Clinical Trials
How much weight did people lose, what did TRIUMPH-4 show, how do I join a trial, and when are more results coming?
What clinical trials have been completed for retatrutide?
As of March 2026, retatrutide has completed Phase 1, Phase 2, and the first Phase 3 trial (TRIUMPH-4). The Phase 2 program included a 48-week obesity trial (NCT04881706, published in the New England Journal of Medicine) and a 36-week type 2 diabetes trial (NCT04867785, published in The Lancet). TRIUMPH-4 Phase 3 topline results were announced in December 2025 showing 28.7% weight loss at 12 mg over 68 weeks. Both Phase 2 trials produced positive results that supported advancement to Phase 3.
What were the main results of the Phase 2 obesity trial?
The Phase 2 obesity trial demonstrated mean weight loss of up to 24.2% at 48 weeks in the highest dose group (12 mg), with 100% of participants at that dose losing at least 5% of body weight. The trial also showed an approximately 82% relative reduction in liver fat, improvements in blood pressure and lipids, and a manageable gastrointestinal side effect profile. These were the highest weight loss results ever reported for a pharmacological agent.
What were the main results of the Phase 2 diabetes trial?
The Phase 2 type 2 diabetes trial showed HbA1c reductions of up to 2.02 percentage points at 36 weeks in the highest dose group. Approximately 95% of participants at the highest dose achieved an HbA1c below 7.0% (the standard treatment target), and approximately 62% reached HbA1c below 5.7% (the non-diabetic range). Retatrutide at higher doses significantly outperformed the active comparator, dulaglutide 1.5 mg.
What is the TRIUMPH program?
TRIUMPH (Triple Receptor Agonist Intervention Utilizing Metabolic Pathways in Health) is the Phase 3 clinical development program for retatrutide focused on obesity and weight management. It includes 4 numbered trials: TRIUMPH-1 (obesity/overweight without T2D, with nested OSA and OA baskets), TRIUMPH-2 (obesity/overweight with T2D, with nested OSA basket), TRIUMPH-3 (Class II/III obesity with established cardiovascular disease), and TRIUMPH-4 (obesity with knee osteoarthritis, completed December 2025). TRIUMPH-Outcomes is a separate 10,000-patient cardiovascular outcomes trial. The separate TRANSCEND program addresses the standalone T2D indication.
When will Phase 3 results be available?
TRIUMPH-4 reported topline results in December 2025 (the first Phase 3 readout). Per Eli Lilly's Q4 2025 earnings call (February 2026), 6 additional Phase 3 readouts are expected in 2026, and Lilly plans to file a New Drug Application (NDA) with the FDA in 2026. The core obesity (TRIUMPH-1) and diabetes (TRIUMPH-2) results are among those expected in 2026.
Can I participate in a retatrutide clinical trial?
This resource does not facilitate clinical trial enrollment. If you are interested in participating in a clinical trial, discuss this with your healthcare provider or search for registered studies on ClinicalTrials.gov using the search term 'retatrutide' or 'LY3437943'. Eligibility criteria vary by trial and are determined by the study investigators.