A Study to Learn About How Changing Therapy From Emicizumab to Marstacimab Affects People With th… (NCT06703606) | Clinical Trial Compass
RecruitingPhase 1
A Study to Learn About How Changing Therapy From Emicizumab to Marstacimab Affects People With the Severe Hemophilia A.
United States, India, Turkey (Türkiye)15 participantsStarted 2025-05-13
Plain-language summary
The purpose of the study is to learn about safety, how the body processes marstacimab and how it works in patients with severe hemophilia A without inhibitors. Hemophilia A is rare bleeding disorder where the blood doesn't clot normally. This causes a person to bleed a lot, even from a small cut.
These patients who are on emicizumab medicine for routine prophylaxis for at least 6 months, and desire to switch to marstacimab medicine. Inhibitors are antibodies that the immune system develops because it sees the infused clotting factor as a foreign substance that needs to be destroyed. Antibodies are proteins that eat up the activated factor before it has time to stop the bleeding. Prophylaxis are preventive medicines.
This study is seeking for participants:
* with severe Hemophilia A withouth inhibitors who are on emicizumab treatment for at least 6 months.
* must be 12 to less than 75 years old
* must have a body weight of at least 35 kilograms. The results from this study will serve as a guide to doctors and their hemophilia A patients who will change their medicines in the real-world clinical setting. Patients who can take part in the study will receive marstacimab medicine as weekly injections under the skin of 150 milligrams for 4 months. Study treatment with marstacimab will be initiated no earlier than 14 days after last dose of emicizumab. The study can last up to 6 months. The sponsor will provide marstacimab. Patients will continue their usual treatment with the infused clotting factor for their bleeds when taking part in the study. Roll-over into an optional study treatment extension period will be available to participants who wish to continue prophylaxis with marstacimab in countries where it is not commercially available.
Who can participate
Age range
12 Years – 74 Years
Sex
MALE
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
. Male and 12 to \<75 years of age with a minimum body weight of 35 kg at the time of signing the informed consent.
. Diagnosis of severe hemophilia A (FVIII activity \<1%) without inhibitors.
. On emicizumab therapy at a standard clinical dose for ≥6 months.
Exclusion criteria
. Previous or current treatment for or history of coronary artery diseases, venous or arterial thrombosis, or ischemic disease.
. Any medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Incidence of marstacimab-related adverse events (AEs)
Timeframe: 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
2
Incidence of marstacimab-related serious AEs (SAEs)
Timeframe: 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
. Known hemostatic defect other than hemophilia A.
. Current use of any prohibited concomitant medication(s) or unwillingness or inability to use a required concomitant medication(s).
. Previous administration of an investigational product (drug or vaccine) within 30 days or 5 half-lives preceding the first dose of study intervention used in this study (whichever is longer). Participation in studies of other investigational products (drug or vaccine) at any time during participation in this study.
. Platelet count \<100,000/μl or hemoglobin \<10 g/dL.
. Clinically significant renal or hepatic function abnormality based on laboratory results at screening, or known kidney or liver disease.