Umbilical Cord Mesenchymal Stromal Cells for Steroid-Refractory Acute Graft-versus-Host Disease.

Background: Steroid-refractory acute graft-vs.-host disease (SR-aGVHD) is a complication of allogeneic hematopoietic stem cell transplantation with a dismal prognosis and for which there is no consensus-based second-line therapy. Ruxolitinib is not easily accessible in many countries. A possible therapy is the administration of mesenchymal stromal cells (MSCs).

Methods: In this retrospective study, 52 patients with severe SR-aGVHD were treated with MSCs from umbilical cord (UC-MSCs) in nine institutions.

Results: The median (range) age was 12.5 (0.3-65) years and the mean ± SD dose (×10/kg) was 4.73 ± 1.3 per infusion (median of four infusions). Overall (OR) and complete response (CR) rates on day 28 were 63.5% and 36.6%, respectively. Children ( = 35) had better OR (71.5% vs. 47.1%, = 0.12), CR (48.6% vs. 11.8%, = 0.03), overall survival ( = 0.0006), and relapse-free survival ( = 0.0014) than adults ( = 17). Acute adverse events (all of them mild or moderate) were detected in 32.7% of patients, with no significant difference in children and adult groups ( = 1.0).

Conclusions: UC-MSCs are a feasible alternative therapy for SR-aGVHD, especially in children. The safety profile is favorable.