Large Scale Manufacturing of Wharton's Jelly Mesenchymal Stromal Cells for Clinical Use

Therapies utilizing human mesenchymal stromal cells (MSCs) are advancing through clinical trials, emphasizing the need for reliable, scalable, and cost-efficient manufacturing processes to support the lot sizes necessary for commercial-scale production. Wharton's jelly MSCs (WJMSCs) are valued for their regenerative abilities and immunomodulatory and anti-inflammatory properties, which contribute to tissue repair. With growing therapeutic demand, the production of WJMSCs must scale to yield billions of cells while maintaining their essential characteristics-identity, purity, and potency-necessary for clinical and regulatory compliance. Achieving such magnitude of expansion entails the utilization of current good manufacturing practice (cGMP)-compliant scalable culture systems that allow bioprocess control and monitoring. This study aimed to establish a scalable serum-/xeno-free expansion process representing a critical step towards a cGMP-compliant large-scale production platform for WJMSC-based clinical applications. Using our in-house GMP-manufactured WJMSCs, which were tested in a Phase Ib clinical trial (NCT03158896), we have previously optimized various culture parameters using a microcarrier (MC)-based three-dimensional (3D) culture system in spinner flasks and demonstrated successful WJMSC expansion. In the present study, we successfully translated culture conditions to a 2 L followed by a STR50 (50 L) stirred-tank bioreactor (BR) (STR), adhering to cGMP requirements. The culture system in the 2 and 50 LBRs supported cell concentrations of approximately 1.2 x 10⁶ cells/mL and attained 24-fold and 27-fold expansion, respectively, with a yield of approximately 37 billion cells in the 50 L culture system after 7 days with a 95% harvest efficiency. Following expansion, WJMSCs preserved their characteristic phenotypes, differentiation potential, chromosomal stability, functional capabilities, and sterility across all tested culture systems. We conclude that the large-scale expansion process of WJMSCs in the STR described herein is highly adaptable to the scale necessary to fulfill the commercial demand for high quality clinical-grade MSCs.