Optimization of gmp-compatible biobanking of allogeneic bone marrow-derived clonal mesenchymal stromal cells for cell therapy applications

Abstract

Background & Aim: Allogeneic mesenchymal stromal cells (MSCs) are valuable therapeutic candidates used extensively in various clinical trials. However, the findings of Phase III clinical trials raise concerns about the efficacy of MSCs, which are rooted mainly in the applied populations’ heterogeneity. Although several factors, one of the most crucial causes of this heterogeneity is the lack of an optimized cell culture technique to manufacture a homogenous cultured MSCs. Moreover, it is necessary to provide a good manufacturing practice (GMP) platform to ensure the safety of final cell therapy products (CTPs) and satisfy the legal requirements for clinical applications. Establishing a tired cell bank system is the final step to support the proper translation of producing MSCs into medicine by ensuring standardization of the entire cell manufacturing process, accredited identity, function and safety assessments, and transparent sharing of standard operating procedures (SOPs) data. Methods, Results & Conclusion: Here, clonal MSCs (cMSCs) were isolated based on the subfractionation culturing method (SCM) protocol under the GMP-compatible condition and through an innovative, cost-effective screening approach. Then, cMSCs were compared with their heterogeneous counterparts in terms of identity and function. The validated clones were stored in a four-tiered cell bank system consisting of an initial, master, working, and end of product cell banks (ICB, MCB, WCB, and EoPCB). Additionally, to further develop towards GMP- compatible cMSCs production, several identities, quality, and safety assessments were performed during all banking phases. Finally, the cells stored in the EoPCB were released as a drug product (DP) for the Phase I/II clinical trial of coronavirus disease-2019 (COVID-19). Regarding senescence assessment and capability to serial passaging, three similar passagable clones were manufactured. Remarkably, the clones’ genomic stability was fully retained after 15 passages and were neither tumorigenic nor immunogenic. Altogether, this study presents a technical and translational overview of GMP-compatible cMSCs manufacturing technology, which could be used as a guide for the development of similar production processes with the therapeutic goals.