By: IPP Bureau
Last updated : May 21, 2026 7:48 pm
All three dose levels, 4 mg, 9 mg and 12 mg, successfully met the primary and key secondary endpoints in 80 weeks
Eli Lilly and Company has announced positive topline findings from the Phase 3 TRIUMPH-1 clinical trial evaluating retatrutide, an investigational first-in-class triple hormone receptor agonist targeting GIP, GLP-1 and glucagon receptors.
The trials involved adults with obesity or overweight and at least one weight-related comorbidity, excluding diabetes.
At 80 weeks, all three retatrutide dose levels, 4 mg, 9 mg and 12 mg, successfully met the primary and key secondary endpoints, demonstrating substantial and clinically meaningful weight reduction.
“This study underscores the need for innovative therapies that address the complex biology of obesity and related metabolic disorders,” said Ania Jastreboff, Professor of Medicine & Pediatrics (Endocrinology) at the Yale School of Medicine, Director of the Yale Obesity Research Center (Y-Weight), and lead investigator of the trial.
“Every retatrutide dose delivered significant weight reduction for the vast majority of participants, with those on the highest dose achieving an average 30% reduction in body weight over two years,” added Jastreboff.
For the primary endpoint, participants receiving retatrutide 9 mg and 12 mg achieved average weight reductions of 29.2 kg (25.9%) and 31.9 kg (28.3%), respectively, while those on the 4 mg dose recorded an average loss of 21.4 kg (19.0%).
Notably, 65.3% of participants on the 12 mg dose reduced their BMI below 30 by week 80, including 37.5% of individuals who began the study with class 3 obesity (BMI ≥40).
In a pre-specified extension study involving participants with BMI ≥35, those continuing on retatrutide 12 mg through 104 weeks experienced an average weight reduction of 38.5 kg (30.3%).
The therapy also demonstrated improvements across several cardiovascular risk markers, including waist circumference, triglycerides, non-HDL cholesterol, systolic blood pressure and high-sensitivity C-reactive protein (hsCRP).
“TRIUMPH-1 reinforces the importance of providing differentiated treatment options for people living with obesity,” said Kenneth Custer, Executive Vice President and President, Lilly Cardiometabolic Health.
“From the 4 mg dose achieving nearly 20% weight loss with minimal escalation, to the 12 mg dose delivering weight reduction levels comparable to bariatric surgery, retatrutide has the potential to offer a highly patient-centric approach to obesity management,” added Custer.