CagriSema: Cagrilintide + Semaglutide REDEFINE 1 Results

The short answer

REDEFINE 1 put cagrilintide and semaglutide in a single weekly injection and produced 20.4% mean body weight reduction at 68 weeks versus 3.0% with placebo (Garvey et al., NEJM 2025). That is a bigger result than semaglutide alone has ever produced in a phase 3 trial. It is also slightly smaller than tirzepatide's best numbers. Both things are true, and the gap matters.

The combination (marketed as CagriSema) is Novo Nordisk's answer to tirzepatide. Instead of adding a GIP agonist to GLP-1 like Eli Lilly did, Novo paired semaglutide with cagrilintide, a long-acting amylin analog with a 159 to 195 hour half-life (Enebo et al., Lancet 2021). Two peptides. Two different appetite circuits. One weekly shot.

Here is what the research actually shows, and where cagrilintide fits if you are tracking the obesity pipeline.

What cagrilintide is, without the marketing layer

Cagrilintide is a synthetic long-acting version of amylin. Amylin itself is a 37-amino-acid hormone co-secreted with insulin from pancreatic beta cells after meals. It acts on the area postrema and nucleus tractus solitarius in the hindbrain, slows gastric emptying, suppresses postprandial glucagon, and produces satiety through a circuit that runs parallel to GLP-1 without overlapping it.

The problem with native amylin is that it aggregates into amyloid fibrils at therapeutic concentrations. That instability is why pramlintide, the first approved amylin analog, still requires three injections a day with meals and has never broken out beyond adjunct-to-insulin use in diabetes.

Cagrilintide solves the stability problem with a lipid-based acylation strategy that stretches the half-life into a range where once-weekly dosing becomes viable. The medicinal chemistry paper from Thomas Kruse and colleagues at Novo Nordisk walks through the screening of over 100 analogs before they selected the final candidate (Kruse et al., J Med Chem 2021).

The practical effect: cagrilintide acts on a satiety pathway that GLP-1 drugs do not touch. That is why stacking it with semaglutide produces additive weight loss rather than overlap.

Phase 2 monotherapy: the standalone baseline

Before CagriSema became a thing, cagrilintide was tested as a solo weight loss drug.

David Lau and colleagues ran the dose-finding phase 2 trial: 706 adults with overweight or obesity, 26 weeks, cagrilintide doses from 0.3 mg up to 4.5 mg weekly (Lau et al., Lancet 2021). At the 4.5 mg dose, cagrilintide produced 10.8% placebo-adjusted weight loss versus 3.0% with liraglutide 3.0 mg in the active-controlled arm. That is unusual, because liraglutide was the reigning GLP-1 weight loss standard at the time, and cagrilintide beat it as a solo compound.

Taken alone, cagrilintide would already be a competitive weight loss drug. Novo Nordisk chose not to develop it that way, because they already owned semaglutide in the same weight class and wanted to build something bigger.

That decision is the origin of the combination strategy.

Phase 1b: proving the co-administration actually works

The Enebo phase 1b trial tested cagrilintide 0.16 to 4.5 mg weekly on top of semaglutide 2.4 mg for 20 weeks in 96 participants (Enebo et al., Lancet 2021). Three findings set up everything that came later.

First, cagrilintide pharmacokinetics were dose-proportional with a half-life of 159 to 195 hours. That confirms once-weekly dosing aligns cleanly with semaglutide's own schedule.

Second, cagrilintide did not affect semaglutide exposure. The two peptides coexist in the same injection without cannibalizing each other's plasma levels.

Third, weight loss at 20 weeks hit 15.7% at the top dose versus 9.8% with semaglutide alone. A small study, with an open question about whether the additive effect would hold at scale, but the signal was strong enough to greenlight phase 3.

REDEFINE 1: the headline trial

This is the 20.4% trial.

3,417 adults with BMI of 30 or higher (or 27 with one obesity complication), no type 2 diabetes, randomized across cagrilintide-semaglutide 2.4/2.4 mg, semaglutide alone, cagrilintide alone, and placebo. 68 weeks of treatment. Primary endpoint was percent change in body weight (Garvey et al., NEJM 2025).

The key numbers:

Under the efficacy estimand (the "if patients took every dose" analysis), the number went even higher: 22.7% mean weight reduction in the CagriSema arm. That figure is what Novo Nordisk puts on the slide deck, and it is the one you see in most press coverage.

