Lilly reports strong results for its next-generation obesity pill

Eli Lilly (LLY) reported strong late-stage results for its next-generation obesity drug retatrutide, sending the company’s shares higher in premarket trading. The Phase 3 TRIUMPH-4 study showed more than 23 percent weight loss over 68 weeks, marking the strongest effect seen so far in a late-stage obesity trial.

The study enrolled adults with obesity or overweight and knee osteoarthritis. Most participants began with a body mass index of 35 or higher. Retatrutide is a triple agonist targeting GIP, GLP-1, and glucagon receptors.

Lilly said both high-dose regimens, 9 milligrams and 12 milligrams, met all primary and key secondary goals. Average weight loss reached as high as 28.7 percent, equal to 71.2 pounds, at week 68.

Patients also reported major improvements in knee pain. The highest responses included a 4.5-point reduction on the WOMAC pain scale, a 75.8 percent decrease. The company said physical function improved alongside weight and pain outcomes.

Kenneth Custer, executive vice president and president of Lilly Cardiometabolic Health, said the results highlighted the drug’s impact on weight, pain, and mobility. He said seven additional Phase 3 readouts are expected in 2026 and noted the drug’s potential value for patients with high weight-loss needs and complications such as knee osteoarthritis.

Some participants left the trial early after losing significant weight, especially those whose BMI fell below 35. The highest dose produced an 18 percent dropout rate tied to side effects including nausea, diarrhea, constipation, and occasional mild dysesthesia.

In remarks to investors in October, Chief Scientific Officer Daniel Skovronsky said not all patients require this degree of efficacy. He said the therapy may be most appropriate for people with very high BMI or obesity-related conditions that call for substantial weight reduction.

The results add pressure to the broader obesity-drug market. Shares of Novo Nordisk fell sharply last year after data showed its experimental GLP-1 candidate CagriSema produced average weight loss of 20.4 percent, well below expectations.