Current FDA Status
- Phase 2 trials complete: Amgen completed Phase 2 studies of maritide (maridebart cafraglutide, formerly AMG 133), a monthly injectable GLP-1 agonist + GIP antagonist for obesity and type 2 diabetes
- Phase 3 MARITIME program launched: Initiated in March 2025 with 4,500+ participants across obesity, cardiovascular, and heart failure trials
- Phase 3 readouts expected: Early 2027 for primary obesity trials (MARITIME-1/2)
- NDA (New Drug Application) submission: Expected 2027-2028
- FDA decision timeline: Projected 2029-2030 (assuming successful Phase 3 results)
Safety and efficacy established
MARITIME program trials
Application filing to FDA
6–12 month review period
FDA approval expected
Phase 2 Trial Results
In Phase 2 trials (NCT05669599), maritide demonstrated exceptional weight loss with monthly dosing:
- In adults with obesity without type 2 diabetes (Cohort A, n=465), participants achieved up to 20% weight loss at 52 weeks (efficacy estimand: 16.3-19.9% across doses) versus 2.6% with placebo.[1]
- In adults with obesity and type 2 diabetes (Cohort B, n=127), weight loss reached up to 17% at 52 weeks versus 1.4% with placebo.[1]
- No plateau observed: Weight loss continued through 52 weeks without leveling off, suggesting potential for further reduction with extended treatment.[2]
- Glycemic control: In participants with type 2 diabetes, HbA1c reductions averaged up to 2.2% from baseline.[1]
- Cardiometabolic improvements: Significant reductions in blood pressure, triglycerides, waist circumference, and high-sensitivity C-reactive protein (hs-CRP) across all doses.[1]
- Exceptional tolerability: Gastrointestinal adverse events occurred less frequently with dose escalation strategies. Over 90% of eligible participants chose to continue into the extension phase.[2]
Monthly Dosing Advantage
Maritide's 21-day half-life enables dosing every 4 weeks—40 fewer injections per year compared to weekly GLP-1 therapies like Wegovy (semaglutide) and Zepbound (tirzepatide). This represents a significant potential advantage for treatment adherence and patient satisfaction.
Development Timeline
Maritide's development reflects Amgen's strategic focus on monthly dosing convenience combined with best-in-class efficacy. Here's how the program has progressed:
| Phase | Status | Timeframe | Description |
|---|---|---|---|
| Phase 1 (Safety & Dosing) | ✓ Complete | ~2020–2022 | First-in-human studies, dose ranging (NCT04478708) |
| Phase 2 (Proof-of-Concept) | ✓ Complete | ~2022–2024 | Obesity/T2D efficacy trials (NCT05669599) |
| Phase 3 - MARITIME-1 | ⟳ Ongoing | 2025–2027 | 3,500 participants, obesity without T2D |
| Phase 3 - MARITIME-2 | ⟳ Ongoing | 2025–2027 | 999 participants, obesity with T2D |
| Phase 3 - MARITIME-HF | ⟳ Ongoing | 2025–2027 | Heart failure with preserved ejection fraction |
| Phase 3 - MARITIME-CV | ⊙ Planned | 2025 | Cardiovascular outcomes (ASCVD) |
| NDA Submission (Obesity) | ⧗ Pending | 2027–2028 | Formal filing for regulatory approval |
| FDA Review & Decision | ⊕ Projected | 2029–2030 | Approval decision expected |
Summary for Readers: Maritide has completed early development phases and is now in the pivotal Phase 3 MARITIME program—the largest clinical trial series required for FDA approval. With over 4,500 participants enrolled across multiple trials, Amgen is testing maritide not only for obesity but also for heart failure and cardiovascular outcomes.
