Testing marstacimab for hemophilia a
Official title: A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B
AN OPEN-LABEL STUDY IN PEDIATRIC (<18 YEARS OF AGE), SEVERE HEMOPHILIA A PARTICIPANTS (COAGULATION FACTOR ACTIVITY <1%) WITH OR WITHOUT INHIBITORS OR MODERATELY SEVERE TO SEVERE HEMOPHILIA B PARTICIPANTS (COAGULATION FACTOR ACTIVITY ≤2%) WITH OR WITHOUT INHIBITORS COMPARING 12 MONTHS OF HISTORICAL STANDARD TREATMENT TO MARSTACIMAB PROPHYLAXIS
- Phase 3
- 1 group
- Sites in Edmonton and Hamilton
- Recruiting
Interventions
- Medication
marstacimab
marstacimab
Canadian Sites (2)
2 of 2 recruiting
- Recruiting
Stollery Children's Hospital
Edmonton, Alberta
- Recruiting
Hamilton Health Sciences - McMaster University/McMaster Children's Hospital
Hamilton, Ontario
Eligibility Criteria
See who this study is looking for31 criteria
The trial’s own eligibility text, word for word from the registry. Only the trial site can say who takes part.
Inclusion
- +Participants aged 12 to 17 years must be at least 25 kgs at time of consentInformed consentThe process of being told what taking part involves, then choosing freely.Read more →.
- +Participants aged 6 to 11 years must be at least 19 kgs at time of consent.
- +Minimum weight requirement for participants aged 1 to 5 years is to be determined.
- +Male participants of appropriate age and required minimum weight
- +Participants with a diagnosis of severe hemophilia A or moderately severe to severe hemophilia B
- +Participants must have at least 1 year of diary and/or medical records available in which exogenous FVIII or FIX replacement or bypass agent infusions and hemophilic bleeding episodes were consistently documented over the 12 months prior to the time of consent.
- +Participants who are enrolledEnrolmentThe number of participants a study plans to include, or has included.Read more → into the Non-Inhibitor CohortCohortA group of participants sharing a characteristic, followed together.Read more → must also meet the following criteria:
- +No current detectable inhibitor and no documented history of inhibitors in the 5 years prior to consent
- +Must have at least 50 exposure days to FVIII/FIX replacement products
- +Must be at least 80% compliant with a stable and effective routine prophylaxis regimen with FVIII/FIX replacement products, for at least 12 months prior to consent
- +Participants who are enrolled into the Inhibitor Cohort must also meet the following criteria:
- +Documentation of current high titer inhibitor (≥5 BU/mL); or current low titer inhibitor (\<5 BU/mL) refractory to FVIII or FIX replacement and with FVIII or FIX recovery \<60% of expected within previous 12 months prior to the time of consent
- +Participants who have documented inhibitors while on factor-replacement therapy but who do not meet the high quantitative inhibitor criteria described in the prior bullet at the time of screeningScreeningThe checks done before joining, to see whether a study fits.Read more → (eg, participant with a previously documented high-titer inhibitor ≥5 BU/mL) and whose condition precludes re-challenge with FVIII or FIX replacement may be considered for eligibilityEligibility criteriaThe full list of requirements for taking part in a study.Read more → on a case-by-case basis with discussion and agreement from the Pfizer medical monitor.
- +Hemophilia A participants with on-demand treatment regimen with ≥12 bleeding episodes or hemophilia B participants with on-demand treatment regimen with ≥8 bleeding episodes (spontaneous or traumatic) necessitating treatment with bypass factor in the 12 months prior to informed consent
- +Participants must be on an on-demand bypass treatment regimen during the 12 months prior to informed consent
Exclusion
- −Individuals with known allergic reaction or hypersensitivity to hamster protein or other components of the study intervention
- −CD4 cell count ≤200/uL if HIV-positive
- −Known coronary artery, thrombotic, or ischemic disease, or current evidence of congenital or acquired thrombophilic disease such as Anti-thrombin III deficiency, Factor V Leiden mutation, prothrombin 20210 mutation, protein C deficiency, protein S deficiency and antiphospholipid syndrome.
