The US Food and Drug Administration (FDA) has delayed the start of a clinical trial that plans to use human embryonic stem cells (ES cells) to treat spinal cord injury. The trial is being run by Californian based company Geron. The FDA originally gave the go-ahead for the trial in January, but now has halted the start in order to review new data submitted by Geron.
The company has created oligodendrocyte precursors from human ES cells. Oligodendrocytes support nerve cells and Geron hopes the cell therapy, called GRNOPC1, can promote healing in people with recently severed spinal cords. Geron has been testing GRNOPC1 on animals, studying its effect in increasing doses and in other neurological diseases. The FDA has put the trial on hold while it reviews the new animal data.
There has been speculation as to what the halt means. It could be that the new data has raised concerns about the safety of the product. A particular concern with any stem cell therapy is that the cells could grow uncontrollably, giving rise to tumours. Alternatively, the FDA may just need more time to consider the new data.
The halting of clinical trials is not unusual, especially with such new or innovative treatments. Stem cells offer exciting promise for future therapies, but there are many significant technical hurdles to overcome before they will be seen in clinics. Many researchers believe that ES cells have the potential to be developed into new treatments for cancer, neurological diseases, diabetes and more. Some religious and pro-life groups contest the use of ES cells, but research that seeks new treatments for currently incurable diseases continues.