Extended Treatment With Mesenchymal Stromal Cells-Frankfurt am Main in a Pediatric Patient With Steroid-refractory Acute Gastrointestinal Graft-Versus-Host Disease: Case Report and Review of the Literature.

In acute graft-versus-host disease (aGVHD) following allogeneic hematopoietic stem cell transplantation, there are various options available after the failure of initial steroid therapy. Since the publication of the first study in 2008, mesenchymal stromal cells (MSCs) have also been used with increasing frequency, including in pediatric patients with steroid-refractory aGVHD, and the manufacturing process has undergone further development. MSC-Frankfurt am Main (MSC-FFM, Obnitix), which is manufactured from pooled mononuclear bone marrow cells from 8 donors using a standardized process, resulted in a response rate of 84% in children with steroid-refractory aGVHD. We report on a 13-year-old female patient with acute myeloid leukemia who received Obnitix as a third-line treatment for gastrointestinal (GI) aGVHD in a life-threatening situation. The patient was initially given a total of 4 Obnitix infusions as per the regulatory approval, with her symptoms improving from day 9 after the first infusion. The second cycle of 4 Obnitix infusions followed due to persistent severe protein-losing enteropathy and resulted in complete remission. A systematic review of the literature on MSC in pediatric patients with steroid-refractory aGVHD confirms that MSC treatment beyond 4 weeks is employed in accordance with treatment protocols or on a case-by-case basis. To summarize, aGVHD activity can be checked endoscopically in patients with persistent GI symptoms and a second Obnitix cycle can then be administered if appropriate, with the goal of achieving complete remission. Future studies should also investigate the potential influence of tissue repair properties as an element in MSCs' efficacy in GI aGVHD.