Cagrilintide got a phase 3 test on its own. It finished third of four arms.

What is actually under FDA review

On December 18, 2025 Novo Nordisk announced it had submitted a New Drug Application for CagriSema, a once-weekly injection containing a fixed dose of cagrilintide 2.4 mg together with semaglutide 2.4 mg, for weight management in adults with obesity, or overweight plus at least one weight-related condition. The same release states the product is not approved in the US or EU.[4]

This distinction is the whole story. Cagrilintide is bought and discussed as a compound in its own right — our own price index tracked 121 cagrilintide listings across 64 vendors on August 1, 2026 — while the trial programme, the regulatory filing and almost all of the published evidence describe it bolted to semaglutide.

Evidence ledger

The human record, by what was actually tested

Cagrilintide has a real and growing clinical programme, which separates it from most compounds in this market. Reading it accurately means keeping track of which arm was the drug alone.

Separate trials, not one pooled population. Only the first two rows test cagrilintide on its own.[1][5][7][11]

The one phase 3 test of cagrilintide by itself

REDEFINE 1 was a 68-week, multicentre, double-blind, placebo-controlled and active-controlled phase 3a trial in adults without diabetes who had a BMI of 30 or higher, or 27 or higher with at least one obesity-related complication. Participants were randomized 21:3:3:7 to the combination, semaglutide 2.4 mg alone, cagrilintide 2.4 mg alone, or placebo — 2,108, 302, 302 and 705 people respectively. Mean baseline weight was 106.9 kg.[1][2]

The peer-reviewed report gives the headline comparison: mean body-weight change at week 68 was −20.4% with the combination against −3.0% with placebo (difference −17.3 percentage points, 95% CI −18.1 to −16.6, p<0.001).[1] The monotherapy arms are reported in the sponsor's headline-results announcement: analysed regardless of adherence, cagrilintide 2.4 mg alone produced 11.5% and semaglutide 2.4 mg alone 14.9%; assuming adherence, 11.8% and 16.1% against 2.3% on placebo.[2]

Two cautions on that ranking. First, the trial's coprimary endpoints compared the combination with placebo; lining the two monotherapy arms up against each other is a descriptive comparison, not the question REDEFINE 1 was powered to answer.[1] Second, the registry entry for the trial had no posted results at the time of writing, so the arm-level detail here rests on a company announcement rather than a results table.[3]

One number does point the other way for the standalone drug. At week 68, 82.5% of the cagrilintide-alone group were still on the highest dose, against 70.2% on semaglutide alone and 57.3% on the combination.[2] People stayed on the amylin analogue at full dose more often than they stayed on either comparator. Whether that reflects better tolerability is a reasonable reading, not a demonstrated one.

Before that, the standalone evidence was one 26-week trial

The dose-finding study is a 2021 phase 2 trial: randomized, double-blind, placebo- and active-controlled, run at 57 sites in ten countries. It assigned 706 participants to once-weekly cagrilintide at 0.3, 0.6, 1.2, 2.4 or 4.5 mg, 99 to daily liraglutide 3.0 mg, and 101 to placebo, over 26 weeks.[5]

Assuming adherence, mean weight reductions ran from 6.0% to 10.8% across the cagrilintide doses versus 3.0% on placebo, and the 4.5 mg dose beat liraglutide 3.0 mg by 1.8 percentage points (10.8% vs 9.0%, p=0.03).[5] The most frequent adverse events were gastrointestinal: 41–63% of participants on cagrilintide against 32% on placebo, chiefly nausea at 20–47% against 18%.[5] Ten percent discontinued treatment permanently, similarly across groups.[5]

Note the dose. The best standalone result in that trial came from 4.5 mg, and the dose carried into the phase 3 programme was 2.4 mg — the dose that fits the combination pen, not the one that performed best alone.[5][1]

The combination missed its head-to-head against tirzepatide

REDEFINE 4 was an open-label, 84-week trial in 809 people with obesity and at least one comorbidity, mean baseline weight 114.2 kg, comparing CagriSema against Tirzepatide 15 mg. Assuming adherence, CagriSema produced 23.0% weight loss against 25.5% for tirzepatide; regardless of adherence, 20.2% against 23.6%. The trial did not achieve its primary endpoint of demonstrating non-inferiority.[7]

