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 September 2026, retatrutide has completed Phase 1, Phase 2, and all five pivotal Phase 3 trials with positive topline results: TRIUMPH-4 (obesity + knee osteoarthritis, December 2025, -28.7% at 12 mg/68 weeks), TRANSCEND-T2D-1 (type 2 diabetes, March 2026, published in The Lancet June 6, 2026), TRIUMPH-1 (obesity, May 21, 2026, -28.3% at 12 mg/80 weeks), TRIUMPH-2 (obesity + type 2 diabetes, July 23, 2026, -20.8%) and TRIUMPH-3 (severe obesity + cardiovascular disease, July 23, 2026, -22.6%). The TRIUMPH-Outcomes cardiovascular trial, TRANSCEND-T2D-2 and the SYNERGY/MACELD liver trials are still running.
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?
All five pivotal readouts are in: TRIUMPH-4 (December 2025), TRANSCEND-T2D-1 (March 19, 2026), TRIUMPH-1 (May 21, 2026), and TRIUMPH-2 and TRIUMPH-3 (July 23, 2026). Full TRIUMPH-2 results are scheduled for an EASD symposium on September 30, 2026. Still to come on longer timelines: TRANSCEND-T2D-2 (head-to-head against semaglutide), TRIUMPH-Outcomes (cardiovascular outcomes) and the SYNERGY/MACELD liver trials.
Is there a compassionate use or expanded access program for retatrutide?
Yes, since August 2026, and it is narrow. Eli Lilly runs a single-patient expanded access program (ClinicalTrials.gov NCT07629401) for adults with a BMI of 35 or higher despite the highest dose of an approved weight-management drug, two or more serious obesity-related complications, and no accessible clinical trial. Only a treating physician can request it, through the Lilly Answers Center (1-800-545-5979), and meeting the criteria does not guarantee supply.
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.