FDA approves drug made from donor mesenchymal stromal cells for treating children
Historic FDA Approval of MSC Therapy for Children with Steroid-Resistant GvHD
At the end of 2024, the global medical community received groundbreaking news:The U.S. Food and Drug Administration (FDA) officially approved the use of allogeneic (donor-derived) mesenchymal stromal cells (MSCs) from bone marrow to treat steroid-refractory acute graft-versus-host disease (GvHD) in pediatric patients as young as two months old.
“Today’s decision marks an important milestone in the use of innovative cell‑based therapies to treat life‑threatening diseases with devastating impacts on patients, including children,” said Dr. Peter Marks, Director of the FDA Center for Biologics Evaluation and Research. “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.”
Why Is This Approval So Important?
The FDA is the most influential organization in the world with strict requirements for the quality of drugs. Although MSCs have long been studied for their potential in treating GvHD, this is the first time the FDA has officially approved such a therapy.
Until now, the FDA had only approved cell therapies in which stem cells differentiate into specific target tissues. For example, hematopoietic stem cells from cord blood or bone marrow are used to regenerate the blood and immune systems in patients undergoing transplant for leukemia.
MSCs, however, are more complex. They can transform into different cell types and exert broad immunomodulatory and regenerative effects that are difficult to fully track or standardize. These complexities have historically posed regulatory challenges.
Still, years of global clinical research have confirmed that MSCs derived from cord tissue, placenta, bone marrow, and adipose tissue are safe and potentially effective, even in patients who do not respond to traditional treatments.
The FDA's green light paves the way for more innovation in cell-based and personalized therapies - offering new hope to patients with previously untreatable or life-threatening diseases.
Understanding Steroid-Refractory Acute GvHD
Graft-versus-host disease (GvHD) is a severe complication that may occur after a patient receives hematopoietic stem cells (from bone marrow or cord blood) from an unrelated donor. These transplants are typically used to treat blood cancers, hematologic disorders, and immune deficiencies.
In some cases, the donor cells begin attacking the recipient’s organs. This immune overreaction, known as GvHD, can significantly reduce quality of life or lead to death.
Steroid-refractory GvHD means that the condition does not respond to standard steroid-based immunosuppressive therapy. These cases require alternative approaches - and until now, very few options were available for young children.
The Ryoncil Study: Key Facts
The FDA approval was based on a multicenter, single-arm study involving 54 pediatric patients.
Participants received intravenous infusions of Ryoncil, a proprietary MSC therapy derived from adult donor bone marrow, twice a week for four weeks (8 infusions total). Those with partial or mixed responses could receive additional infusions once a week for another four weeks.
Outcomes at 28 Days Post-Treatment:
30% (16 patients) achieved complete response
41% (22 patients) showed partial improvement
The severity of GvHD and affected organs were assessed using the International Bone Marrow Transplant Registry (IBMTR) criteria.
Potential Risks Included:
Allergic reactions to donor proteins or DMSO (cryoprotectant)
Infusion-related symptoms (fever, hypertension)
Risk of viral transmission from donor
Because of individual patient differences, doctors must tailor treatment plans and dosing carefully.
Ryoncil received:
Orphan Drug status
Fast Track designation
Priority Review designation
This accelerated the review process, recognizing the drug’s potential to address an urgent unmet need.
