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Emicizumab prophylaxis for people with Type 3 von Willebrand disease

A Phase III, Multicenter, Open-Label Study to Evaluate the Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of Emicizumab Prophylaxis in Patients With Type 3 Von Willebrand Disease

Phase 3 Interventional Hoffmann-La Roche · NCT06998524

This trial will test whether regular emicizumab injections reduce bleeds compared with on-demand standard therapy for people aged 1 month and older with Type 3 von Willebrand disease, while also studying people already on prophylaxis using their prior data.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment75 (estimated)
Ages1 Month and up
SexAll
SponsorHoffmann-La Roche Industry-sponsored
Drugs / interventionsemicizumab
Locations27 sites (Sacramento, California and 26 other locations)
Trial IDNCT06998524 on ClinicalTrials.gov

What this trial studies

This is a Phase III, multicenter, open-label study testing emicizumab as prophylaxis in participants with confirmed Type 3 von Willebrand disease. Participants currently using on-demand therapy are randomized to emicizumab prophylaxis or continuation of on-demand standard of care, while participants already on prophylactic standard therapy will receive emicizumab and be compared to their own prior non-interventional study data (WP45335). The trial measures bleeding outcomes along with safety, pharmacokinetics, and pharmacodynamics, and allows use of VWF/FVIII concentrates or bypassing agents as clinically needed. Eligible ages start at 1 month for the on-demand/randomized arms and at 2 years for the prophylaxis arm, with required baseline organ function and documentation of prior treatment patterns.

Who should consider this trial

Good fit: Ideal candidates are people with a confirmed diagnosis of Type 3 VWD who meet the age and prior-treatment criteria (≥1 month old with prior on-demand use and ≥2 treated bleeds in 24 weeks for randomized arms, or ≥2 years old with prior regular prophylaxis for the intra-participant arm) and who have adequate hematologic, hepatic, and renal function.

Not a fit: Patients without Type 3 VWD, those who do not meet the trial's age or prior-treatment requirements, or those with medical conditions that make participation unsafe are unlikely to benefit from this study.

Why it matters

Potential benefit: If successful, emicizumab prophylaxis could reduce bleeding frequency and decrease the need for frequent intravenous VWF/FVIII infusions in people with Type 3 VWD.

How similar studies have performed: Emicizumab has proven major benefit in hemophilia A, and there is limited early and non-interventional data supporting exploration in Type 3 VWD, but large randomized evidence in this population is currently limited.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Confirmed diagnosis of Type 3 von Willebrand disease (VWD), based on medical records
* Preexisting medical record verifying the status of von Willebrand factor (VWF) inhibitor (positive or negative, including titer if available)
* Adequate hematologic, hepatic, and renal function
* For participants of childbearing potential: agreement to remain abstinent or adhere to the contraception requirements

Additional Inclusion Criteria for Arms A and B:

* Age ≥1 month at the time of signing Informed Consent/Assent Form
* Documented previous use of on-demand therapy with intermittent (less than once a week) on-demand SOC therapy for VWD
* Having ≥2 treated bleeds (except menstrual bleeds) with factor concentrate within 24 weeks prior to enrollment

Additional Inclusion Criteria for Arm C:

* Age ≥2 years at the time of signing Informed Consent/Assent Form
* Documented and confirmed previous use of SOC prophylactic therapy for VWD (1-3 times weekly, as per prescribed dose) as described in the eligibility of Study WP45335
* Have completed all study requirements as defined in the WP45335 protocol for at least 24 weeks

Exclusion Criteria:

* Inherited or acquired bleeding disorder other than Congenital Type 3 VWD
* History of gastrointestinal bleeding within 18 months prior to enrollment, or any previous diagnosis of angiodysplasia
* History of intracranial hemorrhage
* Previous or current treatment for thromboembolic disease or signs of thromboembolic disease
* Other conditions (e.g., certain autoimmune diseases) that may increase risk of bleeding or thrombosis
* History of clinically significant hypersensitivity associated with monoclonal antibody therapies or components of the emicizumab injection
* Use of systemic immunomodulators (e.g., interferon) at enrollment or planned use during the study, with the exception of anti-retroviral therapy

Where this trial is running

Sacramento, California and 26 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Von Willebrand Disease, Type 3
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.