BOSTON (Reuters) – Osiris Therapeutics Inc said on Thursday that Canadian health regulators have approved its treatment for acute graft-versus-host disease in children, making it the first stem cell drug to be approved for a systemic disease anywhere in the world.
Symptoms of graft-versus-host disease (GvHD), a potentially deadly complication of bone marrow transplant, range from abdominal pain and skin rash to hair loss, hepatitis, lung and digestive tract disorders, jaundice and vomiting.
The disease kills up to 80% of children affected. To date there have been no approved treatments for the disease. Canadian authorities approved the therapy, Prochymal, for use in children who have failed to respond to steroids.
Prochymal is made up of bone marrow stem cells derived from an adult donor and is designed to control inflammation, promote tissue regeneration and prevent scar formation. It is not entirely clear how it works to help patients with GvHD, of which there are between 3,500 to 4,000 worldwide, Mills said.
Prochymal was approved with the condition that Osiris conduct further testing after it reaches the market. C. Randal Mills, the company’s chief executive, said in an interview that could take three to four years.
In 2009, two late-stage clinical trials failed to show the drug was more effective overall than placebo in treating the disease, though it showed promise in certain subgroups of patients.
Since then, the company has mined data from all its clinical trials to show that in patients with severe refractory acute GvHD — those who have more or less failed all other therapies — Prochymal demonstrated a clinically meaningful response at 28 days after therapy began in 61% to 64% of patients.
In addition, treatment with Prochymal resulted in a statistically significant improvement in survival when compared with a historical control population of pediatric patients with refractory GvHD. The Canadian authorities approved the drug on the basis of that data, the company said.
Osiris, which is based in Columbia, Maryland, plans to apply for marketing authorization with the U.S. Food and Drug Administration by the end of this year, including the newly-analyzed information. Mills said that if the FDA were to approve the drug, he would expect it to be on similarly conditional terms as outlined by the Canadian authorities.
In general, the FDA does not approve drugs based on subset analyses.
Dozens of adult stem cell therapies are moving through clinical trials, and Canada’s approval of Osiris’s drug will likely boost optimism in the sector.
Athersys Inc said last month it had met with the FDA to discuss the results of a recently completed clinical trial of its MultiStem stem cell treatment to prevent GvHD in patients being treated for leukemia or other conditions that place them at risk of the complication.