Beyond GLP-1: Cagrilintide, Amycretin & What's Coming Next

CagriSema: Cagrilintide + Semaglutide — Novo Nordisk's Next Major Candidate

CagriSema represents the most clinically advanced next-generation obesity medication and the one closest to potential regulatory approval. It is a fixed-dose combination of cagrilintide (2.4 mg) and semaglutide (2.4 mg) delivered in a single weekly subcutaneous injection. The combination rationale is rooted in the complementary physiological mechanisms of the two hormonal systems it targets.

Semaglutide acts on GLP-1 receptors to suppress appetite, slow gastric emptying, and improve insulin sensitivity — mechanisms that are well-characterized and have produced semaglutide's approximately 15% weight loss in monotherapy. Cagrilintide targets amylin receptors. Amylin is a 37-amino acid peptide hormone co-secreted with insulin by pancreatic beta cells during meals. Endogenous amylin acts centrally to reduce meal size, slow gastric emptying, and suppress glucagon secretion. Importantly, amylin's satiety pathways in the brain are largely distinct from GLP-1's pathways — they converge at the level of the hypothalamus but originate from different brainstem and hindbrain circuits, particularly the area postrema and nucleus tractus solitarius.

The Phase 2 CAGRISEMA trial demonstrated that the combination produced substantially greater weight loss than either drug alone, with approximately 15.6% weight loss at 32 weeks compared to approximately 8.1% for semaglutide alone and approximately 6.0% for cagrilintide alone at matched doses. The Phase 3 REDEFINE trials expanded on this, with Phase 3 data showing approximately 22–25% weight loss over 68 weeks — a result that rivals or slightly exceeds tirzepatide's Phase 3 SURMOUNT trial outcomes.

Beyond weight loss, CagriSema has shown improvements in glycemic control, lipid profiles, and blood pressure. Novo Nordisk has indicated that regulatory submission is planned for 2025–2026, positioning CagriSema as a direct competitor to tirzepatide in the premium obesity medication segment. If approved, it will be the first amylin-based combination therapy for obesity since pramlintide (a shorter-acting amylin analog that never achieved wide adoption for weight management due to its three-times-daily injection requirement and modest efficacy). For a detailed comparison of current leading options while awaiting next-generation drugs, see our tirzepatide vs. semaglutide 2026 comparison.

Amycretin: Novo Nordisk's Oral Triple-Action Molecule

If CagriSema represents the evolution of injectable obesity therapy, amycretin represents something potentially more revolutionary: the first oral molecule that simultaneously activates multiple obesity-relevant receptor systems and produces injectable-level efficacy in pill form. Amycretin is a unimolecular compound — a single chemical entity engineered to activate both GLP-1 receptors and amylin receptors, combining two hormonal signaling pathways in one molecule that can be taken by mouth.

The early Phase 1 clinical data for amycretin, presented at the American Diabetes Association Scientific Sessions in 2024, was genuinely remarkable. In a dose-escalation study, patients taking amycretin achieved an average of 13.1% weight loss over just 12 weeks. To put this in context, injectable semaglutide (Wegovy) achieves approximately 6–8% weight loss in the same 12-week window. Achieving 13% in 12 weeks with an oral pill — if replicated in larger trials — would represent a generational advance in oral obesity pharmacotherapy.

The mechanism by which amycretin achieves oral bioavailability while targeting two receptor systems is a significant pharmaceutical achievement. GLP-1 receptor agonists are peptides, and peptides are notoriously difficult to deliver orally because digestive enzymes break them down in the gut before they can be absorbed. The existing oral semaglutide (Rybelsus) uses an absorption enhancer called SNAC (sodium N-[8-(2-hydroxybenzoyl)aminocaprylate]) to protect the drug in the stomach and facilitate absorption through the gastric mucosa. Amycretin appears to employ a modified molecular architecture that achieves sufficient oral bioavailability to produce pharmacological activity at the required concentrations.

Phase 2 trials for amycretin are expected to initiate or report in 2026, and Phase 3 enrollment — if Phase 2 is successful — would follow in 2027–2028. A realistic availability timeline for amycretin, assuming uninterrupted development success, would be 2028–2029. The significance of an oral medication approaching injectable efficacy cannot be overstated in terms of patient accessibility, adherence, and global reach.

Retatrutide: Eli Lilly's Triple Agonist — The Speed Record Holder

Retatrutide is Eli Lilly's next major obesity drug candidate — a triple receptor agonist that simultaneously activates GIP receptors, GLP-1 receptors, and glucagon receptors. While tirzepatide (Lilly's current flagship) is a dual GIP/GLP-1 agonist, retatrutide adds glucagon receptor agonism as a third therapeutic target, and this additional mechanism appears to produce meaningfully greater weight loss. For a comprehensive review of retatrutide's mechanisms, see our dedicated article on retatrutide as a triple agonist.

