Eli Lilly announced Thursday it will file for regulatory approval of its next-generation obesity drug retatrutide in the first quarter of 2027, as the treatment succeeded in two additional late-stage trials. The pharmaceutical company delayed its filing timeline from earlier this year to gather and verify manufacturing and quality-control data required by regulators. The weekly injection demonstrated significant weight loss and blood sugar improvements in adults with obesity and complications including Type 2 diabetes and cardiovascular disease, positioning retatrutide as a potential pillar in the expanding obesity treatment market.
Retatrutide Delivers Up to 22.6% Weight Loss in Phase Three Trials
In one phase three trial, adults with obesity and Type 2 diabetes taking retatrutide lost up to an average of 20.8% of their weight, or nearly 50 pounds, at 80 weeks. This population typically struggles to lose weight. In a separate trial, adults with severe obesity and established cardiovascular disease, with or without diabetes, lost up to an average of 22.6% of their weight, or 55.8 pounds, at 80 weeks. The drug meaningfully reduced certain cardiovascular risk factors in patients, according to Lilly. Kenneth Custer, president of Lilly Cardiometabolic Health, stated the company believes it has the data necessary to file for approval globally for retatrutide as a potential treatment for obesity, knee osteoarthritis pain, and obstructive sleep apnea. Five late-stage trials on retatrutide now show positive results.
Triple Hormone Mechanism Differentiates Retatrutide from Existing Treatments
Retatrutide targets GLP-1, GIP, and glucagon hormones, earning the designation "triple G" drug. This mechanism differs from existing treatments that target only one or two hormones. Tirzepatide, the active ingredient in Lilly's Zepbound, mimics GLP-1 and GIP. Novo Nordisk's semaglutide, the active ingredient in Wegovy, mimics only GLP-1. The triple hormone approach appears to have more potent effects on appetite and satisfaction with food than other treatments.
Common Side Effects Include Gastrointestinal Symptoms
The side effects associated with retatrutide were consistent across the two trials and previous studies. The most common side effects included diarrhea, nausea, and constipation, which are also seen across the broader GLP-1 class of medications.
Lilly Positions Retatrutide as Next Portfolio Pillar After Zepbound
Lilly is positioning retatrutide as the next pillar of its obesity portfolio after its injection Zepbound and newly launched pill Foundayo. TD Cowen analysts estimated in a January note that retatrutide could rake in sales of $3.8 billion in 2030. The drug is critical to the drugmaker's plan to maintain its market share majority over Novo Nordisk in the weight loss and diabetes drug market. Some analysts estimate the segment could be worth about $100 billion by the 2030s.
FAQ
When will Eli Lilly file for approval of retatrutide?
Eli Lilly announced it will file for regulatory approval of retatrutide in the first quarter of 2027. The company delayed its filing from earlier this year to gather and verify manufacturing and quality-control data required by regulators.
How much weight did patients lose in retatrutide trials?
In phase three trials, adults with obesity and Type 2 diabetes lost up to an average of 20.8% of their weight (nearly 50 pounds) at 80 weeks. Adults with severe obesity and established cardiovascular disease lost up to an average of 22.6% of their weight (55.8 pounds) at 80 weeks.
How does retatrutide differ from existing obesity drugs?
Retatrutide targets three hormones—GLP-1, GIP, and glucagon—earning the designation "triple G" drug. Existing treatments like Lilly's Zepbound target GLP-1 and GIP, while Novo Nordisk's Wegovy targets only GLP-1. The triple hormone mechanism appears to have more potent effects on appetite and food satisfaction.
