Amylin receptor agonist (revision 30)
Old revision·23:57, 23 Apr 2026·Chromatokid
| Amylin receptor agonistDrug class | |
|---|---|
| Endogenous ligand | Amylin |
| Receptors | AMY1, AMY2, AMY3 (calcitonin receptor plus RAMP) |
| Design problem | Removing amyloidogenicity from the human sequence |
| Topic infobox · conventions | |
Amylin receptor agonists are engineered analogues of amylin designed to reproduce its actions on gastric emptying, glucagon secretion and food intake without the aggregation behaviour of the native human sequence.[1]
Two generations exist. Pramlintide, approved in 2005 as an adjunct to insulin, substitutes three prolines into the human sequence to disrupt β-sheet formation; its short half-life requires injection at each meal, which limited uptake. Cagrilintide is a long-acting analogue employing acylation for weekly dosing and is under development principally in combination with semaglutide as CagriSema.[2]
The clinical interest in the class rests on the observation that amylin-mediated satiety is mechanistically distinct from GLP-1-mediated satiety and appears additive to it, so that a combination produces more weight loss than either component alone at the doses studied.[2]
Design
[edit]The problem to be solved is amyloidogenicity. Human amylin forms cross-β fibrils at concentrations well below those needed for a pharmaceutical formulation, and a peptide that aggregates in the vial is not a medicine.[1]
Pramlintide takes the rodent solution: rat amylin does not aggregate because prolines at three positions in the central region prevent β-sheet stacking, and pramlintide introduces those substitutions into the human sequence. The result is soluble and stable but retains a short half-life of about 48 minutes, and its acidic formulation cannot be mixed in a syringe with insulin.
Cagrilintide adds acylation for albumin binding, reaching a half-life supporting weekly administration. It engages the calcitonin receptor as well as the amylin receptors, and whether that broader engagement contributes to or detracts from the clinical effect is not established.[2]
Clinical findings
[edit]Pramlintide reduces postprandial glucose excursions in insulin-treated diabetes and produces modest weight reduction, on the order of 1–2 kg. Its adoption was limited by mealtime dosing, a separate injection from insulin, and hypoglycaemia when insulin doses were not reduced at initiation.[1]
Cagrilintide monotherapy produced approximately 10% weight reduction at 26 weeks in a phase 2 trial. In combination with semaglutide, reported weight reduction exceeds that of either component alone; the combination programme is covered at CagriSema.[2]
The gastrointestinal adverse-effect profile resembles that of the incretin agonists, with nausea predominating and concentrated during escalation. Whether combining two agents that both delay gastric emptying compounds this is a question the combination trials address only indirectly.
Analytical notes
[edit]Amylin analogues are among the more demanding peptides to characterise, precisely because of the property they were engineered to remove. Residual aggregation propensity means that size-exclusion chromatography and, where available, orthogonal light-scattering methods carry more weight in a specification than they would for a non-aggregating peptide.[3][4]
The distinction between reversible self-association and irreversible aggregation matters here as it does for acylated peptides: a size-based method run under dissociating conditions can report a clean profile on material that shows high-molecular-weight species under native conditions. See Peptide aggregation.
A certificate for an amylin analogue that reports only reverse-phase area percent omits the attribute most likely to fail for this chemistry. That is a statement about method coverage rather than about any particular material.
See also
References
- ^ a b c Hay DL, Chen S, Lutz TA, Parkes DG, Roth JD. "Amylin: pharmacology, physiology, and clinical potential." Pharmacological Reviews 67(3):564–600 (2015). PMID 26071095.
- ^ a b c d Lau DCW, Erichsen L, Francisco AM, et al. "Once-weekly cagrilintide for weight management in people with overweight and obesity: a multicentre, randomised, double-blind, placebo-controlled trial." The Lancet 398(10317):2160–2172 (2021). PMID 34798060.
- ^ United States Pharmacopeia, General Chapter <1503>, Quality Attributes of Synthetic Peptide Drug Substances.
- ^ International Council for Harmonisation, Q6B: Specifications — Test Procedures and Acceptance Criteria for Biotechnological/Biological Products (1999).