Approval Milestones
| Milestone | Date | Status | Details |
|---|---|---|---|
| Phase 1 Completion | ~2022 | ✓ Complete | Safety, tolerability, PK/PD established |
| Phase 1 Data Presented | December 2022 | ✓ Complete | WCIRDC 2022 conference presentation |
| Phase 1 Publication | February 2024 | ✓ Complete | Nature Metabolism peer-reviewed publication |
| Phase 2 52-Week Results | November 2024 | ✓ Complete | Up to 20% weight loss announced |
| Phase 2 ADA Presentation | June 2025 | ✓ Complete | Full results at ADA 85th Scientific Sessions |
| Phase 2 NEJM Publication | June 2025 | ✓ Complete | Peer-reviewed publication in NEJM |
| MARITIME-1/2 Initiation | March 2025 | ✓ Complete | Phase 3 obesity trials launched |
| MARITIME-HF Initiation | Mid-2025 | ✓ Complete | Heart failure trial enrollment started |
| MARITIME-CV Initiation | Late 2025 | ⧗ Pending | Cardiovascular outcomes trial |
| MARITIME-1/2 Primary Readout | Early 2027 | ⊕ Projected | 72-week efficacy and safety data |
| NDA Submission (Obesity) | 2027-2028 | ⊕ Projected | Application filing to FDA |
| FDA Acceptance for Review | ≈ 60 days post-submission | ◯ Future | Agency confirms completeness |
| PDUFA Date Set | Upon acceptance | ◯ Future | Target decision deadline assigned |
| FDA Decision (Obesity) | 2029-2030 | ⊕ Projected | Assuming standard review timeline |
| Commercial Launch | 2030 | ⊕ Projected | If approved |
Summary for Readers: Amgen has successfully completed all early-stage development and is now conducting the large-scale Phase 3 trials required for FDA approval. Primary data from the pivotal obesity trials is expected in early 2027, which would support an NDA submission later that year or in 2028.
Approval Predictions
Best-Case Scenario
Timeline: Late 2029 approval
What would need to happen:
- Phase 3 readout early 2027 with compelling efficacy (≥20% weight loss)
- NDA submission Q3-Q4 2027
- Priority Review granted (monthly dosing addresses unmet need)
- Clean safety profile with no manufacturing issues
- 6-month priority review instead of standard 10-12 months
Most Likely Scenario
Timeline: 2030 approval
Assumptions:
- Phase 3 primary readout early 2027 with positive results
- NDA submission in 2028 (after complete data package)
- Standard review (~10-12 months)
- Possible minor FDA questions requiring additional analyses
- Approval mid-to-late 2030
Delayed Scenario
Timeline: 2031 or later
Potential causes:
- Phase 3 results miss primary endpoints or show safety concerns
- FDA requests additional cardiovascular outcomes data (MARITIME-CV results)
- Complete Response Letter (CRL) requiring trial amendments
- Manufacturing/quality issues delaying submission or approval
Historical Comparison: Similar Drug Approvals
| Drug | Developer | Indication | NDA to Approval | Notes |
|---|---|---|---|---|
| Semaglutide (Wegovy) | Novo Nordisk | Obesity | ~7 months (priority) | Priority review granted; approved 2021 |
| Tirzepatide (Zepbound) | Eli Lilly | Obesity | ~6 months (priority) | Priority review granted; approved 2023 |
| Setmelanotide (Imcivree) | Rhythm Pharma | Rare Obesity | ~8 months (priority) | Monthly injection; approved 2020 |
Historical context: Recent obesity medications have frequently received priority review (6-8 month timeline) when they address significant unmet medical needs. Maritide's monthly dosing and robust efficacy profile position it as a strong candidate for priority designation.
Summary for Readers: Based on recent obesity drug approvals and Amgen's development timeline, approval in 2029-2030 is most realistic. A faster decision is possible with priority review; delays could occur if additional safety or efficacy data is required.
FDA Approval Process
Once Amgen submits its New Drug Application (NDA) for maritide, the drug will move through a structured FDA review process. Here's what that journey looks like:
NDA Submission
Amgen will submit a complete application package containing all Phase 3 clinical trial data from the MARITIME program, manufacturing details, proposed labeling, and risk evaluation/mitigation strategies.
FDA Filing Decision
FDA reviews the application for completeness. If accepted, they assign a PDUFA date (the target decision deadline) and determine if it qualifies for Priority Review (6 months) or Standard Review (10-12 months).
