Biomanufacturing of Therapeutic Cells: State of the Art, Current Challenges, and Future Perspectives

Abstract

Stem cells and other functionally defined therapeutic cells (e.g., T cells) are promising to bring hope of a permanent cure for diseases and disorders that currently cannot be cured by conventional drugs or biological molecules. This paradigm shift in modern medicine of using cells as novel therapeutics can be realized only if suitable manufacturing technologies for large-scale, cost-effective, reproducible production of high-quality cells can be developed. Here we review the state of the art in therapeutic cell manufacturing, including cell purification and isolation, activation and differentiation, genetic modification, expansion, packaging, and preservation. We identify current challenges and discuss opportunities to overcome them such that cell therapies become highly effective, safe, and predictively reproducible while at the same time becoming affordable and widely available.

Perspectives on Manufacturing of High-Quality Cell Therapies

“…Beyond automation, the inherent variability of source cells, especially autologous cells, necessitates the inclusion of flexible built-in process automation that can be adjusted based on CQA measurements and on feedback from real-time analytics. 5,6,12 Novel cell separation technologies, such as acoustic waves, microfluidic separation platforms, 13 and phase-change hydrogel substrates, 14 may be integrated into these systems. Further enrichment of specific cell subsets may be promoted by cytokines or small molecules whose biological activities need to be defined against established standards.…”

“…It also limits wide distribution owing to constraints in storage and transportation. 6 Future research should explore improved and alternative methods for live cell transportation that integrate measurements of product quality.…”

“…4 As living drugs, cell therapies pose unique commercialization challenges in terms of manufacturing, standardization, and distribution. [4][5][6] Automated, robust, and costeffective production platforms compliant with current good manufacturing practices (cGMP) coupled with robust analytics, which ensure reproducible cell quality, are needed to broaden the availability and realize the commercialization potential of these complex, predominantly personalized, therapeutic modalities.…”

“…The inter-institution and inter-patient variability that are inherent to apheresis collection and composition, the paucity of well-defined and quantifiable critical quality attributes (CQAs), and the requirement for cGMP-grade culture media components and ancillary genetic modifiers, such as viral vectors and CRISPR/Cas9 components, add to the complexity of these therapeutic modalities. [5][6][7] To decrease the production scale and shorten the time in culture, cell subsets known to provide optimal therapeutic effects and limited toxicities may be selected to initiate manufacturing 8,9 or may be selectively expanded/differentiated during manufacturing. Unfortunately, for most cell therapies, these biological attributes…”

Essential design considerations for the resazurin reduction assay to noninvasively quantify cell expansion within perfused extracellular matrix scaffolds

“…In response to a shift toward 3D cell culture, often carried out within bioreactors [5–8] or intricate cell-based microfluidic systems [9], there is a need to accurately measure viable cell numbers without disturbing or sacrificing the complex tissue under examination [10], which may be produced from scarce patient-specific cells [11–13] or patient-derived induced pluripotent stem cells [14]. In addition to providing information on cellular growth kinetics within these systems, noninvasive measurement of cell number is necessary to provide an accurate reference point for tissue function and phenotype.…”