Two things to hold at once. A 23% mean weight loss is a large effect by any historical standard. And a trial designed to show the new combination was no worse than the incumbent did not show that. These results were reported in a company announcement on February 23, 2026; we found no peer-reviewed publication of REDEFINE 4 as of this writing, so the detail available is topline only.[7]

The rest of the programme has published. REDEFINE 2 randomized 1,206 adults with type 2 diabetes 3:1 against placebo and reported −13.7% versus −3.4% at 68 weeks.[6] REDEFINE 5 randomized 331 participants in Japan and Taiwan against semaglutide alone and reported −18.4% versus −11.9%.[10] REIMAGINE 1, a smaller 40-week trial in 189 adults with early type 2 diabetes, reported an HbA1c fall of 1.8 percentage points on the 2.4 mg combination against 0.1 on placebo.[9] All three studied the combination.

What an independent synthesis says

A network meta-analysis published in The BMJ in July 2026 pooled 262 randomized trials and 99,791 participants across 19 obesity drugs, with GRADE certainty ratings and Cochrane risk-of-bias assessment. At one year, against lifestyle modification alone, it put CagriSema at −14.8% (95% CI −16.9 to −12.7) and tirzepatide at −14.9% (−16.0 to −13.9), both on moderate-to-high certainty evidence.[8]

That analysis is also where the harms sit in context. It found discontinuation because of adverse events to be highest with a group of drugs that includes CagriSema, with risk ratios across that group running from 1.9 to 4.2, and it singled out increased fatigue risk with CagriSema at a risk ratio of 3.2, an absolute 92 more people per 1,000 over a year.[8] Its overall conclusion is worth quoting in shape if not in full: larger benefits generally came with greater harms and more discontinuation, and most agents did not improve quality of life meaningfully.[8]

In REDEFINE 1 itself, gastrointestinal adverse events affected 79.6% of the combination group against 39.9% on placebo, described as mainly transient and mild to moderate.[1] The published abstract does not break that figure out for the cagrilintide-alone arm, so we are not attributing it to the standalone drug.

The mechanism work is largely animal work

Amylin is a pancreatic hormone that induces satiety, and cagrilintide is a long-acting analogue of it.[5] The most detailed recent account of how it acts is a 2026 Nature Metabolism paper that built a transcriptomic atlas of more than 530,000 cells across the caudal brainstem of rats, mice and macaques, and identified two conserved calcitonin-receptor-expressing neuronal populations in the dorsal vagal complex that cagrilintide regulates.[12]

That is animal research, and we are labelling it as such. It is a strong piece of mechanistic biology and it says nothing about what dose does what in a person. Notably, the same paper reports that chemogenetically activating one of those populations in rats failed to affect long-term food intake and body weight — a reminder that even a well-mapped mechanism does not translate cleanly into an outcome.[12]

Amylin analogues are not new; this one is

An amylin analogue has been an approved US drug for two decades. Pramlintide, a synthetic analogue of human amylin, has carried an FDA-approved label since 2005, and is indicated as an adjunct to mealtime insulin in adults with type 1 or type 2 diabetes who have not reached glucose targets on insulin alone.[14][13] Its label opens with a boxed warning: used with insulin it increases the risk of severe hypoglycemia, particularly in type 1 diabetes, typically within three hours of an injection.[13]

Pramlintide is a different molecule, a different dosing schedule and a different indication, so its warning is not cagrilintide's warning. It is offered here only as a check on the idea that the amylin pathway is novel and therefore unexamined. The pathway is old; the once-weekly analogue and the weight-management use are what is new.

Which brings the question back to the vial. A research-market product labelled cagrilintide shares a peptide name with the molecule in these trials. It is not the fixed-dose combination that produced the 20.4% figure, it is not the pen Novo Nordisk filed for approval, and it does not inherit the identity, purity, formulation or evidence of either. The honest summary of the standalone compound is narrower than its reputation: one 26-week dose-finding trial, one 302-person phase 3 arm, and no approval anywhere.

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