Issue 1 — April 8, 2026

Welcome to the first issue of The Peptide Signal. Each Tuesday, four sections: a landmark study broken down, a protocol examined, a mechanism explained, and the week's regulatory news, without the vendor spin. The intro is free. Full issue is for subscribers.

THIS WEEK

The biggest obesity drug data drop in years. A mitochondrial peptide gets its first FDA approval. And the most consequential regulatory shift in the peptide compounding space since 2023, with an important caveat that most coverage is missing.

STUDY OF THE WEEK

CagriSema at 20.4%: The Trial That Disappointed Wall Street and Shouldn't Have

Novo Nordisk's stock dropped 9% the morning of June 22, 2025. The headline from REDEFINE 1: CagriSema produced 20.4% mean body weight reduction at 68 weeks in adults with obesity. That number was below the 25% the market had been expecting, and investors sold.

The same morning, researchers published that result in the New England Journal of Medicine.

Here is what actually happened in that trial, and why the market reaction tells you more about analyst expectations than it does about the compound.

What CagriSema is

CagriSema is a fixed-dose combination of two once-weekly injectable compounds: cagrilintide 2.4 mg (a long-acting amylin analogue) and semaglutide 2.4 mg (the same active ingredient as Wegovy). The two compounds target different but complementary appetite pathways. Semaglutide works primarily through GLP-1 receptor activation in the gut and brain. Cagrilintide works through amylin and calcitonin receptors in the hindbrain and hypothalamus, areas involved in both hunger signaling and satiety. The theoretical basis for combining them is that they hit the same behavioral outcome through independent biological routes.

What REDEFINE 1 actually found

REDEFINE 1 enrolled 3,417 adults without type 2 diabetes who had obesity or overweight with at least one weight-related complication. Participants were randomized in a 21:3:3:7 ratio to CagriSema, semaglutide 2.4 mg alone, cagrilintide 2.4 mg alone, or placebo. All groups received lifestyle intervention. The trial ran 68 weeks.

The results by arm: CagriSema 20.4% mean weight loss (treatment-policy estimand), semaglutide alone 14.9%, cagrilintide alone 11.5%, placebo 3.0%. The combination outperformed either component alone. The difference between CagriSema and semaglutide monotherapy was 5.5 percentage points. 60% of CagriSema participants achieved at least 20% body weight reduction. 23% achieved at least 30%. On the trial-product estimand, the number rises to 22.7%. The combination also improved systolic blood pressure, waist circumference, lipid levels, and glycemic control. In participants with prediabetes, 88% returned to normoglycemia.

The bottom line

CagriSema works. The combination adds meaningful weight loss beyond what either component achieves alone. The 20.4% figure is better than every approved drug on the market, framed against the actual clinical comparison set rather than analyst models. The high GI adverse event rate is the real limitation to watch as more safety data emerges. The market got this one wrong. The biology is intact.

Full premium section: mechanism of dual-pathway satiety suppression, cagrilintide DACRA profile versus pramlintide, REDEFINE 2 diabetes population results (13.7% weight loss), 88% normoglycemia reversal context, and competitive positioning through 2027.

For research and educational purposes only · Not medical advice · Consult a qualified physician before any human use