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marstacimab

Phase 3

Hemophilia A | Small molecule | Hematology |Pfizer, Inc.|Last Updated: Aug 10, 2026

Target and mechanism

Molecular targetTFPI
Target classInhibitor
ModalitySmall molecule

Success Probability

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Market & Valuation

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Trial Design

UNCONTROLLEDDMC
Total Trials1
Total Enrollment100

FDA Designations

No designations recorded

Clinical trial landscape

marstacimab · 2 trials · 3 indications

Phase 3 1Phase 1 1
NCT05611801A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia BHemophilia A
RECRUITING100 Analytics
PHASE3RECRUITING
A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B
Hemophilia AUnlock trial analytics

Study Endpoints

Primary Endpoints

Annualized bleeding rate (ABR) of treated bleeding events
Baseline to end of 12-month treatment period

Derived for each subject for each period (historical and study treatment) by using the following formula: ABR = number of bleeds requiring treatments/ (days on treatment period / 365.25)

Incidence of adverse events and serious adverse events
Screening through end of follow-up period (approximately 14 months)
Incidence and severity of thrombotic events
Baseline to end of 12-month treatment period
Incidence and severity of thrombotic microangiopathy
Baseline to end of 12-month treatment period
Incidence and severity of disseminated intravascular coagulation/consumption coagulopathy events
Baseline to end of 12-month treatment period
Immunogenicity (incidence of ADA and clinically significant persistent NAb against marstacimab)
Baseline to end of 12-month treatment period
Incidence and severity of injection site reaction
Baseline to end of 12-month treatment period
Incidence of severe hypersensitivity and anaphylactic reactions
Baseline to end of 12-month treatment period
Incidence of marstacimab-related adverse events (AEs)
Approximately 178 days: from the time the participant provides informed consent, through and including a minimum of 28 calendar days after last dose of study treatment
Incidence of marstacimab-related serious AEs (SAEs)
Approximately 178 days: from the time the participant provides informed consent, through and including a minimum of 28 calendar days after last dose of study treatment

Secondary Endpoints

Incidence of joint bleeds (treated)
Baseline to end of 12-month treatment period
Incidence of spontaneous bleeds (treated)
Baseline to end of 12-month treatment period
Incidence of target joint bleeds (treated)
Baseline to end of 12-month treatment period
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Study Design & Arms

AllocationNA
MaskingNONE
ModelSINGLE_GROUP
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
marstacimab (PF-06741086)EXPERIMENTALWeekly subcutaneous injections.
MARSTACIMABEXPERIMENTALMarstacimab 150 mg subcutaneous (SC) once weekly (QW)

Interventions

NameTypeDescription
marstacimabDRUGmarstacimab
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Eligibility Criteria

Age Range1 Year to 17 Years
SexMALE
Healthy VolunteersNo
Study Sites64

Inclusion Criteria: * Male participants of appropriate age and required minimum weight * Participants aged 12 to 17 years must be at least 25 kgs at time of consent. * Participants aged 6 to 11 years must be at least 19 kgs at time of consent. * Minimum weight requirement for participants aged 1 to...

Countries:United StatesArgentinaAustraliaAustriaBrazilCanadaChinaCzechiaDenmarkFranceGermanyIndiaIsraelItalyJapanMexicoSaudi ArabiaSlovakiaSouth AfricaSouth KoreaSpainTaiwanTurkey (Türkiye)United Kingdom
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Recent Changes (Last 90 Days)

LOWAug 11, 2026NCT05611801lastUpdatePostDate: changed
LOWAug 11, 2026NCT05611801lastUpdatePostDate: changed
LOWAug 11, 2026NCT05611801lastUpdatePostDate: changed

Frequently asked questions about marstacimab

What is Marstacimab used for?

Marstacimab is an investigational antibody being developed for hemophilia A, including severe hemophilia A. It is being studied in clinical trials for patients with hemophilia A and hemophilia B, with a focus on pediatric and adult populations. The drug is currently in clinical development and has not been approved by regulatory authorities.

What does Marstacimab target?

Marstacimab is a monoclonal antibody, indicated by its -mab suffix. It is being studied for its role in treating hemophilia A and B. The specific molecular target of Marstacimab has not been disclosed in the available information, but as an antibody, it is designed to interact with specific proteins involved in blood clotting.

Who makes Marstacimab?

Marstacimab is being developed by Pfizer, Inc., a global pharmaceutical company listed on the New York Stock Exchange under the ticker symbol PFE. Pfizer is conducting clinical trials to evaluate the safety and efficacy of Marstacimab in patients with hemophilia A and B.

What phase is Marstacimab in?

Marstacimab is in Phase 1 clinical development. While one trial listed under the drug is a Phase 3 study, the most advanced stage of development for Marstacimab itself is Phase 1, as indicated by the drug's overall phase designation. It remains an investigational agent and is not yet approved.

What clinical trials is Marstacimab in?

Marstacimab is being studied in two clinical trials. NCT05611801 is a Phase 3 trial in pediatric patients with hemophilia A or B, enrolling 100 participants across multiple countries. NCT06703606 is a Phase 1 trial studying the switch from emicizumab to Marstacimab in patients with severe hemophilia A, enrolling 15 participants.

Is Marstacimab the same as emicizumab?

No, Marstacimab is not the same as emicizumab. They are different drugs. One clinical trial, NCT06703606, is specifically studying what happens when patients switch from emicizumab to Marstacimab, indicating they are distinct therapies with potentially different mechanisms of action.