Second primary malignancies after commercial CAR T-cell therapy: analysis of the FDA Adverse Events Reporting System.

Second primary malignancies were reported in 536 of 12 394 (4.3%) adverse event reports following chimeric antigen receptor T-cell therapies in the Food and Drug Administration Adverse Event Reporting System. Myeloid and T-cell neoplasms were disproportionately more frequently reported, warranting further follow-up.