- −Known planned surgical procedure during the planned study period
- −Known hemostatic defect other than hemophilia A or B
- −Abnormal hematology, renal or hepatic function laboratory results at screeningScreeningThe checks done before joining, to see whether a study fits.Read more →
- −Other acute or chronic medical or psychiatric condition that may increase the risk associated with study participation or investigational product administration or may interfere with the interpretation of study results and, in the judgment of the investigatorPrincipal investigatorThe doctor or researcher responsible for running the study at a site.Read more →
- −Current routine prophylaxis with bypassing agent, non-coagulation non-factor replacement therapy (eg, emicizumab), or any previous treatment with a gene therapy product for treatment of hemophilia
- −Participants with inhibitors who are being treated using a prophylaxis treatment regimen with a bypass agent, and, participants who have previously received non-factor-based hemophilia therapy (eg, fitusiran, concizumab, emicizumab) will be considered on a case-by-case basis, only after discussion and agreement between the investigator and the Pfizer medical monitor
- −Regular use of immunomodulatory medications (eg, IVIG, routine systemic corticosteroids, rituximab)
- −Use of systemic antifibrinolytics, medications that may increase the risk of bleeding, and certain non-steroidal anti-inflammatory drugs within 120 hours of first dose of study intervention and while on study
- −Ongoing or planned use of ITI, or prophylaxis with FVIII or FIX replacement at any time after initiation of treatment with study intervention
- −Participation in other studies involving investigational drug(s) or investigational vaccine(s) within 30 days (or as determined by local requirements) or 5 half-lives prior to study entry or during study participation
- −Previous exposure to marstacimab during participation in other marstacimab clinical studies
- −Abnormal ECG of clinical relevance that may affect participant safety or interpretation of study results
- −Investigator siteTrial siteA hospital or clinic where a study is actually run.Read more → staff members directly involved in the conduct of the study and their family members, site staff members otherwise supervised by the investigator, and sponsorSponsorThe organisation responsible for the study overall.Read more → and sponsor delegate employees directly involved in the conduct of the study and their family members
In plain language
Assembled directly from this trial’s registry record. Every sentence traces to a field below — nothing here is generated or interpreted.
What this study is
This study is testing a treatment for a condition.
Phase 3Phase 3A large study comparing a treatment against the current standard.Read more → — a large study comparing this against the current standard, usually across many hospitals.
From the trial registry
Built from these fields:
- designModule.designInfo.primaryPurpose
- designModule.phases
Who receives what
Everyone in this study is in one group and receives marstacimab.
From the trial registry
Built from these fields:
- armsInterventionsModule.armGroups[].label
- armsInterventionsModule.armGroups[].type
- armsInterventionsModule.armGroups[].interventionNames
How the study is run
There is only one group in this study, so there is no assignment to different treatments.
This study is open-labelOpen-labelEveryone knows which treatment is being given — nothing is hidden.Read more →: everyone knows which treatment is being given, including you and the study team.
From the trial registry
Built from these fields:
- designModule.designInfo.allocation
- designModule.designInfo.maskingInfo.masking
Is there a placebo?
This study does not list a placeboPlaceboA dummy treatment with no active medicine, used for comparison.Read more → group.
From the trial registry
Built from these fields:
- armsInterventionsModule.armGroups[].type
- armsInterventionsModule.armGroups[].interventionNames
Who the study is looking for
The study lists an age range of 1 year to 17 years.
The study lists male participants only.
The study does not accept healthy volunteersHealthy volunteerSomeone without the condition being studied who takes part anyway.Read more →.
These are the criteria the study lists. Only the trial siteTrial siteA hospital or clinic where a study is actually run.Read more → can decide whether someone can take part.
From the trial registry
Built from these fields:
- eligibilityModule.minimumAge
- eligibilityModule.maximumAge
- eligibilityModule.sex
- eligibilityModule.healthyVolunteers
How big and how long
The study aims to enrol about 100 people.
The study is currently expected to finish around September 2028.
The main measurement is taken over: BaselineBaselineYour starting measurements, taken before treatment begins.Read more → to end of 12-month treatment period.
From the trial registry
Built from these fields:
- designModule.enrollmentInfo.count
- statusModule.completionDateStruct.date
- outcomesModule.primaryOutcomes[].timeFrame
What the study measures
Annualized bleeding rate (ABR) of treated bleeding events — measured over BaselineBaselineYour starting measurements, taken before treatment begins.Read more → to end of 12-month treatment period.
Incidence of adverse eventsAdverse eventAny medical problem that happens during a study, whether or not the treatment caused it.Read more → and serious adverse eventsSerious adverse eventAn adverse event meeting a formal severity threshold, such as requiring hospital admission.Read more → — measured over ScreeningScreeningThe checks done before joining, to see whether a study fits.Read more → through end of follow-up periodFollow-upContinued check-ins after the treatment part is finished.Read more → (approximately 14 months).
Incidence and severity of thrombotic events — measured over Baseline to end of 12-month treatment period.
Incidence and severity of thrombotic microangiopathy — measured over Baseline to end of 12-month treatment period.
The study lists 4 further main measurements.
From the trial registry
Built from these fields:
- outcomesModule.primaryOutcomes[].measure
- outcomesModule.primaryOutcomes[].timeFrame
Source: NCT05611801 on ClinicalTrials.gov. The full registry text is further down this page — this summary never replaces it.
Not medical advice. What do these terms mean?
What is being tested — in plain terms
About marstacimabDrug
marstacimab
From the trial registry — its own words, unedited.
