Recurrent Status Epilepticus in the Setting of Chimeric Antigen Receptor (CAR)-T Cell Therapy

Axicabtagene ciloleucel (AC) is an FDA-approved anti-CD19 autologous chimeric antigen receptor T-cell (CAR-T) therapy for refractory diffuse large B cell lymphoma (DLBCL). While its efficacy in DLBCL has been promising, neurotoxicity remains a significant concern. We present a case of a 22-year-old woman with chemotherapy-refractory DLBCL who exhibited Grade IV neurotoxicity in the setting of sepsis, after undergoing AC infusion. Despite prophylactic levetiracetam given per guidelines,(1,2) she experienced a precipitous mental status decline on post-infusion day 8 (D8) followed by hypoxic respiratory failure in the setting of clinical status epilepticus on D11 and nonconvulsive status epilepticus (NCSE) on D18. While neuroimaging was unremarkable, EEG demonstrated diffuse slowing and 2.5-3 Hz generalized periodic discharges consistent with NCSE. Seizures were initially refractory to lorazepam, increasing doses of levetiracetam, and phenobarbital, requiring a midazolam drip titrated to 50-70% burst suppression for resolution. Methylprednisolone and tocilizumab were used to treat neurotoxicity and cytokine release syndrome, respectively. Empiric antibiotics were used for sepsis. After cessation of sedatives on D19, mental status improved to near baseline. PET/CT just prior to discharge showed a complete response of the DLBCL (Deauville 3). She was discharged on D37 with no further seizure activity. Unfortunately, a 3-month interval PET/CT demonstrated disease progression which continued through salvage pembrolizumab eventually leading to death 1.2 years post-CAR-T infusion. This case illustrates the clinical management challenges of a complex and rare neurotoxic side effect of CAR-T cell therapy, namely NCSE following status epilepticus.