For years, scientists have held out the promise that embryonic stem cells could repair damaged spinal cords and cure other serious ailments.
Scientists today got one step closer to making that promise a reality as they began an embryonic stem-cell treatment on a patient with spinal cord injuries. It is the first time a medical therapy has been used on a human in a government approved study.
"This is the dawn of a new era in medical therapeutics. We are leaving behind the days of using pills to treat symptoms, and entering a new era where we're using living human cells to permanently restore organ function damaged by a disease or an injury," said Tom O'Karma, president and CEO of Geron Corporation, the company conducting the trial.
It's a cautious start. Scientists from Geron injected the first human subject Friday at the Sheperd Center, a 132-bed spinal cord and brain injury rehabilitation hospital and clinical research center in Atlanta -- one of seven potential sites in the country that can enroll patients in the new clinical trial for the therapy. The company says it will add eight to 10 additional patients to the other national sites in the next year.
The company won Food and Drug Administration approval after showing promising results in lab rats. Rodents with little use of their back legs and tails were able to walk again within weeks; the embryonic stem cells helped repair their damaged nervous system.
For now the company is playing down expectations in the human trial.
"We can only admit one patient a month for the first few patients, so it will take about six months to a year before we have enough rigorous data to be able to say something about safety and any possible efficacy that we detect," O'Karma said.
If the stem cell therapy, which in this case is for the treatment of spinal cord injuries, is deemed safe, it will be seen as a milestone. Improvement of the patients in this trial would be viewed as an astounding success.
However, if the treatment fails -- or worse, if patients die -- doctors said it will be a devastating setback for the use of embryonic stem cells.
"This is a huge milestone for the field, marking the first time a product of a human [embryonic stem cell] has been transplanted into a patient," said Dr. George Daley, director of Stem Cell Transplantation at Children's Hospital Boston and the Dana-Farber Cancer Institute in Boston. "It has taken years and reams of regulatory documentation to get to this milestone. I hope the trial proceeds safely and that this represents just the first of many trials to follow."
"This is an important milestone," said Sean Morrison, director of the Center for Stem Cell Biology at the University of Michigan in Ann Arbor. "Nonetheless, we must bear in mind that there is a real concern about safety, since these cells have not been used clinically before.
"If the cells do prove to be safe in this trial, that would represent another milestone that would make it easier to perform future trials involving cells obtained from [human embryonic stem] cells," Morrison said. "If they observe adverse events in the patients, such as tumor formation, this could really set the field back."
The stem cells used in this trial come from human embryos left over from fertility treatments. These cells have been manipulated so that they have become precursors to certain types of nerve cells. The researchers involved with the trial hope that they will travel to the site of a recent spinal cord injury and release compounds that will help the damaged nerves in the cord regenerate.
The study is what is known as a Phase I trial -- one that is designed to show only that using the stem cells in this way is safe. If the trial is a success, it will be up to future trials to show whether the treatments are effective.
Even though the research is in its preliminary stages, some stem cell researchers say it is encouraging that such trials are going forward so soon after scientists uncovered the properties of these stem cells.
"It is remarkable that only 12 years after the discovery of human embryonic stem cells, regenerative medicine therapies based this technology are entering clinical trial," Pera said. "Much of the preliminary data on the safety and efficacy of this treatment is of course proprietary, so it is difficult to assess its likelihood of success, but the entire stem cell field will be watching the progress of this trial very carefully."
Some researchers said the trial bodes well for the future of other therapies as well.
"There is great hope that these revolutionary treatments will be effective, not only in spinal cord injury but also in other diseases, including Parkinson's disease, ALS, forms of heart disease, diabetes and more," said Dr. Timothy Kamp, co-director of the Stem Cell and Regenerative Medicine Center at the University of Wisconsin Medical School in Madison. "However, it is only with such careful clinical trials that we can accurately determine if embryonic stem cell therapies truly can treat these major diseases without excessive risks."
The study and use of the cells, however, has been fraught with controversy. Opponents say it is unethical to use human embryos to make the cells and that alternatives exist.
"The press release that they have just started their human experiment may help Geron's stock price, but not science or patients," said Dr. David Prentice, senior fellow for Life Sciences on the Family Research Council, a Christian advocacy organization.
"We wish the patient well, but think Geron is irresponsible for this premature hype, given that it will be at least a year before any hard evidence that this isn't just endangering patients," he said. "Meanwhile, adult stem cells have already shown published scientific evidence documenting actual effective treatment for spinal cord injury."
However, in the months-long wait for results, proponents of human embryonic stem cell research hope for the best -- even as they prepare for all possibilities.
"This is only the first attempt and we should anticipate lots of failures before we learn how to deliver cells safely and effectively," Daley said. "I wish this brave patient well."