Enrichment of CD7+CXCR3+ CAR T-cells in infusion products is associated with durable remission in relapsed or refractory diffuse large B-cell lymphoma

Abstract

Background: Chimeric antigen receptor (CAR) T-cell therapy is the standard of care for relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL). However, more than half of patients fail to achieve durable remission. Identifying predictive biomarkers within the CAR T-cell infusion product (IP) may guide strategies to improve clinical outcomes.

Patients and methods: This single-center observational study, conducted at Lausanne University Hospital (CHUV), Switzerland, analyzed IPs from 13 patients with R/R DLBCL who underwent standard-of-care CAR T-cell therapy. A 39-marker mass cytometry panel was used to compare phenotypic and functional markers between long-term responders (R) and nonresponders (NR). Unsupervised and supervised analytic approaches were applied to IP data, and longitudinal peripheral blood samples were collected over 30 days after infusion to track CAR T-cell subpopulation dynamics.

Results: At a median follow-up of 13.5 months, median progression-free survival (PFS) was 13.3 months [95% confidence interval (CI) 9.7-24.3 months] in R (n = 8) versus 3.5 months (95% CI 0.5-5.4 months) in NR (n = 5) (hazard ratio 56.67, 95% CI 7.3-439.3, P = 0.0001). A CD3⁺CXCR3⁺CD7⁺ CAR T-cell subpopulation-found in both CD4⁺ and CD8⁺ compartments-was significantly enriched in R. These cells showed increased expression of perforin, granzyme B, and NKG2D (restricted to CD8⁺ cells). In contrast, NR had a higher frequency of CXCR3⁺CD7⁺LAG3⁺ CAR T-cells. Surface expression of CD3, CD7, CXCR3, and NKG2D were higher in R, whereas LAG3, Ki67, and CD71 were elevated in NR. A predictive cut-off ratio of CD3⁺CXCR3⁺CD7⁺LAG3⁺CAR⁺ T-cells <0.83 and CD3⁺CXCR3⁺CD7⁺NKG2D⁺CAR⁺ T-cells >1.034 yielded a predictive accuracy of 0.92. Serum CXCL9 and CXCL10 concentrations did not differ between groups.

Conclusions: Enrichment of CD7⁺CXCR3⁺ CAR T-cells alongside elevated NKG2D expression in R, in contrast to higher LAG3 and CD71 in NR, emerged as potentially robust correlates of therapeutic outcome. Although derived from a small, hypothesis-generating cohort, these findings suggest that targeted analysis of IP composition may inform the development of biomarker-driven strategies to optimize CAR T-cell products and improve the likelihood of durable remission in R/R DLBCL.

Keywords: CD7; CD71; CXCR3; LAG-3; NKG2D; anti-CD19 CAR T cell infusion products.