Might improve function in paralyzed patients, experts say
FRIDAY, Jan. 23 (HealthDay News) -- The first human trial using embryonic stem cells as a medical treatment has been approved by the U.S. Food and Drug Administration.
Geron Corp., a California-based biotech company, has been given the OK to implant embryonic stem cells in eight to 10 paraplegic patients who can use their arms but can't walk. Stem cell injections will be given within two weeks of the injury. The study will begin this summer, and will be conducted at up to seven different medical centers.
"This marks the dawn of a new era in medical therapeutics," Dr. Thomas B. Okarma, Geron's president and CEO said during a Friday morning teleconference. "This approach is one that reaches beyond pills and scalpels to achieve a new level of healing."
Ultimately, this type of therapy might have the power to restore permanent organ and tissue function, Okarma said. The goal of this first trial is to see if injecting embryonic stem cells into humans is safe. However, the researchers will also be looking for signs of improvement in the patients' ability to feel sensation in or move their legs.
Patients will receive injections at the site of the injury. It is hoped these cells will mature into cells that will repair damaged nerves and produce chemicals that nerve cells need to function and grow.
This phase I trial will be limited to patients whose injury is located in the middle of the spine. If the trial is successful, Okarma said, the hope is to extend the treatment to patients with cervical spine injuries who are paralyzed from the neck down.
Okarma said the injections must be given early after the injury, before scar tissue has developed that would prevent the cells from growing, but after the initial swelling has subsided.
In addition, patients will receive anti-rejection drugs for about two months, after which they should no longer need those drugs. Patients will be followed for at least one year, he said.
The treatment is not expected to restore full function to patients, but the researchers hope to see modest gains. "Any return of bladder or bowel function, a return of sensation, or a return of lower extremity locomotion would be a very exciting finding," Okarma said.
In experiments with rats, researchers found these cells were safe and did restore some function. "These cells insulate as well as stimulate nerve fibers, leading to restoration of function in animal models of spinal cord injury," Okarma said.
The cost of this therapy isn't known yet, but Okarma said it would be "affordable."
Embryonic stem cells are the most basic human cells. These cells are believed to be capable of growing into any type of cell.
The controversy surrounding the use of these cells has become a political issue, with some objecting that the use of these cells destroys potential life because they must be extracted from human embryos. This belief resulted in the Bush administration banning federal funding for embryonic stem cell research.
While the Obama administration has indicated that it will lift the ban, the stem cells used in this trial were obtained from one of the Bush administration's approved stem cell lines. However, no federal funds were used in the development of this treatment.
A decade has passed since the first embryonic stem cells were isolated at the University of Wisconsin, in groundbreaking research that was funded by Geron Corp.
Geron is also working on using embryonic stem cells to treat failing hearts and to create insulin-producing islets for type 1 diabetics, Okarma said.
"Embryonic stem cells are really nature's own way of making more of ourselves," Okarma said. "We are simply harnessing the biology of normal human development in our attempts to achieve permanent cures to chronic disease and injury."
Peter Kiernan, chairman of the Christopher And Dana Reeves Foundation, said he's excited about this latest development in stem cell research.
"This is not just a comet across our sky, this is really more like dawn," Kiernan said. "We are beginning a vast human experiment, and we have been waiting an extremely long time to get to this point. This is a very significant development."
At the same time, Kiernan said he does not overestimate what can be expected from this trial.
"Of the millions of people dealing with paralysis in our nation, they are all delighted with subtle increases in function," Kiernan said. "We eat, drink, sleep getting people out of wheelchairs, but the reality of the world we are in is if people get bowel function, some sexual function, some ability for movement, that is a wonderful outcome."
For more on embryonic stem cells, visit the U.S. National Institutes of Health.
SOURCES: Jan. 23, 2009, teleconference with Thomas B. Okarma, Ph.D., M.D., president and CEO, Geron Corp., Menlo Park, Calif.; Peter Kiernan, chairman, Christopher And Dana Reeves Foundation, Short Hills, N.J.
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