On December 18, 2024, the Food and Drug Administration approved remestemcel-L-rknd (Ryoncil, Mesoblast, Inc.), an allogeneic bone marrow-derived mesenchymal stromal cell (MSC) therapy, for steroid-refractory acute graft versus host disease (SR-aGVHD) in pediatric patients 2 months of age and older. Ryoncil is the first FDA-approved MSC therapy.