Trial to Test Stem Cell Treatment of Spinal Cord Injuries

Spinal cord injury treatment could take a major step forward this year with a safety trial that will test the efficacy of injecting stem cells directly into the injury site.

The University of California-San Diego’s Institutional Review Board approved Neuralstem Inc.’s clinical trial protocol, which also has the blessing of the U.S. Food and Drug Administration. The first eight trial enrollees will be paraplegics who sustained a thoracic spinal cord injury one to two years ago and have no motor or sensory function below the point of their spinal cord injury. Thoracic spinal cord injuries are rare, according to the Christopher and Dana Reeve Foundation, because of the protection afforded by a person’s rib cage. In addition to the loss of function in legs, patients also experience a loss of physical sensation, bowel and bladder problems and sexual dysfunction. However, in most cases, function of the arms and hands are not affected.

“Moving our spinal cord cells into human trials for a second indication in the U.S. is a major step forward for the company,” Neuralstem Board Chairman and Chief Scientific Officer Karl Johe Ph.D., said. “We have demonstrated that the surgical route of administration is safe and robust; that the cells survive transplantation and are biologically active in the patients, and that both the cells and the surgery are well-tolerated and safe. In animals, we have shown compelling proof-of-principle of return of significant function. With 30 successful spinal surgeries completed in our ALS trials, we feel we are ready to tackle spinal cord injury and are excited to begin this study.”

Neuralstem’s latest trial will involve injecting stem cells into patients’ spines. The trial is designed to show the drug — in this case, stem cells — is safe, although researchers hope to provide some benefit as well.

In 2009, California-based Geron Corp. injected the first stem cells into a patient’s spinal cord, using the highly controversial derivative of human embryonic stem cells.But after treating at least four patients, the company ended the trial in 2011 due to expense and the company’s focus on cancer research.

That same year, Neuralstembeganitsclinical trial in patients with amyotrophic lateral sclerosis, also known as ALS or Lou Gehrig’s disease. That trial used a new device to inject stem cells into the spine without causing additional injury to the spinal cord. Neuralstem’s cells are not embryonic stem cells but rather cells taken from fetal spinal cords, which already have started to becomenerve cells.

Unlike the goal of the Geron trial, which was to re-mylenate nerve cells to re-establish connections from the spine to the brain — like fixing an exposed wire by providing a new cover — the goal in this new trial is to “actually build new circuitry,” Neuralstem CEO Richard Garr said.

“The stem cells are injected directly into the area of the injury and jump the gap with the new circuitry we’ve built,” he told CNN. “These cells don’t migrate to the site.”

In animal experiments, rats were injected with these human stem cells and recovered significant function in all lower extremity joints, according to Neuralstem. “The cells turned into neurons which grew a ‘remarkable’ number of axons that extended for ‘very long distances,’ bridging above and below the point of severance,” the company said in a statement, quoting study results from August 2012.

Neuralstem is trying to reconnect the nerve cells from below the injury site to cells above the point of injury to re-establish signals going to the brain, Johe said. He hopes to treat the first trial patient by July. “And then it would occur about once a month,” he noted.

The most recent discussed a much simpler method called epidural stimulation — a complimentary approach, according to Johe. This month, researchers showed that four patients with spinal cord injuries for more than two years ‘reawakened’ their muscles by moving their legs when electrodes implanted in the back were turned on, providing electrical stimulation to the spinal cord.

“There has been debate whether the motor neuron circuitry is intact below the injury point,” Johe said. “So now we know for sure (it is).”