Eli Lilly reported positive results from two new Phase 3 trials of its obesity drug retatrutide in patients with type 2 diabetes or cardiovascular disease. The company now plans to submit a Food and Drug Administration application in the first quarter of 2027, later than previously anticipated,…
Eli Lilly on Thursday announced positive results from two additional Phase 3 trials of its experimental obesity medicine retatrutide, strengthening the case for regulatory approval. The company said it intends to file for approval of the drug next year, with a submission to the Food and Drug Administration planned for the first quarter of 2027.
The new studies, called Triumph-2 and Triumph-3, build on findings released in May 2026 from the Triumph-1 trial. That earlier study showed that retatrutide could help people lose 30% of their body weight after 104 weeks, a level of weight loss comparable to bariatric surgery. The two new trials enrolled overweight or obese patients who also had either type 2 diabetes or cardiovascular disease.
In the Triumph-2 study, which included patients with type 2 diabetes, the average weight loss at the highest dose after 80 weeks was 21% of body weight. In the Triumph-3 study, which enrolled patients with cardiovascular disease, the average weight loss at the highest dose after 80 weeks was 23% of body weight. While these results are lower than the 30% loss seen in the Triumph-1 study, they met expectations for patients with underlying conditions, according to RBC Capital Markets analyst Trung Huynh. In a note to clients, Huynh wrote that patients with conditions like diabetes often lose less weight than those without such conditions.
Eli Lilly initially indicated earlier in 2026 that retatrutide might be among a group of medicines slated for regulatory submission by the end of 2026. However, the company now says it will file a new drug application with the FDA in the first quarter of 2027. Lilly told CNBC that it needed additional time to gather manufacturing and quality-control data for the agency.
The delay reflects the complexity of preparing a comprehensive submission for a drug that has drawn extraordinary attention. Some patients have resorted to purchasing retatrutide on the black market, and a published report from Stat News revealed that one 79-year-old patient obtained special access to the drug in April 2026. That report prompted lawmakers to press U.S. officials to determine whether that patient was President Donald Trump.
Retatrutide is designed to stimulate three hormone receptors: GLP-1, GIP, and glucagon. This triple mechanism is intended to supercharge weight loss. By contrast, Novo Nordisk's Ozempic and Wegovy work only on GLP-1, while Lilly's own Mounjaro and Zepbound target GLP-1 and GIP. Retatrutide has shown powerful weight loss results in clinical trials, but it also appears to come with more side effects than some competing drugs.
Most patients who experienced side effects while taking retatrutide reported symptoms such as diarrhea, nausea, constipation, and vomiting. Some analysts have suggested that these side effects might limit the drug's use to patients who have the most weight to lose.
Analysts are paying close attention to retatrutide's impact on heart health. While the Lilly studies were not designed to definitively prove whether retatrutide could lower the risk of heart attacks or strokes, investigators tracked the drug's effects on these outcomes. In the Triumph-3 study, there were 27 MACE-3 events cardiovascular deaths, heart attacks, or strokes in the treatment group compared to 23 in the placebo group. Another measure, MACE-5, which includes all-cause death, heart attack, stroke, heart failure, and instances of a specific cardiovascular medical procedure, favored the treatment group over placebo in that study.
In its press release, Lilly mentioned that these events occurred less frequently than the company had expected. However, the relatively small sample size and follow-up time make it difficult to draw solid conclusions at this point, according to William Blair analyst Andy Hsieh. In a note to clients, Hsieh wrote that one possibility is that placebo group patients were using a weight-loss drug off the record.
Lilly aims to be the first drugmaker to offer this new triple-agonist approach in the increasingly crowded obesity treatment market. The company has already seen great success with its market-leading injectable tirzepatide, sold as Mounjaro for diabetes and Zepbound for obesity. Tirzepatide recently became the best-selling medicine in the world and helped Lilly become the first pharmaceutical company worth more than $1 trillion.
Retatrutide would enter a market with multiple effective options that has recently been shaken up by the arrival of oral alternatives, including Novo Nordisk's Wegovy pill and Lilly's own Foundayo. Other companies, including Pfizer, Kailera Therapeutics, and Amgen, are also vying to improve on the class. The competitive landscape means that retatrutide will need to demonstrate clear advantages to succeed despite its side-effect profile and the delay in regulatory submission.
Peptides referenced: Semaglutide, Tirzepatide, Retatrutide, Glucagon, GLP-1.
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