Incidence, predictors, and outcomes of veno-occlusive disease/sinusoidal obstruction syndrome after reduced intensity allogeneic hematopoietic cell transplantation.

•Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is rare after reduced-intensity conditioning (RIC) transplantation with a cumulative incidence of 1.6% in our large modern cohort.•VOD/SOS continues to be associated with a high nonrelapse mortality (NRM); in our cohort, day 100 NRM was 23% in patients with VOD/SOS compared with 6.4% in patients without VOD/SOS.•VOD/SOS in RIC patients often does not meet classical Baltimore/Seattle criteria and has a later onset, a lower peak bilirubin, and better survival than VOD/SOS in patients with myeloablative conditioning.•VOD/SOS after RIC is strongly associated with higher-dose busulfan (6.4 versus 3.2 mg/kg) in the RIC regimen and use of sirolimus in the graft-versus-host disease prophylaxis regimen.