Novo Nordisk has finished enrolling 7,076 heart patients into the trial that will decide whether its combination obesity drug protects the heart, or merely fails to harm it. The design, out this week, shows the company asking the safety question first and the benefit question second.
The drug is CagriSema, a once-weekly shot that pairs two injectable hormones in one pen: cagrilintide ↗, which mimics amylin, a satiety hormone from the pancreas, and semaglutide ↗, the GLP-1 drug already sold as Ozempic and Wegovy. The trial is REDEFINE 3, and its design and baseline numbers were published October 6 in the American Heart Journal ↗.
Who is in it
The enrolled population is sick, not merely heavy. Across 575 sites in 24 countries, randomized between January 2023 and December 2024, the average participant is 66 years old and has established cardiovascular disease. Sixty-two percent (4,369 people) have already had a heart attack. Nineteen percent have had a stroke, 11 percent have peripheral artery disease, and 61 percent (4,348 people) also have type 2 diabetes, with blood sugar running at a mean HbA1c of 7.7 percent and a mean diabetes duration of 12 years. Three-quarters are obese by body mass index; the rest are overweight with a qualifying heart condition. Everyone gets standard care on top of the study drug or a placebo.
The structure is the story
Read the two objectives in order and the trial's posture becomes clear. The primary objective is a safety one: show that CagriSema is noninferior to placebo on a three-part measure of cardiovascular death, nonfatal heart attack, and nonfatal stroke. Only after that clears does the trial test the efficacy objective, superiority on a four-part measure that adds coronary revascularization, the stents and bypasses.
Safety-first is normal for an obesity drug seeking a cardiovascular label. But it reads differently for CagriSema specifically. The drug's headline obesity readout underwhelmed: in the REDEFINE 1 trial published last year in the New England Journal of Medicine ↗, CagriSema produced 22.7 percent mean weight loss at 68 weeks, real but short of the 25 percent the company had signaled and the market had priced in. A cardiovascular trial built to first prove the drug does not raise heart risk is a trial hedging against a modest-benefit outcome.
There is a deeper limitation baked into the comparator. REDEFINE 3 tests CagriSema against placebo, not against semaglutide alone. And semaglutide, the GLP-1 half of this combination, already carries its own cardiovascular-outcomes win on record for people with established heart disease. So whatever heart benefit REDEFINE 3 eventually shows cannot be credited to the amylin half. The trial can tell you that CagriSema helps hearts. It cannot tell you that cagrilintide added anything the GLP-1 drug was not already doing on its own.
What it changes
For patients and prescribers, the practical answer is years away. REDEFINE 3 is event-driven, meaning it runs until enough heart events accrue to settle the statistics, and the trial registry ↗ does not expect results before 2027. Until then, CagriSema's cardiovascular case rests on the semaglutide component's established record and on inference.
The amylin bet is the one worth watching. Cagrilintide is the lead of a wave of amylin-targeting obesity drugs, and the whole class is wagering that hitting the amylin and calcitonin receptor family ↗ on top of the GLP-1 receptor ↗ buys more than either does alone. On weight, REDEFINE 1 left that case merely decent. On the heart, REDEFINE 3 is structured so that it may never have to answer the question at all.