Novel Use of Extracorporeal Blood Purification for Treatment of Severe, Refractory Neurotoxicity After Chimeric Antigen Receptor T-Cell Therapy—A Case Report

Singbartl, Kai; Rosenthal, Allison; Leis, Jose; Patel, Bhavesh; Sen, Ayan

BACKGROUND: Chimeric antigen receptor T-cell therapies (CAR-T) are transforming the treatment of B-cell leukemias and lymphomas. Cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome represent common, potentially life-threatening toxicities from chimeric antigen receptor T-cell therapy treatment. CASE SUMMARY: We present a 53-year-old patient with primary refractory high-grade B-cell lymphoma who developed severe, refractory neurotoxicity following chimeric antigen receptor T-cell therapy but exhibited complete recovery after extracorporeal blood purification with CytoSorb (CytoSorbents, Monmouth Junction, NJ). Six days after chimeric antigen receptor T-cell therapy infusion, the patient developed cytokine release syndrome grade 3, prompting administration of dexamethasone and tocilizumab, a monoclonal antibody against the interleukin-6 receptor. His C-reactive protein levels started to decrease with tocilizumab and dexamethasone treatments. However, his ferritin levels continued to rise, and his interleukin-6 levels were above the upper detection threshold. Thirty-six hours later, the patient showed improved cytokine release syndrome but developed severe immune effector cell-associated neurotoxicity syndrome with predominant encephalopathy (grade 3) despite treatment with dexamethasone/methylprednisolone, tocilizumab, and anakinra. We therefore sought a rescue strategy to remove inflammatory mediators. Following emergency use authorization, we initiated extracorporeal blood purification with CytoSorb (CytoSorbents). Four-day extracorporeal blood purification resulted in complete resolution of immune effector cell-associated neurotoxicity syndrome and greater than 95% reduction in interleukin-6 levels without side effects. The patient was discharged home 10 days later with no signs of neurotoxicity or other secondary end-organ dysfunction. CONCLUSIONS: Our case represents the first reported, successful application of extracorporeal blood purification with CytoSorb (CytoSorbents) to treat severe, refractory neurotoxicity following chimeric antigen receptor T-cell therapy.