FDA Review Period
FDA scientists evaluate safety, efficacy, manufacturing quality, and labeling. They may request additional data or schedule an advisory committee meeting if needed. For maritide, the FDA will carefully review the unique GLP-1 agonist + GIP antagonist mechanism and monthly dosing safety profile.
PDUFA Date Decision
By the PDUFA date, the FDA must issue one of three decisions:
- Approval: Drug can be marketed
- Complete Response Letter: Issues need to be addressed before approval
- Extend review: More time needed (rare)
Summary for Readers: The FDA approval process typically takes 6-12 months after submission. Maritide's unique monthly dosing and compelling Phase 2 results could position it for priority review, potentially shortening the timeline to 6-8 months.
Post-Approval Rollout
If Approved:
- 1-3 months - Commercial launch begins: Product stocked in pharmacies/specialty distributors
- 3-6 months - Payer negotiations: Formulary inclusion decisions; Amgen will likely emphasize monthly dosing as adherence advantage
- 6-12 months - Broader insurance coverage: Patient-assistance programs and co-pay cards introduced
- Post-marketing studies: FDA may require Phase 4 studies to monitor long-term safety and cardiovascular outcomes (MARITIME-CV results)
If Delayed or Not Approved:
- The FDA could issue a Complete Response Letter (CRL) requesting more data on long-term safety, cardiovascular outcomes, or manufacturing quality
- Additional cardiovascular outcome studies might be required before approval (MARITIME-CV trial results)
- Manufacturing or quality issues could delay approval by 6-18 months while Amgen addresses FDA concerns
- The company may resubmit with additional data, adding 6-24 months to the timeline
Summary for Readers: After FDA approval, most drugs reach pharmacies within 1-3 months. Insurance coverage typically follows within 6-12 months as payers complete formulary reviews and negotiate pricing. Amgen's established commercial infrastructure should enable a rapid launch.
FAQs
If Phase 3 trials (MARITIME-1/2) deliver positive results in early 2027 as expected, Amgen could submit an NDA in 2027-2028. With a standard FDA review (10-12 months), approval would most likely occur in 2029-2030. However, if maritide receives priority review (which is possible given its monthly dosing advantage), approval could come as early as late 2029.
No. Maritide is not yet FDA-approved and is not available for prescription use. Access is currently limited to participants in clinical trials. You can search for active MARITIME trials at ClinicalTrials.gov by searching "maritide," "AMG 133," or "maridebart cafraglutide."
The PDUFA date (Prescription Drug User Fee Act date) is the FDA's target deadline for completing its review of the NDA. It's typically set approximately 60 days after the FDA accepts the NDA for filing. For maritide, we'll likely know the PDUFA date in late 2027 or 2028 (assuming an NDA submission that year). This date gives patients, clinicians, and investors a concrete timeline for when to expect a decision.
Maritide uses a unique antibody-peptide conjugate structure that combines a GLP-1 receptor agonist peptide with a GIP receptor antagonist antibody. This design achieves a 21-day half-life—three times longer than weekly GLP-1 therapies like Wegovy and Zepbound. The longer half-life enables monthly dosing (or potentially less frequent), reducing injection burden from 52 injections per year to just 12. This could significantly improve treatment adherence and patient satisfaction.
Insurance coverage will depend on several factors: FDA-approved indications, payer formulary decisions, and prior authorization requirements. Based on current GLP-1 coverage patterns, we expect:
- Obesity: Variable coverage; some insurers exclude obesity medications entirely, while others cover them with strict criteria (e.g., BMI ≥30 or ≥27 with comorbidity)
- Monthly dosing advantage: Amgen will likely argue that monthly dosing improves adherence and reduces healthcare costs, which could help formulary negotiations
Amgen will likely negotiate with payers for favorable formulary placement, and patient assistance programs will be available for those without coverage. More information will be available closer to launch.
Maritide and tirzepatide (Zepbound) both target GLP-1 and GIP receptors but use opposite mechanisms:
- Tirzepatide: Activates both GLP-1 and GIP receptors (dual agonist); weekly dosing; 21% weight loss at 72 weeks
- Maritide: Activates GLP-1 but blocks GIP receptors (agonist + antagonist); monthly dosing; 20% weight loss at 52 weeks (no plateau observed)
Both show similar efficacy (~20% weight loss), but maritide's monthly dosing could offer a significant convenience advantage—40 fewer injections per year.
