Journal de recherche et de thérapie sur les cellules souches

Abstrait

Large-Scale Clinical Expansion of Mesenchymal Stem Cells in the GMP-Compliant, Closed Automated Quantum® Cell Expansion System: Comparison with Expansion in Traditional T-Flasks

Chantal Lechanteur, Stefano Baila, Michiel Etienne Janssens, Olivier Giet, Alexandra Briquet, Etienne Baudoux and Yves Beguin

Objectives: Significant advances have been achieved regarding the knowledge of the immunoregulatory properties of mesenchymal stem cells (MSC). We are currently involved in several clinical protocols evaluating these properties in different settings including hematopoietic cells or solid organ transplantation, and severe or refractory autoimmune disorders. Considering the large number of ex-vivo expanded cells required for these clinical protocols (MSC dose varies from 1 to 4x10-6 MSC/kg patient per infusion), we evaluated the Quantum® device, a GMPcompliant, functionally closed, automated hollow fiber bioreactor system and compared it with our traditional clinical culture system in flasks. Methods: Primary and pre-enriched MSC expansions were simultaneously conducted in both culture systems and evaluated in terms of expansion rates and compliance with quality specifications and ISCT-release criteria. Due to practical considerations, most of the experiments conducted in the bioreactor (P1 and P2 expansions) used thawed MSC. These were compared with both fresh and thawed MSC expansions in flasks. Results: The Quantum® device reproducibly produced therapeutic MSC doses that fulfill ISCT-release criteria, are sterile, devoid of mycoplasma and endotoxin, have normal karyotypes and demonstrate immunosuppressive and differentiation capacities in vitro. Cells also grew faster in the bioreactor than in flasks during passage P1 (doubling time 40 compared to 56 hours in flasks) and P2 expansions but not during the primary expansion phase (P0). Seeding 20x10-6 thawed P2-preselected cells on the device allowed us to harvest 110-276x10-6 MSC after a 7 day expansion; seeding 50x10-6 cells resulted in 291-334x10-6 MSC harvested. Conclusion: In conclusion, the Quantum® device is an excellent system to produce a clinical dose of MSC but cost-effectiveness varies as a function of the manufacturing strategy in place. For our particular situation, the use of the Quantum device didn't result in a cost saving solution.