CagriSema: Semaglutide Plus Amylin Analog for Obesity
Cagrilintide/CagriSema
20.4% weight loss
In the REDEFINE 1 trial, adults with obesity who received CagriSema lost a mean of 20.4% of their body weight at 68 weeks, compared to 15.7% with semaglutide alone and 3.0% with placebo.
Garvey et al., NEJM, 2025
Garvey et al., NEJM, 2025
View as imageCagriSema is Novo Nordisk's fixed-dose combination of two peptide drugs: semaglutide 2.4 mg (a GLP-1 receptor agonist) and cagrilintide 2.4 mg (a long-acting amylin analog), administered together as a once-weekly subcutaneous injection. The logic is straightforward: semaglutide and cagrilintide suppress appetite through different receptor systems, and combining them produces greater weight loss than either drug alone.[1] The Phase 3 REDEFINE trials confirmed this hypothesis, and Novo Nordisk filed for FDA approval in 2026. This article examines the clinical evidence, the pharmacology behind the combination, and the questions that remain. For detailed coverage of the amylin component, see Cagrilintide: The Amylin Analog Half of the CagriSema Equation.
Key Takeaways
- CagriSema produced 20.4% mean weight loss at 68 weeks in REDEFINE 1 (adults without diabetes), versus 15.7% for semaglutide alone, 8.3% for cagrilintide alone, and 3.0% for placebo (Garvey et al., NEJM 2025)
- In adults with type 2 diabetes (REDEFINE 2), CagriSema produced 13.7% weight loss versus 3.4% for placebo (Davies et al., NEJM 2025)
- Cagrilintide acts through brain amylin receptors 1 and 3 (AMY1R and AMY3R), a mechanism distinct from GLP-1 receptor activation (Carvas et al., 2025)
- Gastrointestinal adverse events occurred in 79.6% of CagriSema patients versus 39.9% on placebo; most were mild-to-moderate and transient
- A systematic review and meta-analysis confirmed CagriSema's superiority over semaglutide monotherapy for weight reduction (Gadelmawla et al., 2026)
- CagriSema also reduced systolic blood pressure by approximately 7 mmHg more than placebo in REDEFINE 1 (Verma et al., 2026)
Why Combine Two Appetite Peptides
Semaglutide alone produces roughly 15-17% weight loss, which is clinically transformative but still leaves the majority of patients above their target weight. The rationale for CagriSema is that appetite is regulated by multiple parallel peptide systems, and activating two of them simultaneously should produce additive or synergistic effects.
Semaglutide activates GLP-1 receptors in the hypothalamus, brainstem, and gut to slow gastric emptying, reduce hunger, and decrease the rewarding value of food. It is the most validated peptide drug for weight management, with extensive Phase 3 data (STEP trials) and cardiovascular outcome benefits.
Cagrilintide is a long-acting analog of amylin, a 37-amino-acid peptide co-secreted with insulin from pancreatic beta cells. Natural amylin has a half-life of approximately 15 minutes; cagrilintide's acylation extends this to approximately 160 hours, enabling once-weekly dosing. Cagrilintide acts through amylin receptors (AMY1R and AMY3R) in the area postrema and nucleus tractus solitarius of the brainstem to reduce food intake.[2]
The critical insight is that GLP-1 and amylin pathways converge on appetite suppression but through different receptors and different brain regions. GLP-1 acts heavily in the hypothalamic arcuate nucleus; amylin acts primarily in the brainstem area postrema. Engaging both circuits simultaneously creates a more comprehensive suppression of appetite than either alone.[3] For a broader discussion of why combining peptide mechanisms can outperform monotherapy, see the related article.
REDEFINE 1: The Pivotal Obesity Trial
The REDEFINE 1 trial enrolled 3,417 adults with BMI of 30 or higher (or 27+ with at least one obesity-related complication) and without type 2 diabetes. Participants were randomized to receive once-weekly CagriSema (cagrilintide 2.4 mg + semaglutide 2.4 mg), semaglutide 2.4 mg alone, cagrilintide 2.4 mg alone, or placebo for 68 weeks.[4]
Weight loss results
| Group | Mean % Weight Loss at 68 Weeks |
|---|---|
| CagriSema | 20.4% |
| Semaglutide alone | 15.7% |
| Cagrilintide alone | 8.3% |
| Placebo | 3.0% |
CagriSema's 20.4% mean weight loss was statistically superior to both semaglutide alone (difference: 4.7 percentage points) and placebo. The additive effect of cagrilintide on top of semaglutide was approximately 4.7 percentage points of additional weight loss.
