Lilly reports up to 20.8% weight loss in retatrutide study

Eli Lilly announced results from its Phase 3 TRIUMPH-2 trial evaluating retatrutide in adults with type 2 diabetes who have obesity or are overweight. Across the 80-week study, participants taking the highest dose of 12 mg lost an average of 49.6 lbs, or 20.8% of their body weight. Among those with a baseline body mass index of 35 or higher, weight loss reached an average of 60.8 lbs, or 23.4%.

By the end of the trial, 59.5% of participants receiving the 12 mg dose no longer met the BMI criteria for obesity. Lower doses of 4 mg and 9 mg delivered average weight loss of 29.8 lbs (12.7%) and 45.4 lbs (19.1%), respectively. Retatrutide also lowered A1C blood sugar levels by an average of 1.4% at 4 mg, 1.6% at 9 mg, and 1.5% at 12 mg, with up to 40.0% of participants achieving an A1C below 5.7%.

The 12 mg dose also showed improvements in cardiovascular risk markers, reducing triglycerides by 39.5%, non-HDL cholesterol by 19.6%, systolic blood pressure by 10.8 mmHg, waist circumference by 6.7 inches (16.9 cm), and high-sensitivity C-reactive protein by 58.3%.

The study randomized 1,152 participants. The most common side effects across the 4 mg, 9 mg, and 12 mg doses versus placebo were diarrhea (27.4%, 33.5%, and 33.6% versus 13.2%), nausea (13.7%, 20.8%, and 28.0% versus 8.0%), constipation (14.0%, 16.2%, and 16.8% versus 9.4%), decreased appetite (5.8%, 12.3%, and 17.1% versus 4.5%), and vomiting (5.5%, 10.2%, and 15.7% versus 4.2%). Discontinuation rates due to adverse events were 3.8% for 4 mg, 11.6% for 9 mg, and 7.7% for 12 mg, compared with 4.9% for placebo. Lilly plans to submit a Biologics License Application to the US Food and Drug Administration in the first quarter of 2027.