The glucagon receptor agonism component is what differentiates retatrutide from all currently approved medications. Glucagon, traditionally known as the counter-regulatory hormone to insulin, has complex metabolic effects beyond simply raising blood sugar. In the liver, glucagon stimulates fatty acid oxidation (fat burning) and thermogenesis (heat generation). In adipose tissue, glucagon receptor activation promotes lipolysis and fatty acid release. In the context of a GLP-1/GIP/glucagon triple agonist, the glucagon component's hyperglycemic effect is largely offset by the strong glucose-lowering actions of GLP-1 and GIP, while its metabolic-activating effects on fat tissue and liver remain — creating a net effect of increased energy expenditure and fat mobilization beyond what appetite suppression alone would produce.

Phase 2 data for retatrutide, published in NEJM in 2023, showed 24.2% body weight reduction at 48 weeks in patients with obesity but without diabetes — the highest weight loss recorded in any obesity drug trial at that time. Notably, the weight loss trajectory had not plateaued by the end of the trial at 48 weeks, suggesting that further weight loss would have continued with longer treatment. Higher-dose groups lost even more weight, with some patients approaching 30% weight loss.

The Phase 3 TRIUMPH trial program for retatrutide is currently enrolling and recruiting across multiple indications including obesity, type 2 diabetes, and metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH). Results from the obesity arm are anticipated in 2026–2027, with FDA submission potentially following in 2027. If Phase 3 data replicates the Phase 2 magnitude of effect, retatrutide would become the most effective approved obesity medication by a significant margin.

Orforglipron and the Race for Oral GLP-1

Beyond amycretin, several other oral GLP-1 receptor agonists are in late-stage development. Eli Lilly's orforglipron is a non-peptide small molecule that activates the GLP-1 receptor without being a peptide — which means it does not face the same digestive degradation challenges as peptide-based oral GLP-1s. This is a fundamentally different chemical approach to oral GLP-1 agonism that has been in development for over a decade.

Phase 3 data for orforglipron, published in NEJM in 2024, showed approximately 9–10% body weight reduction over 36 weeks in patients with obesity. This is meaningfully better than the placebo-adjusted weight loss from older oral medications like orlistat or phentermine-topiramate, but it falls short of injectable semaglutide and tirzepatide. Orforglipron also demonstrated significant improvements in blood glucose for patients with type 2 diabetes.

The significance of orforglipron's 9–10% oral efficacy is context-dependent. For patients who have needle phobia, prefer not to use injectables, or have logistical barriers to injectable medications, an oral option achieving ~10% weight loss represents a genuine improvement over previous oral therapies. An FDA decision on orforglipron is anticipated in 2025–2026.

Pfizer's danuglipron, another oral GLP-1 small molecule, was discontinued in 2024 after Phase 2 studies showed unacceptable rates of nausea, vomiting, and liver enzyme elevations at effective doses. This underscores that not all oral GLP-1 candidates will succeed — achieving oral bioavailability while maintaining tolerability is genuinely challenging.

For patients currently comparing injectable options while awaiting oral alternatives, our detailed comparison of Zepbound vs. Mounjaro provides a framework for choosing between current tirzepatide formulations.

Bimagrumab: Solving the Muscle Loss Problem

One of the most significant limitations of current GLP-1-based obesity therapy is lean mass loss during weight reduction. When patients lose weight on semaglutide or tirzepatide, approximately 25–40% of the weight lost comes from lean mass (muscle, bone mineral density, and organ tissue) rather than exclusively from fat. This is not unique to GLP-1 medications — caloric restriction generally produces some lean mass loss — but it is a clinically important concern because lean mass is metabolically active tissue that determines long-term metabolic health, physical function, and weight maintenance.

Bimagrumab represents a completely different therapeutic approach: it is a monoclonal antibody that blocks the activin type II receptor (ActRII), specifically inhibiting myostatin — a protein that normally limits muscle growth. By blocking myostatin, bimagrumab promotes muscle growth and maintenance even in the context of caloric restriction. This mechanism is independent of GLP-1 and acts on a completely different physiological axis.

The combination approach of bimagrumab with semaglutide has produced some of the most striking body composition data ever reported in obesity research. A Phase 2 study published in JAMA Network Open showed that patients receiving bimagrumab plus semaglutide lost approximately 5.4 times more fat mass than semaglutide alone while simultaneously gaining significant lean mass. The net effect was a dramatic improvement in body composition — reducing fat while preserving and building muscle — that goes beyond what is achievable with weight loss alone.

The clinical implications are profound. If the lean mass preservation effect of bimagrumab can be verified in larger trials, it could address one of the most important gaps in current GLP-1 therapy. The reduction in muscle mass that occurs with GLP-1-mediated weight loss is associated with impaired functional outcomes in older adults, reduced resting metabolic rate (which contributes to weight regain after stopping medication), and potentially worse long-term metabolic health than fat mass alone would predict. Bimagrumab plus GLP-1 combination therapy could theoretically produce weight loss that is both greater in fat reduction and superior in metabolic quality to GLP-1 monotherapy.

Timeline: What Patients Should Realistically Expect

Understanding the realistic development timeline for these next-generation medications helps patients and physicians make informed decisions about whether to start currently available therapy or await future options. The general rule in drug development — that promising early data often takes years to translate to approved medications — applies here.

For patients currently deciding between semaglutide and tirzepatide, our comprehensive 2026 comparison provides the most detailed current guidance. Both are highly effective therapies that should not be deferred while awaiting drugs that remain years from approval.