CLIC-1901

We studied the efficacy and safety of the combined treatment with programmed cell death 1 (PD‐1) inhibitors and anti‐CD19 chimeric antigen receptor (CAR) T‐cell therapy and subsequent PD‐1 inhibitor maintenance treatment in patients with relapsed/refractory (R/R) diffuse large B‐cell lymphoma (DLBCL) and high tumor burden. Forty‐four R/R DLBCL patients with high tumor burden were enrolled in this study. The experimental group of 26 patients received combined therapy with PD‐1 inhibitors and anti‐CD19‐CAR T cells, while the control group of 18 patients received anti‐CD19‐CAR T‐cell therapy alone. The objective response rate (ORR) was 65.39% and 61.11% in the combination and control groups, respectively. The PD‐1 inhibitor maintenance therapy was selected for patients who achieved complete response or partial response in the combination therapy group. Progression‐free survival and overall survival rates in the combination group were higher than those in the control group 3 and 12 months after CAR T‐cell infusion. There was no significant difference in the grade of cytokine release syndrome or immune effector cell associated neurotoxic syndrome between the two groups. In the maintenance therapy group, only eight patients experienced grade 1 Common Terminology Criteria for Adverse Events (CTCAE) and three grade 2 CTCAE. Overall, we found that the ORR was not affected by the combination therapy with PD‐1 inhibitors and anti‐CD19‐CAR T cells. However, patients who had achieved the ORR might benefit from PD‐1 inhibitor maintenance therapy after combination therapy without increased side effects.