cagrilintide and CagriSema: the long-acting amylin program

cagrilintide is a once-weekly amylin analog developed by Novo Nordisk under the code AM833. it activates the amylin receptor complex in the dorsal brainstem to drive central satiety, slows gastric emptying, and suppresses postprandial glucagon. paired with semaglutide as CagriSema, it produced the largest weight loss of any arm in the REDEFINE-1 phase 3 trial in obesity. neither the monotherapy nor the combination is FDA-approved.

what is cagrilintide?

cagrilintide is a 32-amino-acid synthetic peptide engineered as a long-acting amylin analog. it carries a C20 fatty-diacid sidechain conjugated via a gamma-glutamic-acid linker, which lets the molecule tether reversibly to circulating albumin and supports once-weekly subcutaneous dosing. the parent hormone amylin is co-secreted with insulin from pancreatic beta cells.

amylin (also called islet amyloid polypeptide, or IAPP) was identified in the 1980s as a 37-amino-acid peptide co-secreted with insulin in roughly a 1:100 molar ratio. it acts as a satiety hormone and regulator of gastric emptying and postprandial glucagon, complementing insulin's anabolic actions. the first FDA-approved amylin analog, pramlintide, reached the market in 2005 as an adjunct to mealtime insulin in type 1 and insulin-using type 2 diabetes. pramlintide validated amylin agonism as a tractable target but its short half-life requires three daily injections at mealtimes. cagrilintide is the long-acting successor: substitutions in the amylin backbone prevent the amyloidogenic aggregation that characterizes native human amylin, and the C20 acylation strategy is the same chemistry concept used by semaglutide and survodutide [1].

"CagriSema" refers to co-administration of cagrilintide with semaglutide. as of mid-2026 CagriSema is delivered as a co-formulated single-pen product in phase 3 trials, although early-phase work used separate injections. the REDEFINE phase 3 program (REDEFINE-1 through REDEFINE-6) is the named series of CagriSema trials covering obesity, type 2 diabetes, weight maintenance, and cardiovascular outcomes.

how does it work?

cagrilintide engages the amylin receptor complex, a heterodimer of the calcitonin receptor with a receptor activity-modifying protein (RAMP1, RAMP2, or RAMP3). this receptor is densely expressed in the area postrema and nucleus tractus solitarius in the dorsal brainstem, where it drives central satiety. the molecule also slows gastric emptying via vagal output and suppresses postprandial glucagon via brainstem-mediated suppression of pancreatic alpha cells.

three physiologic effects dominate. first, central satiety. the area postrema is a circumventricular organ with a permeable blood-brain barrier, making it a primary sensor for blood-borne satiety signals. lesion and viral-depletion studies in rodents show that area postrema amylin receptor signaling is both necessary and sufficient for amylin's anorexic effect, with downstream projections engaging hypothalamic arcuate POMC and AgRP populations and reaching mesolimbic dopaminergic circuits to reduce reward-driven palatable-food intake [2]. second, gastric emptying. amylin slows gastric emptying by central modulation of vagal output, reducing the rate at which nutrients reach the small intestine and contributing to postprandial fullness. the effect is dose-dependent and partially overlapping with GLP-1's gastric-emptying effect, but operates through distinct receptors. third, glucagon suppression. amylin agonism suppresses inappropriate postprandial glucagon secretion via brainstem-mediated suppression of alpha-cell output, improving postprandial glycemia without raising hypoglycemia risk.

the mechanistic rationale for combining cagrilintide with semaglutide is precisely that amylin and GLP-1 engage different receptors and different brain circuits. semaglutide acts through GLP-1 receptors expressed on pancreatic beta cells, gastric smooth muscle, hypothalamic POMC neurons, brainstem AP/NTS, and vascular and renal cells. cagrilintide acts through the calcitonin receptor plus RAMP complex in the same brainstem region but through a distinct receptor pool. the combination is mechanistically additive in a way that mono-receptor titration cannot achieve, with the amylin arm potentially preferentially reducing reward-driven feeding while the GLP-1 arm drives broader meal-size effects.

what does the evidence show?

cagrilintide monotherapy showed about 10.8 percent mean weight loss at the 2.4 mg dose in the Lau 2021 phase 2 trial. CagriSema produced greater weight loss than either monotherapy in the REDEFINE-1 phase 3 trial in obesity (68 weeks), met co-primary endpoints for both weight and HbA1c in the REDEFINE-2 trial in obesity with type 2 diabetes (68 weeks), and showed consistent effects in the East Asian REDEFINE-5 trial. effect sizes should be cited from the peer-reviewed NEJM papers, not from earlier press-release toplines.

the Lau 2021 phase 2 dose-ranging trial randomized 706 adults with obesity to cagrilintide 0.3, 0.6, 1.2, 2.4, or 4.5 mg weekly, with placebo and active comparator liraglutide 3.0 mg daily, for 26 weeks. the 2.4 mg cagrilintide arm produced a mean 10.8 percent weight loss versus 3.0 percent on placebo and 9.0 percent on liraglutide, establishing cagrilintide monotherapy as a clinically meaningful weight-loss agent in its own right [3]. the Enebo 2021 phase 1b co-administration study confirmed that cagrilintide and semaglutide could be combined without clinically meaningful pharmacokinetic interaction, anchoring the 2.4 mg / 2.4 mg co-formulation that the phase 3 program adopted.

