Retatrutide phase 3 results

What happened

Lilly announced the detailed results of TRIUMPH-2 in a news release dated 29 September 2026, and presented them at a retatrutide symposium during the 62nd Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan on 30 September 2026. The release says the results were published at the same time in The Lancet.

TRIUMPH-2 is a phase 3 trial, which means a large, late-stage study. Lilly describes it as 80 weeks long, randomized, double-blind and placebo-controlled. In plain terms, chance decided who received retatrutide and who received placebo (an inactive treatment), and neither the participants nor the researchers knew which. It enrolled 1,152 adults with type 2 diabetes and obesity or overweight, assigned to retatrutide 4 mg, 9 mg or 12 mg, or to placebo. People on retatrutide started at 2 mg once weekly, and the dose went up in steps every four weeks until they reached their target dose. That stepwise increase is called titration.

Lilly said all three doses of retatrutide delivered weight loss and reductions in A1C, a blood test used to track blood sugar, at 80 weeks. Its release lists the change in body weight at 80 weeks as the primary endpoint, the main thing the trial was designed to measure. Lilly’s release has the numbers. We don’t repeat them, because one trial can’t tell you what a medicine will do for you. See our editorial policy.

On safety, Lilly said the most common adverse events, meaning unwanted health events that happen during a trial whether or not the medicine caused them, were gastrointestinal: diarrhea, nausea, constipation, decreased appetite and vomiting. It said these were generally mild to moderate and that most resolved during treatment. The release lists other adverse events and discontinuation rates with figures, which we don’t repeat here.

How retatrutide works

Retatrutide is a triple agonist. An agonist is a drug that activates a receptor, the docking point on a cell that a hormone normally switches on. Lilly describes retatrutide as one molecule that activates the receptors for three hormones: glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) and glucagon.

Active ingredient (Canadian brands)	Receptors it activates
semaglutide (Ozempic, Wegovy)	GLP-1
tirzepatide (Mounjaro, Zepbound)	GIP and GLP-1
retatrutide (investigational)	GIP, GLP-1 and glucagon

A product monograph is the document that describes an authorized drug and how it works. The Wegovy monograph describes semaglutide as a GLP-1 receptor agonist. GLP-1 is a hormone the body makes, and the monograph calls it a regulator of appetite and caloric intake. The Mounjaro monograph describes tirzepatide as both a GIP and a GLP-1 receptor agonist, which makes it a dual agonist. Retatrutide adds a third target, the glucagon receptor.

Glucagon is another hormone the body makes. Mounjaro’s patient information describes it as a hormone that prevents blood sugar from falling too much. That is the mechanical difference worth knowing. The semaglutide and tirzepatide monographs describe those medicines as lowering glucagon, in a way that depends on blood sugar levels. Retatrutide, according to Lilly, activates the glucagon receptor. We describe where each medicine acts. We don’t compare what they do for people, and a mechanism alone doesn’t tell you that.

What it means in Canada

Health Canada’s list of new drug submissions under review does not include retatrutide. A new drug submission is a company’s formal request for Health Canada to authorize a new medicine. The list we read on 3 October 2026 was current as of 31 August 2026, and Health Canada last modified the page on 24 September 2026. A submission accepted into review after 31 August 2026 wouldn’t show yet. Lilly’s release names a planned filing with the US Food and Drug Administration (FDA) and doesn’t mention Health Canada.

Two other medicines in the same therapeutic area, which the list labels “Drugs used in diabetes”, do appear on it: orforglipron from Eli Lilly Canada Inc and cagrilintide with semaglutide from Novo Nordisk Canada Inc. See our report on those reviews.

Lilly’s release describes retatrutide as an investigational molecule that can’t be legally sold or marketed for human use. If you see retatrutide offered for sale online or by a clinic, ask a pharmacist or prescriber about it before you buy or use it. Lilly’s tirzepatide medicines, Mounjaro and Zepbound, are the Lilly medicines our price pages cover.

What hasn’t changed

Availability, price and coverage. We list no price for retatrutide and have no coverage information for it, because we haven’t found a Canadian product to price or a plan rule to read. Our coverage pages cover the GLP-1 medicines that are available now.

What one trial covers. TRIUMPH-2 studied adults with type 2 diabetes and obesity or overweight. It doesn’t tell us about other groups of people. Lilly’s release says the wider TRIUMPH program began in 2023, has enrolled more than 5,800 participants, and expects additional results within a year of the release.

Your own care. If you’re thinking about changing a medicine, talk to your prescriber or pharmacist first.

What happens next

Lilly said it plans to submit a Biologics License Application, its formal request for approval, to the FDA in the first quarter of 2027. BioPharma Dive reported on 23 July 2026 that Lilly had earlier included retatrutide among medicines that might be submitted by the end of 2026, and that Lilly told CNBC it needed more time to gather manufacturing and quality-control data for the agency.

Lilly also said results from the sleep apnea trial inside TRIUMPH-2 will be presented at a future medical meeting and published in a peer-reviewed journal.

A US filing is a separate process from a Health Canada submission. Neither Lilly’s release nor Health Canada’s list gives a Canadian date, and we won’t guess at one. We’ll update this article if Health Canada’s list shows a retatrutide submission.