A Stanford researcher has injected 2 million human embryonic stem cells into the spinal cord of a paralyzed patient at Santa Clara Valley Medical Center, marking the first West Coast effort to test the potential therapy.
The experiment, announced Tuesday, is designed only to test safety, but doctors will also note whether it improves sensation or helps the patient regain movement.
The patient is the fourth of 10 people who will receive the cells, developed and manufactured by Menlo Park’s Geron Corp. Only newly injured patients with paraplegia are eligible for the small trial, being held at seven sites around the U.S. The patient’s name was not released. Although just a first step, the study “signifies a major advance in translating an innovative research discovery into clinical therapy,” said Stanford neurosurgeon Dr. Gary Steinberg, who implanted the cells.
Following last Saturday’s surgery, the patient entered an intensive inpatient rehabilitation program at Valley Med under the supervision of spinal cord injury specialists Dr. Stephen McKenna and Dr. James Crew.
Interest in the field of spinal repair was sparked by a 1982 discovery by Canadian scientist Albert Aguayo that injured neurons could grow and make new connections. This suggested a future where paralysis could be limited, perhaps even reversed.
It gained momentum with the inspiration of the late actor Christopher “Superman” Reeve, who as a quadriplegic urged a more aggressive approach to paralysis research. He also backed the 2004 passage of Proposition 71, creating a state-run Institute for Regenerative Medicine to expand the use of embryonic stem cells.
The hope is to help not just the 11,000 people who suffer spinal cord injuries every year, but the many more living with neural damage due to stroke, cerebral palsy, Parkinson’s or Lou Gehrig’s disease.
Insulating sheath
This new trial with the cells, called GRNOPC1, is the first to have been reviewed by the Food and Drug Administration. After repeated delays, last year the FDA finally gave Geron Corp. the green light.
Scientists hope that the cells, which are precursors to central nervous system cells called oligodendrocytes, will form a restorative, myelin sheath around the damaged spinal cord.
This sheath is necessary for the transmission of the electric signals along the spinal cord that trigger muscles to move, and relay our sense of touch and temperature. Damage to this sheath is a common cause of paralysis.
Some critics urged that the cells undergo greater testing, in dogs or monkeys, before injection in humans. They worry this first high-profile human test could create unrealistic expectations — and if it fails, it would dash hopes spawned by the discovery of embryonic stem cells.
Scientists concede that they don’t yet know whether these cells will survive, migrate to the proper part of the damaged nervous system and then restore the myelin sheath.
And it remains unclear how much of a difference this new myelin would make to people with spinal cord injuries. People are paralyzed largely because the nerves themselves — the wires — are cut or damaged. Simply restoring the insulation doesn’t fix that break.
To complicate things further, spinal cord injuries can be highly unpredictable. Sometimes patients simply improve on their own.
Special teams
But researchers believe that some neurons remain intact after an injury and could be saved. In rat experiments, paralyzed animals started shuffling after treatment, according to findings by UC Irvine’s Dr. Hans Keirstead, who collaborates with Geron.
Geron reportedly spent months training special teams of doctors at seven secret sites around the country so that they could be ready to act quickly. Then the teams waited for a patient who met the study’s strict criteria.
In June, Geron reported preliminary results of the trial on the first two patients at two meetings: the 2011 International Conference on Spinal Cord Medicine and Rehabilitation and the 2011 Spine Symposium. The results so far show no significant adverse effects experienced by either patient. If the new trial of 10 patients shows that the treatment is safe, future trials will be designed to determine whether the cells are able to improve participants’ clinical symptoms.
“I believe it is critically important to encourage and take part in stem cell trials like this,” said Stanford’s Steinberg, “which represent a new era in the effort to restore function for patients with stroke, brain injury, Parkinson’s disease and other devastating neurologic disorders.”
Contact Lisa M. Krieger at 408-920-5565.
stem cell study
STUDY: Safety, not effectiveness. Ten patients, seven sites. (Two received surgery in Atlanta, one in Chicago.) This was the first patient west of the Mississippi River.
ELIGIBILITY: Only patients with damage to a specific region of their thoracic spine — from the shoulder blades to the base of the rib cage. They must have paraplegia, which occurred within two weeks.
SPONSOR: Geron Corp. of Menlo Park, Calif.
FUNDING: Geron received a $25 million grant from the California Institute for Regenerative Medicine.
FOR MORE INFORMATION: http://clinicaltrials.gov/ct2/show/NCT01217008
