Maritide vs Tirzepatide
Comparison of Amgen's long-acting investigational GLP-1/GIP dual agonist maritide with FDA-approved tirzepatide for obesity and type 2 diabetes.
Last updated: January 28, 2026
Dossier labels summarize each dossier's research scope. They do not establish comparative treatment benefit or safety. Read the comparison below in that context.
MariTide
Dossier overview
Tirzepatide
Dossier overview
Overview
Maritide (AMG 133) is Amgen’s investigational dual GLP-1/GIP receptor agonist being developed for obesity, while tirzepatide (Mounjaro, Zepbound) is an FDA-approved dual agonist from Eli Lilly for type 2 diabetes and obesity.
Key distinction: Tirzepatide is an approved medication with extensive clinical data; maritide is still in clinical development with promising but limited data.
Key Facts
| Aspect | Maritide (AMG 133) | Tirzepatide |
|---|---|---|
| Developer | Amgen | Eli Lilly |
| Class | GLP-1 agonist / GIP antagonist | GLP-1/GIP dual agonist |
| FDA Status | Investigational (Phase 2) | Approved (2022/2023) |
| Brand Names | N/A | Mounjaro, Zepbound |
Mechanism Comparison
| Aspect | Maritide | Tirzepatide |
|---|---|---|
| GLP-1 Receptor | Agonist | Agonist |
| GIP Receptor | Antagonist | Agonist |
| Approach | Blocks GIP while activating GLP-1 | Activates both receptors |
| Half-life | ~21+ days | ~5 days |
How They Work
Maritide:
- GLP-1 receptor agonist component stimulates insulin secretion and satiety
- GIP receptor antagonist component blocks GIP action
- Rationale: Some research suggests GIP antagonism may enhance weight loss
- Long half-life allows monthly dosing
- Bispecific antibody-peptide fusion technology
Tirzepatide:
- Dual agonist at both GLP-1 and GIP receptors
- GIP activation enhances GLP-1 effects on metabolism
- Single peptide molecule with dual receptor activity
- Weekly dosing maintains consistent drug levels
Evidence Quality
Maritide Research
| Trial Phase | Status | Key Findings |
|---|---|---|
| Phase 1 | Completed | Demonstrated GLP-1 agonism + GIP antagonism |
| Phase 2 (Obesity) | Ongoing/Reported | Significant weight loss (up to ~15-17% reported) |
| Phase 3 | Not yet initiated | Pending |
| Long-term data | Not available | — |
Current evidence:
- Limited to Phase 1/2 data
- Promising weight loss results in early trials
- Monthly dosing demonstrated feasibility
- Full safety profile not yet established
Tirzepatide Research
| Trial Phase | Status | Key Findings |
|---|---|---|
| SURPASS (T2D) | Completed | 1.5-2.4% A1c reduction |
| SURMOUNT (Obesity) | Completed | 15-22% weight loss |
| Phase 3 | Extensive | Multiple completed trials |
| Real-world data | Growing | Post-marketing experience |
Established evidence:
- Largest RCTs in obesity showed ~20%+ weight loss
- Superior efficacy to semaglutide in head-to-head trials
- Approved for both type 2 diabetes and chronic weight management
- Well-characterized safety profile from large trials
Evidence Strength Comparison
| Factor | Maritide | Tirzepatide |
|---|---|---|
| Peer-reviewed studies | Limited | Extensive |
| Phase 3 trials | None completed | Multiple completed |
| Total patients studied | Hundreds | Thousands |
| Long-term safety | Unknown | Established (2+ years) |
| Overall quality | Low (early development) | High |
Efficacy Comparison
Weight Loss
| Metric | Maritide | Tirzepatide |
|---|---|---|
| Phase 2 weight loss | ~14-17% (reported) | 15-22% |
| Phase 3 weight loss | Pending | 15-22% |
| Maintenance data | Not available | Available |
| Certainty | Low | High |
Glycemic Control
| Metric | Maritide | Tirzepatide |
|---|---|---|
| A1c reduction | Limited data | 1.5-2.4% |
| Diabetes indication | Not pursued | FDA approved |
| Data quality | Early | Robust |
Side Effects
Maritide (Limited Phase 2 Data)
| Side Effect | Reported | Notes |
|---|---|---|
| Nausea | Yes | Common with GLP-1 class |
| Vomiting | Yes | Common with GLP-1 class |
| Diarrhea | Yes | GI effects expected |
| Injection site reactions | Yes | — |
Tirzepatide (Established Profile)
| Side Effect | Incidence | Management |
|---|---|---|
| Nausea | 12-33% | Dose titration helps |
| Diarrhea | 12-21% | Usually transient |
| Vomiting | 5-12% | Dose-dependent |
| Constipation | 6-12% | Common |
| Injection site reactions | 2-7% | Mild, transient |
Safety Considerations
Maritide:
- Full safety profile unknown
- Long-acting nature could prolong adverse effects
- Monthly dosing may be advantage if well-tolerated
- GIP antagonism effects long-term unknown
Tirzepatide:
- GI side effects most common, usually improve with time
- Rare pancreatitis risk (class warning)
- Thyroid C-cell tumor warning (rodent findings)
- Not for patients with MEN2 or medullary thyroid cancer history
Regulatory Status
| Aspect | Maritide | Tirzepatide |
|---|---|---|
| FDA (T2D) | Not approved | Approved (Mounjaro, 2022) |
| FDA (Obesity) | Not approved | Approved (Zepbound, 2023) |
| EMA | Not approved | Approved |
| Development stage | Phase 2 | Post-marketing |
| Availability | Clinical trials only | Prescription available |
Cost Considerations
| Factor | Maritide | Tirzepatide |
|---|---|---|
| Current cost | N/A (investigational) | ~$1,000+/month retail |
| Insurance coverage | N/A | Variable, often limited |
| Projected cost | Unknown | — |
Who Might Consider Each
Tirzepatide May Be Appropriate For:
- Type 2 diabetes requiring additional glycemic control
- Chronic weight management with BMI criteria
- Those who want established, approved treatment
- Patients who can manage weekly injections
Maritide (If Approved) Could Be For:
- Patients preferring less frequent injections
- Those who have tried other GLP-1 agents
- Obesity treatment (primary focus)
- Must await regulatory approval
Summary
| Factor | Maritide | Tirzepatide |
|---|---|---|
| Evidence quality | Low (Phase 2) | High (Phase 3, approved) |
| Efficacy (weight loss) | Promising (~15-17%) | Established (15-22%) |
| Mechanism | GLP-1 agonist / GIP antagonist | GLP-1/GIP dual agonist |
| Availability | Investigational | Prescription |
| Safety profile | Incomplete | Well-characterized |
Key takeaway: Tirzepatide is an approved medication with extensive data supporting its use. Maritide shows promise with monthly dosing and a novel mechanism but remains investigational. Patients should only access maritide through clinical trials until approval.
This comparison is for educational purposes only. Maritide is not FDA-approved; tirzepatide requires a prescription. Consult a healthcare provider for treatment decisions.
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Disclaimer: This comparison is for educational purposes only and does not constitute medical advice. Individual responses to medications vary. Always consult a qualified healthcare provider before making treatment decisions.