Impressive data in hand, Lilly obesity drug heads to phase 3

June 27, 2023

Eli Lilly announced impressive phase 2 data from its investigational molecule, retatrutide, being studied for the treatment of obesity.

In the 338-person trial, retatrutide met the primary endpoint for efficacy in participants living with obesity or overweight without diabetes, demonstrating a mean weight reduction up to 17.5% at 24 weeks. In a secondary endpoint, retatrutide demonstrated a mean weight reduction up to 24.2% at the end of the 48-week treatment duration. 

Lilly's retatrutide is an investigational single molecule that activates the body's receptors for three hormones – glucagon, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 (GLP-1). The acylated peptide is suitable for weekly injection.

The drug will now advance into the TRIUMPH phase 3 development program evaluating the safety and efficacy for chronic weight management, obstructive sleep apnea, and knee osteoarthritis in people with obesity and overweight. 

Weight loss drugs currently have momentum coupled with a large potential market — Novo estimates that there are 764 million people living with obesity globally — and Lilly has a thriving pipeline.

Back in April, Lilly announced a successful phase 3 trial evaluating tirzepatide for managing chronic weight issues. The trial, which involved 938 adult participants who had type 2 diabetes and were either overweight or obese, met all primary and secondary objectives. 

Based on these results, Lilly plans to complete its FDA submission for tirzepatide in obese or overweight adults shortly and expects regulatory action as early as the end of the year. Given that the drug was already approved by the FDA last May to improve glycemic control in adults with type 2 diabetes, it will likely get the green light from the regulator. Analysts are predicting tirzepatide has the potential to usurp Humira to become the best-selling drug of all time.