• Antleron NV

Bioreactors - Satisfying global cell manufacturing needs

With the rise of biopharma and advanced therapies, cells have become a sought-after material in the pharmaceutical industry. Whether as a starting material in a cell therapy, or as a production solution for a monoclonal antibody, great numbers of cells are needed to satisfy global needs. Reliance on classical, manual approaches in manufacturing translate into higher costs and less reproducible manufacturing. The rapid growth of biopharmaceuticals and the accelerating advanced therapy field as well as many other biotech applications mean that the cell supply in the coming years may not cover total market demand. One of the emerging solutions are fixed bed bioreactors, which are designed to condense large surface areas in a small footprint.

Before discussing bioreactors, it is necessary to take a look at the current manufacturing landscape in biotherapeutics. Still more often than not, advanced therapies are being produced in manual processes housed in large cleanroom facilities. These are expensive to maintain, requiring many operators to be run. Overall, this approach is not a robust solution to produce cell-based therapies. Additionally, the use of flasks limits quality control to destructive readouts performed at the end of culture, which does not facilitate process control. The situation is slightly different in mAb manufacturing where large stainless steel bioreactors are used, although single-use approaches are being implemented. The large footprint and extensive cleaning procedures in stainless steel bioreactors between runs were also proven to be more expensive than single-use solutions (1). An additional limitation is the adaptation of cell lines to thrive in suspension cultures. While this has worked sufficiently so far, e.g. viral protein yields were proven to be higher in a fixed bed culture as opposed to stirred tank culture (2).

To date, various bioreactor approaches have been developed, including fixed beds, membranes, microcarriers, stirred tank, bag, planar, vertical wheel and rotary cell culture systems (3). Each has its own specificity and application area, largely defined by target cell types. For example, adherent cells require a different setup than suspension cells. The final indication, mode of treatment and type of drug substance also have an impact on the technology to be implemented into the manufacturing process. Cell therapies typically require the cells to be harvested before infusion into patients, whereas viral vector-based gene therapies or mAbs require the recovery of the particles of interest. This has implications not only for bioreactor systems but also other upstream and downstream equipment required in the process. Few systems are currently able to accommodate an entire bioprocess.

Novel bioreactor approaches are intended to bring value in various aspects. Process automation and footprint reduction are the most obvious ones. The increase in surface-to-volume ratio in fixed beds (in adherent cell-oriented systems) has also a positive impact on costs. For example, less cell culture medium and increased transfection efficiency will save money on valuable resources, such as chemically defined media and transfection reagents. Additionally, the integration of soft sensors provides insights into process progression and enable closed-loop process, further reducing the need for expensive cleanrooms and enabling more sophisticated automation. Unfortunately, as described by Klein et al. (4), monitoring, controlling and reporting of the process parameters is currently being neglected, despite its benefits. Nonetheless, bioreactor systems provide more in-process control than manual processes.

On the other hand, current 3D bioreactor solutions have limitations. Typically they focus on parts of processes, like expansion and expression of a protein or viral vector production in case of certain specific therapies. Moreover, many 3D bioreactors still offer limited customization of the fixed bed structure, using standardized materials like microcarriers, woven macro carriers or hollow fibre membranes. This means that product recovery, especially cell harvesting, can be challenging. Additionally, heterogenous cell distribution, nutrient diffusion and suboptimal mechanical (e.g. shear stress) conditions can lead to suboptimal product yields and quality (5). Therefore alternative approaches are still needed, not only to develop customized fixed bed structure, suitable for target cell types, but also ones that take into account bioprocess related considerations. After all, end-product quality, and its price, are the result of the full process, not just a single component.

A solution to overcome these limitations presents itself in the form of additive manufactured (3D printed) fixed beds. 3D printing is a manufacturing technology which offers more design flexibility compared to classical approaches. Moreover, the reproducible nature of the 3D printing technology promises geometrically more customized and controlled fixed bed structures, resulting in better cell distribution, and thus higher product yields. Using a set of in-house developed tools and methodologies, we at Antleron develop fixed bed bioreactor solutions customized towards cell type, application and target system.

Using the Antleron R&D toolbox, we offer a number of custom bioprocess solutions to our partners and customers within cell and gene therapy, and diagnostics sectors. By merging the potential of a risk-based methodology, in silico simulations, additive manufacturing and non-invasive monitoring solutions we develop custom, optimized and scalable bioprocess blueprints and manufacturing solutions. During development, we consider technical specifications, but also process economics and scalability as well as regulatory aspects. All information is managed in a centralized risk-based framework which is guiding the R&D activities. Moreover, our collaborations with both bioreactor providers, such as VivaBioCell, and bioreactor users, puts us in a unique position to deliver well-informed and customer-focused answers to various needs from the market.

In a future blogpost we will explain the Antleron approach to custom develop optimized fixed beds for cell-based processes and how it can benefit your bioprocess.

(1) Lopes, A. G. (2015). Single-use in the biopharmaceutical industry: A review of current technology impact, challenges and limitations. In Food and Bioproducts Processing (Vol. 93, pp. 98–114). Elsevier BV. https://doi.org/10.1016/j.fbp.2013.12.002

(2) Lesch, H. P., Valonen, P., & Karhinen, M. (2020). Evaluation of the Single‐Use Fixed‐Bed Bioreactors in Scalable Virus Production. In Biotechnology Journal (Vol. 16, Issue 1, p. 2000020). Wiley. https://doi.org/10.1002/biot.202000020

(3) Zhang, H., Kent, D. E., Albanna, M., Lhu, L., Sun, X. S., Eaker, S., & Somara, S. (2021). Bioreactor Technology for Cell Therapy Manufacturing in Regenerative Medicine. In Current Stem Cell Reports (Vol. 7, Issue 4, pp. 212–218). Springer Science and Business Media LLC. https://doi.org/10.1007/s40778-021-00200-x

(4) Klein, S. G., Alsolami, S. M., Steckbauer, A., Arossa, S., Parry, A. J., Ramos Mandujano, G., Alsayegh, K., Izpisua Belmonte, J. C., Li, M., & Duarte, C. M. (2021). A prevalent neglect of environmental control in mammalian cell culture calls for best practices. In Nature Biomedical Engineering (Vol. 5, Issue 8, pp. 787–792). Springer Science and Business Media LLC. https://doi.org/10.1038/s41551-021-00775-0

(5) Zhang, H., Kent, D. E., Albanna, M., Lhu, L., Sun, X. S., Eaker, S., & Somara, S. (2021). Bioreactor Technology for Cell Therapy Manufacturing in Regenerative Medicine. In Current Stem Cell Reports (Vol. 7, Issue 4, pp. 212–218). Springer Science and Business Media LLC. https://doi.org/10.1007/s40778-021-00200-x