Sinusoidal Obstruction Syndrome With Inotuzumab Ozogamicin Combined With Ponatinib for Philadelphia‐Chromosome‐Positive Lymphoblastic Malignancies

Introduction Sinusoidal obstruction syndrome, also known as veno‐occlusive disease (SOS/VOD), can occur after exposure to inotuzumab ozogamicin (InO), a calicheamicin‐based antibody‐drug conjugate. Case Presentation We experienced two cases of SOS/VOD after treatment with InO combined with intermittent administration of ponatinib without hematopoietic stem cell transplantation for Philadelphia‐chromosome‐positive (Ph+) lymphoblastic malignancies. Both cases developed SOS/VOD after two courses of InO. Ultrasound scoring system and pathological assessment were useful for diagnosis of SOS/VOD. Conclusion This is the first report warning of the potentially high risk of developing SOS/VOD with the combination of InO and ponatinib, both of which can induce endothelial cell damage. Trial Registration The authors have confirmed clinical trial registration is not needed for this submission