New shot could help hemophilia patients switch treatments
NCT ID NCT06703606
First seen Jun 24, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This early-stage study tests a new medicine called marstacimab in people with severe hemophilia A who want to switch from their current preventive treatment, emicizumab. The study includes 15 adolescents and adults who will receive weekly injections of marstacimab for 4 months. Researchers will monitor safety and how the body processes the drug to guide future use in clinical practice.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- marstacimab
- What this could lead to
- If successful, this could offer a new preventive treatment option for people with severe hemophilia A who want to switch from their current medication.
- What could go wrong
- This is a very early Phase 1 study with only 15 participants, so safety and effectiveness are not yet proven. It may not work for everyone or could have unexpected side effects.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 1
The first testing in people. Mainly checks safety and dose, usually in a small group.
- Participants
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About 15 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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May 2025
- Expected to finish
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May 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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12 to 74 years
- Sex
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Male participants only
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Male and 12 to \<75 years of age with a minimum body weight of 35 kg at the time of signing the informed consent. 2. Diagnosis of severe hemophilia A (FVIII activity \<1%) without inhibitors. 3. On emicizumab therapy at a standard clinical dose for ≥6 months. Exclusion Criteria: 1. Previous or current treatment for or history of coronary artery diseases, venous or arterial thrombosis, or ischemic disease. 2. 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. 3. Known hemostatic defect other than hemophilia A. 4. Current use of any prohibited concomitant medication(s) or unwillingness or inability to use a required concomitant medication(s). 5. 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. 6. Platelet count \<100,000/μl or hemoglobin \<10 g/dL. 7. Clinically significant renal or hepatic function abnormality based on laboratory results at screening, or known kidney or liver disease. 8. CD4 cell count ≤200/μl if HIV positive. 9. Screening 12-lead ECG that demonstrates clinically significant abnormalities that, in the opinion of the investigator, may affect participant safety or interpretation of study results. 10. Known planned surgical procedure. 11. Hypersensitivity or allergic reaction to hamster protein or other components of the study intervention. 12. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor-delegate employees directly involved in the conduct of the study and their family members.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The places running it
7 sites in 3 countries. The list below names each one and where it is.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
Contacts and locations
Locations
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Brody School of Medicine at East Carolina University
RECRUITINGGreenville, North Carolina, 27834, United States
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ECU Health Medical Center
RECRUITINGGreenville, North Carolina, 27834, United States
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Ege University Faculty of Medicine Dean's Office
RECRUITINGBornova, İzmir, 35100, Turkey (Türkiye)
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Istanbul Universitesi Tıp Fakultesi Onkoloji Enstitusu
RECRUITINGFatih, İ̇stanbul, 34093, Turkey (Türkiye)
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K J Somaiya Hospital & Research Centre
RECRUITINGMumbai, Maharashtra, 400022, India
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Nirmal Hospital Pvt Ltd.
RECRUITINGSurat, Gujarat, 395002, India
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Orthopaedic Institute for Children/Orthopaedic Hemophilia Treatment Center
RECRUITINGLos Angeles, California, 90007, United States
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Once-a-Week shot aims to stop bleeds in severe hemophilia a
- A Once-a-Week shot could transform hemophilia Care—Even for those with inhibitors
- Can a new clotting factor offer better bleed protection for severe hemophilia?
- New clotting factor aims to cut bleeding episodes in severe hemophilia a
- New clotting factor aims to stop bleeding in severe hemophilia a
- Monthly shot could free kids with hemophilia from frequent infusions