One Small Step for Embryonic Stem Cells
FDA approves first clinical trial for stem cell treatment
In our shrill political climate let’s celebrate the quiet passing of a science milestone.
Last week the Food and Drug Administration gave its first approval for a clinical trial of an embryonic stem cell treatment. Embryonic stem cells are special because they can grow, or differentiate, into any kind of human tissue. Many believe they hold great promise for treating a wide range of diseases and disorders, from Alzheimer’s to cancer to spinal cord injuries to blindness.
The FDA had put the application from biopharmaceuticals company Geron Corp, which produced the cells, on clinical hold after some mice given the treatment developed tiny spinal cysts. But another animal study found no cysts. The testing will involve patients with recent spinal cord injuries, who will receive infusions of embryonic stem cells that have been differentiated into cells that can produce myelin, the coating that conducts electrical impulses in the spine.
There is no expectation that this cell treatment would magically regenerate spinal cords, though much could be learned from a greater understanding of how new cells integrate into damaged tissue. Rather, the goal is to facilitate some improved potential for movement along with strenuous physical rehabilitation. It is thought that recently injured patients might be more susceptible to improvement.
The company is reported to have spent $150 million to get the trial approved.
The stem cells developed by the company are derived from an embryo that was left over following fertility treatment. It had to be donated with full informed consent by the couple. Geron was able to proceed with the lab work to develop the treatment in spite of the Bush administration policy that severely limited federally funded embryonic stem cell research. Several years ago the company produced dramatic footage of injured rats that had been treated with the cells and were able to regain movement.
The greatest concern that experts have about the trial is that potent cells injected into the spine might develop into tumors called teratomas. This worry explains the FDA’s cautious approach. Although there are nonembryonic stem cell treatments for spinal cord injury that have been tried, they have been criticized for inadequate safety data from animals and unclear explanations of surgical procedures. By contrast, owing to the potential harm, novelty, and public controversy, the Geron trial is surely among the most intensively reviewed proposed clinical trials in history.
All this does not guarantee success, of course, nor does it guarantee that no harms will result. This is biology in the real world, not a computer simulation. But it does establish a reasonable regulatory pathway for human embryonic stem cell treatments for serious diseases that currently have only very inadequate therapies, a milestone that would have been all but political science fiction just a few years ago.
Meanwhile, thanks to the Obama administration’s responsible stem cell policies, dozens of new embryonic stem cell lines are being approved for federally funded research under grants from the National Institutes of Health. This should lead to more academic centers engaging in targeted research with these and other stem cells sources.
While the FDA’s approval of the Geron trial is just a small incremental step forward for potentially lifesaving research, it represents a significant break from past bickering, and raises the inkling of hope that someday we may wonder what all the shouting was about.
Jonathan D. Moreno, Ph.D., is the David and Lyn Silfen University Professor of Ethics and Professor of Medical Ethics and of the History and Sociology of Science at the University of Pennsylvania, and the Editor-in-Chief of Science Progress.
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