and emerging biotech rivals, by offering a differentiated profile in musculoskeletal health. Until topline results are shared, the main effect is likely to be cautious optimism and sustained interest in Lilly’s broader metabolic portfolio rather than an immediate re-rating of the stock.

The study record for this completed trial has been recently updated, and further details are available on the ClinicalTrials portal.

To learn more about LLY’s potential, visit the Eli Lilly And Company drug pipeline page.