Actively Recruiting
An Open-Label Study of Marstacimab Prophylaxis Compared to Historical Treatment in Pediatric Males With Severe Hemophilia A or Moderate to Severe Hemophilia B
Led by Pfizer · Updated on 2026-05-07
100
Participants Needed
34
Research Sites
N/A
Total Duration
On this page
AI-Summary
What this Trial Is About
This research aims to learn about the safety and effects of marstacimab, a study medicine being evaluated for treating Hemophilia in pediatric patients. It focuses on children aged 1 to 17 years with severe Hemophilia A or moderate to severe Hemophilia B, including those with or without inhibitors. The study compares participant experiences on marstacimab with their past standard treatments to see if it helps prevent bleeding episodes common in Hemophilia. All participants will receive weekly marstacimab injections under the skin. The first dose is administered at the study site, and subsequent doses during the 12-month treatment period can be given at home or the study site. The study enrolls participants in age groups sequentially, starting with adolescents 12-17 years, followed by children 6-11 years, and then 1-5 years. The full participation lasts about 14 months, including screening, treatment, and follow-up periods. Participants will visit the study site at least 10 times and have 6 scheduled phone calls every two months. Researchers will monitor bleeding rates, adverse events, immune reactions, and joint health, along with quality of life changes. Safety assessments cover the entire study period, including follow-up, to evaluate marstacimabs effects and tolerability in children with Hemophilia.
CONDITIONS
Brief Title
A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Male participants aged 12 to 17 years must weigh at least 25 kg at consent
- Male participants aged 6 to 11 years must weigh at least 19 kg at consent
- Weight requirement for participants aged 1 to 5 years is to be determined
- Diagnosis of severe Hemophilia A or moderately severe to severe Hemophilia B
- At least 1 year of accurate records documenting factor infusions and bleeding episodes prior to consent
- Non-inhibitor participants must have no inhibitors in past 5 years and at least 50 exposure days to factor replacement
- Non-inhibitor participants must be at least 80% compliant with stable routine prophylaxis for at least 12 months prior to consent
- Inhibitor participants must have documented high or low titer inhibitor meeting study criteria
- Inhibitor participants must have on-demand bypass treatment with specified bleeding episodes in prior 12 months
- On-demand bypass treatment regimen during 12 months prior to consent
You will not qualify if you...
- Known coronary artery, thrombotic, ischemic, or thrombophilic diseases
- Planned surgery during study period
- Hemostatic defects other than Hemophilia A or B
- Abnormal blood, kidney, or liver lab results at screening
- Other medical or psychiatric conditions increasing risk or affecting study results
- Known allergy to hamster protein or study components
- Current routine prophylaxis with bypassing agents or previous gene therapy for Hemophilia
- Use of immunomodulatory medications or certain drugs increasing bleeding risk near first dose
- Ongoing or planned immune tolerance induction or prophylaxis with factor replacement after starting study treatment
- Participation in other investigational drug or vaccine studies recently or currently
- Previous exposure to marstacimab in other studies
- Low CD4 count if HIV-positive
- Abnormal ECG affecting safety or study interpretation
- Investigator site staff and their family or those closely involved in the study
Research Team
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