What a drug is here: A medicine — a chemical or small-molecule treatment — given as the thing being studied.
Read the full explanation → · in clinical review
Common questions
Answered from this trial’s registry record. Where the record doesn’t say, these answers say so rather than filling the gap.
Am I eligible for this trial?
Only the trial siteTrial siteA hospital or clinic where a study is actually run.Read more → can decide whether someone can take part. Concord cannot make that determination, and neither can any tool that has not examined you.
What the study lists: an age range of 1 year to 17 years.
The full inclusionInclusion criteriaThe things you must have or be for a study to consider you.Read more → and exclusion criteriaExclusion criteriaThe things that would prevent someone from taking part.Read more → are published on this page, exactly as the study team wrote them.
The useful next step is to bring this trial to your doctor. Answering a few questions first gives them something concrete to review.
From the trial registry
- eligibilityModule.minimumAge
- eligibilityModule.maximumAge
- eligibilityModule.eligibilityCriteria
Is there a placebo?
This study does not list a placeboPlaceboA dummy treatment with no active medicine, used for comparison.Read more → group.
From the trial registry
- armsInterventionsModule.armGroups[].type
Would I know which treatment I am getting?
This study is open-labelOpen-labelEveryone knows which treatment is being given — nothing is hidden.Read more →: everyone knows which treatment is being given, including you and the study team.
There is only one group in this study, so there is no assignment to different treatments.
From the trial registry
- designModule.designInfo.maskingInfo.masking
- designModule.designInfo.allocation
Who can join?
The study lists an age range of 1 year to 17 years.
It lists male participants only.
It does not accept healthy volunteersHealthy volunteerSomeone without the condition being studied who takes part anyway.Read more →.
Only the trial siteTrial siteA hospital or clinic where a study is actually run.Read more → can confirm whether a particular person can take part.
From the trial registry
- eligibilityModule.minimumAge
- eligibilityModule.maximumAge
- eligibilityModule.sex
- eligibilityModule.healthyVolunteers
How long would this take?
The study's main measurement is taken over: BaselineBaselineYour starting measurements, taken before treatment begins.Read more → to end of 12-month treatment period.
The study as a whole is currently expected to finish around 2028-09-10.
How long any one person takes part can differ from the study length. The study team can tell you what the schedule looks like in practice.
From the trial registry
- outcomesModule.primaryOutcomes[].timeFrame
- statusModule.completionDateStruct.date
How many people are taking part?
The study aims to enrol about 100 people.
From the trial registry
- designModule.enrollmentInfo.count
Where is this happening?
This study lists 2 locations, including: Edmonton, Alberta, Canada; Hamilton, Ontario, Canada.
Sites can open and close during a study, so confirm with the team before travelling.
From the trial registry
- trial_locations
About This Trial
The purpose of this clinical trial is to learn about the safety and effects of the study medicine (called marstacimab) for the potential treatment of hemophilia in pediatric patients. This study will enroll pediatric participants from ages 1 to 17 years in a sequential manner. The study will open enrollment to adolescent participants aged 12 to 17 years first. Then children aged 6 to 11 years will be permitted to enroll. Lastly, children aged 1 to 5 years will be permitted to enroll. This study will enroll participants who: * have severe Hemophilia A or moderately severe to severe Hemophilia B (with or without inhibitors) * have accurate historical records documenting all factor VIII, factor IX, or bypass agent infusions and hemophilia bleed events for at least 1 year prior to entering the study * if a non-inhibitor patient, must be on a stable routine prophylaxis regimen with factor VIII or factor IX replacement products for at least 12 months prior to study entry * if an inhibitor patient, must be on an on-demand bypass treatment regimen during the 12 months prior to study entry All participants in this study will receive marstacimab to use prophylactically. Marstacimab will be given once a week as a subcutaneous (under the skin) shot. The first dose of marstacimab will be given at the study site by the study site staff. During the 12-month treatment period, weekly doses of marstacimab can be given at home, or if preferred, the doses may be given by the study site staff. To help us determine if the study medicine is safe and effective, we will compare participant experiences when they are taking the study medicine to a historical period when they were not. Researchers want to see if the study medicine works to prevent the bleeding episodes commonly experienced by patients with Hemophilia. Participants will be in this study for about 14 months (approximately 1 month in a Screening period, 12 months receiving treatment, and 1 month in a follow-up period) during which they will visit the study site at least 10 times. If preferred, and if local regulations allow it, 2 of the study visits can be completed at the participant's home instead of at the study site. There will also be 6 scheduled telephone calls approximately every 2 months.
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See if this trial could fit youThis page is for informational purposes only and does not constitute medical advice. Clinical trial eligibility can only be determined by the trial site after proper screening. Trial information is sourced from ClinicalTrials.gov and may not reflect the most current status. Always consult your healthcare provider before making decisions about clinical trial participation.