Abstract 4058: In vitro binding, efficacy and safety studies to support engineered T cell therapies

Abstract Engineered T cell therapies such as Chimeric Antigen Receptor (CAR) T cells and T cell receptor (TCR)-engineered T cells have emerged as a promising cancer therapy. To date, four anti-CD19 CAR-T and two anti-BCMA CAR-T products have been approved by the FDA for the treatment of hematological malignancies. Many more T cell therapy products are currently being explored, directed towards both liquid and solid tumors as well as for other clinical indications. High-quality and robust in vitro and in vivo assays are essential for the discovery and characterization of lead T cell therapy products. Furthermore, despite demonstrating therapeutically successful, the further development of T cell immunotherapies has been hindered by safety concerns. Selected target antigens might be expressed in healthy tissues or engineered T cells may non-specifically bind to antigens in healthy tissues, potentially resulting in severe side effects. In addition, the random integration of the CAR- or TCR-encoding DNA cassettes in the host cell genome has the potential risk of causing insertional mutagenesis and may contribute to oncogenic transformation of the T cells. The aim of this study was to develop several in vitro assays for the assessment of target cell binding, efficacy and safety of T cell therapies using CAR-T cells targeting the Human Epidermal growth factor Receptor 2 (HER2) as a model system. The z-Movi cell avidity analyzer was used to study the binding strength between the CAR-T cells and target tumor cells. Cytotoxicity co-culture assays were developed using increasing effector:target cells ratios and an impedance-based readout to quantify the viability of HER2-positive and -negative cancer cell lines in real-time, to confirm the activity and selectivity of the HER2-CAR-T cells. Furthermore, co-culture assays were also developed for a variety of primary or iPSC-derived healthy human cells (representing various tissues) to assess potential off-tumor effects of the HER2-CAR-T cells against healthy cells. In addition, an oncogenicity assay was developed to quantify the survival and proliferation of the HER2-CAR-T cells in the absence and presence of cytokines by flow cytometry, to determine whether the genomic editing of the T cells affected their cytokine-dependency. In conclusion, Charles River Laboratories developed several in vitro assays for the preclinical assessment of T cell therapy binding, efficacy, potency, specificity and safety to aid early-stage lead discovery, optimization and development, and to support Investigational New Drug (IND) applications. Charles River has the capabilities to support a full CAR/TCR program from inception to IND filing. Citation Format: Sophie Vermond, Benita Quist, Monique Hazenoot, Rene McLaughlin, David Cobeta Lopez, Namrata Jayanth, Folkert Verkaar, Omar Aziz, Maria LH Vlaming, Sabrina de Munnik, Gemma Moiset. In vitro binding, efficacy and safety studies to support engineered T cell therapies. [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 4058.