The safety and effectiveness of remestemcel were evaluated in a multicenter, single-arm study in 54 pediatric study participants with steroid-refractory acute graft-versus-host disease after undergoing allogeneic hematopoietic (blood) stem cell transplantation. Study participants received intravenous infusion of remestemcel twice weekly for four consecutive weeks, for a total of eight infusions. Each study participant's condition at baseline was analyzed using the international blood and marrow transplantation registry severity index criteria (IBMTR) to evaluate which organs have been affected and the overall severity of the disease. The effectiveness of remestemcel was based primarily on the rate and duration of response to treatment 28 days after initiating remestemcel. Study participants who had a partial or mixed response to treatment—meaning that there was improved condition in one organ with either no change (partial) or worsening condition (mixed) in another organ—received additional infusions once weekly for an additional four weeks. Sixteen study participants (30%) had a complete response to treatment 28 days after receiving remestemcel, while 22 study participants (41%) had a partial response. The US
Food and Drug Administration (FDA) granted the application for remestemcel
fast track,
orphan drug, and
priority review designations. The FDA granted approval of Ryoncil to Mesoblast, Inc. == Society and culture ==