Japan approved Stemirac, a stem cell treatment for spinal cord injuries, Nature reports.
The trial underlying the treatment's approval was not double-blinded, as Japanese regulations do not require double-blinded studies for approval. The unpublished study comprised 13 people who experienced spinal cord injuries. Approximately 50 million to 200 million mesenchymal stem cells were extracted from the participants' bone marrow and intravenously infused back into patients 40 days after their injuries. Researchers found the patients regained some lost sensation and movement, according to the report.
On the basis of this trial, Japan granted Stemirac conditional approval. It can be marketed and sold if researchers collect data from the participants over the next seven years to demonstrate its efficacy. Neurosurgeon Osamu Honmou, MD, PhD, who helped develop the treatment, claimed that after six months, 12 of the 13 patients improved by at least one level on the American Spinal Injury Association impairment scale.
However, previous studies in have found that intravenously infused MSCs tend to get stuck in the lungs. NIH stem cell researcher Pamela Robey, PhD, told Nature, "The fact that the cells are trapped in the lungs makes it difficult to see how they can be effective in the spinal cord." According to Jeffery Kocsis, PhD, a neurology researcher who has collaborated with Dr. Honmou, the cells may be of some benefit, but further work is necessary to substantiate the treatment's efficacy.
Once the treatment is sold to patients, it will be harder for the research team to gather evidence that it is effective, according to UC San Francisco neurologist Arnold Kriegstein. Paying for treatments can increase the likelihood that a patient will experience a placebo effect. "I do not think it is morally justified to charge patients for an unproven therapy that has risks," Dr. Kriegstein told Nature.