Lilly's Next-Gen Weight-Loss Drug Clears Trial With Near-Bariatric Surgery Results

Eli Lilly reported positive Phase 3 results for its next-generation obesity drug, retatrutide, which delivered weight-loss results on par with those of bariatric surgery.

In the TRIUMPH-1 trial, overweight adults, but without diabetes, achieved meaningful weight loss across all tested doses after 80 weeks:

• 12 mg dose: average weight loss of 70.3 pounds, or 28.3% of body weight.

• 9 mg dose: average weight loss of 64.4 pounds, or 25.9%.

• 4 mg dose: average weight loss of 47.2 pounds, or 19%

Ahead of the results, RBC Capital Markets analyst Trung Huynh said the key success range would be 28% to 30% weight loss.

Lilly's 12 mg dose appears to have cleared the low end of Huynh's bar, with patients losing an average of 28.3% of their body weight over 80 weeks.

"We're in a zone that's historically been associated with bariatric surgery, and you're getting it with a medicine," Kenneth Custer, president of Lilly Cardiometabolic Health, told Bloomberg in an interview.

Custer added, "I think we can definitively check the box" based on the data that "retatrutide moves the goalpost on max efficacy."

Retatrutide is a first-in-class triple hormone receptor agonist targeting GIP, GLP-1, and glucagon, positioning it as potentially superior to current weight-loss drugs such as Lilly's Zepbound, Novo Nordisk's Wegovy, and copycat GLP-1s.

Lilly noted some downsides to taking the drug in the trial:

Events of dysesthesia and urinary tract infections were generally mild to moderate, the majority resolved during treatment, and most participants continued taking retatrutide

In markets, Lilly shares rose about 1% in premarket trading in New York, while shares of the Wegovy competitor, Novo Nordisk, traded in Copenhagen, fell slightly.

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The key question is whether bariatric surgery begins to lose favor among patients as next-generation obesity medications replicate, or come close to replicating, surgery-level weight loss without an invasive procedure.