Intrathecal Cytarabine and Hydrocortisone for the Early Treatment of ICANS in Patients Undergoing CAR T Therapy for Non Hodgkin Lymphoma

PRIMARY OBJECTIVE: I. Efficacy of IT therapy to reduce high-grade ICANS in participants who receive axi-cel in NHL compared to historical experience. SECONDARY OBJECTIVE: I. Impact of IT therapy on CAR T toxicities. II. Adverse events from IT therapy. III. Feasibility of IT therapy. IV. Impact of IT therapy on standard of care (SOC) manage (CRS) and ICANS. V. Impact of IT therapy on disease outcomes. VI. Impact of IT therapy on participants quality of life (QoL) OUTLINE: Patients receive standard of care cyclophosphamide based chemotherapy on day -5 to -3 and receive CAR T on day 0. Patients with grade 1/2 ICANS receive hydrocortisone and cytarabine IT along with standard of care dexamethasone or methylprednisolone. Patients with persistent or recurrent grade 1/2 ICANS receive hydrocortisone and cytarabine IT \> 48 hours after initial treatment and patients with ≥ grade 3 ICANS receive hydrocortisone and cytarabine IT \> 24 hours since initial treatment. Treatment is given in the absence of disease progression or unacceptable toxicity for a maximum of 2 treatments. Additional standard of care therapies may given if no improvement in 48 hours of IT therapy for grade 2 or 24 hours of IT therapy for grade 3/4 ICANS after discussion with study team. Patients undergo lumbar puncture for cerebrospinal fluid (CSF) collection on study and blood sample collection throughout the study.