Development of Cagrilintide, a Long-Acting Amylin Analogue
Kruse T, Hansen JL, Dahl K, Schäffer L, Sensfuss U, Poulsen C, Schlein M, Hansen AMK, +7 more
Journal of Medicinal Chemistry (2021)
The molecular design paper for cagrilintide — a stabilised, lipidated long-acting analogue of pramlintide engineered around the same C20-fatty-diacid + albumin-binding architecture that produced once-weekly semaglutide, here transplanted onto an amylin backbone.
This 2021 paper from Novo Nordisk's medicinal chemistry group is the foundational design paper for cagrilintide and the disclosure of the structure-activity work that produced the molecule now anchoring the CagriSema combination program. The design problem was the same one that had constrained amylin pharmacology for two decades: native human amylin has a strong propensity to self-aggregate into amyloid fibrils, making the unmodified hormone pharmaceutically unworkable; pramlintide (Symlin, FDA-approved 2005) had solved the fibrillation problem through proline substitutions at positions 25, 28, and 29 but still required three-times-daily mealtime dosing because of its short circulating half-life. The Kruse team's contribution was a molecule that combined the anti-amyloid backbone of pramlintide with additional stabilising substitutions — notably 14E and 17R, designed to form a salt bridge across the central helix — together with C-terminal amidation, N-terminal acetylation, and a C20 eicosanedioic fatty diacid attached at the N-terminus through a γ-glutamic acid linker. The fatty-acid moiety binds reversibly to plasma albumin and slows renal filtration and proteolysis, extending the elimination half-life from the minutes-scale of endogenous amylin to roughly one week. The resulting molecule is a balanced agonist across the amylin receptor subtypes (AMY1, AMY2, AMY3 — heterodimers formed when the calcitonin receptor associates with RAMP1, RAMP2, or RAMP3 respectively) that also retains affinity for the calcitonin receptor itself.
The paper presents the structure-activity-relationship work behind the selection: how each residue change was scored against amyloid-fibril formation, receptor potency, solubility at formulation pH, and pharmacokinetic profile in animal models. Preclinical pharmacology data accompany the chemistry — cagrilintide induced significant weight loss when dosed alone in obese animal models, and the weight effect was further enhanced when the compound was co-administered with semaglutide. That preclinical signal was the proof-of-concept that motivated the entire downstream clinical program: the Phase 1b PK study published in parallel (Enebo et al. 2021), the Phase 2 monotherapy dose-finding trial (Lau et al. 2021), the Phase 2 type 2 diabetes combination study (Frias et al. 2023), and the Phase 3 REDEFINE program (Garvey et al. 2025).
The molecule that emerged from this design program is one of only two long-acting amylin analogues to reach clinical development — the other being a Zealand/Boehringer amylin analogue still in earlier-phase work as of 2026 — and it is the molecule that will determine whether amylin agonism becomes a clinically meaningful pharmacological category alongside the GLP-1 / GIP / glucagon-receptor incretin family or whether it remains a footnote to the GLP-1 era.
This is a medicinal-chemistry design paper, not a clinical trial. The pharmacological characterisation is in vitro and in animal models; the human pharmacokinetic and clinical efficacy data come from subsequent papers in the program. The structure-activity work the paper presents is necessarily backward-looking — the published account selects a clean design narrative through what was almost certainly a much messier development process, and reads as a polished design rationale rather than a record of all paths considered or molecules dropped. Industry origin (Novo Nordisk) is the operative context: the authors are all Novo Nordisk staff and the molecule was advanced into Novo Nordisk's pipeline; an independent replication of the fibril-stability work has not, to this entry's knowledge, been published. The mechanistic claims about balanced agonism across AMY1/AMY2/AMY3 rest on cellular assays in the paper; the relative contribution of each amylin-receptor subtype to the in-vivo weight effect remains an active research question. Readers seeking the underlying chemistry will find this paper useful for understanding why cagrilintide looks the way it does and why the once-weekly dosing profile is achievable; readers seeking the clinical translation should follow the citations into the Phase 1b, Phase 2, and Phase 3 trial reports.
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