Serum-free process development: improving the yield and consistency of human mesenchymal stem cell production

Background: The cost effective production of hMSCs for off-the-shelf and patient specific therapies will require an increasing focus on improving product yield and driving manufacturing consistency. Methods: Bone-marrow derived hMSCs from two donors were expanded for 36 days in monolayer with medium supplemented with either fetal bovine serum (FBS) or PRIME-XV® Serum-free Medium (SFM). Cells were assessed throughout culture for proliferation, mean cell diameter, colony forming potential, osteogenic potential, gene expression and metabolites. Results: Expansion of BM-hMSCs in PRIME-XV® SFM resulted in a significantly higher growth rate (p < 0.001) and increased consistency between donors compared with FBS-based culture. FBS-based culture showed an inter batch production range of 0.9 and 5 days per dose compared with 0.5 and 0.6 days in SFM for each BM-hMSC donor line. The consistency between donors was also improved by the use of PRIME-XV® SFM, with a production range of 0.9 days compared with 19.4 days in FBS-based culture. Mean cell diameter has also been demonstrated as a process metric for BM-hMSC growth rate and senescence via a correlation (R2 = 0.8705) across all conditions. PRIME-XV® SFM has also shown increased consistency in BM-hMSC characteristics such as per cell metabolite utilisation, in vitro colony forming potential and osteogenic potential despite the higher number of population doublings. Conclusions: We have increased the yield and consistency of BM-hMSC expansion between donors, demonstrating a level of control over the product, which has the potential to increase the cost effectiveness and reduce the risk in these manufacturing processes.