Characteristics of premanufacture CD8(+) T cells determine CAR-T efficacy in patients with diffuse large B-cell lymphoma

Although chimeric antigen receptor (CAR) T cells have become an important treatment option for patients with relapsed/refractory B-cell malignancies, more than 60% of patients with diffuse large B-cell lymphoma (DLBCL) treated with CAR-T cell therapies fail to achieve a durable response. To reveal changes in CAR-T cell therapy and identify response biomarkers, we conducted a retrospective analysis of pre-manufacture source T cells and CAR-T cell products and their association with outcome in 58 patients with r/rDLBCL who received tandem CD19/CD20 CAR-T cell therapy. We performed bulk RNA-Seq, single-cell RNA-Seq, and paired T cell receptor sequencing on CAR-T cell products and pre-manufacture T cells from DLBCL patients. We note that a CD8(+) stem cell-like memory T cell population with a higher proportion and enhanced activating capacity of the CAR-T cell products was key to achieving durable clinical response. By analysing autologously-derived, pre-manufacture T cells, our data suggest that heterogeneity in the cellular and molecular features of pre-manufacture T cells contribute to the variation in efficacy after CAR-T cell therapy in DLBCL. The differences in anti-tumour efficacy of CAR-T cells among patients with different clinical outcomes appear to be due to the loss of CCR7 gene expression, coupled with increased expression of activation- and inhibitor-related genes in the CD8(+) naïve-T cell populations among the apheresis T cells from patients with a poor molecular response. These findings significantly advance our understanding of the underlying molecular determinants of pre-manufacture T cell function.