(497b) Modeling and Manufacturing Methods for Downsizing a Centrifugal Bioreactor for Use in Cancer Immunotherapy

In the fight against cancer, it is of major interest to shift treatments to targeted, systemic therapies such as immunotherapy, in which we harness the power of our own immune systems. With cell-based therapies, though, rapid expansion of cell cultures that maintain phenotypic activity is necessary to achieve the high cell requirements per treatment. Over the years, our group has produced a centrifugal bioreactor (CBR) system that can be used for a number of applications including suspension and anchorage-dependent cell culture, but we are particularly interested in using it to manufacture cytotoxic T lymphocytes (CTLs) for cancer immunotherapy. It is a modified COBE Spectra (now Terumo BCT) blood apheresis system, where the centrifugal force and fluid forces are balanced to act similarly to a fluidized bed and maintain high cell densities in the reactor chamber. In addition to the forces acting within the reactor chamber, the CBR’s ability to produce high-density cultures is also due to operating in perfusion mode, which allows the cells to be continuously refreshed with medium and nutrients. In previous work, the CBR has been used to rapidly expand cultures up to 2 x 10⁸ cells/mL in an 11.4 mL chamber over the course of 7 days. Currently, the CBR is at a larger scale than ideal, as half of the system exists outside of a biosafety cabinet, and a major issue in using the CBR for T cell expansion is the numerous sources for potential contamination. While the current system does work with careful technique, we have shifted our recent efforts to miniaturizing the bioreactor to fit within a biosafety cabinet. Various combinations of the cell chamber volume, rotor disc radius, centrifugal force, and feed flow rate can be modeled to determine optimal parameters for maintaining fluidization. In this presentation, we will share mathematical modeling for downscaling this centrifuge-based bioreactor and manufacturing methods for the prototype system.