A Novel Approach for Quantifying the Pharmacological Activity of T-Cell Engagers Utilizing In Vitro Time Course Experiments and Streamlined Data Analysis

Abstract

CD3-bispecifc antibodies are a new class of immunotherapeutic drugs against cancer. The pharmacological activity of CD3-bispecifcs is typically assessed through in vitro assays of cancer cell lines co-cultured with human peripheral blood mononuclear cells (PBMCs). Assay results depend on experimental conditions such as incubation time and the efector-to-target cell ratio, which can hinder robust quantifcation of pharmacological activity. In order to overcome these limitations, we developed a new, holistic approach for quantifcation of the in vitro dose–response relationship. Our experimental design integrates a time-independent analysis of the dose–response across diferent time points as an alternative to the static, “snap-shot” analysis based on a single time point commonly used in dose–response assays. We show that the potency values derived from staticin vitro experiments depend on the incubation time, which leads to inconsistent results across multiple assays and compounds. We compared the potency values from the time-independent analysis with a model-based approach. We fnd comparably accurate potency estimates from the model-based and time-independent analyses and that the timeindependent analysis provides a robust quantifcation of pharmacological activity. This approach may allow for an improved head-to-head comparison of diferent compounds and test systems and may prove useful for supporting frst-in-human dose selection.