Oct. 2, 2009
Speaking of clinical trials, in case you missed it the FDA has put another hold on Geron's proposed experiments to put embryonic stem cells into human spinal cord injury patients. Geron's human experiment was approved back in January 2009, and they were supposed to start experiments with patients in July.
As an aside, one excuse offered by Geron as to why the trial had not yet started was car airbags... apparently the airbags in accidents are keeping patients from getting severe spinal cord damage to qualify for the trial.
Many have expressed concern about the risky nature of Geron's experiments with patients, including some embryonic stem cell researchers. Evan Snyder, a leader in the stem cell field, has noted that "A clinical trial is nothing more than an experiment on a human," he says. "Most experiments fail." And James Wilson, gene therapy researcher, warns stem cell scientists not to repeat the mistakes of his own field, including rushing into unsafe clinical trials.
The FDA hold is likely due to further safety concerns with embryonic stem cells. That would seem to be the only grounds for a hold based on federal regulations under CFR sec. 312.42. Geron claims that no teratomas have been observed in animal studies, though they do admit "In some animals, human non-neural differentiated cell types were observed in the injury site". After the current FDA hold was iissued, Geron put out a statement explaining that cysts developed at the injury sites of treated animals, and they are working with FDA to answer any questions. They claim no teratomas have been seen, and hopefully nothing like this.
Still, there is cause for concern. Dr. Steven Goldman says
Its not ready for prime time, at least not in my mind, until we can be assured that the transplanted stem cells have completely lost the capacity for tumorigenicity.
But with the political pressure in favor of embryonic stem cell research, the hold will likely be release and the experiments on patients move ahead. And Geron will likely claim success (to get another stock bump.) Despite the fact that adult stem cells have already shown documented evidence not only of their safety, but of their efficacy at treating spinal cord injury.