International Society for Cellular Therapy perspective on immune functional assays for mesenchymal stromal cells as potency release criterion for advanced phase clinical trials

Abstract

Mesenchymal stromal cells (MSCs) as a pharmaceutical for ailments characterized by pathogenic autoimmune, alloimmune and inflammatory processes now cover the spectrum of early- to late-phase clinical trials in both industry and academic sponsored studies. There is a broad consensus that despite different tissue sourcing and varied culture expansion protocols, human MSC-like cell products likely share fundamental mechanisms of action mediating their anti-inflammatory and tissue repair functionalities. Identification of functional markers of potency and reduction to practice of standardized, easily deployable methods of measurements of such would benefit the field. This would satisfy both mechanistic research as well as development of release potency assays to meet Regulatory Authority requirements for conduct of advanced clinical studies and their eventual registration. In response to this unmet need, the International Society for Cellular Therapy (ISCT) addressed the issue at an international workshop in May 2015 as part of the 21st ISCT annual meeting in Las Vegas. The scope of the workshop was focused on discussing potency assays germane to immunomodulation by MSC-like products in clinical indications targeting immune disorders. We here provide consensus perspective arising from this forum. We propose that focused analysis of selected MSC markers robustly deployed by in vitro licensing and metricized with a matrix of assays should be responsive to requirements from Regulatory Authorities. Workshop participants identified three preferred analytic methods that could inform a matrix assay approach: quantitative RNA analysis of selected gene products; flow cytometry analysis of functionally relevant surface markers and protein-based assay of secretome. We also advocate that potency assays acceptable to the Regulatory Authorities be rendered publicly accessible in an “open-access” manner, such as through publication or database collection.

Mesenchymal Stromal Cells Modulate Macrophages in Clinically Relevant Lung Injury Models by Extracellular Vesicle Mitochondrial Transfer

“…These data have lent support to phase I/II clinical trials in which researchers are testing MSC administration to patients with ARDS (15,16). Currently, however, there are no potency assays in place to aid in the selection of MSC donors before administration of MSCs to patients (17), and despite rapid progression of MSCs to clinical trials, a complete understanding of the mechanisms of MSCs' immunomodulatory effects remains elusive.…”

Morphological features of IFN-γ–stimulated mesenchymal stromal cells predict overall immunosuppressive capacity

“…A major challenge in the development of consistently effective MSC-based immunosuppressive therapies is that MSC lines derived from different donors and manufacturing processes (i.e., cell expansion) can possess markedly dissimilar immunosuppressive function (3,5,6). Although methods exist to assess MSC immunosuppression in vitro, they are often based on only a few measured outcomes, assay culture conditions, and donor MSC samples (5,(7)(8)(9). To improve upon these methods, we developed an experimental and analytical approach to quantify MSC-mediated immune suppression using principal-component analysis (PCA) to integrate multiple measurements of T-cell activation assessed at a range of MSC densities.…”

Functional Outcome of Human Adipose Stem Cell Injections in Rat Anal Sphincter Acute Injury Model

“…Monoclonal antibodies against CD14‐phycoerythrincyanine (PE‐Cy7), CD19‐PE‐Cy7, CD45RO‐allophycocyanin (APC), CD54‐Fluorescein isothiocyanate (FITC), CD73‐phycoerythrin (PE), CD90‐APC (BD Biosciences, Franklin Lakes, NJ, USA), CD105‐PE (R&D Systems Inc., Minneapolis, MN, USA, http://www.rndsystems.com), CD34‐APC and HLA‐DR‐PE (Immunotools GmbH, Friesoythe, Germany, http://www.immunotools.de) were used. According to the International Society for Cellular Therapy standard criteria, cells positive for CD73, CD90 and CD105 but negative for CD14, CD34, CD45, and HLA‐DR are considered as MSCs 32, 33.…”