Indolent CD4+ CAR T-Cell Lymphoma after Cilta-cel CAR T-Cell Therapy.

Indolent CD4+ cytotoxic chimeric antigen receptor (CAR) T-cell lymphoma involving the small intestine was diagnosed in a patient who had previously received ciltacabtagene autoleucel (cilta-cel) CAR T-cell therapy for treatment of myeloma. Targeted messenger RNA sequencing revealed the presence of CAR gene product in tumor cells. Whole-genome sequencing of samples of tumor and peripheral blood identified a single lentiviral insertion site within the second intron of the gene. In addition, numerous genetic alterations that may have contributed to malignant transformation were identified in the tumor sample. (Funded by MedStar Georgetown University Hospital.).