Maridebart cafraglutide / MariTide

What it is

MariTide is not a simple peptide. The original paper describes maridebart cafraglutide as an antibody that blocks the GIP receptor while carrying two linked GLP-1-like agonist peptides. AMG 133 is the development code; MariTide is the program name.

The clinical record concerns sponsor-controlled subcutaneous investigational material with protocol-defined identity and handling. The names MariTide, maridebart cafraglutide, or AMG 133 do not establish molecular architecture, concentration, purity, sterility, aggregation state, stability, storage history, or trial equivalence for another product.

Why people care

MariTide combines GLP-1-receptor agonism with GIP-receptor antagonism in a long-acting antibody-peptide construct. Its published phase 2 weight results and large phase 3 program attract attention, but those records are often blurred into approval, head-to-head superiority, complete safety, or product-authentication claims they cannot support.

What humans actually show

Maridebart cafraglutide, called MariTide and formerly AMG 133, is an investigational antibody-peptide conjugate with published randomized phase 2 obesity evidence and an active phase 3 program. The dated sources do not contain an FDA-approved maridebart-cafraglutide label. Phase 3 enrollment does not establish approval, final safety, or the identity of a product outside the clinical program.

• randomized human — 592 adults in a phase 2 trial: 465 with obesity and 127 with obesity and type 2 diabetes; Route: Subcutaneous maridebart cafraglutide in multiple dose-ranging schedules or placebo; Outcome: Percent change in body weight at week 52 and glycated hemoglobin in the type 2 diabetes cohort: In the obesity cohort, mean weight change by the treatment-policy estimand ranged from -12.3% to -16.2% across active groups versus -2.5% with placebo. In the obesity-and-diabetes cohort, it ranged from -8.4% to -12.3% versus -1.7%; mean glycated-hemoglobin change ranged from -1.2 to -1.6 percentage points versus an increase of 0.1 percentage points with placebo. The seam: This was a phase 2 dose-ranging trial rather than an FDA benefit-risk review; Cohort, estimand, and assignment differences must remain visible; The trial did not establish cardiovascular-event, mortality, or postmarketing outcomes; Separate-trial percentages cannot establish superiority to another medicine; Clinical-trial results cannot authenticate a product outside the trial.
• randomized human — Adults with obesity in a phase 1 randomized double-blind placebo-controlled study; Route: Subcutaneous AMG 133 in single- and multiple-ascending-dose cohorts or placebo; Outcome: Early safety, tolerability, pharmacology, and body-weight change: The investigators reported dose-dependent weight loss and persistence of weight change after the final administration in multiple-ascending-dose cohorts. The seam: Phase 1 primarily supports early pharmacology and proof of concept; Small early cohorts cannot establish a complete safety profile; Persistence after the final administration is not proof of permanent benefit; The paper was authored by sponsor researchers.

Mechanistic and nonhuman evidence

• cell — Recombinant receptor and cell-based systems; Route: In-vitro exposure to AMG 133; Outcome: GIP-receptor antagonism and GLP-1-receptor agonism: The original paper reports both intended receptor activities in cell-based assays. The seam: Cell activity does not establish a human clinical outcome; Receptor potency does not establish final dosing, safety, or approval; The construct is not interchangeable with other GLP-1 or GIP medicines.
• animal — Obese mouse models and obese cynomolgus monkeys; Route: Investigational AMG 133 exposure in preclinical studies; Outcome: Body weight and metabolic markers: The original paper reports reduced body weight and improved metabolic markers in the studied animal models. The seam: Animal outcomes cannot substitute for human phase 3 results; Species and model differences limit transfer; The studies were part of a sponsor development program.
• mechanistic — Engineered antibody-peptide construct; Route: GIP-receptor antagonism combined with GLP-1-receptor agonism; Outcome: Proposed long-acting dual-pathway pharmacology: The construct was designed to combine two linked GLP-1 agonist peptides with an anti-GIP-receptor antagonist antibody. The seam: Drug design does not establish benefit-risk conclusions; Mechanism does not prove superiority over another medicine; The intended activity does not establish combination safety.

FDA and U.S. status

ClinicalTrials.gov lists maridebart cafraglutide in an active phase 3 MARITIME program. The July 29, 2026 intervention search returned 25 records, including MARITIME-1 and MARITIME-2 with estimated primary completion in 2027 and no posted results. An exact openFDA Drugs@FDA active-ingredient query returned no match. The no-match query is preserved as a dated search result and is not used alone; the active phase 3 registry records establish that the cited United States program remains investigational.

