Caution: inotuzumab before transplant (veno-occlusive disease)

This caution pairing concerns inotuzumab ozogamicin, the CD22 antibody-drug conjugate, used as a bridge to allogeneic stem cell transplantation in acute lymphoblastic leukaemia. Its calicheamicin payload damages the hepatic sinusoidal endothelium, which is then further injured by conditioning chemotherapy, and the result can be severe veno-occlusive disease after transplant. In INO-VATE a substantial fraction of patients who proceeded to transplant developed veno-occlusive disease, and the risk rises with more than two cycles of inotuzumab, dual-alkylator conditioning and prior hepatic injury; the label carries a boxed warning. Current guidance is to limit inotuzumab to two cycles before transplant, avoid busulfan-thiotepa conditioning, and consider defibrotide prophylaxis.