Approximately 40% of CagriSema patients achieved 20% or greater weight loss, compared to roughly 25% on semaglutide alone. Around 16% achieved 25% or greater weight loss with CagriSema.
These results fell slightly short of the 25% weight loss target that Novo Nordisk had initially projected, which caused a temporary decline in the company's stock price when interim data was released in late 2024. The final REDEFINE 1 data published in NEJM in 2025 confirmed the 20.4% figure.
Blood pressure effects
A secondary analysis by Verma et al. (2026) showed CagriSema reduced systolic blood pressure by approximately 7 mmHg more than placebo, consistent with the cardiovascular benefits observed with GLP-1 receptor agonists in other trials.[5]
REDEFINE 2: Adults with Type 2 Diabetes
The REDEFINE 2 trial enrolled adults with both obesity and type 2 diabetes, a population that typically achieves less weight loss with GLP-1 drugs than non-diabetic individuals.[6]
CagriSema produced a mean weight loss of 13.7% at 68 weeks versus 3.4% for placebo in this population. For context, semaglutide alone produces approximately 10% weight loss in diabetic populations (from the STEP 2 trial), suggesting cagrilintide adds roughly 3-4 percentage points of additional weight loss in patients with type 2 diabetes.
CagriSema also improved glycemic control: HbA1c reductions were greater with CagriSema than placebo, though the trial was not powered to test glycemic endpoints as primary outcomes.
Phase 2 Data: The Earlier Signal
Before the REDEFINE trials, a Phase 2 study by Frias et al. (2023) tested multiple dose combinations of cagrilintide and semaglutide over 32 weeks.[7] The highest dose combination (cagrilintide 2.4 mg + semaglutide 2.4 mg) produced approximately 15.6% weight loss at 32 weeks, with a trajectory that suggested continued weight loss beyond the trial period. This Phase 2 data provided the dose selection rationale for the REDEFINE Phase 3 program.
How Cagrilintide Works in the Brain
Recent research has clarified cagrilintide's central mechanism. Carvas et al. (2025) demonstrated that cagrilintide lowers body weight through brain amylin receptors 1 and 3 (AMY1R and AMY3R), which are heterodimeric receptors composed of calcitonin receptor (CTR) combined with receptor activity-modifying proteins (RAMPs).[3]
Cao et al. (2025) characterized the structural and dynamic features of cagrilintide binding to calcitonin and amylin receptors, revealing how the peptide's acyl chain modification enables prolonged receptor engagement without altering binding selectivity.[8]
In a preclinical mechanistic study, Jacobsen et al. (2025) showed that CagriSema drives weight loss in rats by reducing energy intake rather than increasing energy expenditure.[9] This finding is consistent with the combination acting primarily through appetite suppression rather than metabolic rate enhancement.
The Amylin Pathway: What Makes It Different from GLP-1
The amylin and GLP-1 systems share a common purpose (appetite suppression) but differ in their biology in ways that make their combination more than just "more of the same."
Different production sites. GLP-1 is produced by intestinal L-cells in response to food. Amylin is co-secreted with insulin from pancreatic beta cells. In type 2 diabetes, both systems are impaired: GLP-1 secretion is reduced, and amylin secretion declines as beta cells deteriorate. CagriSema replaces both deficient peptide signals simultaneously.
Different brain targets. GLP-1 receptors are densest in the hypothalamic arcuate nucleus, paraventricular nucleus, and the reward circuits of the mesolimbic system. Amylin receptors concentrate in the area postrema and nucleus tractus solitarius of the brainstem. These are physically separate brain regions that independently influence food intake through distinct neural circuits. Activating both creates two separate "brake pedals" on appetite rather than pressing one brake harder.
Different meal effects. Endogenous GLP-1 primarily signals post-meal satiety (stopping eating). Endogenous amylin primarily signals satiation during meals (feeling full while eating). This temporal complementarity means the combination may reduce both meal size (amylin effect) and inter-meal hunger (GLP-1 effect), covering the full eating cycle.
