MariTide
Maridebart Cafraglutide (MariTide, AMG 133)
Also known as: Maridebart cafraglutide, AMG 133
Amgen's monthly-dosed obesity drug that pairs GLP-1 activation with GIP receptor blockade, reaching around 20% weight loss in Phase 2.
Overview
MariTide is Amgen's investigational obesity therapy that uniquely combines a GLP-1 receptor agonist peptide with a GIP receptor antagonist antibody, an unusual design since other leading drugs activate GIP rather than block it. Phase 2 reported up to about 20% weight loss at 52 weeks with once-monthly dosing (efficacy estimand; 12.3% to 16.2% versus 2.5% for placebo in the NEJM treatment-policy analysis), and it has advanced to Phase 3 (MARITIME). Update, September 2026: the Phase 3 MARITIME-1 and MARITIME-2 weight-management trials are ongoing with primary readouts expected in 2027. The monthly schedule could set it apart from weekly injectables.
Mechanism of action
Activates the GLP-1 receptor while blocking the GIP receptor, delivered as a long-acting peptide-antibody conjugate for monthly dosing.
Key studies & citations
- Human2025
Once-monthly maridebart cafraglutide for the treatment of obesity: a phase 2 trial
592 participants: 12.3% to 16.2% weight loss at 52 weeks in the obesity cohort versus 2.5% with placebo (treatment-policy estimand), with no plateau.
New England Journal of Medicine - Human2025
Results from Amgen's Phase 2 obesity study of monthly MariTide presented at the American Diabetes Association 85th Scientific Sessions
Up to about 20% weight loss (efficacy estimand) in obesity and about 17% with type 2 diabetes at 52 weeks; Phase 3 MARITIME program initiated.
Amgen press release
Frequently asked questions
Why does MariTide block GIP when other drugs activate it?
It is a live scientific debate. Both GIP activation (as in tirzepatide) and GIP blockade (as in MariTide) can aid weight loss, and trials are testing which approach wins.