Cagrilintide

Background

Cagrilintide is a long-acting analog of human amylin, the 37-amino-acid hormone co-secreted with insulin by pancreatic β-cells. Native amylin is rapidly cleared and aggregates into amyloid fibrils — both reasons it has never been a practical therapeutic. Pramlintide (Symlin) was the first stabilized amylin analog approved as a meal-time injection. Cagrilintide takes the same idea further: amino acid substitutions plus a fatty-acid linker yield a peptide with a half-life of approximately one week.

The asset belongs to Novo Nordisk and is being developed primarily as the amylin half of CagriSema, a fixed-dose combination with semaglutide.

Mechanism in depth

Cagrilintide is a dual amylin–calcitonin receptor agonist. Its effects converge on two anatomical sites:

1. Area postrema and hindbrain satiety circuits. Amylin receptor signaling (a heteromer of the calcitonin receptor + RAMP1/2/3) suppresses food intake centrally. Unlike GLP-1, which acts strongly on arcuate POMC neurons, amylin's primary site is hindbrain — explaining the additive, non-redundant effect when combined with GLP-1 agonists.
2. Gastric emptying. Slowed gastric emptying contributes to early satiety and lower postprandial glucose excursions.

The fatty-acid side chain enables albumin binding, which is the kinetic mechanism that converts amylin from a meal-time hormone into a weekly drug.

Human evidence

Cagrilintide has a substantial clinical dataset:

• Lau 2021 (phase 2 monotherapy, n=706) — 26 weeks of cagrilintide produced dose-dependent weight loss, peaking around 10.8% at 4.5 mg weekly vs 3.0% with placebo and 9.8% with liraglutide 3.0 mg.
• Enebo 2021 (phase 1b combo, n=95) — established the safety and pharmacokinetic compatibility of cagrilintide + semaglutide co-administration.
• CagriSema phase 2 (n=92, 32 weeks) — ~15.6% weight reduction in T2D, materially exceeding semaglutide monotherapy.
• REDEFINE phase 3 program — multiple trials in obesity (REDEFINE 1, 2) and T2D (REDEFINE 3) are reading out 2024–2025.

The clinical signal is strong and replicated. Outstanding questions are durability, long-term safety, and how the combination compares head-to-head against tirzepatide.

Preclinical evidence

Rodent diet-induced obesity models showed dose-dependent reductions in food intake and body weight with cagrilintide, with kinetics matching the long half-life. Importantly, additive (rather than redundant) effects with semaglutide were demonstrated in mice before the human combination trials — providing the mechanistic rationale that informed CagriSema's development.

Stack synergy

The defining stack is cagrilintide + semaglutide (CagriSema), supported by phase 3 data. The mechanistic rationale — hindbrain amylin signaling + arcuate GLP-1 signaling — is sound.

Stacking cagrilintide with tirzepatide is mechanistically interesting (amylin + GIP/GLP-1) but unstudied; the GI side-effect burden would likely be prohibitive at full doses.

Avoid co-administration with pramlintide (redundant pathway) or with insulin/sulfonylureas without dose adjustment.

Open questions

• How does CagriSema compare to tirzepatide in head-to-head trials at maximum tolerated doses?
• What is the long-term (>2 year) safety profile? Pancreatitis and gallbladder signals shared with the GLP-1 class need to be ruled out for the combination.
• Does cagrilintide preserve lean mass better than GLP-1 monotherapy? Animal data is suggestive; human DEXA data is sparse.
• What happens on discontinuation? Weight regain is universal across this class but the trajectory specifically for amylin agonists is not yet characterized.