Scale up of allogeneic cell therapy manufacturing in single-use bioreactors: Challenges, insights and solutions

Background & Aim Many allogeneic cell therapy drug candidates are getting closer to commercialization. However, lack of a scalable manufacturing platform to meet commercial demands could be a potential bottleneck for the future success of the cell therapy industry. With the benefits of high volumetric productivity and controllability of cell culture processes, single-use bioreactors are recognized as promising solutions for large-scale manufacturing of cell therapy products. However, cell therapy products have unique bioprocessing requirements as not only is the final product the cell itself, but they are anchorage-dependent and grow on microcarriers or as cell aggregates. These microcarriers and cell aggregates require greater power input to be suspended in a bioreactor, which can lead to hydrodynamic sheer stress and damage to cells. A single-use bioreactor that can suspend the large particles homogeneously in a low shear environment and provide evenly distributed dissipation energy inside the vessel consistently across various working volumes would be greatly beneficial for scale up of cell therapy manufacturing. Methods, Results & Conclusion A novel, single-use Vertical-Wheel (VW) bioreactor system was designed in an attempt to provide a solution to these challenges. Experiments with various cell types such as human mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), pluripotent stem cells (PSCs), and chondrocytes were performed in different sizes of VW bioreactors with the following results. Comparable final cell densities of MSCs in a xeno-free microcarrier culture was achieved in four different scales of VW bioreactors (0.1L, 3L, 15L, and 80L). More uniform size ESC aggregates were achieved in 0.5L VW bioreactors compared to the ESCs grown in stirred-type spinner flasks. Furthermore, the narrow range of cell aggregate size distribution achieved in 0.5L VW bioreactors was reproduced to larger 3L scale. A test by specific surface marker identifiers indicated that the pluripotency of PSC aggregates after cell expansion in the bioreactor was maintained. Subsequent directed differentiation of PSCs after cell expansion in a single-use bioreactor is another challenge of manufacturing scale up. VW bioreactors have been used to successfully differentiate PSCs into different types of target cells, such as insulin-producing islets or cerebellar organoids. Further details regarding manufacturing challenges, experimental data, and potential solutions will be discussed in this presentation. Many allogeneic cell therapy drug candidates are getting closer to commercialization. However, lack of a scalable manufacturing platform to meet commercial demands could be a potential bottleneck for the future success of the cell therapy industry. With the benefits of high volumetric productivity and controllability of cell culture processes, single-use bioreactors are recognized as promising solutions for large-scale manufacturing of cell therapy products. However, cell therapy products have unique bioprocessing requirements as not only is the final product the cell itself, but they are anchorage-dependent and grow on microcarriers or as cell aggregates. These microcarriers and cell aggregates require greater power input to be suspended in a bioreactor, which can lead to hydrodynamic sheer stress and damage to cells. A single-use bioreactor that can suspend the large particles homogeneously in a low shear environment and provide evenly distributed dissipation energy inside the vessel consistently across various working volumes would be greatly beneficial for scale up of cell therapy manufacturing. A novel, single-use Vertical-Wheel (VW) bioreactor system was designed in an attempt to provide a solution to these challenges. Experiments with various cell types such as human mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), pluripotent stem cells (PSCs), and chondrocytes were performed in different sizes of VW bioreactors with the following results. Comparable final cell densities of MSCs in a xeno-free microcarrier culture was achieved in four different scales of VW bioreactors (0.1L, 3L, 15L, and 80L). More uniform size ESC aggregates were achieved in 0.5L VW bioreactors compared to the ESCs grown in stirred-type spinner flasks. Furthermore, the narrow range of cell aggregate size distribution achieved in 0.5L VW bioreactors was reproduced to larger 3L scale. A test by specific surface marker identifiers indicated that the pluripotency of PSC aggregates after cell expansion in the bioreactor was maintained. Subsequent directed differentiation of PSCs after cell expansion in a single-use bioreactor is another challenge of manufacturing scale up. VW bioreactors have been used to successfully differentiate PSCs into different types of target cells, such as insulin-producing islets or cerebellar organoids. Further details regarding manufacturing challenges, experimental data, and potential solutions will be discussed in this presentation.