Exploring the High-Grade and Refractory Neurotoxicity of Teclistamab: An Underreported Entity.

T-cell re-directing bispecific antibodies targeting B-cell maturation antigens have recently entered real-world use in relapsed/refractory multiple myeloma. While no head-to-head comparison has been done, they have generally been observed to have lower-grade toxicities compared with their chimeric antigen receptor T-cell (CAR-T) counterparts. However, in our real-world, single-institution experience, we have encountered two patients receiving teclistamab who experienced high-grade and refractory immune effector cell-associated neurotoxicity syndrome (ICANS) that did not respond to traditional toxicity mitigation strategies of high-dose corticosteroids or other immunosuppressive therapies. As we increase our use of these novel and vital agents, caution must be warranted.