A Study to Assess the Efficacy and Safety of Emicizumab in Participants With Type 3 Von Willebrand Disease

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