Introduction: Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication of hematopoietic cell transplantation (HCT) conditioning that may also develop after high-dose chemotherapy. Multiorgan failure (MOF) is associated with the most severe form of VOD/SOS and, if untreated, may result in a mortality rate of >80%. Defibrotide is approved for the treatment of hepatic VOD/SOS with renal or pulmonary dysfunction post-HCT in the US and for severe hepatic VOD/SOS post-HCT in patients aged >1 month (mo) in the EU. The DEFIFrance study collected real-world data on the efficacy and safety of defibrotide from HCT centers in France. This analysis presents final, long-term data on the primary study population: patients who received defibrotide treatment for severe/very severe VOD/SOS post-HCT.