Kris Boesen in 2016, after doctors at Keck Medical Center of USC injected 10 million stem cells into his damaged spine as part of a multisite clinical trial. (Greg Iger/Keck Medicine of USC))
Update Sept. 23: You can read our original post about the remarkable case of Kris Boesen after this update. But some data on the trial that Boesen is participating in was released last week by Asterias Biotherapeutics, the company that developed the stem cells injected into Boesen and other patients with cervical spinal cord injuries.
Asterias says the trial results to date are encouraging. The sample is still extremely small and nothing is really proven at this point, but the data are certainly positive for other patients besides Boesen.
There are two groups of patients: three who received a dose of 2 million stem cells and five who received a larger dose of 10 million.
To measure improvement, researchers use the Upper Extremity Motor Scale, or UEMS. The scale runs from zero, which indicates total paralysis, to five, which means a patient has active movement.
First cohort, 2 million stem cells injected: On the six-point UEMS scale, one of three patients improved one motor level on one side of the body, while the other two patients improved one level on both sides.
Second cohort, 10 million stem cells: One of four patients improved two levels on both sides. Two other patients showed two levels of improvement on one side. And the fourth patient improved one level on one side. (One of the five patients in this group has not yet reached the 90-day point at which results are measured, so no report on that patient yet.)
The other significant finding, Asterias said, is that no one showed any measurable negative effects of the therapy -- researchers started with the smaller dose to make sure patients weren't harmed by the experimental trial, then went to the higher 10-million-cell dose.
Researchers have said the optimal dosage target is 20 million cells, but that point has not been reached yet in the trial.
The next milestone for getting a clearer picture of the results will be at the six-month mark for the second cohort, in January 2017.
All patients in the trial, being conducted at six sites around the country, have either "lost all movement below their injury site and experience severe paralysis of the upper and lower limbs," or "lost all motor function but may retain some minimal sensory function below their injury site," according to Asterias.
Rod Boesen says his son, Kris, was so bad off he couldn't move a muscle from the neck down, and needed a ventilator to keep him drawing breath.
In March, Kris, then 20, was driving on a wet road when he crashed his car into a tree and a telephone poll, crushing three of his vertebrae. The accident left him with almost no feeling south of his neck, and doctors foresaw that he would lead the life of a paraplegic.
"They thought he was going to be totally, from the head on down, paralyzed," says Rod
But that has not been the case; Kris has regained the use of his hands and arms.
In April, as part of a research trial, a surgical team from USC's Keck Medical Center injected millions of embryonic stem cells into Boesen's spine. Two weeks later, Boesen began to show some improvement. After six weeks, he was discharged and returned home to Bakersfield, California to continue his rehabilitation.
Now, five months after the stem cell injection, Boesen is remarkably self-sufficient, considering the initial prognosis. From feeding himself to talking on the phone to being able to twist the cap off a soda bottle, life is a degree more normal than anyone thought possible.
"We used to lift weights, that's something we used to do together," his dad says. "Now we're doing that again. Only it's a lot less weight."
The goal of the experimental stem cell treatment is to regrow the protective myelin sheath around each nerve, giving them a chance to heal. Whether this has occurred in Boesen yet is unknown--doctors would need to administer a spinal tap to find out, and that is dangerous for patients in this condition.
So researchers don't know yet whether Boesen's recovery is due to the injection of stem cells. All they can say is that his progress has been remarkable, if not unprecedented for this type of spine injury.
The clinical mid-stage trial is very small; if it's successful, FDA approval would still be many years away. But the results in Boesen and four other patients have thus far been very encouraging.
With most spinal injuries, doctors and physical therapists usually look to see what's still intact, then try to make incremental improvements. As a matter of course, people don't recover much of the movement or function they've lost.
Charles Liu, a neurosurgeon and director of the USC Neurorestoration Center that's leading the research, says the goal is not to attempt to repair the entire vertebral column, but to target the cervical spine and restore neurological function.
The other four patients in the cohort have shown some progress, but not as much as Boesen, according to Liu. Each person received one shot of stem cells, and the other patients got lower doses than the 10 million stem cells injected into Boesen's cervical spinal cord.
Boesen's recovery may have been helped by his young age, and by the fact that he received the stem-cell injection so soon – just five weeks after his car crash, Liu said.
"This is unique, yes," Liu said of the clinical trial. "No one has taken this approach before."
Or achieved these kind of results. Liu cautioned that not all spinal injury victims will benefit from this type of treatment, but he said it does offer hope that there may be a remedy for some spinal injuries.
Data from patients in the study is set to be released on Wednesday.
Get the best of KQED's science coverage in your inbox weekly.