|The Good Manufacturing Practice (GMP) Laboratory (Anne-Marie McReynolds)|
A Menlo Park biotech firm said Friday that federal regulators will let it proceed with the world's first human test of a treatment made from embryonic stem cells, a much-anticipated but controversial study of patients with spinal cord injuries that had been placed on hold for nearly a year because of safety concerns.
If the treatment from Geron works, it "would be revolutionary," said Dr. Richard Fessler, a neurological surgeon at Northwestern University, who will lead the study of a stem-cell treatment designed to be injected into patients with spinal injuries to restore their motor function. "The therapy would provide a viable treatment option for thousands of patients who suffer severe spinal cord injuries each year."
Geron has spent 15 years and more than $150 million to develop the treatment, and "getting it into a clinical trial, just by itself, is a big deal," added Fessler, who has no financial ties to the company.
Many people hope that human embryonic stem cells, which can turn into any type of tissue in the body, could prove useful for everything from generating organs for transplants to helping test drugs on numerous diseases. But because the cells are derived from discarded 3- to-5-day-old embryos, their use by researchers has sparked ethical concerns and a highly contentious national debate.
The Food and Drug Administration had put the study on hold last year after a few animals the company was testing with its treatment
developed small cysts. Although similar cysts had appeared in earlier animal studies, they appeared with "a higher frequency" in more recent animal tests, the company said at the time.
FDA officials declined to comment on why they decided to lift their hold on the study. However, Geron said Friday that it determined the cysts "did not lead to any adverse consequences to the animals" and that the company changed some of its procedures "to minimize the likelihood of cyst formation."
After Geron's announcement, its stock price rose 83 cents, or about 17 percent, to $5.63 at the close of trading.
In studies several years ago, Geron reported that its spinal treatment had helped paralyzed rats walk. The company's treatment involves turning embryonic cells into another type of cell, which helps nerve fibers replace myelin, a fatty insulating substance that often gets stripped away when spines are injured, inhibiting the body's ability to transmit sensory signals.
However, no people have ever been tested using human embryonic stem cells,
That's partly because critics - many of them involved in religious and anti-abortion groups - argue that research with the cells is unethical because the embryos the cells come from are life-forms.
In addition, some scientists have feared that if the cells are injected into people they might form teratomas, which are growths of unwanted cells.
Supporters of human embryonic stem-cell studies argue that the cells' potential benefits outweigh any ethical concerns about where they come from and Geron has said it has found no teratomas among the vast numbers of animals it has tested with its treatment.
Having Geron's study given the go-ahead, "is an important milestone for the whole field," said Alan Trounson, president of the California Institute for Regenerative Medicine, a state agency that promotes research with human embryonic stem cells. "We are looking with hope and expectation that the transplant will be safe and effective."
Adult stem cells, which appear in the body about 12 weeks after conception and typically produce a limited variety of tissue types, have been tested on people in various ways.
To be selected for the study, patients must have mid-back spinal cord injuries that leave them paralyzed below the site of their injuries, which must be one to two weeks old.
Geron has identified seven U.S. medical centers that may participate in the study, which is primarily intended to gauge how safe the treatment is. The tests are expected to involve only a small number of patients. Geron did not disclose when the treatments would begin, though Fessler said it might take a couple of months to get the medical center personnel prepared for the study.
Geron isn't the only company seeking FDA permission to test a human embryonic stem cell treatment on people. Santa Monica-based Advanced Cell Technology hopes to win approval soon to study a treatment it has developed for patients suffering from an eye disease called Stargardt's macular dystrophy.
"We're also hoping we can begin our clinical trials in the next few months," said Dr. Robert Lanza, the company's chief scientific officer. "Of course, it's not important who does the first clinical trial," he added, "but, rather, whether your therapy helps patients."
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