Scalable upstream process development for the suspension-based production of lentiviral vectors for CAR T cell therapies with multiparallel & benchtop bioreactor systems & DoE methodology
Cell & Gene Therapy Insights 2021; 7(6), 689–700
Cell and gene-based therapies present a new treatment paradigm that have the potential to address unmet clinical needs. Viral vectors such as adenoviruses, adeno-associated viruses, retroviruses and lentiviruses are effective delivery systems for genetic material used in cell and gene therapies and vaccines. HEK-293 cells and derivatives are commonly used as a workhorse cell line for lentiviral vector (LVV) production for cell and gene therapy applications. Adherent production processes with these cells utilize static flask cultures, and this adherent method is quite easy to develop and perform. However, it also significantly lacks the ability for automation and scalability. Typical bioreactors based either on a rocking motion or stirred tank agitation can provide these features. Therefore, to scale up viral vector production for commercialization, adherent processes should be shifted to a suspension-based process, a significant challenge for the regenerative medicine industry. The use of a suspension adapted HEK-293 cell line and the Ambr® 15 microbioreactor system can facilitate transition from adherent cultures to suspension cultures by enabling fast process optimization with the ability to screen in parallel many parameters in small volumes. As a proof-of-concept study, we established here such a transitional protocol for the cultivation of suspension adapted HEK-293T cells and the production of CD19-CAR lentivirus in small and benchtop scale stirred bioreactors.