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A Clinical Trial of Study Medicine (Marstacimab) in Pediatric Patients With Hemophilia A or Hemophilia B

NCT05611801 · Status: RECRUITING · Phase: PHASE3 · Type: INTERVENTIONAL · Enrollment: 100

Last updated 2026-05-07

No results posted yet for this study

Summary

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.

Conditions

Interventions

DRUG

marstacimab

marstacimab

Sponsors & Collaborators

Principal Investigators

  • Pfizer CT.gov Call Center · Pfizer

Study Design

Allocation
NA
Purpose
TREATMENT
Masking
NONE
Model
SINGLE_GROUP

Eligibility

Min Age
1 Year
Max Age
17 Years
Sex
MALE
Healthy Volunteers
No

Timeline & Regulatory

Start
2022-12-09
Primary Completion
2028-09-10
Completion
2028-09-10
FDA Drug
Yes

Countries

  • Argentina
  • Australia
  • Austria
  • Canada
  • China
  • Czechia
  • Denmark
  • Germany
  • Italy
  • Japan
  • Mexico
  • Saudi Arabia
  • Slovakia
  • South Korea
  • Spain
  • Taiwan
  • Turkey (Türkiye)
  • United Kingdom

Study Locations

More Related Trials

Entities

Diseases
Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05611801 on ClinicalTrials.gov