Neurotoxicity-associated sinus bradycardia after chimeric antigen receptor T-cell therapy

The advent of chimeric antigen receptor (CAR) T-cell therapy has changed the therapeutic landscape of relapsed/refractory aggressive B-cell lymphomas. Cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome (ICANS) are the typical adverse events associated with this therapy. Cardiovascular toxicities have also been reported in this setting. However, there is scarce data regarding the development of sinus bradycardia after CAR T-cell therapy. Here, we detail the clinical course of 4 patients with aggressive B-cell malignancies who received CAR T-cells and developed transient and reversible sinus bradycardia in the context of ICANS. We also discuss several hypotheses behind the pathophysiology of this potential new adverse event.