Oct. 11, 2010 - The first person treated with embryonic stem cells is an Atlanta patient paralyzed by a recent spine injury.
The clinical trial is a first step toward an eventual cure for paralysis, says study leader Richard Fessler, MD, PhD, professor of neurological surgery at Northwestern University Feinberg School of Medicine and a surgeon at Northwestern Memorial Hospital.
"We would love to see paralysis cured. Will that happen with this study? Of course not. We would be thrilled to see any beneficial effect at all," Fessler tells WebMD. "This is merely the first step in a long process that will take 10-25 years."
The study, taking place at up to seven medical centers, will enroll 10 patients in its first stage. Patients with complete grade A thoracic spinal cord injuries will be treated seven to 14 days after their injury. Such patients cannot move or feel their lower bodies and usually lose bladder and bowel control. Physical therapy has only limited benefits.
Embryonic Stem Cells Mature Before Injection
Before being given to patients, the embryonic cells are matured into "precursor cells" destined to become oligodendrocytes. These are the cells that make up the myelin sheaths that protect nerves in the spinal cord.
It's hoped that the GRNOPC1 cells will restore spinal function by replacing lost myelin and by giving off chemical signals that promote new nerve growth.
The cells are injected directly into the site of the spinal injury using a syringe positioning device that attaches to the frame of the operating room table.
Patients in the study must undergo short-term immune-suppressing therapy to ensure that their bodies do not reject the new cells.
The Atlanta patient, and nine more patients to be enrolled in the first phase of the clinical trial, get only small doses of the GRNOPC1 cells. It's the human equivalent of the smallest dose to show benefit in animal studies. If the treatment proves safe, the next phase of the study will use up to tenfold larger doses of the cells.
Key questions are whether the stem cells will spur growth of tumors called teratomas, whether the cells will be rejected by the immune system, and whether there will be unintended consequences such as nerve pain.
In preclinical studies, animals with severe spinal injuries regained the ability to walk after treatment with OPC1 cells. The animals did not develop teratomas, reject the cells, or suffer nerve pain.
In addition to showing clinical improvement, treated animals' damaged nerves became coated with new myelin and there was new nerve growth in the vicinity of the injected cells.
Whether humans will respond as well as animals remains an open question. Study patients will be followed closely, and must agree to check-up visits for 15 years.
So far, the only active clinical trial centers are at Northwestern University in Chicago and the Shepherd Spinal Center in Atlanta.
Fessler notes that this study is not the first time he's explored using embryonic tissues to repair spinal injuries. In the late 1990s, when he was at the University of Florida, Fessler and colleagues explored the use of fetal spinal tissue to treat paralysis.
Overall, this treatment showed little effect. But individual patients had substantial improvement -- and Fessler says that crucial knowledge gained in that study planted the seeds of the stem-cell trial that began today.
In addition to the GRNOPC1 cells for nervous system diseases, Geron is also making six other cell types from embryonic stem cells:
- Heart muscle cells for treatment of heart failure and heart attack
- Pancreatic islet cells for the treatment of diabetes
- Cartilage cells for the treatment of osteoarthritis
- Liver cells for drug testing
- Antigen-presenting cells for immunotherapy of cancer and infectious diseases
- Bone cells for the treatment of osteoporosis and bone fracture