Baseline Immune State and T cell Clonal Kinetics are Associated with Response to CAR-T Therapy in Large B-cell Lymphoma

Engineered cellular therapy with CD19-targeting chimeric antigen receptor T-cells (CAR-T) has revolutionized outcomes for patients with relapsed/refractory Large B-Cell Lymphoma (LBCL), but the cellular and molecular features associated with response remain largely unresolved. We analyzed serial peripheral blood samples ranging from day of apheresis (day -28/baseline) to 28 days after CAR-T infusion from 50 patients with LBCL treated with axicabtagene ciloleucel (axi-cel) by integrating single cell RNA and TCR sequencing (scRNA-seq/scTCR-seq), flow cytometry, and mass cytometry (CyTOF) to characterize features associated with response to CAR-T. Pretreatment patient characteristics associated with response included presence of B cells and increased lymphocyte-to-monocyte ratio (ALC/AMC). Infusion products from responders were enriched for clonally expanded, highly activated CD8+ T cells. We expanded these observations to 99 patients from the ZUMA-1 cohort and identified a subset of patients with elevated baseline B cells, 80% of whom were complete responders. We integrated B cell proportion and ALC/AMC into a two-factor predictive model and applied this model to the ZUMA-1 cohort. Estimated progression free survival (PFS) at 1 year in patients meeting one or both criteria was 65% versus 31% for patients meeting neither criterion. Our results suggest that patients’ immunologic state at baseline affects likelihood of response to CAR-T through both modulation of the T cell apheresis product composition and promoting a more favorable circulating immune compartment prior to therapy. These baseline immunologic features, measured readily in the clinical setting prior to CAR-T, can be applied to predict response to therapy. PBMC samples were collected at day of apheresis (~day -28) and at days +7 and +14 post-treatment. Infusion products were collected by rinsing the infusion bag. Samples were analyzed with CITE-seq and scTCR-seq. ***Submitters state that raw data is available through dbGaP (phs002922.v2)***