A phase 1 multicentre open label dose-escalation study of unrelated, major histocompatibility (MHC)-unmatched mesenchymals stem cells (MSC) for the treatment of steroid refractory acute graft versus host disease in recipients of allogeneic heamatopoietic stem cell transplants

This study has been designed as a phase I multicentre open label dose-escalation study. In addition to institutional standard-of-care for steroid-refractory acute graft-versus-host disease, patients will receive three infusions of mesenchymal stem cell (MSC) one week apart. The first 3 patients will receive an intravenous infusion of human bone marrow-derived MSC at a dose of 1 x 106 MSC/kg weekly for three consecutive weeks (days 1, 8 and 15, with day 1 being the day of the first infusion of MSC). If no serious adverse events are detected 1 week after the last MSC infusion in patient 3, patients 4, 5 and 6 will receive an intravenous infusion of human bone marrow-derived MSC at a dose of 3.3 x106 MSC/kg weekly for three consecutive weeks. If no serious adverse events are detected 1 week after the last MSC infusion in patient 6, the last 3 patients (patients 7, 8 and 9) will receive an intravenous infusion of human bone marrow-derived MSC at a dose of 10 x 106 MSC/kg weekly for three consecutive weeks. The MSC in this study will be derived from bone marrow obtained from a volunteer normal healthy donor unrelated to, and MHC-unmatched with, the recipient and with the transplanted heamatopoietic stem cells (HSCs)