In a move signaling the beginning of a new age in stem cell research, the Food and Drug Administration (FDA) has approved the first-ever clinical trial of stem cell therapy on human subjects. The trial, funded by the biotech company Geron, will test a procedure to repair spinal cord damage.
The therapy in questions involves the injection of precursor cells into the spine, where the cells will then differentiate into oligodendrocytes, the cells type that sheathes and protects the nerves of the spinal cord. As a Phase One trial, Geron's test will only examine the safety of the therapy, not the actual effectiveness.
"This is an important trial, there's a lot of hope riding on it," said Wise Young, director of the W M Keck Center for Collaborative Neuroscience at Rutgers University. "With this trial, we need to lower the expectations a bit. People are expecting miracles from a first trial, but it was only designed to test safety."
Geron, which first applied for FDA four years ago, expected to begin the trial last May, but became derailed by last minute objections from the FDA. Over the following months, Geron worked closely with the FDA to get the trial approved. The effort finally culminated today, with the announcement that the FDA would allow the trial to go ahead.
While Young did say that passing the rigorous, 4-year approval process earned the study the benefit of the doubt, he urged caution about overstating the significance of this study. Calling this the "first shot across the bow," Young compared the stage of stem cell therapy development to where antibiotics were in the 1940s.
For many in the field, the announcement resulted in more apprehension than excitement. "I think everyone in the field is taking their collective deep breath and hoping nothing bad happens," said Evan Snyder, Director of Stem Cells and Regenerative Medicine Program at Burnham Institute for Medical Research, "What would happen then would set the field back dramatically. I don't think it was ready for clinical trials."
Mark Noble, a professor in the Biomedical Genetics department at the University of Rochester echoed Young and Snyder's concerns. Noble noted that of the ten different types of cells that have been tested in spinal injury transplants, recent studies have shown that at least three can cause chronic pain syndromes after transplantation.
Noble and Snyder also worried that not enough work had been done to show that the implanted cells wouldn't form a stem cell tumor called a teratoma. But Young, reflecting the division within the research community about the trial, saw teratoma formation as unlikely due to the fact that the procedure uses precursor cells, which are less prone to form teratoma than more potent stem cells.
The trial also has limited applications. The procedure would only help people with recent spinal injuries, whose nerves remained intact. Even if later Phase two and Phase three show succeed, the procedure still wouldn't help people already in a wheel chair.
But just as Noble, Snyder and Young cautioned against expecting miracles from this early study, so too did they caution against taking a negative result as a failure of the field at large.
"In this early stage of stem cell medicine, its already clear that there will be some spectacular successes, but there will also be some failures," said Noble. "Even if this particular trial did not provide benefit or actually caused problems, this should not cause spinal injury patients to lose hopes, there are other technologies that are moving forward very rapidly."
