Abstract 884: Development of allogeneic persistence-enhanced PB-derived NK cells in treating solid tumors
Authors: Chao Wang, Tingting Liu, Qin Wang, Yanxue Gong, Fanxiang Gao, Feng Zhou, Zhuoxiao Cao
Journal: Cancer Research (2025)

Abstract Although chimeric Antigen Receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach to fight cancers, the utilization is limited due to safety concerns such as serious cytokine release syndrome, neurotoxicity, or graft-vs-host-disease. Natural killer (NK) cells can be derived from multiple sources and scaled manufactured as an off-the-shelf product likely with fewer toxicities. While NK cell therapies have been demonstrated to elicit clinical efficacy against hematopoietic malignancies, many challenges exist including issues related to cell persistence, overcoming the immunosuppressive microenvironment, and optimizing specific cytotoxic efficiency. To address those challenges, we used a single retroviral vector to engineer peripheral blood (PB) derived NK to express: soluble IL15 armor for proliferation and activation, a non-cleavable CD16 with high affinity to Fc receptor to enhance ADCC response, alloimmune defense receptor (ADR) targeting alloreactive T cells to overcome host immune cell-mediated rejection. Our preclinical results demonstrated the multiplexed engineered PBNK (eNK) showed improved persistence, resistance to allorejection, as well as anti-tumor efficacy. To evaluate ADRs functions, both anti-rejection CD5 and CD70 ADRs expressing eNK were generated and characterized. eNK with CD5 ADR displayed comparable phenotype and expansion to non-transduced NK, whereas eNK with CD70 ADR showed significantly aberrant growth due to CD70-mediated fratricide. eNKs with CD5 ADR demonstrated better persistence and enhanced tumor cells killing when cocultured with tumor cells and allogeneic T cells in a mixed lymphocyte reaction, compared to eNK cells without CD5 ADR or eNK with CD70 ADR. To determine whether non-cleavable CD16 and IL15 engineering could improve eNK proliferation and ADCC, serial re-stimulation in vitro cytotoxicity assays (luciferase-/RTCA-based) were performed in the presence and in the absence of Cetuximab, at a 1:2 E:T ratio. eNK plus Cetuximab showed more potent cytotoxicity against HCT116 colon cancer cells and NCI-H1975 lung cancer cells compared to non-transduced NK combo, eNK only and EGFR targeted CAR-NK cells. Using different xenograft mouse models, we demonstrated eNKs combined with therapeutic antibodies could performed superior tumor inhibition and extended NK persistence. Taken together, these results supported the development of allogeneic PB-derived NK cell therapies armoring with soluble IL15, non-cleavable CD16 and anti-allorejection ADR, and demonstrated the efficacy and safety of eNK mono and combination treatments, significantly enhancing their therapeutic potential in clinical settings. Citation Format: Chao Wang, Tingting Liu, Qin Wang, Yanxue Gong, Fanxiang Gao, Feng Zhou, Zhuoxiao Cao. Development of allogeneic persistence-enhanced PB-derived NK cells in treating solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 884.