Mesoblast Limited today announced that it has submitted its completed Biologics License Application (BLA) to the United States Food and Drug Administration (US FDA) for Ryoncil™ (remestemcel-L), its lead allogeneic cell therapy for the treatment of children with steroid-refractory acute graft versus host disease (SRaGVHD).

Mesoblast filed the final module of the rolling BLA submission, covering quality control and manufacturing, with the FDA on January 31.

The Company has requested Priority Review of the BLA by the FDA under the product candidate’s existing Fast Track designation for SR-aGVHD.

If approved, RYONCIL is expected to be launched in the US in 2020.

Mesoblast Chief Executive Dr Silviu Itescu stated: “This is a major corporate milestone for Mesoblast. We look forward to working closely with the FDA to potentially bring RYONCIL to market and providing our innovative biologic therapy to the many children with this life-threatening condition.”

Acute GVHD occurs in approximately 50% of patients who receive an allogeneic bone marrow transplant (BMT). Over 30,000 patients worldwide undergo an allogeneic BMT annually, primarily during treatment for blood cancers, and these numbers are increasing1. In patients with the most severe form of acute GVHD (Grade C/D or III/IV) mortality is as high as 90% despite optimal institutional standard of care2,3.

There are currently no FDA-approved treatments in the US for children under 12 with SR-aGVHD. Mesoblast’s product candidate RYONCIL has been used in 309 children with SR-aGVHD across three separate studies. RYONCIL was used as salvage therapy in an expanded access program in 241 children with SR-aGVHD (80% Grade C/D) who failed institutional standard of care. RYONCIL was also used as first-line therapy in Mesoblast’s open-label Phase 3 trial in 55 children with SR-aGVHD, 89% of whom had Grade C/D disease.

RYONCIL, is an investigational therapy comprising culture expanded mesenchymal stem cells derived from the bone marrow of an unrelated donor. It is administered to patients in a series of intravenous infusions.

RYONCIL is believed to have immunomodulatory properties to counteract the inflammatory processes that are implicated in SRaGVHD by down-regulating the production of pro-inflammatory cytokines, increasing production of anti-inflammatory cytokines, and enabling recruitment of naturally occurring anti-inflammatory cells to involved tissues.


1. Niederwieser D, Baldomero H, Szer J. (2016) Hematopoietic stem cell transplantation activity worldwide in 2012 and a SWOT analysis of the Worldwide Network for Blood and Marrow Transplantation Group including the global survey.

2. Westin, J., Saliba, RM., Lima, M. (2011) Steroid-refractory acute GVHD: predictors and outcomes. Advances in Hematology.

3. Axt L, Naumann A, Toennies J (2019) Retrospective single center analysis of outcome, risk factors and therapy in steroid refractory graft-versus-host disease after allogeneic hematopoietic cell transplantation. Bone Marrow Transplantation.

Share Button