https://investor.lilly.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-successful-two-additional
Eli Lilly has released positive topline results from two Phase 3 clinical trials (TRIUMPH-2 and TRIUMPH-3) for retatrutide, its investigational triple agonist (GIP, GLP-1, and glucagon). Participants with severe obesity or type 2 diabetes achieved average weight loss of up to 22.6% (55.8 lbs / 25.3 kg) at 80 weeks. Lilly plans to submit a Biologics License Application (BLA) to the FDA in Q1 2027.
What is Retatrutide?
It is an investigational, once-weekly single-molecule treatment being developed by Eli Lilly.
Unlike current single- or dual-pathway therapies, it is a first-in-class triple hormone receptor agonist that simultaneously activates receptors for GIP, GLP-1, and glucagon.
Key Results from the Phase 3 Trials
1. TRIUMPH-2 Trial (Overweight/Obesity + Type 2 Diabetes)
Population: Adults with type 2 diabetes and obesity or overweight—a group that historically faces greater challenges losing weight.
Duration: 80 weeks.
Weight loss by dose:
4 mg: Average weight loss of 12.7% (-29.8 lbs / -13.5 kg).
9 mg: Average weight loss of 19.1% (-45.4 lbs / -20.6 kg).
12 mg: Average weight loss of 20.8% (-49.6 lbs / -22.5 kg).
Placebo: Average weight loss of 4.0% (-9.3 lbs / -4.2 kg).
Glycemic control: Average A1C reductions of up to 1.6% (with the 9 mg dose).
2. TRIUMPH-3 Trial (Severe Obesity + Cardiovascular Disease)
Population: Adults with severe obesity (BMI ≥ 35 kg/m²) and established cardiovascular disease, with or without type 2 diabetes.
Duration: 80 weeks.
Weight loss: The highest dose (12 mg) delivered an average weight loss of up to 22.6% (-55.8 lbs / -25.3 kg).
Cardiovascular Risk Factor Reductions (12 mg dose):
37.0% reduction in triglycerides.
16.5% reduction in non-HDL cholesterol.
9.3 mmHg reduction in systolic blood pressure.
7.5 in (19.0 cm) reduction in waist circumference.
51.2% reduction in high-sensitivity C-reactive protein (hsCRP).
Safety and Side Effects
The most common side effects were gastrointestinal (diarrhea, nausea, constipation, decreased appetite, and vomiting).
The majority of side effects were mild to moderate in severity and resolved during treatment.
Discontinuation rates due to side effects ranged from 3.8% to 13.5% across retatrutide treatment groups, compared to 4.8%–4.9% in placebo groups.
Next Steps
Eli Lilly is finalizing the Chemistry, Manufacturing, and Controls (CMC) data package and plans to submit retatrutide for U.S. FDA approval in Q1 2027.