REDEFINE-1 (Garvey et al., NEJM 2025) tested CagriSema 2.4 mg / 2.4 mg once-weekly versus cagrilintide alone, semaglutide alone, and placebo over 68 weeks in adults with obesity without type 2 diabetes. the CagriSema arm produced the largest mean weight loss, exceeding both monotherapies and placebo, with a strong responder distribution at the 10, 15, and 20 percent loss thresholds [4]. REDEFINE-2 (Davies et al., NEJM 2025) extended the combination to adults with obesity and type 2 diabetes, where the dual-mechanism story is most clinically distinct: the amylin arm contributes glucagon suppression and gastric-emptying delay on top of GLP-1 receptor agonism, and the trial met co-primary endpoints for both weight loss and HbA1c reduction [5]. REDEFINE-5 (Yamauchi et al., Lancet Diabetes Endocrinol 2026) confirmed the effect generalizes to Japanese and Taiwanese populations with lower mean baseline BMI than the global REDEFINE cohorts.

the honest framing point is that an earlier December 2024 topline press release for REDEFINE-1 produced widely circulated "underwhelming" interpretations relative to market expectations. the peer-reviewed paper contextualizes the result more conservatively, and the meaningful comparison is not against a market expectation but against semaglutide monotherapy (where CagriSema is consistently better) and against tirzepatide SURMOUNT-1 and retatrutide phase 2 (where CagriSema is competitive but not clearly dominant).

FDA and regulatory status

cagrilintide and CagriSema are investigational. no FDA, EMA, or PMDA approval exists as of mid-2026. Novo Nordisk has guided that an NDA submission for CagriSema in chronic weight management will follow assembly of the REDEFINE phase 3 program. cagrilintide is not on the FDA Drug Shortage List, so 503A or 503B compounding is not a lawful pathway, and "research-grade" cagrilintide sold online is regulatory-noncompliant.

the cardiovascular outcomes question is still open. CagriSema does not have a dedicated CVOT readout as of mid-2026; its CV story is currently extrapolated from semaglutide's SELECT trial (which showed a 20 percent MACE reduction in obesity without diabetes) plus the assumption that adding cagrilintide does not undo semaglutide's CV benefit. that assumption is reasonable but unproven, and a published CVOT will be required to formalize a cardiovascular label claim.

sports anti-doping context is also in flux. GLP-1 receptor agonists (including the semaglutide arm of CagriSema) are on the WADA 2026 monitoring program rather than the fully prohibited list, with policy under active review. amylin agonists are not specifically scheduled as of mid-2026, but the class is in scope for the same metabolic-modulator surveillance.

safety profile and side effects

gastrointestinal adverse events dominate: nausea, vomiting, diarrhea, constipation, dyspepsia, decreased appetite. these are titration-dependent and led to clinically meaningful but manageable discontinuation rates in the phase 3 program. detailed rates should be cited from the peer-reviewed REDEFINE-1 and REDEFINE-2 papers directly because they vary by population.

beyond GI events, the class concerns familiar from semaglutide and tirzepatide carry over. pancreatitis is a low-frequency class signal that was not specifically enriched in cagrilintide datasets but the class warning persists. gallbladder disease is an incretin-class signal at the higher rates of rapid weight loss. acute kidney injury is a dehydration-mediated risk during severe GI losses. thyroid C-cell tumor risk is a rodent finding for GLP-1 class with no established human relevance, but cagrilintide's amylin and calcitonin-receptor engagement adds a theoretical mechanistic interest in C-cell biology because calcitonin is the native C-cell hormone. no human safety signal has been reported. bone turnover is a theoretical concern from calcitonin-receptor crosstalk; no clinically meaningful signal has emerged.

contraindications include personal or family history of medullary thyroid carcinoma (MTC) and multiple endocrine neoplasia syndrome type 2 (MEN2), carried as a class contraindication for the GLP-1 arm. pregnancy is expected to be a contraindication, mirroring semaglutide guidance. the longest formal exposure dataset is approximately 68 to 72 weeks; no published data beyond that, no CVOT, and no real-world post-marketing data because the drug is not yet on the market.

where it fits in peptide therapy

cagrilintide is the long-acting weekly successor to pramlintide and the first long-acting amylin analog to reach phase 3. CagriSema sits in the same competitive band as tirzepatide and retatrutide for weight loss magnitude, but adds a different second hormone (amylin vs GIP vs glucagon). choice between investigational classes will likely be indication-driven once the regulatory pictures settle.

the direct precursor is pramlintide, the only approved amylin analog. pramlintide is short-acting (three daily mealtime injections) and is approved as an insulin adjunct rather than as a weight-loss agent. cagrilintide's once-weekly dosing is the central engineering advance. the closest investigational comparator is eloralintide (LY3841136, Lilly), a competing long-acting amylin agonist in earlier-stage clinical development, which means the "long-acting amylin agonist" category is becoming a class rather than a single molecule.

the relevant combination comparators are tirzepatide (GIP/GLP-1 dual) and retatrutide (GIP/GLP-1/glucagon triple). all three are weekly weight-loss peptides built around a GLP-1 core with a second or third hormonal arm added, and the choice across them will be driven by the specific add-on biology. the partner molecule is semaglutide, whose biology is covered in detail on its own page, and the next-door peptide in the survodutide direction is survodutide (GLP-1/glucagon dual). for foundational biology on the amylin and incretin axes, our free peptides and your body module covers the underlying physiology.