FDA Approves First Mesenchymal Stromal Cell Therapy
Paula Cannon, PhD - January 14, 2025
Ryoncil is a mesenchymal stromal cell (MSC) therapy that is both the first MSC therapy to be approved by the FDA, as well as the first off-the-shelf allogeneic cell therapy product.
I am pleased to share news of the FDA approval of a cell therapy that represents two important firsts. Ryoncil is a mesenchymal stromal cell (MSC) therapy that is both the first MSC therapy to be approved by the FDA, as well as the first off-the-shelf allogeneic cell therapy product. It offers a new treatment option for children suffering from steroid-refractory acute graft-versus-host disease (SR-aGVHD).
The FDA approved Ryoncil (remestemcel-L-rknd) on Dec. 18 for SR-aGVHD in pediatric patients two months or older. SR-aGVHD is a serious complication that develops after allogeneic (donor) hematopoietic stem cell transplants (allo-HSCT), which children receive to treat certain types of blood cancer, blood disorders, or immune system disorders. It occurs in up to 50% of allo-HSCT recipients when T cells in the donor HSCT attack the recipient’s cells as foreign. The standard therapy is corticosteroids, but for the 50% of those patients who do not respond to steroids, there are few, if any, treatment options. SR-aGVHD can be a life-threatening situation with “significant, wide-ranging health consequences, including damage to multiple organs, reduced quality of life and risk of death in affected patients,” explained Nicole Verdun, MD, director of the Office of Therapeutic Products in CBER in the agency’s announcement.
Ryoncil works by using MSCs isolated from the bone marrow of healthy adult donors. MSCs play various roles in the body and can differentiate into other types of cells. Previous studies have shown that MSCs can have immunosuppressive and immunomodulatory effects – properties that could prevent the immune attacks in aGVHD.
In results from a phase 3 study appearing in Transplantation and Cellular Therapy, researchers reported that 54 children were treated twice weekly with Ryoncil for four weeks. At 28 days, the overall response rate was 69.1%. At 100 and 180 days, 74.5% and 68.5% of patients, respectively, were still alive.
This approval decision fills a much-needed treatment gap for children already going through challenging circumstances, since there were previously no approved therapies for SR-aGVHD in children younger than 12. Developing an innovative therapy for any indication is a long, complex road; I am encouraged that the product sponsor and regulators were able to work together to ensure a safe and effective therapy could become available. It is my hope that this approval will allow fewer families to suffer from transplant complications and further boost the utility and development of off-the-shelf cell therapies. Thank you to all of the researchers whose work contributed to this landmark approval.
Dr. Cannon is ASGCT President.
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