Neurotoxicity Prophylaxis With Intrathecal Dexamethasone and Simvastatin Post Axi-Cel

This trial gathers preliminary information on the potential effect of the combination of dexamethasone and simvastatin on treating Neurotoxicity (NT) in the patient population. The rate of patients completing all required study treatments and the rate of NT will be determined. Simvastatin 40 mg/day will be started at least 5 days prior to apheresis and will be continued until day +30 after infusion. Intrathecal dexamethasone 8 mg will be administered on days (related to CAR-T infusion) -1, +6, +13, (+/- 2 days). CSF samples (3 ml) will be collected at these time points. Peripheral blood samples of 4 ml will be collected on days -1, +1, +6, and +13. The care team will check weekly CK and LFTs to ensure safety of simvastatin. Patients who develop NT will be allowed to continue treatment if feasible along with standard of care management.