Immune Effector Cell-Associated Neurotoxicity Delayed Relapse After Chimeric Antigen Receptor T-Cell Therapy: A Case Report.

objectivesImmune effector cell-associated neurotoxicity syndrome (ICANS) is typically a monophasic condition with a variable onset after chimeric antigen receptor T-cell (CAR T-cell) therapy. We report an exceedingly rare case of late-onset ICANS relapse, highlighting challenges in its recognition and management.

methodsA patient receiving CAR T-cell therapy for large B-cell lymphoma was monitored for neurotoxicity. Clinical, neuroimaging, and laboratory evaluations were performed to assess symptom progression and guide treatment.

resultsThe first ICANS episode occurred 14 days after infusion, presenting as grade 4 ICANS with coma, requiring intubation and intensive care. The patient was treated with methylprednisolone and anakinra, resulting in full recovery. A second episode occurred on day 40, characterized by disorientation, confabulation, and focal seizures (grade 3 ICANS). Treatment with levetiracetam, anakinra, and dexamethasone led to resolution. DISCUSSION: This case highlights the potential for delayed ICANS relapse beyond typical time frames, underscoring the need for prolonged monitoring. These findings support a possible biphasic course of ICANS, warranting further research on its pathophysiology and optimal long-term management.