CagriSema: The REDEFINE-1 Titration Protocol That Achieved 22.7% Weight Loss

Semaglutide acts on GLP-1 receptors in the hypothalamus and brainstem, reducing appetite and slowing gastric emptying. Cagrilintide acts on amylin receptors (AMY1-3) in the area postrema and nucleus tractus solitarius - the same regions involved in satiety signaling after a meal. These are distinct receptor populations with complementary effects: GLP-1 reduces hunger drive centrally, while amylin signaling reinforces post-meal satiety and blunts the rebound hunger that limits single-agent GLP-1 therapy.

The practical result is additive weight loss without proportionally increased side effects. REDEFINE-1 showed that nausea rates for CagriSema were similar to semaglutide monotherapy, suggesting the amylin pathway adds efficacy through a different mechanism rather than simply intensifying GLP-1 signaling. This is the same principle behind co-agonist drug design - using complementary receptor biology to exceed the ceiling of any single target.

The REDEFINE-1 trial used a 16-week titration schedule to minimize GI side effects (nausea, vomiting, diarrhea) during dose escalation. Both components escalate together at the same rate - there is no offset titration between cagrilintide and semaglutide in the approved protocol.

In research settings, cagrilintide and semaglutide are typically reconstituted as separate vials and administered as sequential injections at the same session. The most common vial size is 10 mg for both compounds. Standard reconstitution for each: 10 mg vial + 2 mL bacteriostatic water = 5 mg/mL concentration. At this concentration, the draw volumes for each dose step are as follows:

For lower concentration preference: 10 mg + 4 mL BAC water = 2.5 mg/mL. At this dilution, a 2.4 mg maintenance dose draws 0.96 mL (96 units) - easier to measure precisely on a standard U-100 insulin syringe.