Secondary findings were also clinically meaningful. Systolic blood pressure dropped by 9.9 mm Hg and diastolic by 5.0 mm Hg compared to placebo. 88% of participants who had prediabetes at baseline had normoglycemia at week 68. The weight number gets the attention, but the cardiometabolic shifts are the reason cardiologists started paying attention.

REDEFINE 2: the diabetes trial

Patients with type 2 diabetes typically lose less weight on GLP-1 drugs than patients with obesity alone. That gap has been consistent across the SUSTAIN and STEP programs.

REDEFINE 2 tested CagriSema specifically in adults with obesity and T2D: 1,206 patients, 68 weeks, same dosing as REDEFINE 1 (Davies et al., NEJM 2025). Weight loss landed at 13.7% with CagriSema versus 3.4% with placebo, which is consistent with the T2D penalty seen across the GLP-1 class but still meaningfully above semaglutide's diabetes-population numbers.

The glycemic data mattered more here. 73.5% of CagriSema patients hit HbA1c of 6.5% or less versus 15.9% in the placebo group. That is a glucose control result strong enough to justify CagriSema as both a diabetes drug and an obesity drug, not just the latter.

Gastrointestinal adverse events were common (72.5% of the CagriSema arm versus 34.4% of placebo), but discontinuation for AEs was 8.4% versus 3%. High enough to notice, low enough that most patients stayed on drug.

REDEFINE 4: the tirzepatide comparison

Open label head to head. 809 adults with obesity. CagriSema 2.4/2.4 mg versus tirzepatide 15 mg. Primary endpoint was non-inferiority for percent weight change at 72 weeks.

The result: CagriSema produced 23.0% weight loss versus 25.5% for tirzepatide (efficacy estimand). On the treatment regimen estimand, CagriSema came in at 20.2% versus tirzepatide 23.6%. CagriSema did not meet the non-inferiority margin.

This matters for how you interpret the REDEFINE 1 headline. At maximum doses, in a direct comparison, tirzepatide still beat CagriSema by roughly 2.5 to 3.5 percentage points. That puts the two combinations in the same general weight class, with tirzepatide holding the narrow edge and retatrutide (triple agonist, 24.2% at 48 weeks) sitting above both at shorter durations.

For anyone ranking the pipeline, the current order for phase 3 weight loss runs roughly: retatrutide > tirzepatide ≈ CagriSema > semaglutide > liraglutide. Precise positioning depends on dose, duration, and population, but that is the shape of the data as it exists today.

How the mechanism compares to the other weekly injectables

Four receptor combinations. Four efficacy ceilings. The pattern is clear: adding a second complementary receptor beats pushing a single receptor harder.

CagriSema's specific contribution is that it targets the amylin pathway, which none of the other late-stage obesity drugs do. If you hyper-respond to GLP-1 but cannot tolerate higher doses because of nausea, adding amylin may give you more weight loss without forcing you further up the semaglutide curve. If you tolerate GLP-1 fine but plateau early, the additional satiety signal from amylin can restart the slope.

That is the theoretical case. The trial data supports the additive effect, but individual response varies and no published biomarker predicts who benefits most from the amylin addition specifically.

Safety: what the GI profile actually looks like

Gastrointestinal side effects are the story with any GLP-1 based drug, and CagriSema is no exception. In REDEFINE 1, 79.6% of the combination arm reported GI adverse events versus 39.9% on placebo. Breaking that down:

• Nausea: 55% CagriSema versus 12.6% placebo
• Constipation: 30.7% versus 11.6%
• Vomiting: 26.1% versus 4.1%

Most events were mild to moderate and transient. The discontinuation rate for adverse events was 5.9% versus 3.5% in REDEFINE 1, and 8.4% versus 3% in REDEFINE 2. Those numbers are roughly comparable to semaglutide and tirzepatide in their own phase 3 trials, which tells us adding amylin did not meaningfully worsen tolerability.

Titration matters a lot here. CagriSema is designed to be started low and escalated over 16 to 20 weeks to the 2.4/2.4 mg target dose. Skipping the titration accelerates GI events without improving efficacy. If you are simulating the trial protocol, match the schedule rather than jumping straight to target.

