Abstract 888: Vδ1γδT-Cells: A unique allogeneic cell therapy platform for the treatment of a broad range of malignancies

Abstract

The treatment of haematologic malignancies with adoptive cell therapy is largely limited to platforms based on patient-derived, autologous αβ T cells. Although successful, this approach comes with challenges including associated toxicities, risk of relapse, high production costs and a requirement to gene edit cells to avoid graft vs host disease (GvHD) risk if the therapy is to be used in an allogeneic setting. In contrast to αβ T cells, human Vδ1 γδ T cells are a subset of T cells defined by expression of heterodimeric T cell receptors (TCRs) composed of a γ chain paired to a Vδ1 chain. Vδ1 γδ T cell function is highly differentiated from αβ T cells, as target cell recognition is not MHC restricted and γδ T cells are not alloreactive. Allogeneic matching of patients is therefore not required for Vδ1 γδ T cell therapeutic approaches. Instead Vδ1 T cells elicit direct anti-tumour responses via activation of diverse receptor repertoires that recognise multiple ligands upregulated on the surface of transformed cells. These key features of Vδ1 T cell biology therefore confer several advantages when generating an allogeneic cell therapy platform. We have developed a good manufacturing practice (GMP) compliant, scalable process to generate αβ T cell depleted, γδ T cell cultures (93.5% ± 3.7 of live), enriched for Vδ1 T cells (67.9% ± 2.2% of live). The cryopreserved therapeutic product shows good recoverability and proliferation after thawing, an activated innate phenotype and produces high levels of IFNγ and chemokines which can stimulate activation of other cells of the immune system. Post-thaw, Vδ1 T cell product has cytotoxic activity against a variety of malignant leukaemia and lymphoma cells in vitro and the cells home to the bone marrow and mediate anti-tumour activity following IV dosing in an in vivo xenograft model. Importantly, Vδ1 T cells have a good safety profile and do not mediate; cytotoxic activity against healthy tissues, mixed lymphocyte reactions or GvHD in in vivo models. Building on our expertise for expanding Vδ1 T cells, we have now developed scalable transient and stable gene engineering platforms for the generation of Vδ1 T cells expressing chimeric antigen receptors (CAR) and other molecules. Genetically engineered cells show good expansion kinetics and recoverability and viability post-cryopreservation. The cells also maintain a favourable activated phenotype post-thaw characterised by high levels of expression of CD27, NCR receptors (DNAM1, NKG2D and NKp30) and stable CAR expression at the cell surface. We have now used the Vδ1 CAR-T platform to develop and screen CAR constructs designed to generate allogeneic CAR-T cell therapies that exploit the unique safety and activity profile of Vδ1 T cells while additionally potentiating on-target tumour cell killing. Using this approach and tool constructs containing CARs targeting CD19, we have demonstrated potent and enhanced killing of a B-cell tumour cell line without eliciting on-target bystander killing of healthy B cells. In addition, the Vδ1 CAR-T anti-tumour activity is not associated with release of cytokines that may potentiate off-target toxicities. These data demonstrate that Vδ1 T cells have the potential to provide a unique CAR-T platform capable of targeting a broader cancer antigen profile than is possible for conventional CAR-T therapies. Citation Format: Istvan Kovacs, Andre Simoes, Tim Recaldin, Elizabeth Reynolds, Katharina Bergerhoff, Mihil Patel, Rebecca Alade, Victoria Hillerdal, Andrew Hutton, Daniel Fowler, Joanna Kawalkowska, Kalle Soderstrom, Valentino Parravicini, Michael Koslowski, Oliver Nussbaumer, Alice Brown. Vδ1γδT-Cells: A unique allogeneic cell therapy platform for the treatment of a broad range of malignancies [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 888.