Defibrotide 200mg/2.5ml solution for injection vials

Introduction: Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a major complication following hematopoietic stem cell transplantation, resulting from immune and chemical toxicity in the sinusoidal endothelium and hepatocellular damage. In the most severe cases, multiorgan dysfunction occurs, so it is essential to promptly identify patients at greater risk of SOS/VOD and to adopt prophylactic strategies. Objectives: This study aims to systematize the impact of different approaches as primary prophylaxes against SOS/VOD in patients undergoing hematopoietic stem cell transplantation (HSCT). Methods: A systematic review and meta-analysis of randomized clinical trials evaluating different strategies for primary prophylaxis of SOS/VOD was carried out in pairwise fashion and with a consistent network structure. The odds ratio (OR) and corresponding confidence intervals were calculated using the random-effects model. Heterogeneity was assessed by the I2 method and the efficacy of each approach was estimated by SUCRA (surface under the cumulative ranking curve). Results: Considering all patients undergoing HSCT, ursodeoxycholic acid (UDCA) [OR = 0.38, 95%CI 0.14-1.06, SUCRA = 0.720] was associated with a lower incidence of VOD while defibrotide reached a modest reduction in its incidence [OR = 0.64, 95%CI 0.23-1.67; SUCRA = 0.486]. Considering the subgroup of patients undergoing hematopoietic progenitors allotransplantation, defibrotide scored higher [OR = 0.51, 95%CI 0.09-2.85, SUCRA = 0.650] by comparison with UDCA [OR = 0.53, 95%CI 0.14-1.96, SUCRA = 0.639]. Conclusions: This is the first meta-analysis comparing primary prophylaxes against SOS/VOD. UDCA yielded more promising results when considering all patients undergoing hematopoietic stem cell transplantation, yet, in a subgroup analysis of the ones exposed to allogeneic grafts, it becomes not significantly overrun by defibrotide.

Abstract licence: CC BY

SOS/VOD is a life-threatening complication of hematopoietic stem cell transplantation, especially in children, with incidences reaching up to 15–20%. Despite efforts, SOS/VOD remains unpredictable with significant morbidity and mortality. High-risk criteria are clearly defined, and the pediatric EBMT diagnostic criteria have improved sensitivity, reducing treatment delays and enhancing outcomes. A meta-analysis combining retrospective and prospective studies found a risk ratio of 0.30 for SOS/VOD with defibrotide (DF) prophylaxis. Additionally, two prospective trials were conducted: the pediatric prevention trial (NCT00272948) and the Harmony Trial (NCT02851407), involving adults and children, with primary outcomes of incidence and SOS/VOD-free survival, respectively. The trials produced conflicting results regarding the effectiveness of prophylactic DF. Despite significant limitations of the Harmony trial, a direct healthcare professional communication (DHPC) from the European Medicines Agency (EMA) advised against prophylactic DF. This recommendation has serious consequences for children, especially infants, who are among the most vulnerable groups receiving HSCT. Therefore, a panel of experts issued guidelines for children at high risk for SOS/VOD, in which DF prophylaxis is considered justified. These guidelines include a weighted scoring system based on all relevant high-risk criteria to predict SOS/VOD, supporting decisions regarding the use of prophylactic DF in children.

Abstract licence: CC BY