Glofitamab-Associated Immune Effector Cell-Associated Neurotoxicity Syndrome (ICANS) Presenting as Serial Seizures and Responding Positively to Antiseizure Drugs and Anakinra: A Case Report.

Immune effector cell-associated neurotoxicity syndrome (ICANS) is a well-known side effect of chimeric antigen receptor (CAR) T-cell therapy but has occasionally been described with immune checkpoint inhibitors as well. Glofitamab-associated ICANS with a bispecific monoclonal antibody has rarely been reported. The patient is a 63-year-old male with a history of mantle cell lymphoma, diagnosed at age 37, and aggressive large-cell B-cell lymphoma, diagnosed at age 50. Despite adequate chemotherapy, immunotherapy, autologous stem cell transplantation, and CAR T-cell therapy, there were several relapses, including meningeal carcinomatosis at age 61 and intracerebral lymphoma at age 62. For this reason, glofitamab was started. One week after the ninth cycle, the patient developed drowsiness, behavioral changes, word-finding difficulties, aphasia, focal to bilateral tonic-clonic seizures, and focal onset seizures, which resolved after 16 days with levetiracetam, valproic acid, lorazepam, and midazolam. Since there was no infectious disease, electrolyte disturbance, metabolic disorder, cardiovascular disease, or relapse of lymphoma, glofitamab-associated ICANS was suspected, and anakinra was administered. The case shows that ICANS with drowsiness, behavioral changes, aphasia, and seizures can develop with glofitamab and that patients with structural brain abnormalities may be prone to this.