Lilly's Retatrutide Posts Up to 30% Weight Loss in Obesity Trial and 20.8% in Diabetes Study as Novo Touts Wegovy Pill Switch Data

LLY reported two sets of late-stage data for retatrutide, its once-weekly GIP, GLP-1 and glucagon triple agonist. In an obesity trial of 2,339 participants published in the New England Journal of Medicine, patients on the highest dose lost an average of 25% of their body weight after 80 weeks and 30% after an extension to 104 weeks, and more than a third lost 30% or more. The drug also reduced knee pain by up to 62% in participants with knee osteoarthritis and cut sleep apnea events by up to 57%.

In TRIUMPH-2, a Phase 3 trial of 1,152 adults with type 2 diabetes and obesity or overweight, presented at the EASD meeting in Milan and published in The Lancet, the 12 mg dose produced average weight loss of 49.6 lbs (20.8%) over 80 weeks, and 59.5% of those patients no longer met the BMI criteria for obesity. A1C fell by an average of up to 1.6%, and up to 40.0% of participants reached a normal level below 5.7%. Gastrointestinal side effects were common, with nausea in 28.0% of patients on 12 mg versus 8.0% on placebo, and discontinuations due to adverse events ran at 7.7% on the top dose against 4.9% for placebo. Lilly plans to submit a Biologics License Application to the FDA in the first quarter of 2027.

NVO countered with real-world data from Ro's telehealth platform. Among 194 patients who switched to the oral Wegovy pill from injections, half from Wegovy shots and half from Lilly's Zepbound, those who stayed on the pill for three months lost roughly 4% more weight, or about 8.8 pounds, on average. Novo cautioned that the data are self-reported and not generalizable to the broader population, and said its next-generation CagriSema is expected to launch early next year.

The readouts show the two leaders competing on different ground: Lilly is pushing the efficacy ceiling higher with a drug that still needs FDA review, while Novo is competing on convenience and on keeping patients who move off injections. What to watch: the filing timeline, full safety data including the 11.6% discontinuation rate on the 9 mg dose, and whether the oral switch results hold up over longer periods.