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In CAR-T cell treatments, the patient鈥檚 blood cells are extracted, and the T-cells are isolated. These T-cells are exposed to a viral vector that integrates the coding sequence for a chimeric antigen receptor (CAR) that is specific for the kind of cells being targeted by the therapy. In 2017, two products gained FDA approval, including Novartis鈥檚 Kymriah and Gilead鈥檚 Yescarta to respectively treat B-cell acute lymphoblastic leukemia and B-cell non-Hodgkin lymphoma. An estimated 10-20% of CAR-T batches fail however due to slow growth rates of T cells during the ex-vivo expansion step of the CAR-T process.

For CART processing, clinical-scale T cell activation and expansion is typically done in reactors that are mixed (GE鈥檚 WAVE and Miltenyi鈥檚 Prodigy) and/or sparged with gas (Wilson Wolf鈥檚 G-rex). For micro-scale growth on a 96 well plate, which can be used as a scaled-down bioreactor for T cells, it is difficult to mix and sparge gas and so it is typically not done. The cell growth media generally include the addition of IL-2 anti-CD3 and anti-CD28 antibodies. With that, T cell expansion is usually conducted using beads conjugated to anti-CD3 and anti-CD28 antibodies, which induce a physiological response by binding to T cells to promote growth and proliferation.

Dr. Kelly's group is working on developing a properly scaled down 鈥渂ioreactor鈥� to improve processing of cell therapy products such as CART therapies. Preliminary work has shown the capabilities of nano-sized magnetic posts for providing mixing and improved oxygen transfer to T cells growing on 96 well plates, and how this can positively impact T cell growth at that microscale. In recent years, more and more pharmaceutical companies are moving toward semi-continuous and perfusion mode operations because they can produce higher cell concentrations more economically. Perfusion processes provide a constant environment for cells through continuous by-product removal and nutrient addition, while retaining the cells in the bioreactor. Dr. Kelly's lab is also focusing on developing more continuous CART processing, including perfusion-based bioreactors.