Remestemcel-L now available to treat steroid-refractory acute graft-versus-host diseaseLatest revision | Image Credit: © MdBabul - © MdBabul - stock.adobe.com.

The FDA-approved allogeneic (donor) bone marrow-derived mesenchymal stromal cell (MSC) therapy, remestemcel-L (Ryoncil; Mesoblast Limited), to treat steroid-refractory acute graft-versus-host disease (SR-aGVHD) in pediatric patients aged 2 months and older is now available for purchase in the United States.¹

According to an announcement from Mesoblast Limited, remestemcel-L is now available for ordering via the established patient access hub "MyMesoblst."

The therapy was the first FDA-approved MSC therapy, and was granted the regulatory decision on December 18, 2024.²

At the time of approval, Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research said, "[The approval] marks an important milestone in the use of innovative cell-based therapies to treat life-threatening diseases with devastating impacts on patients, including children."

"This first mesenchymal stromal cell therapy approval demonstrates the FDA’s commitment to supporting the development of safe and effective products that could improve the quality of life for patients with symptoms that are unresponsive to other therapies," said Marks.

"We have been engaging with commercial and government insurers to expedite patient access to therapy," stated Mesoblast in the recent announcement. "To date nine commercial payers have published favorable medical policies representing approximately 37 million covered lives in the United States," added the company.

Background on SR-aGVHD

The life-threatening and serious condition can occur as a complication of allogeneic hematopoietic (blood) stem cell transplantation (allo-HSCT). In allo-HSCT, a patient receives hematopoietic stem cells from a healthy donor to replace their own stem cells and form new blood cells, a procedure often done as part of treatment for certain types of blood cancers, blood disorders or immune system disorders, stated the FDA.³

Data that led to approval²

The approval was based on the safety and efficacy remestemcel-L demonstrated in a multicenter, single-arm study in 54 pediatric participants with SR-aGVHD after undergoing allo-HSCT.

As Contemporary Pediatrics previously reported, 50% survival through 4 or more years during follow up in remestemcel-L-treated patients was observed in the phase 3 trial. According to a previous announcement from Mesoblast, less than 20% survival was expected based on severity of disease.

A post-hoc propensity matched study was also included in a previous biologics license application, demonstrating that 6-month survival was 67% with remestemcel-L compared to 10% with other non-approved therapies.

According to Mesoblast, the phase 3 trial took place across 20 centers in the Untied States where remestemcel-L was used as the first line of treatment for children who failed to respond to steroids for acute GVHD.

The pre-specified primary endpoint, day 28 overall response (OR), was met, 70.4% vs 45% (P = 0.0003). An overall response at day 28 "was highly predictive of improved survival through day 100 (87% compared to 47% in patients that did not achieve day 28 OR P = 0.0001)," the company previously stated.

Compared to a matched control group of pediatric patients from the Mount SWinai Acute GVHD International Consortium (MAGIC) database, pediatric patients treated with remestemcel-L achieved higher day 28 OR (70% vs 43%), and higher day 100 survival (74% vs 57%).

“The commercial availability of RYONCIL is a significant milestone in our mission to bring innovative cellular medicines to patients in need,” said Silviu Itescu, MBBS, FRACP, CEO, Mesoblast in a statement.¹

"We have made RYONCIL available 3 months after receiving FDA approval, a significant commercial achievement and a reflection of our team and partners who are driven by the overwhelming desire to help children and their families faced with this devasting disease.”

References:

1. Ryoncil is now available for purchase in the United States. Mesoblast Limited. Press release. March 26, 2025. Accessed March 28, 2025. https://investorsmedia.mesoblast.com/static-files/d27cf035-a11e-4afe-bf7d-2c39d1314348

2. Fitch, J. FDA approves remestemcel-L-rknd to treat steroid-refractory acute graft-versus-host disease. December 18, 2025. Accessed March 28, 2025. https://www.contemporarypediatrics.com/view/fda-approves-remestemcel-l-rknd-steroid-refractory-acute-graft-versus-host-disease

3. FDA Approves First Mesenchymal Stromal Cell Therapy to Treat Steroid-refractory Acute Graft-versus-host Disease. FDA. Press release. December 18, 2024. Accessed March 28, 2025. https://www.fda.gov/news-events/press-announcements/fda-approves-first-mesenchymal-stromal-cell-therapy-treat-steroid-refractory-acute-graft-versus-host