Maridebart cafraglutide
MariTide is an investigational Amgen injection designed to be given monthly or less often. It blocks the GIP receptor and activates the GLP-1 receptor. It is not approved.
Maridebart cafraglutide (known as MariTide, formerly AMG 133)
Also searched as: MariTide, AMG 133.
Educational information. This page does not give dosing instructions or tell you what to take. Ask a prescriber about your own care.
In plain English
MariTide (maridebart cafraglutide, earlier called AMG 133) is an unusual design: a lab-made antibody joined to GLP-1-type peptides. The antibody part blocks the GIP receptor, while the peptide part activates the GLP-1 receptor. Tirzepatide does the opposite on GIP, switching it on, so the two drugs take different routes to a similar goal.
Its main appeal is dosing frequency. The antibody part stays in the body for a long time, so the phase 2 trial tested injections every 4 or 8 weeks instead of weekly. After 52 weeks, adults with obesity lost about 12% to 16% of their body weight on average across the dose groups, compared with 2.5% on placebo.
That is phase 2 data. Phase 3 trials are running and the first obesity results are not due until about 2027. MariTide is not approved anywhere.
Brand names and products
A generic name identifies the drug itself. A brand name identifies one company's product. One drug can come in several products with different forms and approved uses, so the brand name often tells you more about what a prescription is for.
No brand name is recorded for this medicine because there is no approved product.
Approved and investigational. Every use of MariTide is investigational. There is no approved product.
How it works
MariTide is a peptide-antibody conjugate. It activates the GLP-1 receptor, which lowers appetite and helps insulin release after eating, and it blocks the GIP receptor. Why blocking GIP, rather than activating it, would help with weight is not settled: both approaches have produced weight loss in people. The antibody portion gives it a long duration of action, which is why monthly dosing is being studied.
Forms and approval status
| Form | How it is taken | U.S. status |
|---|---|---|
| Maridebart cafraglutide injection (investigational) | Once monthly or less often in trials. Available only inside clinical trials. | Not approved. Amgen is running a phase 3 program called MARITIME. The main obesity trials (MARITIME-1 and MARITIME-2) are listed as active, with results not yet reported. |
What the trials found
These are group averages from published trials in adults without diabetes unless stated. See how to read trial numbers before comparing.
MariTide phase 2 (obesity)
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 465 adults with obesity, plus a separate group of 127 adults with obesity and type 2 diabetes
- Length
- 52 weeks
- Compared with
- Placebo. Seven MariTide groups tested different amounts (140, 280 or 420 mg), different gaps between doses (every 4 or 8 weeks) and different dose-escalation steps
- What was measured
- Average change in body weight at week 52, adults with obesity
- Analysis approach
- Treatment-policy estimand: effects regardless of treatment discontinuation
- Other results
- In the diabetes group, weight change ranged from -8.4% to -12.3% on MariTide vs -1.7% on placebo, and HbA1c fell by 1.2 to 1.6 percentage points vs 0.1 on placebo.
- Safety
- Gastrointestinal side effects were common. They were less frequent with a lower starting amount and with gradual dose escalation. The authors reported no unexpected safety signals.
- Limits
- Phase 2, so the groups were small and no single dose group stands for all results. The abstract gives a range across groups, not one figure per group. Funded by the manufacturer. Group averages do not predict one person's result.
Sources: Jastreboff AM 2025
Safety
No FDA label exists for this medicine yet. The information below comes from published trial reports. The points below are a summary and may be incomplete.
Boxed warning and label notes
- Maridebart cafraglutide injection (investigational): Not applicable. Not approved.
Warnings labels describe
- Not approved, so no official label exists. Safety information is limited to trial reports.
- Because it activates the GLP-1 receptor, the safety points seen with that class are expected to be relevant, but the label that would say so does not exist yet.
Most common in trials
- Nausea
- Vomiting
- Other gastrointestinal side effects, more often with higher starting amounts and no dose escalation
Less common but serious
- The published abstract does not list serious side effects and reports no unexpected safety signals. Details are in the full paper.
What is still unknown
- Phase 3 results. The main obesity trials, MARITIME-1 (3,853 adults) and MARITIME-2 (1,105 adults with type 2 diabetes), have a registered primary completion date of January 2027.
- The best dose, dose-escalation schedule and dosing interval. Phase 2 tested many options.
- Whether weight loss is similar to weekly medicines in larger and longer trials, and whether blocking GIP has long-term effects on bone, fat tissue or blood sugar.
- Whether it lowers heart attacks and strokes. A cardiovascular outcomes trial with about 12,800 adults is running.
- Whether and when it will be filed with the FDA.
Compiled from public information: FDA-approved labels, manufacturer websites, ClinicalTrials.gov and published journal articles. Sources are listed at the bottom of this page.
Sources
- MARITIME-1 trial record (NCT06858839) ClinicalTrials.gov identifier NCT06858839. Sponsor: Amgen. Trial registry
- MARITIME-2 trial record (NCT06858878) ClinicalTrials.gov identifier NCT06858878. Sponsor: Amgen. Trial registry
- MariTide cardiovascular outcomes trial record (NCT07037433) ClinicalTrials.gov identifier NCT07037433. Sponsor: Amgen. Trial registry
- ClinicalTrials.gov U.S. National Library of Medicine. Trial registry
- Once-monthly maridebart cafraglutide for the treatment of obesity, a phase 2 trial Jastreboff AM, et al. N Engl J Med. 2025;393(9):843-857. PMID 40549887. Funding: Amgen. Journal article