Eli Lilly is set for another win in the glucagon-like peptide-1 (GLP-1) sector as its triple-g agonist, retatrutide, has succeeded in type 2 diabetes and obesity.
Marking the fourth and fifth positive readouts for the drug, TRIUMPH-2 (NCT05929079) and TRIUMPH-3 (NCT05882045) evaluated the first-in-class glucose-dependent insulinotropic polypeptide (GIP), GLP-1, and glucagon triple hormone receptor agonist. The previous three studies of Lilly’s drug read out in December 2025, March 2026 and May 2026.
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In the two most recent studies, retatrutide met the primary endpoint, delivering substantial weight loss in adults with obesity, type 2 diabetes and established cardiovascular disease.
Dr Kenneth Custer, executive VP and president of Lilly Cardiometabolic Health, said: “Across five positive Phase III studies, retatrutide has shown powerful efficacy, and we believe it could be an important future tool in the management of cardiometabolic health. With the positive results from TRIUMPH-2 and TRIUMPH-3, we now have the clinical data package to support global submissions for retatrutide as a potential treatment for obesity, knee osteoarthritis pain, and obstructive sleep apnoea. We look forward to working with regulators as they evaluate this first-of-its-kind medicine.”
In TRIUMPH-2, all three studied doses of retatrutide (4mg, 9mg, and 12mg) delivered substantial weight loss and improved glycaemic control at 80 weeks in adults with type 2 diabetes and obesity. Patients who received retatrutide lost an average of 29.8lbs (12.7%), 45.4lbs (19.1%), and 49.6lbs (20.8%) in the low, medium and high dose cohorts, respectively, alongside A1C reductions up to an average of 1.6%.
In TRIUMPH-3, both studied doses of retatrutide (9mg and 12mg) delivered substantial weight loss in adults with severe obesity and established cardiovascular disease, with or without type 2 diabetes. Patients lost up to an average of 55.8 lbs (22.6%) at 80 weeks.
In the study, major adverse cardiovascular events (MACE) occurred less frequently than anticipated in both retatrutide and placebo arms. In pre-specified analyses for time to first occurrence of MACE, there were 44 MACE-5 (all-cause death, heart attack, stroke, heart failure event, or coronary revascularisation) events in patients who received retatrutide and 52 events observed in those randomised to placebo. There were 27 MACE-3 (cardiovascular death, heart attack, or stroke) events in the retatrutide cohort and 23 in the placebo arm.
Discontinuation rates due to adverse events (AEs) in TRIUMPH-2 were 3.8% (4mg), 11.6% (9mg), and 7.7% (12mg), compared with 4.9% for placebo. In TRIUMPH-3, these were 9.8% (9mg) and 13.5% (12mg), compared with 4.8% for placebo.
This follows previous analyst concern about the safety profile of the drug after the TRIUMPH-1 study (NCT05929066) readout, where there was an 11.3% discontinuation rate. These two more recent studies, therefore, have an even more significant dropout rate.
In TRIUMPH-1, patients treated with retatrutide lost up to 28.3% of their body weight compared with the 2.2% average in the placebo group. This, according to senior GlobalData analyst Shehroz Mahmood, established retatrutide as “the highest-efficacy pharmacological weight loss agent to date in a large pivotal trial”. These two readouts do not meet this same level of efficacy, but are still significant.
Lilly said it will present more detailed results from TRIUMPH-2 and TRIUMPH-3 at future medical meetings and publish in peer-reviewed journals.
This further win continues to support Lilly’s Chemistry, Manufacturing, and Controls (CMC) data package required for a Biologics License Application (BLA), with Lilly hoping for a Q1 2027 US Food and Drug Administration (FDA) approval of the drug.
Obesity and diabetes space exploding
This data drops while the competition is fierce in the obesity and type 2 diabetes space.
Lilly and Novo Nordisk continue to butt heads, even more so since Novo has filed a lawsuit against its main competitor after alleged misleading and false advertising campaigns.
In a lawsuit filed in the US, the Danish drugmaker alleged that Lilly’s campaign was designed to mislead consumers about the “comparative efficacy” of weight loss and type 2 diabetes drugs in the companies’ respective portfolios. The company claims it did this through a “nationwide pattern of deceptive advertising”.
Both Lilly and Novo are also fighting for dominance in the oral weight loss space, with both companies having marketed their first oral obesity drugs in 2026. Novo has gained a first-to-market advantage in the US, Europe and the UK, which are some of the key regions for these therapies.
In a Q1 earnings call, Novo’s CEO, Mike Doustdar, said: “It is no secret that the Wegovy pill is off to a record-breaking start in the US.”
In Q1 alone, the total prescriptions for oral Wegovy (semaglutide) hit 1.3 million.
Lilly will soon debut data on its oral offering Foundayo (orfiglipron), which gained FDA approval in April 2026. Its Q2 earnings, which will be on 5 August, will offer the first real understanding of how the drug is performing on the US market.
GlobalData’s report, “GLP-1 Innovation Landscape 2026: Industry Insights,” reveals that the use of GLP-1RA drugs is rapidly expanding beyond treatments for diabetes and into mainstream weight management because they are effective at increasing satiety and reducing food intake, resulting in rapid weight loss.
Use among patients without diabetes but with overweight or obesity in the US rose 700% from 2019 to 2023, according to researchers from the University of Pennsylvania and Cedars-Sinai Medical Center.
While injectables remain the growth engine through 2031, the convenience and affordability of the GLP‑1RA pill format is expected to expand the user base, with pill market sales expected to rise from $3.2bn in 2025 to $34.3bn in 2031, according to GlobalData’s Pharmaceutical Intelligence Centre.
GlobalData is the parent company of Clinical Trials Arena.
