At the 42nd Annual Meeting of the European Society for Blood and Marrow Transplantation (EBMT), held in Valencia, Spain, Paul Richardson, MD, from Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, discusses the clinical development and approval of the novel polydisperse oligonucleotide defibrotide for the treatment of patients with severe veno-occlusive disease (sVOD) following a hematopoietic stem cell transplant (HSCT).