Cyclophosphamide for the treatment of refractory immune effector cell-associated neurotoxicity syndrome following CD19-targeted CAR T-cell therapy

A case study of a 51-year-old male with relapsed/refractory Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia who developed grade 4 immune effector cell-associated neurotoxicity syndrome (ICANS) following brexucabtagene autoleucel CAR T-cell therapy. Because the patient’s neurotoxicity was refractory to high-dose corticosteroids, anakinra, and intrathecal chemotherapy, he received low-dose cyclophosphamide. The patient achieved full neurological recovery, warranting further investigation into earlier, lower-dose cyclophosphamide as a strategy to mitigate ICANS.