RecruitingPhase 2ProcedureIntrathecal Cytarabine, Methotrexate, and Hydrocortisone for the Prevention of High-Grade Chimeric Antigen Receptor T-Cell-Associated Neurotoxicity SyndromeThis phase II trial tests how well cytarabine (Ara-C), methotrexate, and hydrocortisone given between the spinal cord and the membranes that protect it (intrathecal \[IT\]) works in preventing high-grade immune effector-associated neurotoxicity syndrome (ICANS) in patients receiving chimeric antigen receptor (CAR) T-cell therapy. ICANS is a challenging complication of CAR T-cell therapy that causes neurological effects varying from mild headaches or temporary confusion to hallucinations, swelling in the brain, and seizures. Between 20%-70% of patients receiving CAR T-cell therapy show symptoms of neurotoxicity.