Where cagrilintide fits for research

CagriSema as a fixed-dose combination is in regulatory review. Cagrilintide itself (as a research compound) is available separately and can be dosed alongside a separate semaglutide vial to recreate the trial pharmacology.

The trade-off is practical. A fixed combination means one injection, one titration, one logistics problem. Running cagrilintide and semaglutide as two separate compounds means twice the reconstitution, twice the titration math, and the ability to adjust each lever independently. Researchers interested in teasing apart the amylin contribution from the GLP-1 contribution generally prefer the separated approach. Researchers trying to replicate the REDEFINE 1 protocol exactly prefer to match the trial and dose both at 2.4 mg weekly after a standard titration.

For dose calculations, the reconstitution calculator handles either scenario. A typical starting point for replicating REDEFINE 1 titration is 0.25 mg weekly for both peptides, doubling roughly every four weeks until the 2.4/2.4 mg target dose is reached.

Cagrilintide is available from Ascension Peptides with 50% off using code ENHANCED. The same discount applies to semaglutide and to the rest of the injectable catalog if you want to run both compounds in parallel.

How to think about CagriSema against the alternatives

Already running tirzepatide and tolerating it well? REDEFINE 4 suggests tirzepatide will still produce slightly more weight loss at matched time points. The 2 to 3 percentage point advantage is small enough that individual variation can flip it either way, but the trial-average edge is with tirzepatide.

Running semaglutide alone and hitting a plateau? The amylin pathway is the single most evidence-backed addition on the market today. CagriSema phase 3 data shows the additive effect is real and meaningful at 5 to 8 percentage points beyond semaglutide monotherapy at matched doses.

Research-staging the retatrutide pipeline while waiting for approval? The comparison gets closer. Retatrutide's 24.2% at 48 weeks is competitive with CagriSema's 22.7% at 68 weeks, but the trial designs differ enough that a head-to-head read requires caution. The next 12 months of data (especially the retatrutide phase 3 readouts) will clarify the ordering.

For anyone comparing the broader pipeline, our Retatrutide vs Tirzepatide vs Semaglutide deep dive covers the same data with the other compounds as the focus. For dosing specifics, the Retatrutide 12-week titration protocol is the closest analog to how CagriSema is likely to titrate in practice, since both use a four-week dose-doubling structure.

The regulatory and pricing question

Novo Nordisk submitted the NDA for CagriSema in December 2025. FDA review is expected to complete in 2026, which means commercial availability could land inside the second half of this year if the review stays on track.

Pricing is the open question. At parity with Wegovy, CagriSema will take significant semaglutide share. Priced as a premium combination (which is historically how combination drugs get launched), tirzepatide may hold its ground on cost per point of weight loss. The launch strategy will signal which of those Novo Nordisk thinks is the winning move.

Insurance coverage is the bigger variable. Cagrilintide is not currently paid for by commercial insurers at any meaningful rate for weight loss indications. CagriSema's ability to reach the mass market depends on whether it gets the same coverage as semaglutide-for-obesity in 2026, which has improved from historical GLP-1 coverage but still falls well short of universal.

The bottom line

CagriSema is the cleanest published example of amylin adding real phase 3 weight loss on top of GLP-1. The 20.4% mean reduction in REDEFINE 1 is one of the largest numbers the obesity literature has ever produced, and the mechanism makes biological sense: two complementary satiety circuits beat one.

It is not the winner of the class. REDEFINE 4 established that tirzepatide still holds a small edge at maximum doses, and retatrutide's triple agonism sits in the same range at shorter durations. CagriSema is a strong second that earns its place by targeting a receptor the rest of the class does not.

For anyone tracking the obesity pipeline, the 2026 FDA decision will determine whether CagriSema becomes a clinical option or stays a research-only compound. For anyone already research-staging these peptides, cagrilintide is a distinct mechanism worth understanding on its own terms. The amylin pathway is going to matter more as the class expands, and cagrilintide is the first long-acting entry that actually delivered the data at scale.

Further reading

• Cagrilintide compound guide
• Semaglutide compound guide
• Tirzepatide compound guide
• Retatrutide compound guide
• Tirzepatide vs Semaglutide 2026
• Reconstitution Calculator

---

This article is for educational and research purposes only. None of the compounds discussed are approved for general human use in the configurations described. All information is derived from published clinical research and is intended for research purposes only. Consult a qualified healthcare professional before making any decisions about peptide research or obesity pharmacotherapy.