Eli Lilly and Company secured another meaningful result in late-stage clinical trials of its next-generation obesity treatment, retatrutide. By again confirming a greater weight-loss effect than existing GLP-1 class therapies, the drug's chances of becoming a flagship product have grown.
However, the U.S. filing, originally expected this year, has been pushed to early next year to supplement manufacturing and quality data.
Lilly said on the 23rd (local time) that retatrutide demonstrated weight-loss and metabolic marker improvements in two global phase 3 trials conducted in patients with obesity and type 2 diabetes, and in patients with obesity and cardiovascular disease.
In the trial of patients with both obesity and type 2 diabetes, after 80 weeks of treatment, the average body weight in the highest-dose (12 mg) group fell by 20.8%. That equates to about 50 pounds (about 22.7 kg). Hemoglobin A1c (HbA1c) also improved significantly. Obese patients with diabetes are known to have more difficulty losing weight than those with obesity alone.
In another trial, patients with severe obesity and cardiovascular disease cut their weight by an average of 22.6% over 80 weeks. The average reduction reached 55.8 pounds (about 25.3 kg). The company said cardiovascular risk factors, including blood pressure, triglycerides, non-HDL cholesterol, and inflammatory markers, also improved.
With these results, retatrutide has now achieved positive outcomes in all five late-stage trials conducted to date. Based on this, Lilly plans to seek global approvals not only for obesity but also for indications including knee osteoarthritis pain and obstructive sleep apnea.
However, the U.S. Food and Drug Administration (FDA) submission timeline has been delayed somewhat. Lilly said it plans to file a biologics license application (BLA) in the first quarter of next year to obtain and validate additional manufacturing and quality control data required by regulators. The company had previously projected that a filing could be possible within this year.
Retatrutide is known as a "Triple G" drug. Unlike existing obesity treatments that target GLP-1 or both GLP-1 and GIP, it simultaneously activates three hormones—GLP-1, GIP, and glucagon. The company says it can deliver greater weight loss by suppressing appetite while increasing energy expenditure.
Lilly's currently marketed obesity treatment, zepbound (Korea name Mounjaro), contains tirzepatide, which targets GLP-1 and GIP, while Novo Nordisk's Wegovy targets only GLP-1.
Daniel Skovronsky, Lilly's chief scientific officer (CSO), said, "Even at low doses, it showed an effect similar to the highest doses of existing obesity treatments," and added, "Not having to escalate the dose gradually across multiple steps is also an advantage."
Lilly also expects that, if retatrutide is approved as a biologic, it will help curb illegal copycat drugs and unapproved compounding. Biologics face stricter limits on copying and compounding than conventional drugs.
Retatrutide is a pipeline Lilly is developing as a next growth driver following zepbound. The global investment community sees the drug as key to helping Lilly maintain its dominance in the obesity treatment market. In a report early this year, investment bank TD Cowen projected retatrutide's 2030 sales at $3.8 billion (about 5.57 trillion won).