Impact of Tumor Microenvironment on Efficacy of CD19 CAR T-Cell Therapy or Chemotherapy and Transplant in Large B-Cell Lymphoma

The phase 3 ZUMA-7 trial in second-line large B-cell lymphoma demonstrated superiority of anti-CD19 CAR T-cell therapy (axicabtagene ciloleucel; axi-cel) over standard of care (SOC; salvage chemotherapy followed by hematopoietic transplantation). Here, we present a prespecified exploratory analysis examining the association between pretreatment tumor characteristics and the efficacy of axi-cel versus SOC. B-cell gene expression signature (GES) and CD19 expression significantly associated with improved event-free survival (EFS) for axi-cel (P=.0002 for B-cell GES; P=.0165 for CD19 expression) but not SOC (P=.9374 for B-cell GES; P=.5526 for CD19 expression). Axi-cel showed superior EFS over SOC irrespective of B-cell GES and CD19 expression (P=8.56e–9 for B-cell GES high; P=.0019 for B-cell GES low; P=3.85e–9 for CD19 gene high; P=.0017 for CD19 gene low). Low CD19 expression in malignant cells correlated with a tumor GES consisting of immune suppressive stromal and myeloid genes, highlighting the inter-relation between malignant cell features and immune contexture substantially impacting axi-cel outcomes. Tumor burden, lactate dehydrogenase, and cell-of-origin impacted SOC more than axi-cel outcomes. T-cell activation and B-cell GES, which are associated with improved axi-cel outcome, decreased with increasing lines of therapy. These data highlight differences in resistance mechanisms to axi-cel and SOC and support earlier intervention with axi-cel. 256 pretreatment tumor biopsies were analyzed, 134 from the Axicabtagene Ciloleucel arm and 122 from the Standard of Care Chemotherapy arm