A clinical case of inhibitor development in a patient with type 3 von Willebrand disease and the use of emicizumab as hemostatic treatment

Background. Von Willebrand disease is one of the most common bleeding disorders, with a prevalence ranging from 1 in 100 for asymptomatic disease to 1 in 1000 for severe forms of von Willebrand disease associated with bleeds. The mainstay of therapy for von Willebrand disease is desmopressin and replacement therapy with von Willebrand factor concentrate. One of extremely rare and serious complications of this therapy is the development of an inhibitor to von Willebrand factor. Clinical case. This article describes the clinical presentation, phenotype, and bleeding manifestations in a female patient with von Willebrand disease with inhibitors, as well as our experience of using emicizumab as off-label therapy. Conclusion. The development of an inhibitor in patients with von Willebrand disease is an extremely rare complication; this is the first time that we encountered this complication at our center. Physicians should suspect inhibitor development if standard therapy is ineffective or if a patient develops break-through bleedings or allergic reactions to von Willebrand factor concentrate. The off-label use of emicizumab in these patients can reduce spontaneous bleeding episodes and prevent life-threatening bleeding.