CagriSema vs Retatrutide: The 2026 Phase 3 Data Compared
CagriSema hit 22.7% weight loss in REDEFINE 1. Retatrutide hit 28.3% in TRIUMPH-1. Both released peer-reviewed Phase 3 data in 2026. Same category, different mechanisms, different FDA timelines. Here is what the numbers actually mean and which drug is likely to reach the market first.
CagriSema is Novo Nordisk's fixed-dose combination of cagrilintide, a long-acting amylin analog, and semaglutide, the same GLP-1 receptor agonist marketed as Wegovy and Ozempic. Amylin is a peptide co-secreted with insulin by pancreatic beta cells. Its receptor activation triggers CNS satiety signals through the area postrema, slows gastric emptying, and reduces glucagon secretion. Combining amylin with GLP-1 targets two convergent satiety pathways: the GLP-1 axis that suppresses hunger centrally and the amylin axis that reinforces meal termination.
Retatrutide is Eli Lilly's triple agonist at GLP-1, GIP, and glucagon receptors. The GLP-1 and GIP components are the same tirzepatide mechanism scaled up. Glucagon receptor agonism is the differentiator. Glucagon at supraphysiologic activation increases energy expenditure through hepatic glucose output and lipolysis, adding a caloric burn side to the caloric intake reduction driven by GLP-1 and GIP. This is why retatrutide produces higher absolute weight loss numbers: it does not only suppress intake, it also raises expenditure.
REDEFINE 1 published in the New England Journal of Medicine in June 2025 established CagriSema at 22.7% mean weight loss at 68 weeks in adults with obesity and no type 2 diabetes. The synergy claim was confirmed: 22.7% for CagriSema versus 16.1% for semaglutide alone versus 11.8% for cagrilintide alone. 60% of participants reached 20% or greater weight loss and 23% reached 30% or greater. The 2026 REIMAGINE trial series then extended the drug into the diabetes indication with three Phase 3 studies, all meeting primary endpoints and showing superior HbA1c reduction versus semaglutide monotherapy.
Retatrutide TRIUMPH-1 topline data announced May 21, 2026 and presented at ADA 2026 in early June showed 28.3% mean weight loss at 80 weeks in the 12 mg arm across 2,339 participants. 45.3% of 12 mg participants achieved 30% or greater weight loss. A 104-week extension in the BMI 35 or greater subgroup pushed the number to 30.3%. All three doses (4 mg, 9 mg, 12 mg) met primary and key secondary endpoints. This is the largest weight loss ever recorded in a Phase 3 obesity trial.
Retatrutide leads by roughly 5.6 percentage points on the primary weight-loss endpoint. The trials are not directly comparable: TRIUMPH-1 ran 12 weeks longer and used a different placebo arm and population. The direction of the difference is nonetheless robust across every published comparison so far. Retatrutide's glucagon component produces the highest weight loss of any GLP-1 category drug tested to date.
Retatrutide dose calculator CagriSema dose calculatorWeight loss is not the only variable. FDA approval timing, tolerability, and mechanism simplicity all shape which drug reaches patients first and which drug patients actually stay on. Novo Nordisk filed the CagriSema New Drug Application with the FDA in December 2025. Assuming standard priority review, approval decision is expected Q4 2026 or early 2027. Lilly has not filed a retatrutide NDA yet. Submission is expected Q4 2026, which puts an approval decision realistically in late 2027 under priority review or 2028 under standard review. CagriSema will reach the market 6 to 12 months ahead of retatrutide even in the fastest retatrutide scenario.
Tolerability closes some of the weight-loss gap. Retatrutide 12 mg discontinuation was 18% in TRIUMPH-4 versus roughly 11% for CagriSema. Retatrutide's real-world weight loss (accounting for the population that discontinues) will land closer to the CagriSema number than the topline suggests. CagriSema also benefits from the amylin mechanism being simpler to explain to prescribers and payers; the glucagon component of retatrutide requires more education because it appears counterintuitive to a clinician trained to think of glucagon as opposing insulin.
For research & educational use only. Not medical advice. Not affiliated with any pharmaceutical company.