Jan. 23, 2009 -- Geron Corp. will test its OPC1 cells in 10 patients completely paralyzed by recent spinal cord injuries. It's the first FDA-approved study of an embryonic stem cell product in human patients.
A major factor in such injuries is loss of the myelin sheath that protects nerve cells. It's hoped that the OPC1 cells will restore nerve function not only by replacing lost myelin but by giving off chemical signals that promote new nerve growth.
That's the hope. But first things first: The initial 10-patient study will use small doses to make sure the treatment is safe. Only if safety is ensured will the trial be expanded to use therapeutic doses of the cells. However, even this first study will gather data to see if there's any sign of improvement.
"This marks the dawn of a new era in medical therapeutics," Geron CEO Thomas Okarma, MD, PhD, said in a news conference. "We hope to achieve the restoration, perhaps permanently, of organ function by the injection of replacement cells. ... We are simply harnessing the biology of normal human development."
Okarma suggests that the OPC1 cells may not only help restore damaged spinal cords, but might also help patients suffering from multiple sclerosis, stroke, and other diseases of the central nervous system.
The Geron cells are grown in the laboratory from embryonic stem cells. The OPC1 cells used in the treatment are not early stem cells, but have developed into "precursor" cells destined to be oligodendrocytes -- the cells that make up the myelin sheaths that coat nerves in the spinal cord.
Cell biologist Robert McKeon, PhD, studies spinal cord injuries at his Emory University lab. He's familiar with the Geron cells.
"They are asking these cells to do something I don't know they are capable of doing," McKeon tells WebMD. "The hype we often hear is that these cells will reconstitute the spinal cord and provide new tissues to promote recovery. When you ask oligodendrocytes to grow nerve cells, to make synapses, and to modulate the inflammatory damage from the injury -- that is a lot to ask an oligodendrocyte to do."
Okarma notes that the OPC1 cells have restored nerve functions in animal studies. But McKeon says actual human spine injuries are much more complicated than those studied in lab animals.
McKeon says much will be learned from the Geron study. But he warns patients that the treatment is far from proven, and that much work remains to be done.