Abstract 4057: T cells co-expressing a highly potent NY-ESO-1-specific TCR and a chimeric PD1-41BB co-stimulatory switch receptor show a favorable polyfunctional profile for the treatment of solid tumors
Authors: Coluccio Andrea , Tippmer Stefanie , Prinz Petra , Buerdek Maja , Mutze Kathrin , Loesch Barbara , Davari Kathrin , Longinotti Giulia , Schendel Dolores J. 
Published: April 2023

Abstract
T cell receptor (TCR)-based immunotherapies have shown great potential for the safe and efficacious treatment of patients suffering from various solid malignancies. However, novel strategies are needed to overcome the immunosuppressive tumor microenvironment (TME) and to enhance the efficacy of TCR-T cell (TCR-T) therapies in solid tumors. NY-ESO-1 is a cancer/testis antigen that is highly expressed in various solid tumor indications while its expression in healthy tissues is restricted to male germ cells. Our HLA-A2-restricted, NY-ESO-1-specific TCR used here was selected from a non-tolerized T cell repertoire of a healthy donor using Medigene’s proprietary Allo-HLA TCR priming technology and high-throughput TCR isolation and characterization processes. To prevent inhibition of TCR-T cell function via the PD1-PDL1 axis within the TME, the NY-ESO-1-TCR was co-expressed with a chimeric PD1-41BB co-stimulatory switch receptor, consisting of the extracellular domain of PD1 and the intracellular domain of the 41BB co-stimulatory receptor. Thereby, an inhibitory signal from the PD1-PD-L1 axis is turned into a co-stimulatory one, which results in a dual mechanistic benefit, and superior TCR-T cells with respect to tumor cell killing, cell proliferation and poly-cytokine secretion. Co-expression of PD1-41BB on NY-ESO-1 TCR-T cells led to a 3-fold increase in IFN-γ release and a higher proliferation index (~1.5 fold) (after antigen encounter. Under conditions of repeated antigen exposure in vitro using HLA-A2/NY-ESO-1/PDL1-positive tumor spheroids, TCR-T cells co-expressing PD1-41BB showed enhanced functional activities compared to TCR-T cells carrying the TCR alone. In vitro single-cell secretome analyses demonstrated up to a 5-fold increase in polyfunctional T cells and a higher polyfunctional strength index (PSI) for NY-ESO-1 TCR-T cells expressing PD1-41BB compared to “naked” NY-ESO-1 TCR-T cells lacking PD1-41BB. Typical Th1 cytokines/proteins like IFN-γ, TNF-α and Granzyme B mainly contributed to the superior PSI of NY-ESO-1-TCR-T cells co-expressing PD1-41BB. Importantly, our data indicate that transgenic PD1-41BB has the capacity to provide a co-stimulatory signal despite the presence of endogenous PD1 which is upregulated in stimulated “naked“ NY-ESO-1 TCR-T cells. In summary, we find that co-expression of a chimeric PD1-41BB co-stimulatory switch receptor significantly enhances in vitro NY-ESO-1 TCR-T cell proliferation, functionality and anti-tumor activity. Analyses of single-cell T cell cytokine polyfunctionality helped us to unravel the mode of action of NY-ESO-1 TCR-T cells co-expressing PD1-41BB and point to their complex display of effector, stimulatory and chemoattractant cytokines as a potential driver for superior recognition of tumor cells.
Citation Format: Andrea Coluccio, Stefanie Tippmer, Petra Prinz, Maja Buerdek, Kathrin Mutze, Barbara Loesch, Kathrin Davari, Giulia Longinotti, Dolores J. Schendel. T cells co-expressing a highly potent NY-ESO-1-specific TCR and a chimeric PD1-41BB co-stimulatory switch receptor show a favorable polyfunctional profile for the treatment of solid tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4057.