Abstract LB-379: Dominant negative PD1 armored CAR-T cells induce remission in relapsed or refractory non-Hodgkin lymphoma (NHL) patients

Abstract

Abstract The chimeric antigen receptor (CAR) T cell treatment has been demonstrated as an effective therapy to treat relapsed/refractory B cell malignancy. However, tumor microenvironment influences and affects the efficacy of CAR T treatment. For example, programmed death ligand 1/2 (PDL1/2) may inhibit the CAR T cells via interaction with up-regulated programmed cell death protein 1 (PD1) after T cells activation, suppressing the tumor-killing capability of the CAR T cells. Thus, blockade of the PD1-PDL1/2 interaction may enhance the anti-tumor efficacy of CAR T therapy.Here, we generated CAR T expressed an anti-CD19 CAR molecule and a dominant-negative PD1 molecule. Compared with conventional CART cells, these “armored” CART cells showed the enhanced capability of tumor-killing and more “memory-like” phenotypes after multiple-round tumor challenging. These results suggest dominant-negative PD1 molecules may protect CART cells from exhaustion in the tumor microenvironment.Further, we reported the findings of a clinical trial for six relapsed or refractory B-cell non-Hodgkin lymphoma (NHLs) patients treated using our armored CAR T cells. These six patients failed multiple rounds of chemotherapy and radiotherapy. In the clinical trial, the patients were infused with autologous CAR T cells range from1×106/kg to 8×106/kg. PET/CT showed significant tumor shrinkage and SUV max declines in all six patients, and the ongoing responses were monitored. The best overall response rate (ORR)was 100%. Conclusion: The results of these six patients in the clinical trial showed that our armored CAR T cells achieved the significant anti-bulky lymphoma response while causing limited and tolerated cytokine release syndrome and central nervous system toxicity. Thus, dominant-negative PD1 molecules may increase CAR T cells persistence in patients, enhancing the efficacy of CAR T cells for treating blood cancer. Finally, dominant-negative PD1 can be used as a platform technology and may be applied to other adoptive cellular immunotherapies such as TCR-T or TIL in the treatment of solid tumors. We are continuing to monitor current patients and recruit more patients for the clinical trial. Citation Format: Yan Yuan, Liansheng Huang, Yang Su, Chengfei Pu, Tianling Ding, Xibin Xiao, Lina Jin, Zhiyuan Cao, Ting Wu, Tong Chen, Luying Ding, Xiaohong Zhang, Haifeng Lan, Zhao Wu, Lei Xiao. Dominant negative PD1 armored CAR-T cells induce remission in relapsed or refractory non-Hodgkin lymphoma (NHL) patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-379.