Future Medicine Decision Guide
MariTide UK: Definitive Future-Medicine Guide
A UK-focused guide to MariTide (maridebart cafraglutide): monthly dosing, GLP-1 agonism plus GIP receptor antagonism, Phase 2 results, Phase 3 MARITIME development, safety and comparisons.
MariTide: where it stands now
MariTide remains investigational and is now in Phase 3.
Amgen's maridebart cafraglutide — MariTide — is being evaluated in the MARITIME Phase 3 programme for obesity and obesity-related conditions. It is not a routine UK prescription treatment today.
What is MariTide?
MariTide is short for maridebart cafraglutide. It is an antibody-peptide conjugate rather than a conventional weekly GLP-1 injection.
Its design links a GLP-1 receptor agonist component with an antibody directed at the GIP receptor, producing a biological strategy that is almost the mirror image of tirzepatide's GIP agonism.
How does MariTide work?
GLP-1 receptor agonism
Supports appetite reduction and satiety.
GIP receptor antagonism
Blocks rather than activates the GIP receptor — a distinctive approach informed partly by human genetics.
Antibody-peptide design
Creates a long-acting medicine that Amgen is studying for monthly or potentially less frequent dosing.
Why could monthly dosing matter?
Most current injectable obesity medicines are taken weekly. MariTide is being developed around monthly or less frequent administration.
That could reduce treatment burden substantially. Twelve injections a year feels very different from fifty-two. The trade-off is that a very long-acting medicine also needs a carefully understood safety and tolerability profile because you cannot simply “undo” a dose once given.
What did Phase 2 show?
Amgen's Phase 2 study reported up to approximately 20% average weight loss at 52 weeks in people with obesity or overweight without type 2 diabetes, without an observed weight-loss plateau at that time point. Participants with type 2 diabetes lost up to around 17% on average and also showed substantial HbA1c improvement.
Those results were strong enough for Amgen to move into a broad Phase 3 programme.
What is the MARITIME Phase 3 programme?
MARITIME is the umbrella programme studying MariTide across obesity and obesity-related disease. Amgen describes it as evaluating the medicine in obesity/overweight and conditions including type 2 diabetes and cardiovascular-related risk.
Phase 3 is particularly important for MariTide because it needs to confirm whether less-frequent dosing remains effective and acceptable across larger populations and longer follow-up.
Side effects and safety
Gastrointestinal adverse effects such as nausea and vomiting have been important in development, and Amgen has explored dose-escalation approaches designed to improve tolerability.
Because MariTide is long-acting, practical questions around initiation, dose spacing, side-effect duration and discontinuation will matter heavily if it reaches approval.
When might MariTide reach the UK?
There is no confirmed UK launch date. Phase 3 development is ongoing, so any routine UK use remains dependent on completed trials, regulatory submission, MHRA authorisation and subsequent launch decisions.
MariTide vs Mounjaro
| MariTide | Mounjaro | |
|---|---|---|
| GLP-1 | Agonist | Agonist |
| GIP pathway | Receptor antagonist | Receptor agonist |
| Dosing ambition | Monthly or less frequent | Weekly |
| UK status | Investigational | Authorised |
This is a fascinating scientific contrast: both target GLP-1 and the GIP axis, but they manipulate GIP in opposite directions.
MariTide vs Retatrutide
Retatrutide is a weekly triple agonist acting on GIP, GLP-1 and glucagon. MariTide combines GLP-1 agonism with GIP receptor antagonism and aims for much less frequent dosing.
Retatrutide currently has the more dramatic Phase 3 headline weight-loss figures; MariTide's potential differentiator is dosing convenience plus a unique mechanism.
Who might eventually prefer MariTide?
- People who want fewer injections.
- People who struggle to maintain a weekly treatment routine.
- People for whom a long-acting medicine proves more convenient and equally tolerable.
- Potentially people who respond differently to GIP antagonism than to GIP agonism — if future evidence supports that distinction.
Should I wait for MariTide?
No one should delay needed treatment simply because monthly dosing sounds appealing. Current options already have extensive evidence and real UK prescribing pathways. MariTide becomes a real decision only when Phase 3 evidence and regulation make it one.
Questions you haven't thought to ask yet
- If I feel unwell after a monthly dose, how long could effects last?
- Will titration require shorter intervals before monthly maintenance?
- Will monthly dosing actually improve adherence?
- How will it compare with weekly drugs in a true head-to-head trial?
- Could less frequent dosing reduce pharmacy and delivery costs?
- What happens when stopping such a long-acting medicine?
Shift Says
Our take
MariTide may be the most interesting “convenience” play in the pipeline. If monthly dosing can deliver strong weight loss with acceptable tolerability, it could genuinely change what long-term treatment feels like.
But convenience is only valuable once safety, efficacy and durability are proven at Phase 3 scale.
Printable summary
MariTide checklist
- Investigational antibody-peptide conjugate.
- GLP-1 agonism + GIP receptor antagonism.
- Being studied for monthly or less frequent dosing.
- Phase 2 showed up to ~20% average loss at 52 weeks in obesity without diabetes.
- Now in the Phase 3 MARITIME programme.
FAQs
Is MariTide available in the UK?
No. It remains investigational.
What does MariTide stand for?
It is the short name for maridebart cafraglutide.
How often might MariTide be taken?
Amgen is studying monthly or potentially less frequent dosing.
How much weight loss was seen in Phase 2?
Up to approximately 20% average weight loss at 52 weeks in participants without type 2 diabetes.
Is MariTide a GLP-1?
It includes GLP-1 receptor agonism but also blocks the GIP receptor.
Has MariTide reached Phase 3?
Yes. Amgen's MARITIME Phase 3 programme is underway.
Sources & further reading
Future-medicine status changes quickly, so we prioritise regulator, manufacturer and official trial sources and date-stamp the page.
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