CagriSema Explained: The REDEFINE Trials and Novo's Next GLP-1

Novo's GLP-1/amylin combination is filed with FDA and awaiting decision. REDEFINE trial results, the head-to-head with tirzepatide, and what this means if approved.

In December 2025, Novo Nordisk filed CagriSema — a once-weekly injectable combination of semaglutide plus the amylin analog cagrilintide — with the FDA for weight management. An approval decision is expected by late 2026. If approved, it would be the first GLP-1/amylin combination therapy for obesity, joining the incretin-based weight-loss market dominated by tirzepatide and semaglutide.

The Phase 3 REDEFINE trial program produced strong weight-loss results but generated some controversy. A head-to-head comparison with tirzepatide — REDEFINE 4 — showed CagriSema losing to tirzepatide on its primary endpoint despite producing meaningful weight loss. Here's what the data actually show, what CagriSema might mean for patients, and where it fits in the treatment landscape if approved.

What CagriSema Is

CagriSema is a fixed-dose combination of two distinct weight-loss mechanisms:

• Semaglutide 2.4 mg — the same GLP-1 receptor agonist that's in Wegovy, working through GLP-1 receptor activation to reduce appetite and slow gastric emptying
• Cagrilintide 2.4 mg — a long-acting amylin analog that activates amylin and calcitonin receptors, producing additional appetite suppression and satiety through a complementary pathway

Amylin is a hormone produced alongside insulin by pancreatic beta cells. It slows gastric emptying (similar to GLP-1) and signals satiety through different brain regions. Pramlintide — an older amylin analog — has been available for diabetes since 2005, but cagrilintide is the first amylin analog designed specifically for weight management and extended dosing.

The combination approach is meaningfully different from tirzepatide, which activates GLP-1 and GIP receptors in a single molecule. CagriSema pairs two separate molecules targeting two distinct hormone pathways. Theoretically, this allows each component to be optimized independently and potentially reduces redundancy in mechanism.

The REDEFINE 1 Trial (Non-Diabetic Patients)

REDEFINE 1 was the pivotal 68-week trial in 3,417 adults with obesity or overweight with one or more obesity-related complications, without diabetes. Participants were randomized to CagriSema (2.4 mg semaglutide + 2.4 mg cagrilintide), semaglutide 2.4 mg alone, cagrilintide 2.4 mg alone, or placebo.

Results at 68 weeks (treatment-policy estimand — real-world effect regardless of adherence):

Key secondary findings:

• With full treatment adherence, CagriSema's weight loss rose to 22.7%
• 40.4% of CagriSema participants achieved ≥25% weight loss
• 23.1% achieved ≥30% weight loss — a threshold previously reserved for bariatric surgery outcomes
• 50.7% of CagriSema participants reached a BMI below the obesity threshold (vs 10.2% placebo)

CagriSema outperformed semaglutide alone by approximately 5.5 percentage points, suggesting the amylin component added meaningful benefit beyond what GLP-1 alone provides.

The REDEFINE 2 Trial (Type 2 Diabetes)

REDEFINE 2 was a parallel 68-week trial in 1,206 adults with type 2 diabetes and either obesity or overweight. Participants were randomized 3:1 to CagriSema or placebo.

Results at 68 weeks:

• 13.7% weight loss with CagriSema vs 3.4% with placebo
• 15.7% weight loss under the trial-product estimand (full adherence scenario)
• 73.5% of CagriSema patients achieved HbA1c ≤6.5% (vs 15.9% placebo) — strong glycemic control

The diabetic-population weight loss was lower than the non-diabetic population — a pattern seen with every incretin-based therapy. Diabetes-related metabolic dysregulation typically produces less dramatic weight response than obesity without diabetes.

The REDEFINE 4 Controversy

REDEFINE 4 was an 84-week open-label head-to-head trial comparing CagriSema (2.4/2.4 mg) to tirzepatide (15 mg) in 809 adults with obesity. Announced in February 2026, the results were mixed:

• CagriSema produced 23% weight loss (adherent participants)
• Tirzepatide produced 25.5% weight loss (adherent participants)
• CagriSema failed to demonstrate noninferiority to tirzepatide on its pre-specified primary endpoint

Across estimand analyses, tirzepatide consistently produced 2–3 percentage points more weight loss than CagriSema. This is modest in absolute terms but statistically and commercially meaningful — the product that went into development as "the Zepbound killer" instead became "approximately as good as Zepbound, slightly less."

For patients, this means:

• If efficacy is the single most important factor, tirzepatide (Zepbound) remains the injectable GLP-1 with the highest demonstrated weight loss
• CagriSema is not meaningfully inferior for clinical purposes — the absolute difference is small
• The CagriSema mechanism (GLP-1 + amylin) is distinct from tirzepatide (GLP-1 + GIP), which may matter for specific patient situations

Side Effect Profile

Safety data across REDEFINE trials was consistent with the GLP-1 class:

• GI side effects in 79.6% of CagriSema patients vs 39.9% on placebo — the expected nausea, diarrhea, vomiting pattern
• Single-digit discontinuation rates due to adverse events (notably lower than retatrutide's discontinuation rates in TRIUMPH-4)
• No new safety signals beyond those already associated with semaglutide and cagrilintide individually

One notable feature: REDEFINE 1 allowed investigators to keep patients on submaximal doses if clinically indicated. Patients didn't have to titrate to the maximum dose to participate. This "dose-flexible" design reflects real-world practice and likely contributed to the good tolerability numbers.

What CagriSema Might Mean for Patients

If CagriSema receives FDA approval in late 2026, it would offer:

• Strong efficacy — among the top tier of approved obesity medications, within a few percentage points of tirzepatide's best results
• A different mechanism — GLP-1 + amylin rather than GLP-1 + GIP, potentially valuable for patients who haven't responded well to tirzepatide or semaglutide alone
• Dual-disease utility — the REDEFINE 2 data supports use in patients with both obesity and type 2 diabetes
• A new Novo Nordisk option — for patients with established clinical relationships with Novo products (like those on Wegovy who might switch within the manufacturer's portfolio)

The Broader Pipeline Context

CagriSema joins a crowded late-stage pipeline:

The trend is clear: each successive mechanism adds efficacy. GLP-1 alone → GLP-1 + one additional hormone → triple-mechanism approaches. The ceiling of pharmacologic weight loss keeps rising. Obesity medicine specialists increasingly expect approved treatments in 2027–2028 to deliver weight loss that approaches what bariatric surgery achieves.

The Ongoing REDEFINE Program

REDEFINE 1 and 2 supported the initial FDA filing, but the program continues:

• REDEFINE 3: A 7,000-patient cardiovascular outcomes trial — will establish whether CagriSema's combined mechanism produces cardiovascular benefit similar to Wegovy's SELECT results
• REDEFINE 8, 9, 11: Various longer-duration and higher-dose studies exploring CagriSema's full efficacy potential — some going out to 80–104 weeks or testing higher doses

These readouts throughout 2026–2028 will clarify CagriSema's long-term durability, cardiovascular benefit, and optimal positioning in the obesity medicine toolkit.

Questions Worth Preparing For

When CagriSema reaches the market (assuming approval), expected considerations:

• Is my response to existing GLP-1 therapy inadequate enough to warrant switching to CagriSema?
• Would I benefit more from the GLP-1 + amylin mechanism vs tirzepatide's GLP-1 + GIP?
• How does insurance coverage compare between CagriSema, Zepbound, and Wegovy?
• If I'm already doing well on my current medication, is there any reason to switch?
• What's the titration plan — will I tolerate the amylin component?