Department of Medicine 1, Division of Hematology and Hemostasis, Medical University of Vienna, Austria. Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA. Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, and Department of Pathophysiology and Transplantation, Universita degli Studi di Milano, Milan, Italy. Department of Hematology, Reference Center for Thrombotic Microangiopathies (CNR-MAT), Saint-Antoine University Hospital, AP-HP, Paris, France. Department of Haematology, University College London Hospital, Cardiometabolic Programme-NIHR UCLH/UCL BRC, London, United Kingdom. Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. Department of Medicine, Duke University School of Medicine, Durham, NC, USA. Hematology Department, Internal Medicine, School of Medicine and Dentistry, Catholic University of Valencia and Hospital Doctor Peset, Valencia, Spain. Departments of Medicine and Laboratory Medicine, St. Michael's Hospital and University of Toronto, Toronto, ON, Canada. Clinical Development, Ablynx, a Sanofi company, Ghent, Belgium. Formerly Clinical Development, Ablynx, a Sanofi company, Ghent, Belgium. Medical Affairs, Sanofi, Diegem, Belgium.