In the world’s first rigorous clinical trial of a groundbreaking new therapy, millions of stem cells derived from human embryos have been injected into the crushed spine of a paralyzed patient.
The experiment in the United States marks a big step forward for the field and, if all goes well, could open the door to therapies that promise to heal traumatic injuries.
Stem cells, the precursors to the other cells in our body, can regenerate and help repair tissue. In the experiment, the cells are expected to coat the damaged spinal cord and repair the nerves. If successful, the treatment is supposed to allow the patient to regain some of the movement lost due to injury.
Scientists around the world are watching the results closely, with British researcher Chris Mason telling reporters the trial marks “the dawn of the ‘stem-cell age.’ ”
“Without question, this represents a major landmark, it’s a new threshold we’re passing through,” said Michael Rudnicki, scientific director of Canada’s Stem Cell Network. “It’s a very important trial and I hope it will be successful.”
Stem-cell research has long been controversial, particularly among religious groups, which oppose the destruction of human embryos. The field also carries significant risks, as some cells have been shown to spark the growth of tumours. The sheer cost of weeding out cancer-causing cells has made it difficult for researchers in other countries to mount such a trial.
The unidentified patient underwent the therapy Friday at the Shepherd Center, an Atlanta rehabilitation hospital and research centre. The trial, sponsored by California biotech firm Geron Corporation, will perform the experiments on up to 10 people who have suffered traumatic spinal cord injuries less than two weeks before the therapy. The tests will determine whether the cells are safe for use in humans.
While clinics in China and other countries use human embryonic stem cells in treatments, the U.S. trial is the first to closely document the process to assess its risks, experts said.
Geron spent years trying to get the trial off the ground. The company had to demonstrate to the U.S. Food and Drug Administration that it could perform the therapy with little risk of giving the subjects cancer. Geron also raised ethical concerns by opting to perform the trial on patients who had suffered traumatic injuries mere days before.
After several rounds of animal testing, the FDA approved the human trial in July.
“When we started working with [human embryonic stem cells] in 1999, many predicted that it would be a number of decades before a cell therapy would be approved for human clinical trials,” said Geron chief executive officer Thomas B. Okarma in a statement. “This accomplishment results from extensive research and development.”
The U.S. has seen vigorous debate between scientists and the religious right over the use of stem cells. Former U.S. president George W. Bush even imposed restrictions on federal funding for such research. As a private company, however, Geron was able to continue its work.
And while other countries have a more relaxed attitude toward stem-cell research, researchers say the U.S. is the only place where companies have been able to raise the money needed to perform trials.
Despite its relatively small size, Canada is among the countries leading in stem-cell research, but most research focuses on adult cells. Canadian researchers have made significant advancements in isolating cells in the retina that can aid in treating eye disease and developed a method for treating a type of high blood pressure that involves using the patient’s own blood cells to repair their arteries.
In another advance, a team at McGill was able to take stem cells from skin and turn them into brain cells. The use of cells taken from a patient’s own body helps circumvent ethical issues involved in such research and avoid the possibility of the body rejecting cells.
“It doesn’t have the ethical issues of embryonic stem cells and you can transfer them into the patient without fear of immune rejection,” said Mick Bhatia, a stem-cell researcher at McMaster University who primarily works on adult cells.
While that technology is more difficult for Geron to use, thanks to intellectual property restrictions, experts believe it will eventually supplant embryo-derived stem cells in research.
Canadian researchers at McGill University first identified stem cells in the 1950s.
Editor's Note: The original newspaper version of this article and an earlier online version contained incorrect information about who first identified stem cells and where that happened. This online version has been corrected.