Background Hepatic veno-occlusive (VOD) disease is a potentially life threatening complication that mainly occurs after myeloablative conditioning therapy and haematopoietic stem cell transplantation (HSCT). The disease is characterised by increased serum bilirubin concentrations, tender hepatomegaly, fluid retention and weight gain. Severe VOD is one of the most frequent causes of early death in the HSCT setting, with a mortality rate of up to 98% by day +100 post-HSCT. There are few effective options that target the underlying cause. Defibrotide has recently been authorised via the centralised procedure of the EMA for the treatment of severe VOD in adults and children, as it has been associated with complete response (CR) rates of 36–76%, and by 100 days post-HSCT survival rates of 32–79% in clinical trials.

Purpose To determine the CR rate in patients with severe VOD following HSCT treated with defibrotide, and survival rates by 100 days post-HSCT.

Material and methods A retrospective observational study. Adults or children with VOD treated with defibrotide were included. CR was defined as normalisation of total serum bilirubin levels and resolution of multiple organ failure (renal, pulmonary and central nervous system). A secondary endpoint was survival by 100 days post- HSCT.

Results 42 patients (30 adults and 12 children) with VOD received defibrotide. Mean age was 46 (range 19–70) years for adults and 7 (range 0.25–16) years for children. Patients received their first dose at a median of 18 (range 3–56) days after myeloablative conditioning therapy. The mean dose of defibrotide was 25 (range 10–45) mg/kg/day and the median duration of therapy was 11 (range 1–40) days.

After treatment with defibrotide, CR was found in 13 patients (30.95%). By 100 days post-HSCT, CR in the evaluable population was achieved in 12 patients (28.57%) and the survival rate was 50%; 21 patients were still alive with resolution of VOD.

Conclusion Defibrotide has demonstrated a limited effectiveness in our study and other published studies. We have to consider that VOD is a rare disorder, and as a result the first limitation of studies is the small number of patients that can be included. Consequently, more effectiveness studies with more patients are needed.

References and/or Acknowledgements Hospital La Paz

No conflict of interest.