Real-World Data Suggest Effectiveness of Allogeneic Mesenchymal Stromal (MSC-FFM) Cells in Ruxolitinib-Refractory Acute Graft-Versus-Host Disease

Introduction: Acute graft-versus-host disease (aGvHD) remains the leading cause of treatment-related morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Current first-line treatment of aGvHD is with high-dose corticosteroids, the standard for steroid-refractory aGvHD (SR-aGvHD) is the Janus kinase (JAK) inhibitor ruxolitinib. Outcomes for patients with ruxolitinib-refractory or -intolerant aGvHD (RR-aGvHD) are poor. Thus in a recent real-world study of adult patients with RR-aGvHD (Abedin BJH 2021) median survival was 28 days (21 days for ruxolitinib refractoriness, 50 days for ruxolitinib intolerance), the probability of overall survival (OS) at 6, 12, and 24 months were about 20%, 16%, and 10%, respectively. We assessed real-world outcomes of patients with RR-aGvHD treated with the random-donor allogeneic MSC preparation “MSC-FFM,” available via Hospital Exemption in Germany. Patients: Between December 2017 and February 2023, 156 patients, including 33 children and adolescents (