Adipose tissue-derived mesenchymal stromal cells as part of therapy for chronic graft-versus-host disease: A phase I/II study

Background aims. Despite the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT), the procedure is still associated with high toxicity in patients with refractory graft-versus-host disease (GvHD). Mesenchymal stromal cells (MSCs) are a new mode of therapy in the context of allo-HSCT. The objective of this study was to evaluate the safety and feasibility of the use of adipose tissue-derived MSCs (AT-MSCs) in patients with chronic GvHD. Methods. Fourteen patients with moderate (n = 7) or severe (n = 7) chronic GvHD received 1 x 10(6)/kg (group A, n = 9) or 3 x 10(6)/kg (group B, n = 5) AT-MSCs with cyclosporine and prednisone as first-line therapy. Results. Ten of the 14 patients were able to continue under the protocol: 80% were in complete remission, and 100% were off of steroids at week 56. The remaining 4 patients either worsened from chronic GvHD (n = 3) or abandoned the study (n = 1). At the end of the study, 11 of 14 patients are alive (overall survival 71.4%, median survival of 45.3 weeks). No suspected unexpected serious adverse reactions occurred during the trial. Neither relapse of underlying disease nor mortality due to infection was observed in this cohort. Biological studies showed increased CD19, CD4 and tumor necrosis factor-alpha with a temporary decrease in natural killer cells. Discussion. AT-MSCs, in combination with immunosuppressive therapy, may be considered feasible and safe and likely would have an impact on the course of chronic GvHD. More studies are warranted to understand the potential benefits of AT-MSCs in these patients.