Different metabolic effects. Beyond appetite, amylin slows gastric emptying through a mechanism independent of GLP-1, and it suppresses post-meal glucagon secretion. The metabolic benefits of CagriSema in REDEFINE 2 (the diabetes trial) may partly reflect these additive metabolic effects beyond pure appetite suppression.
Safety Profile
The REDEFINE trials documented a safety profile consistent with other GLP-1 and amylin-based drugs:
Gastrointestinal adverse events were the most common: 79.6% of CagriSema patients experienced at least one GI event (nausea, vomiting, diarrhea, constipation, or abdominal pain) versus 39.9% on placebo. Most events were mild-to-moderate in severity, occurred during the dose-escalation phase, and were transient.
Serious adverse events occurred at similar rates across groups. No new safety signals emerged that were not already known from semaglutide or cagrilintide individually.
Heart rate increased modestly with CagriSema, consistent with the known effect of GLP-1 receptor agonists. The clinical significance of small heart rate increases with these drugs remains debated.
Pancreatitis and gallbladder events occurred at low rates, consistent with the class effect of GLP-1 drugs. Amylase and lipase elevations were more common with CagriSema than placebo but were usually asymptomatic.
Context: Where CagriSema Fits in the Peptide Obesity Landscape
CagriSema enters a competitive landscape of combination peptide approaches to obesity:
Tirzepatide (Mounjaro/Zepbound, Eli Lilly) is a dual GLP-1/GIP agonist that achieved up to 22.5% weight loss in the SURMOUNT trials. It uses a different combination strategy: one molecule that activates two receptors, rather than two separate molecules given together.
Survodutide (Boehringer Ingelheim) is a dual GLP-1/glucagon agonist in Phase 3 development.
Retatrutide (Eli Lilly) is a triple GLP-1/GIP/glucagon agonist that achieved approximately 24% weight loss in Phase 2, potentially the highest weight loss yet achieved by any peptide drug.
CagriSema's competitive position depends on whether amylin receptor activation offers advantages beyond weight loss that GIP or glucagon receptor activation does not. The blood pressure reduction data and the distinct brainstem mechanism may differentiate CagriSema from GIP-containing combinations, but head-to-head trials against tirzepatide or retatrutide have not been conducted.[10]
A systematic review and meta-analysis by Gadelmawla et al. (2026) confirmed CagriSema's superiority over semaglutide monotherapy but noted the need for longer-term safety and durability data.[11] For detailed analysis of the REDEFINE trials, see the dedicated REDEFINE trial results article.
Open Questions
Weight loss durability. The REDEFINE trials ran 68 weeks. Whether weight loss continues, plateaus, or partially reverses during longer treatment is unknown. Extension studies are underway.
Weight regain after discontinuation. GLP-1 agonist withdrawal typically produces significant weight regain. Whether adding cagrilintide changes the regain trajectory after treatment cessation has not been studied.
Muscle mass preservation. Weight loss with GLP-1 drugs includes significant lean mass loss (approximately 25-40% of total weight lost). Whether CagriSema preserves more muscle than semaglutide alone has not been reported from REDEFINE. The sarcopenia risk with GLP-1 weight loss is an active area of concern across the class.
Cost and access. CagriSema combines two branded Novo Nordisk peptides in one injection. Pricing and insurance coverage decisions will determine real-world accessibility.[12] The cost-effectiveness debate for GLP-1 drugs applies directly to CagriSema, where the incremental benefit over semaglutide alone must justify the incremental cost.
Comparison to bariatric surgery. CagriSema's 20.4% weight loss approaches but does not match the 25-35% weight loss typically achieved by Roux-en-Y gastric bypass. Whether CagriSema will be positioned as an alternative to surgery or a complement depends on durability and long-term outcome data.
The Bottom Line
CagriSema combines two peptide mechanisms, GLP-1 and amylin receptor activation, into a once-weekly injection that produces approximately 20% weight loss at 68 weeks. The REDEFINE trials confirmed that the combination outperforms either component alone, with cagrilintide adding roughly 4-5 percentage points of additional weight loss beyond semaglutide. The safety profile is dominated by GI side effects similar to other GLP-1 drugs. Novo Nordisk has filed for FDA approval, but questions about durability, muscle mass preservation, cost, and positioning against competing dual/triple agonists remain open.