Abstract 4261: CD27 a new immuno-oncology target shaping innate and adaptive anti-tumor immune responses

Abstract CD27 is a member of the TNF-receptor superfamily, highly expressed on CD4+ and CD8+ T cells as well as on NK and NKT cells. It plays a key role on T cell proliferation and differentiation after stimulation with its ligand CD70. The co-stimulatory signal of CD27 on T cell is mediated via the NFκB pathway but also via the phosphatidylinositol 3 kinase and the protein kinase B. CD27/CD70 co-stimulation has the potential to boost immunity by T-cell activation, clonal expansion and enhanced differentiation into antigen specific cytotoxic and memory T cells. CD27/CD70 also influences the innate immune response via a direct activation of the NK cells and a subsequent secretion of interferon-gamma (IFN-γ). Therefore, CD27 signaling promotes cytotoxic T cell based anti-tumor immunity. With its central role in an immunological response, CD27 is a promising target for antitumor therapy. Previous works have demonstrated the efficacy of an agonistic CD27 antibody in controlling tumor growth and metastasis in different mice models including melanoma, renal cell carcinoma, breast cancer and lymphomas. This anti-tumor effect is mediated in part by an effective recruitment of IFN-γ producing CD8+ T cells within the tumor. Moreover, CD27 stimulation of Tumor Infiltrating Lymphocytes (TILs) can lower their threshold of activation and provide a broader repertoire of Ag-reactive T cells within the tumor. We have selected a lead therapeutic antibody from our library of 147 fully human anti-CD27 monoclonal antibodies generated in the Trianni mice. After confirming its binding potency and selectivity as well as its cross-reactivity with Non-Human Primate (NHP)-CD27 but not with the mouse-CD27, this lead candidate demonstrated strong agonistic proprieties. This was shown by its ability to induce a strong NFκB signal as well as to induce T cell proliferation and activation with secretion of pro-inflammatory cytokines. This antibody demonstrated agonistic proprieties without cross-linking confirming its potency. T cell activation observed after treatment with our anti-CD27 antibody only occurs in the presence of TCR engagement, preventing the risk of spontaneous activation of naïve T cells in vivo. The ability of our CD27 monoclonal antibody to increase an immune response was confirmed in a Mixed Lymphocyte Reaction assay with multiple donors. The role played by the NK cells and their activation via CD27 antibody was also demonstrated. To evaluate the anti-tumor functions of our lead antibody as a single agent or in combination with other immuno-therapies in vivo we have used human CD27 transgenic mice. We have demonstrated in the MB49 bladder tumor model as well as the EG7 thymoma model that our lead antibody induces a strong single agent anti-tumor activity and these tumors were totally controlled in combination with an anti-PD1 antibody. We are now analyzing the pharmacokinetic and pharmacodynamic of our antibody as well as its safety in a NHP model Citation Format: Thierry Guillaudeux, Yulia Ovechkina, Shaarwari Sridhar, David Peckham, Jessica Cross, Nathan Eyde, Emily Frazier, Neda Kabi, Remington Lance, Kurt Lustig, Mei Xu, Tarcha Eric, Shawn Iadonato. CD27 a new immuno-oncology target shaping innate and adaptive anti-tumor immune responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4261.