Intrathecal Chemotherapy As a Potential Alternative Treatment for Steroid-Refractory Immune Effector Cell-Associated Neurotoxicity Syndrome

Introduction

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment paradigm for patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) and other hematologic malignancies. However, its use is associated with serious adverse effects including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Severe ICANS can present with aphasia, mutism, somnolence, seizures, signs of increased intracranial pressure and rarely cerebral edema. Corticosteroids (CS) and IL-6 inhibitors are first line treatment for CRS and ICANS. Prolonged CS use has been associated with decreased over-all survival in CAR T-cell treated patients. Data on effective treatments for CART T-cell induced neurotoxicity is limited, especially in steroid-refractory ICANS. Blood-brain barrier (BBB) disruption and infiltration of myeloid and immune effector cells into the central nervous system are implicated in the pathogenesis of ICANS. This likely explains the role of intrathecal chemotherapy, which has been described in literature for treatment of steroid-refractory ICANS. Here, we report the outcomes of two patients with refractory DLBCL who developed severe ICANS after receiving axicabtagene ciloleucel (axi cel) and treated with intrathecal (IT) chemotherapy.

Case Presentation

Our first case is of a 66 year old male with diagnosis of R/R DLBCL, who was treated with R-CHOP, followed by R-GemOx, with no response then received axi cel. Patient developed grade 2 CRS and grade 1 ICANS (National Cancer Institute Common Terminology Criteria for Adverse Effects v4.03) on day +2 post infusion, treated with tocilizumab and dexamethasone with good response initially. While tapering dexamethasone on day +5, he developed grade 3 CRS and grade 3 ICANS. Brain MRI did not show any intracranial abnormality and EEG showed no seizure activity. Lumbar puncture (LP) was done on day +7 and showed opening pressure of 32 cm H2O, and 12 lymphocytes. He was started on IV solumedrol and tocilizumab was resumed. CRS improved while neurotoxicity progressed to grade 4 prompting intubation and mechanical ventilation on day +8. On day +9, patient received intrathecal methotrexate 12 mg and hydrocortisone 50 mg. On day +12, neurotoxicity improved to grade 1 and patient was extubated on day +13. Steroid taper stopped on +17. Despite disease response, patient remained hospitalized at day +45 for deconditioning and vocal cord paralysis related to a lengthy hospital stay and intubation. He was eventually discharged, however passed away on day +49 from complications of prolonged hospitalization.

Our second case is of a 69 year old female with a diagnosis of R/R DLBCL with CNS involvement, treated with RCHOP x6 followed by salvage chemotherapy with refractory disease, She then received axi cel. Patient developed grade 1 CRS on day +4, treated with tocilizumab and dexamethasone, and patient responded well. On day +9, she developed grade 2 CRS and grade 3 ICANS. At that time, dexamethasone was switched to pulse dose solumedrol and tocilizumab was continued. CT head showed no acute intracranial abnormality and EEG did not show any epileptiform activity. LP showed opening pressure of 21, and 84 lymphocytes. On day +11, patient's CRS resolved, however ICANS developed to grade 4 and patient received 12 mg intrathecal methotrexate and hydrocortisone 50 mg for steroid-refractory ICANS. The very next day, patient showed significant neurological improvement. Steroid taper was initiated and patient's ICANS resolved on day +16. MRI brain showed decrease in size of nodular enhancement along periventricular white matter and left occipital area corresponding to treatment response. She was discharged on day +28 and continues to do well one year out of axi cel infusion

Conclusion

Our abstract adds to the sparse literature about the use IT chemotherapy in cases with severe ICANS. It also highlights its importance as an alternative potential therapy to high doses and prolonged courses of corticosteroids which is associated with increased morbidity and mortality. Steroid-refractory ICANS has limited treatment options and further evaluation of the use of IT chemotherapy in large scale studies is warranted.