Common reasons for approval delays include:
- Phase 3 trial results: If MARITIME-1/2 fail to meet primary endpoints or show unexpected safety signals
- Cardiovascular data requirements: FDA may want MARITIME-CV results before approval (cardiovascular outcomes trial)
- Manufacturing issues: Problems identified during FDA facility inspections
- Complete Response Letter (CRL): FDA's formal notification that the application is not ready for approval, requiring resubmission
- Advisory committee meeting: The FDA may convene an external expert panel to review the data, which can add 3-6 months to the timeline
Amgen's strong track record with biologics manufacturing and maritide's compelling Phase 2 data reduce the likelihood of major delays, but they remain possible.
Likely yes, but not at the same time. The MARITIME Phase 3 program includes separate trials for obesity without diabetes (MARITIME-1) and obesity with diabetes (MARITIME-2). Amgen will likely submit the obesity indication first (2027-2028), similar to how semaglutide was approved for diabetes (Ozempic, 2017) before obesity (Wegovy, 2021). A separate NDA for type 2 diabetes could follow later. Each indication requires separate FDA review and approval.
Sources & References
- Amgen. "Results from Amgen's Phase 2 Obesity Study of Monthly MariTide Presented at the American Diabetes Association 85th Scientific Sessions." Press Release, June 23, 2025. https://www.amgen.com/newsroom/press-releases/2025/06/results-from-amgens-phase-2-obesity-study-of-monthly-maritide-presented-at-the-american-diabetes-association-85th-scientific-sessions
- Amgen. "Amgen Announces Robust Weight Loss with MariTide in People Living with Obesity or Overweight at 52 Weeks in a Phase 2 Study." Press Release, November 26, 2024. https://www.amgen.com/newsroom/press-releases/2024/11/amgen-announces-robust-weight-loss-with-maritide-in-people-living-with-obesity-or-overweight-at-52-weeks-in-a-phase-2-study
- Amgen. "Inside Amgen's Phase 3 MARITIME Program: Advancing the Future of Obesity Care." June 2025. https://www.amgen.com/stories/2025/06/inside-amgens-phase-3-maritime-program---advancing-the-future-of-obesity-care
- Once-Monthly Maridebart Cafraglutide for the Treatment of Obesity — A Phase 2 Trial. New England Journal of Medicine. Published June 23, 2025. https://www.nejm.org/doi/full/10.1056/NEJMoa2504214
- Clemmensen C, Jall S, Kleinert M, et al. A GIPR antagonist conjugated to GLP-1 analogues promotes weight loss with improved metabolic parameters in preclinical and phase 1 settings. Nature Metabolism. 2024;6:290-308. https://pmc.ncbi.nlm.nih.gov/articles/PMC10896721/
- ClinicalTrials.gov. "A Study of AMG 133 in Adults With Obesity or Overweight With and Without Type 2 Diabetes Mellitus." NCT05669599. https://clinicaltrials.gov/study/NCT05669599
- ClinicalTrials.gov. "A Study to Evaluate the Reduction in Heart Failure Events and Cardiovascular Risk With MariTide in Adults With Heart Failure With Preserved or Mildly Reduced Ejection Fraction and Obesity (MARITIME-HF)." NCT07037433. https://clinicaltrials.gov/study/NCT07037433
- Fierce Biotech. "Amgen enters Maritime, launching 2 late-stage obesity trials for MariTide." March 5, 2025. https://www.fiercebiotech.com/biotech/amgen-enters-maritime-launching-2-late-stage-obesity-trials-maritide
- U.S. Food and Drug Administration. "Fast Track, Breakthrough Therapy, Accelerated Approval, Priority Review." https://www.fda.gov/patients/learn-about-drug-and-device-approvals/fast-track-breakthrough-therapy-accelerated-approval-priority-review
Last updated October 6, 2026
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