Risks and warning limits

• human trial: The phase 2 paper reports that gastrointestinal adverse events were common with maridebart cafraglutide and were less frequent with dose escalation and a lower starting exposure.
• human trial: The phase 2 abstract reports no unexpected safety signal during the trial. This does not mean no adverse effects, no rare risks, or an established postmarketing safety profile.
• not characterized: There is no FDA-approved maridebart-cafraglutide prescribing information in the dated source set, so this draft does not assign FDA-labeled contraindications, warnings, or adverse-reaction frequencies.

What remains unknown

• Phase 3 efficacy, discontinuation, adverse-event, and subgroup results remain unknown because the representative MARITIME trials have no posted results and estimated completion dates are in 2027 or later.
• Final FDA benefit-risk conclusions, approved populations, contraindications, warnings, and product specifications are unknown unless and until a future application is reviewed and approved.
• Results of the dedicated oral-contraceptive pharmacokinetic and gastric-emptying studies were not posted in the July 29 registry check.
• The identity, purity, sterility, stability, aggregation state, and storage history of a product outside the clinical program cannot be inferred from the names MariTide or AMG 133.

Product identity and quality limits

• Maridebart cafraglutide is a specific antibody-peptide conjugate and is not semaglutide, tirzepatide, or a generic synonym for a GLP-1-receptor agonist.
• Trial evidence belongs to sponsor-controlled investigational material. A name, vial label, or analytical certificate alone cannot establish the clinical molecule or its quality attributes.

What has been studied together

• Maridebart cafraglutide with oral contraceptives — coadministration studied: A dedicated phase 1 pharmacokinetic study is active but no longer recruiting and had no posted results in the July 29, 2026 registry check. The study title establishes that coadministration is being evaluated, not an interaction conclusion.
• Maridebart cafraglutide with another GLP-1-pathway product — duplicate pathway overlap: Maridebart cafraglutide itself contains GLP-1-receptor agonist activity. The dated search did not identify a result establishing safety or efficacy from adding another GLP-1-pathway product.
• Maridebart cafraglutide and orally administered medicines — no direct evidence: A dedicated gastric-emptying study was completed but had no posted results in the dated registry check. No general oral-medicine interaction conclusion is supported.

What people are hearing

These are claims this profile checks, not established conclusions.

• Claim under review: “A published phase 2 trial or active phase 3 program means MariTide is FDA approved.”
• Claim under review: “Separate weight-loss percentages prove MariTide is superior to an approved medicine.”
• Claim under review: “A product sold under the MariTide or AMG 133 name is the same material used in the clinical trials.”

Questions readers raise

• No reproducible community sample was collected for this profile.

The community-signal layer is not efficacy or safety evidence. Its current limits are:

• No reproducible community sample has been collected for this profile.
• Self-reports would be subject to selection and reporting bias.
• The identity of a product described in a self-report could not be verified.
• Concurrent medicines, health conditions, diet, and behavior could confound an anecdote.
• Reported outcomes could not be independently verified.
• Anecdotes cannot establish efficacy, safety, approval, product identity, or interaction compatibility.

What would change this answer

• Posted and peer-reviewed phase 3 results would change the present phase-2-plus-active-development evidence boundary for their exact populations and outcomes.
• An FDA approval action and final prescribing information would change the current investigational status and establish product-specific indications, contraindications, and warnings.
• Posted results from dedicated pharmacokinetic and gastric-emptying studies could change specific interaction boundaries but would not provide universal combination clearance.

Sources and records

• WADA — 2026 Prohibited List

• Drugs@FDA API exact active-ingredient search for maridebart cafraglutide — U.S. Food and Drug Administration
• Compounding and the FDA: Questions and Answers — U.S. Food and Drug Administration
• ClinicalTrials.gov intervention search for maridebart cafraglutide — ClinicalTrials.gov
• PubMed search for maridebart cafraglutide, AMG 133, or MariTide in human records — National Library of Medicine
• Once-Monthly Maridebart Cafraglutide for the Treatment of Obesity: A Phase 2 Trial — PubMed
• Maridebart cafraglutide phase 2 obesity trial — ClinicalTrials.gov
• A GIPR antagonist conjugated to GLP-1 analogues promotes weight loss in preclinical and phase 1 settings — PubMed
• AMG 133 phase 1 obesity trial — ClinicalTrials.gov
• MARITIME-1 phase 3 obesity trial — ClinicalTrials.gov
• MARITIME-2 phase 3 obesity and type 2 diabetes trial — ClinicalTrials.gov
• Maridebart cafraglutide oral-contraceptive pharmacokinetic study — ClinicalTrials.gov
• AMG 133 gastric-emptying study — ClinicalTrials.gov