Canadian regulators grant world's first approval for a stem cell drug

The world's first stem cell drug has been approved by Canadian authorities. US biotech company, Osiris Therapeutics, has been given the go-ahead to market its drug, Prochymal, for the treatment of graft-versus-host-disease (GvHD) in children who fail to respond to steroids.

Although stem cell transplants are currently used in a number of medical procedures, Prochymal is the first regulatory approved stem cell product to be manufactured and sold by a drug company. It marks a major step forward for the field of regenerative medicine.

'It's really a good day for the concept and the hope behind stem cell therapies becoming a reality', said Dr Randal Mills, the chief executive of Osiris.

GvHD is a complication that can occur following bone marrow transplantation and happens when immune cells in the donated bone marrow start attacking the recipient's organs. GvHD can cause severe damage to the skin, liver and digestive tract and is fatal in up to 80 percent of children affected. Treatment with steroids can help to manage symptoms, but often proves ineffective.

Prochymal is a preparation of mesenchymal stem cells extracted from the bone marrow of young adult donors. It is unclear exactly how the drug works, but clinical trial data has shown that Prochymal is effective in a specific subset of patients. Sixty percent of children with severe cases of GvHD who had not previously responded to steroid treatment showed clinically significant improvement, prompting Canadian authorities to approve the drug for use in this category.

Lead investigator Dr Joanne Kurtzberg, who heads the Pediatric Bone Marrow Transplant Program at Duke University, USA said: 'I have personally seen Prochymal reverse the debilitating effects of severe GvHD in many of my patients and now, after nearly two decades of research, the data demonstrating consistently high response rates, a strong safety profile and improved survival clearly support the use of Prochymal in the management of refractory GvHD'.

The announcement is a positive boost for Prochymal, whose future had looked uncertain. In 2009, two late-stage clinical trials failed to find any difference between Prochymal and a placebo in the treatment of GvHD. Attempts to trial Prochymal as a treatment for illnesses including Crohn's disease and diabetes had also resulted in several failures. In February this year, French pharmaceutical company Sanofi, who held the rights to sell Prochymal outside of North America, announced that it was stopping work on the drug.

Approval was granted upon the condition that testing continues once the drug goes to market. The US Food and Drug Administration has stated it will not consider approving the drug in the USA without further data.

'While today marks the first approval of a stem cell drug, now that the door has been opened, it will surely not be the last', said Dr Mills.

The drug will be commercially available in Canada later this year.