Abstract 5254: The “off-the-shelf ”CD19-CAR-Vδ1T cells demonstrated an enhanced therapeutic effect on B-cell malignancy models
Authors: Chen Dan , You Fengtao , Chen Cheng , Xiang Shufen , Zhang Ping , Wu Hai , Zheng Zhong , Wang Min , Wang Xingbing , Meng Huimin , Yang Nan , Zhang Bozhen , Yang Lin 
Published: March 2024

Background: The commercialization of autologous chimeric antigen receptor T cell (CAR-T) is hindered by the expensive and time-consuming manufacturing process, presenting major challenges. The development of allogeneic products is proposed as an alternative strategy to overcome these obstacles. Vδ1T cells, possessing active homing capability, are known to infiltrate tumor tissues and have been linked with favorable patient prognosis due to their direct killing effect via innate immunity and their sensitive T cell receptors that can broadly recognize tumor antigens. Unlike conventional αβ T cells, Vδ1 TCRs are not restricted by major histocompatibility complexes (MHCs), thus preventing the development of graft-versus-host disease (GVHD). Therefore, Vδ1T cells were hypothesized to be a superior candidate for universal CAR-T cells. Nevertheless, the small portion of Vδ1T cells (less than 1%) in peripheral blood posts a significant challenge for CMC and production. Here we present the successful development of CD19-CAR-Vδ1T cells, which demonstrate enhanced therapeutic efficacy on B-cell malignancy models.

Methods: High-purity CD19-CAR-Vδ1T cells were prepared using PersonGen's proprietary platform technology. Multiple CAR structures were tested for cytotoxicity, and the fourth-generation CAR-transduced Vδ1 cells designated as UTAA09 exhibited sustained killing of CD19+ target cells. UTAA09 underwent in-depth research regarding its anti-tumor efficacy and safety.

Results: The Vδ1T cell purity exceeded 95%, while the residual TCRαβ count remained under 1%. The CAR transduction efficiency remained stable across batches, with medium CAR+~30%, and up to 2×1011 UTAA09 cells were harvested in compliance with GMP standards. The presence of secreted IL-2 significantly increased the persistence of UTAA09 in vitro, and UTAA09 showed comparable anti-tumor activity and expansion rates to CD19-CAR-αβT cells. Notably, no exhaustion phenotype was detected for UTAA09 after multiple antigen stimulation processes. Moreover, UTAA09 lacked detectable IL-17A, indicating a non-promoting characteristic in tumor growth. In the xenograft model, significant inhibition of tumor growth was observed in all mice, of which 40% achieved long-term disease-free survival (p&lt;0.01) . On days 5, 12, and 19 after the administration of UTAA09, Vδ1T cells underwent significant expansion in all 5 mice tested. Subsequent analysis confirmed that the majority of these expanded Vδ1T cells were CAR+ cells, indicating the specific and long-lasting expansion of CD19-CAR+ Vδ1T cells in vivo. Importantly, none of the mice experienced significant weight loss, demonstrating the safety and outstanding in vivo effectiveness of UTAA09.

Conclusion: UTAA09 shows potential as an off-the-shelf allogeneic cellular therapy for the treatment of B-cell malignancies and autoimmune diseases derived from B cells.

Citation Format: Dan Chen, Fengtao You, Cheng Chen, Shufen Xiang, Ping Zhang, Hai Wu, Zhong Zheng, Min Wang, Xingbing Wang, Huimin Meng, Nan Yang, Bozhen Zhang, Lin Yang. The “off-the-shelf ”CD19-CAR-Vδ1T cells demonstrated an enhanced therapeutic effect on B-cell malignancy models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5254.