Eli Lilly retatrutide drug trial has delivered more positive results from two additional Phase 3 studies in a late-stage clinical study. The company announced that the latest findings from the TRIUMPH-2 and TRIUMPH-3 trials build on the previously reported TRIUMPH-1 data, giving Lilly five successful Phase 3 studies supporting retatrutide drug across obesity and obesity-related conditions.
The newly announced Eli Lilly retatrutide drug trial results showed that adults with obesity and type 2 diabetes lost up to 20.8% of their body weight, while adults with severe obesity and established cardiovascular disease achieved weight loss of up to 22.6% after 80 weeks of treatment. Participants with type 2 diabetes also experienced reductions in A1C of up to 1.6%, a measure of average blood sugar levels over the previous two to three months.
Eli Lilly now plans to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) in the first quarter of 2027. The retatrutide trial results further strengthen Lilly’s growing cardiometabolic portfolio as competition intensifies in the global obesity drug market.
What Is Retatrutide Weight Loss Drug and Why Is It Different?
Eli Lilly’s Retatrutide is an investigational once-weekly therapy being developed as one of the next-generation obesity drugs.
Unlike existing medicines that target one or two metabolic hormones, retatrutide activates three hormone receptors involved in appetite regulation, blood sugar control, and energy expenditure:
- GLP-1 (glucagon-like peptide-1), which reduces appetite
- GIP (glucose-dependent insulinotropic polypeptide), which improves insulin response
- Glucagon, which may increase fat burning
This “triple agonist” approach differs from existing medicines such as Zepbound (tirzepatide), which targets GLP-1 and GIP, and Wegovy (semaglutide), which targets only GLP-1.
“Across five positive Phase 3 studies, retatrutide has shown powerful efficacy, and we believe it could be an important future tool in the management of cardiometabolic health,” said Kenneth Custer, Executive Vice President and President of Lilly Cardiometabolic Health.
New Phase 3 Results From Eli Lilly Retatrutide Drug Trial
The Eli Lilly Retatrutide drug trial results showed significant benefits across multiple dosage levels.
TRIUMPH-1: Near-Surgical Weight Loss
The first major Phase 3 study, TRIUMPH-1, evaluated more than 2,300 adults living with obesity or overweight without type 2 diabetes.
The first phase 3 trial reported an average 28.3% body weight reduction with the 12 mg dose. 25.9% average weight loss at the 9 mg dose. Nearly 45% of participants lost at least 30% of their body weight.
An extension study also showed that some participants maintained average weight loss of up to 30.3% after 104 weeks, reinforcing retatrutide’s long-term potential.
New: TRIUMPH-2: Strong Blood Sugar Improvements
The latest Phase 3 TRIUMPH-2 study evaluated 1,152 adults living with obesity or overweight alongside type 2 diabetes.
After 80 weeks, participants receiving retatrutide achieved:
- 20.8% average weight loss with the 12 mg dose
- 19.1% average weight loss with the 9 mg dose
- 12.7% average weight loss with the 4 mg dose
- Up to 1.6% reduction in A1C levels, demonstrating meaningful improvements in blood sugar control.
New: TRIUMPH-3: Benefits for Cardiovascular Disease Patients
Topline results for Phase 3 TRIUMPH-3 study of Eli Lilly’s Retatrutide drug involving nearly 2,000 adults with severe obesity and established cardiovascular disease, with or without type 2 diabetes.
Participants receiving the highest dose achieved an average weight loss of 22.6% (55.8 pounds), while those taking the 9 mg dose lost 21.6% of their body weight after 80 weeks.
Beyond weight reduction, retatrutide improved several cardiovascular risk factors, including triglycerides, non-HDL cholesterol, systolic blood pressure, waist circumference, and high-sensitivity C-reactive protein (hsCRP), a marker of inflammation linked to heart disease.
However, the cardiovascular dataset remains relatively limited, making the findings difficult to interpret. The larger ongoing studies will provide a clearer understanding of retatrutide’s long-term cardiovascular benefits and risks.
Side Effects of Eli Lilly’s Retatrutide Drug
The latest TRIUMPH-2 and TRIUMPH-3 trial results showed that retatrutide’s safety profile remained generally consistent with other incretin-based obesity medicines. Most side effects were mild to moderate gastrointestinal events, like many GLP-1-based obesity treatments.
The Phase 3 Retatrutide trial showed reported side effects:
- Decreased appetite
- Dysesthesia (an abnormal sensation such as tingling or burning)
- Urinary tract infections
- Hyperglycemia in some participants enrolled in TRIUMPH-3
In TRIUMPH-2 and TRIUMPH-3, treatment discontinuation due to adverse events occurred in participants receiving the 4 mg dose, 9 mg dose, and 12 mg dose. Lilly noted that most adverse events were temporary and resolved during treatment.
Eli Lilly’s Retatrutide Plans FDA Submission
Eli Lilly retatrutide drug trial has now delivered positive results across five Phase 3 studies. Following this, Lilly announced that it plans to submit a regulatory approval application for Retatrutide to the U.S. Food and Drug Administration (FDA) in the first quarter of 2027.
In addition to obesity, Lilly plans to seek regulatory approval for retatrutide in other conditions supported by its Phase 3 program, including obstructive sleep apnea and knee osteoarthritis pain.
Ongoing studies are also evaluating the therapy for chronic low back pain, cardiovascular and renal outcomes, and metabolic dysfunction-associated steatotic liver disease (MASLD).
These latest Phase 3 findings strengthen Lilly’s leadership in the rapidly expanding obesity treatment market. The successful TRIUMPH-2 and TRIUMPH-3 studies complete the core clinical package needed for Lilly’s regulatory submission. It positions retatrutide as the potential fourth pillar of the company’s cardiometabolic portfolio alongside Mounjaro, Zepbound, and Foundayo.
