The incidence of secondary primary malignancy after anti-CD19 chimeric antigen receptor (CAR) T-cell immunotherapy is very low, according to a study published online in Nature Medicine. Researchers describe a case of T-cell lymphoma (TCL) occurring three months after CAR T-cell immunotherapy for non-Hodgkin B-cell lymphoma, which was diagnosed from a thoracic lymph node identified at lung cancer surgery. To assess the overall risk of secondary primary malignancy after commercial CART, 449 patients treated at the University of Pennsylvania were reviewed. The researchers found that the CAR transgene was low, while the TCL exhibited CD8+ cytotoxic phenotype and a JAK3 variant. Before CART infusion, the T-cell clone was identified at low levels in the blood, and it was detected in the lung cancer. In the cohort of patients, 3.6% had secondary primary malignancy at a median follow-up of 10.3 months. For solid and hematological malignancies, the median onset time was 26.4 and 9.7 months, respectively. The projected five-year cumulative incidence was 15.2 and 2.3% for solid and hematological malignancies.