Sequencing analysis of CAR T cell products and apheresis cells in DLBCL patients treated with tandemCAR-T cell
In this study, 58 r/r DLBCL patients treated with tandem CD19/CD20 CAR T cells. Twenty-seven patients had durational responses for more than 24 months, and the median PFS was 21.7 months. But 15 patients still did not have an objective response, and 11 patients relapsed within 1 year. The analysis found that CD8+TSCM cells with higher frequency and stronger activation ability in CART products were the key to achieving clinical sustained objective response.   Bulk RNA-Seq and single-cell RNA-Seq then were performed on CAR-T cell products and pre-manufacture T cells of patients with DLBCL. We note that a CD8+ stem cell-like memory T cell population with a higher proportion and stronger activating capacity of the CAR-T cell products was key to achieving durable clinical response. By analyzing 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 accompanied by 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. Overall design: To perform an in-depth characterization of the outcome-associated CAR-T cell populations, we then employed droplet-based 5' scRNA-seq  sequencing to profile a set of infused CAR-T cells and pre-manufacture T cells from 3 DR and 3 resistant patients.