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.