The first embryonic stem cell-based clinical trial in spinal cord patients in the U.S. is screening a lot of patients but has found only four so far who meet the criteria to get the infusion, one of the trial’s principal investigators said.
Dr. Richard Fessler, of Northwestern University, spoke Tuesday at the Charlie Norwood VA Medical Center as part of the First Augusta Research Symposium on Advances in Warrior Care.
Spinal cord injuries affect about 10,000 people a year, and an estimated 250,000 are living with the injury; about 7 percent of injuries are related to the military. Centuries ago, the average life expectancy for a person paralyzed by the injury was about two years, and
it is still about that for someone who is paralyzed and ventilator-dependent, Fessler said.
While at the University of Florida in the late 1990s, Fessler used cells derived from fetal tissue to treat eight patients with spinal cord injuries; at least one showed marked improvement in walking. Those trials were halted when President George W. Bush put stronger restrictions on using embryonic stem cells, Fessler said.
In 2010, Geron Corp. was granted the first permission by the Food and Drug Administration to begin using embryonic stem cell-based therapy in human spinal cord patients. The infusion is actually human embryonic-derived oligodendrocyte progenitor cells that have shown some ability to regrow the myelin sheath surrounding the nerves and to stimulate nerve growth in animal models, according to Geron.
The human trial is meant to show that the infusion is safe and to look at its neurological impact. Fessler acknowledges there are ethical questions to it and his previous work, and he said he has “already had death threats in the study I am doing now.”
Of the 120 patients screened so far, about 45 were candidates but only four have been admitted, Fessler said. A fifth patient is under evaluation. The strict criteria make it difficult to admit patients to the trial, Fessler said. Even a slight fever at the time of infusion can keep a patient out of the trial.
So far, there have been no serious adverse events from the infusions, Fessler said.