Osiris Therapeutics announced that it received marketing authorization from Health Canada to market its stem-cell therapy, Prochymal (remestemcel-L), for the treatment of graft-versus-host disease in children who fail to respond to steroids. Prochymal is a manufactured mesenchymal stem cell therapy derived from the bone marrow of healthy adult donors.

According to the company press release, Health Canada’s marketing authorization marks the world’s first approval of a manufactured stem-cell product, and the first approved treatment for graft-versus-host disease. The product was approved under Health Canada’s Notice of Compliance with conditions pathway, which is an accelerated approval pathway for products that address unmet medical conditions and which have shown a favorable risk/benefit profile in clinical trials. Under this pathway, further clinical trials will be required to verify the anticipated benefit.

Graft-versus-host disease is a complication resulting from bone marrow transplantation in which immune cells contained in the transplant recognize the recipient of the graft as foreign and mount an immune response. Severe graft-versus-host disease is fatal in as much as 80% of cases. Steroids are the first-line treatment, but have a success rate of only 30–50%. According to the company website, Prochymal is currently in Phase III trials in the US for treatment of graft-versus-host disease and Crohn’s disease and has been awarded both Orphan Drug and fast track status from FDA.