Eli Lilly and Company (NYSE: LLY) announced results from two Phase 3 clinical trials of retatrutide, an investigational triple hormone receptor agonist, showing weight loss and improvements in related health conditions.

In the TRIUMPH-1 trial, participants taking retatrutide 12 mg lost an average of 70.3 pounds over 80 weeks, representing a 28.3% weight reduction. The study found 65.3% of participants achieved a BMI below 30, no longer meeting obesity criteria, while 33.3% reached a BMI below 25.

The drug also demonstrated improvements in knee osteoarthritis pain, reducing pain scores by up to 4.3 points, and moderate-to-severe obstructive sleep apnea, decreasing severity by up to 36.1 events per hour. In an extension study for participants with BMI ≥35, those continuing treatment through 104 weeks lost an average of 85.0 pounds.

In the TRANSCEND-T2D-1 trial involving adults with type 2 diabetes, retatrutide achieved A1C reductions of up to 2.0% and weight loss of up to 36.6 pounds at 40 weeks. Up to 90% of participants achieved an A1C below 7.0%, meeting diabetes management targets, while up to 46% reached normal blood sugar levels below 5.7%.

The most common adverse events across both trials included nausea, diarrhea, constipation, and vomiting, consistent with other incretin-based therapies. Discontinuation rates due to adverse events ranged from 4.1% to 11.3% with retatrutide compared to 4.9% with placebo in TRIUMPH-1.

Retatrutide activates receptors for three hormones: GIP, GLP-1, and glucagon. The company is conducting multiple Phase 3 trials evaluating the drug for various obesity-related conditions and has enrolled more than 5,800 participants across its initial clinical development program.

The findings were presented at the American Diabetes Association's 86th Scientific Sessions, with TRANSCEND-T2D-1 results published simultaneously in The Lancet.