Analysis of Time to Complete Response after Defibrotide Initiation in Patients with Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome after Hematopoietic Cell Transplantation

•We analyzed the time to complete response (CR) or discontinuation due to CR in 3 studies of post-hematopoietic stem cell transplantation hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS).•Complete response to defibrotide occurred beyond 21 days in >50% of patients.•Response occurred after more than 28 days of defibrotide treatment in some patients.•The importance of continuing defibrotide until VOD/SOS resolution is highlighted. Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication that occurs after hematopoietic cell transplantation (HCT). The mortality associated with untreated VOD/SOS with multiorgan dysfunction (MOD) has been reported to be >80%. The recommended dose of defibrotide is 6.25 mg/kg every 6 hours, administered as a 2-hour i.v. infusion, for a minimum of 21 days or until resolution of VOD/SOS signs and symptoms. The objective of this analysis was to evaluate the time to complete response (CR) in patients with post-HCT VOD/SOS treated with defibrotide. The time to defibrotide discontinuation due to a CR served as a surrogate for time to CR in an expanded access study (T-IND; ClinicalTrials.gov NCT00628498; n = 1000), and was analyzed separately from the time to CR data pooled from a phase 2 randomized dose-finding study (NCT00003966; n = 74 patients who received 25 mg/kg/day) and a phase 3 historically controlled study (NCT00358501; n = 102). For all studies, a CR was defined as total serum bilirubin