Abstract
Among all stem cell based clinical trials in the world, most of them are related to Mesenchymal Stem Cells whatever the tissue origin. Over time, the uses of cultured cells have increased greatly, particularly since 2009. Cells derived from adipose tissue are also increasingly used in trials compared with bone marrow cells. No real specificity emerged as to the therapeutic uses of the different types of stem cells and the more than half the MSC studies concerned allogeneic MSCs. With the maturation of this field, the requirements of relevant safety and potency cell control assays are now absolutely required for the future phase III and IV but quite different according to the autologous or allogenic setting. If for autologous setting, such assays have to be defined to identify MSC batches not to inject (for safety or lack of efficacy), in allogenic setting, potency assays are required to select the best donor with the maximum of safety. Up to now, most of assays are based on pre-clinical animal studies but need to be largely improved for a better relevance and accuracy. Their development stumbles on two difficulties: MSC themselves and our limited knowledge of their pleiotropic action mechanisms in conjunction with MTI regulatory rules. This indicates that we have to move from simple tests to multi-modal and combinatory approaches. We propose to discuss and illustrate these different points in view of the different clinical trials and how they inform us.
