Abstract 5576: In vitro efficacy and safety studies to support engineered T cell therapies

Engineered T cell therapies such as Chimeric Antigen Receptor T cells (CAR-T) and T Cell Receptor (TCR) T cells have emerged as a promising cancer therapy. To date, four anti-CD19 CAR-T and one anti-BCMA CAR-T products have been approved by the FDA for the treatment of lymphoid 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 assay 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-encoded 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 efficacy and safety of T cell therapies using CAR-T cells targeting the Human Epidermal growth factor Receptor 2 (HER2) as a model system. 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 unwanted 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 efficacy, potency, specificity and safety to aid early-stage lead discovery, optimization and development, and to support Investigational New Drug applications. These assays are only a fraction of the End-to-End solution Charles River L