High-Dimensional Immunophenotyping Panel to Characterize Chimeric-Antigen-Receptor T Cells in Clinical-Trials

Adoptive cell immune therapy (ACT) using Chimeric Antigen Receptor T-cells (CAR-T) is an emerging treatment area for diseases such as advanced malignancies. The design of CAR-T therapies in hematology and solid tumors is becoming more elegant and increasingly complex. Hence, novel techniques are required to characterize the immunophenotyping of CAR-T cells.

Clinical trials with CAR-T therapies often use minimal color flow cytometry panels, which limits the identification of potentially relevant immune cell populations. Adopting advanced flow cytometry approaches such as spectral flow technology, by clinical trial laboratories provides opportunities for deeper phenotyping than has typically been done. Hence, we describe the development and validation of a robust, high-dimensional flow-based assay designed to follow the cellular kinetics and changes in the phenotype of the circulating CAR-T cells, providing insights into the treatment activity. At AstraZeneca, we used this high dimensional panel to support the autologous CAR-T cell programs for solid tumors.

In our presentation, we will walk the audience through the strategies and the challenges of the developing and validating the assays for the global CAR-T cells therapies platform. Broadly, these challenges are as follows.

In cell therapies, the material we have employed for assay development and validation before the study is potentially a poor surrogate for the material collected from patients on treatment.

1. Shifts in staining/ autofluorescence, its impact on analysis, and the strategies to address it.
2. CAR-T cells spiked into healthy control donors, which can trigger donor-specific T cell activation.
3. The stability of the samples and the tube type selection for CAR-T cells is essential.