Decade-long persistence of CD19 CAR T cells in B cell lymphomas

Chimeric antigen receptor (CAR) T cell therapy induces durable remissions in lymphoid malignancies, yet the extent and biology of long-term CAR T cell persistence in B cell lymphoma remain unclear. Here we report the persistence and characteristics of 4-1BB-costimulated anti-CD19 CAR T cells (CART19) up to 10 years after infusion in 38 patients with non-Hodgkin lymphoma. Beyond year five, the CAR19 transgene was detectable in five of eight long-term responders (7.0-10.1 years), with three patients maintaining B cell aplasia, which is consistent with sustained functional activity. In one patient with a progression-free survival of 10.1 years, CART19 cells comprised 1.2% of circulating T cells 9.3 years after infusion. Long-term persisting CART19 cells exhibited a predominant double-negative (CD4^-CD8^-), effector-memory-like phenotype associated with increased aerobic metabolism and T cell activation programs. Longitudinal profiling revealed a progressive transition from CD8⁺ to double-negative CAR T cells over time. Persisting CART19 shared transcriptional features with long-term CAR T cells described in acute and chronic leukemias. T cell receptor sequencing demonstrated oligoclonal persistence at 9.3 years, with a dominant clone (70% of CART19 cells) already detectable at low frequency (<0.1%) at day 14. Lentiviral integration-site analysis identified a predominant integration within PACS1 without evidence of known drivers of CAR T cell expansion. These findings demonstrate that CART19 cells can persist for more than 10 years in lymphoma and identify phenotypic, transcriptional and clonal features associated with exceptionally long-term persistence. ClinicalTrials.gov registration: NCT02030834.