Four patients to be selected for the trial slated to start in autumn will have been diagnosed between two to four weeks beforehand as totally paralyzed with no mobility and sensory functions, the most severe form of spinal cord injury.
Okano, in a news conference at Keio University Hospital in Tokyo’s Shinjuku Ward on Feb. 18 to announce the trials, said it will take a year or so to confirm the safety and validity of the treatment, coupled with rehabilitation, once the first transplants of cells clusters have been performed.
photo credit to: https://www.the-scientist.com
Given that tumors are a potential side effect of the treatment using iPS cells, and therefore a major cause of concern, the team put priority on safety by deciding to use relatively small amounts of cells: 2 million cells for each transplantation.
The subacute phase lasts only for about six months after the onset of injuries, after which patients enter the chronic phase that is characterized by paralysis. Most patients of spinal cord injuries in Japan are in the chronic phase.
Makoto Ohama, who heads Spinal Injuries Japan, an association of people with spinal cord injuries across the country, said targeting patients in the subacute phase could raise hopes for those with a chronic condition.
Patients who were injured within the previous six months, including those in the subacute phase, are deemed more likely to recover than those in the chronic phase due to scar tissue formed by the spinal cord injuries. The presence of such tissue makes the transplantation of iPS cell clusters difficult and hinders regeneration of nerve cells.
However, treatment for patients diagnosed as being completely paralyzed is extremely difficult, especially when they are in the chronic phase. When to convert them into a commercial reality will be decided in light of how the clinical study progresses.
Reference: Ministry OKs 1st iPS cell therapy trial for spinal cord injuries
