Indianapolis, Indiana, U.S., September 29, 2026
Eli Lilly and Company has announced detailed Phase 3 TRIUMPH-2 results showing that its investigational medicine retatrutide produced substantial reductions in body weight and A1C among adults living with obesity or overweight and type 2 diabetes. The findings add to the clinical development program for retatrutide, a first-in-class GIP, GLP-1 and glucagon triple hormone receptor agonist being investigated as a potential treatment for cardiometabolic diseases. Results from the 80-week trial were presented at the 62nd Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy, and were simultaneously published in The Lancet.
Retatrutide Delivers Up to 20.8% Weight Loss
In TRIUMPH-2, participants receiving once-weekly retatrutide experienced substantial weight reductions across the three evaluated doses. At 80 weeks, participants receiving 4 mg lost an average of 12.7% of body weight, while those receiving 9 mg lost 19.1% and those receiving 12 mg lost 20.8%. At the highest dose, the average weight reduction was 49.6 pounds (22.5 kg) from a baseline average body weight of 234.6 pounds. Among participants who started the study with a BMI of 35 or higher, those receiving 12 mg experienced an average weight reduction of 23.4%, equivalent to approximately 60.8 pounds. The study also assessed the proportion of participants achieving clinically meaningful weight-loss thresholds. At 80 weeks, 67.0% of participants receiving retatrutide 12 mg achieved at least 15% weight loss, while 52.0% achieved at least 20% weight loss. In comparison, 6.4% and 1.5% of placebo participants reached those respective thresholds. Lilly also reported that 59.5% of participants receiving 12 mg no longer met the BMI criteria for obesity at the end of the study.
Significant A1C Improvements in Type 2 Diabetes
Alongside weight reduction, retatrutide demonstrated improvements in glycemic control, an important treatment objective for people with type 2 diabetes. Participants receiving 4 mg, 9 mg and 12 mg achieved average A1C reductions of 1.4%, 1.6% and 1.5%, respectively, from a baseline average A1C of 7.7%. By comparison, the placebo group experienced an average reduction of 0.2%. The results also showed that up to 40.0% of participants receiving retatrutide achieved an A1C below 5.7%, the threshold Lilly identified as within the normal range. In addition, approximately 79% of participants receiving either 9 mg or 12 mg achieved an A1C of 6.5% or lower, compared with 26.3% of participants receiving placebo. These findings indicate that the investigational therapy affected both body weight and blood glucose measures in the studied population.
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Lilly Advances Retatrutide Phase 3 Program
Retatrutide remains investigational and is not approved for marketing, meaning the TRIUMPH-2 findings represent clinical-development data rather than an approved indication. The molecule combines activity at GIP, GLP-1 and glucagon receptors, providing a distinct mechanism from currently marketed medicines that target fewer hormone pathways. Lilly is evaluating retatrutide across a broad Phase 3 program addressing obesity and related cardiometabolic conditions.
The TRIUMPH-2 findings build on earlier Phase 3 evidence from TRANSCEND-T2D-1, in which retatrutide also produced reductions in A1C and body weight among adults with type 2 diabetes. In that earlier trial, the 12 mg dose produced an average body-weight reduction of 16.8% at 40 weeks and A1C reductions of up to 2.0%, according to Lilly. For cGxP.wire, this is a Pharma news story focused on clinical development, obesity therapeutics, diabetes treatment and Phase 3 trial results.
Source: Eli Lilly and Company press release
