Efficacy of emicizumab in von Willebrand disease (VWD) patients with and without alloantibodies to von Willebrand factor (VWF): Report of two cases and review of literature

Introduction von Willebrand disease (VWD) is the common bleeding disorder with a clinically relevant bleeding prevalence of 1:10,000. von Willebrand disease patients lack both von Willebrand factor (VWF) and factor VIII (FVIII), which are critical for normal haemostasis. The conventional treatment for VWD includes desmopressin and replacement therapy with plasma derived FVIII with VWF concentrates or recombinant VWF. Development of alloantibodies is a rare occurrence, there is a paucity in the literature of treatment modalities in these patients. Not many reports are available in literature on the efficacy of emicizumab in VWD patients with or without alloantibodies to VWF. Aim To do systematic review of literature on emicizumab in VWD and report our experience of emicizumab in two patients of VWD Methods We used electronic search engines till May 2021 in 'Google scholar' and 'PubMed', to collect the case reports or case series on use of emicizumab for management of VWD. Two of our severe VWD patients were successfully treated with emicizumab. A systematic review was performed and the results discussed. Results The electronic search revealed six case reports using emicizumab for treatment of VWD. Two were in vitro studies and four in patients with VWD type 3 disease. In vitro studies and in VWD patients on emicizumab, showed improvement in thrombin generation and fibrin formation. Among four patients, three had alloantibodies to VWD and one was negative. All these patients were treated with emicizumab for 6-12 m. After starting emicizumab, none of them had spontaneous bleeding requiring treatment. During treatment with emicizumab, one patient had trauma-associated soft tissue hematoma, which was treated with rFVIIa and another patient had bleeding following dental exfoliation treated with Humate P. We treated two of our VWD patients one with and one without inhibitors with emicizumab after failure of other therapies. Both the patients showed marked improvement and continued to remain well and free of bleeding episodes. None of the patients had any thrombosis or thrombotic microangiopathy (TMA) during treatment with emicizumab. Conclusion In conclusion, this review supports the safety and efficacy of emicizumab in type 3 VWD patients with or without alloantibodies. Further large studies are required to confirm the safety and efficacy of emicizumab in VWD.