US Food and Drug Administration announced on Wednesday that it has approved Ryoncil (remestemcel-L-rknd), a mesenchymal stromal cell therapy, for paediatric patients aged two months and older with steroid-refractory acute graft-versus-host disease (SR-aGVHD).

This marks the first FDA approval of a mesenchymal stromal cell therapy. Derived from bone marrow of healthy adult donors, Ryoncil addresses a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT).

SR-aGVHD often arises from allo-HSCT, a procedure used to replace patients' blood-forming stem cells, typically in treating blood cancers, blood disorders, or immune system conditions. Effectiveness was demonstrated in a multicenter, single-arm study of 54 paediatric participants, using International Blood and Marrow Transplantation Registry Severity Index Criteria for disease assessment.

Results showed 30% achieved complete response and 41% had partial responses 28 days post-treatment. Patients with mixed or partial responses received additional weekly infusions for four weeks. Treatment involves eight initial infusions delivered intravenously over four weeks, highlighting significant therapeutic potential for addressing SR-aGVHD.