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))
A small stem cell trial in which patients with severe spinal injuries appeared to make remarkable progress is still showing excellent results, according to the company conducting the research.
One of the patients in the trial is 21-year-old Kris Boesen, from Bakersfield, California, whose story we reported on last year. A car crash had left the Bakersfield, California native with three crushed vertebrae, almost no feeling below his neck, and a grim prognosis. Doctors believed he would live the rest of his life as a paraplegic.
Enter stem cell therapy. Most treatments for serious spinal injuries concentrate on physical therapy to expand the range of the patient's remaining motor skills and to limit further injury, not to reverse the actual damage. But last April, as part of an experimental phase 2 clinical trial called SCiStar, researchers injected Boesen with 10 million stem cells. By July, he had recovered use of his hands to the point where he could use a wheelchair, a computer and a cellphone, and could take care of most of his daily living needs. In recent months his progress has continued, says his father.
Boesen is not the only patient to have improved in the trial, according to Asterias Biotherapeutics, which is conducting the research. Boesen is part of a cohort of six patients who were experiencing various levels of paralysis and were injected with the 10 million stem cell dose. In a Jan. 24 update, the company said five of those patients had improved either one or two levels on a widely used scale to measure motor function in spinal injury patients.
On Tuesday, Asterias issued a new update,announcing that the sixth patient in the cohort has experienced a similar improvement.
While spontaneous recovery for spinal injury patients does occur, the likelihood of all six patients recovering to the degree they have is less likely, researchers say.
“This is as good as you could hope at this point,” said Charles Liu, Boesen’s neurosurgeon and director of the USC Neurorestoration Center. “So far all the evidence is pointing in the right direction.”
To measure improvement in spinal injury patients, researchers use two yardsticks: the Upper Extremity Motor Scale, or UEMS, and the International Standards for Neurological Classification of Spinal Cord Injury, or ISNCSCI. On the UEMS scale, patients are scored from 0 to 5 on their ability to use five key muscles in the wrists, elbows and fingers. The ISNCSCI scale assesses where damage has occurred along the different levels of the cervical vertebrae, which generally determines the scope of impairment to the body and the level of care needed.
For instance, if a patient has sustained damage at the fourth cervical vertebra down, known as C-4, at the base of the neck, it generally means that person is paralyzed from the neck down, requiring round-the-clock care and a ventilator to breathe. A patient with a C-5 injury may not be able to move her arms or hands, requiring about 6 to 12 hours per day of assisted care; and at the C-6 level, better motor function may allow a patient to take care of most of her daily living needs on her own.
Which is all to say that even one level of recovery could substantially improve the daily life of a spinal injury patient.
According to Asterias, all six patients in the 10 million-cell cohort have improved their general UEMS scores, and jumped at least one motor level on the ISNCSCI scale on one or both sides of their body.
Two patients have improved two motor levels on one side; and one patient, Boesen, has improved two motor levels on both sides.
Steve Cartt, president and CEO of Asterias, said another patient, Jake Javier of Danville, California, has gone from partial paralysis to being able to use his hands well enough to consider pursuing a computer science career.
'Throws Like a Regular Throw'
In September, Boesen’s father, Rod Boesen, told us how excited he was that his son had regained some feeling in one of his feet. Last week, at 11 months post-injection, the elder Boesen said Kris has continued to improve.
“Now he can move his toe and his knee together at the same time,” Boesen said. “They’re about to give him a manual wheelchair now [instead of a motorized one]. He can grip with his hands enough to use a manual one.”
Boesen said the movement in his son’s arms and hands has greatly improved since September. Kris, a former high school pitcher, had been flinging a ball to his dog “like people throw hand grenades,” Boesen said. “They kind of cradle them – and that’s how Kris would do it. … But now he throws like a regular throw, tosses that ball down the hall, has that release point down, and just wings it.”
Asterias is currently recruiting patients for a trial in which they'll receive 20 million stem cells, the optimal dose, according to company researchers. Two patients have already started the 20 million stem cell therapy, and six-month results from those patients will be released in the fall, Cartt said.
Patients who received 2 million stem cells in an earlier phase of the study have not shown much change in their condition, according to the Jan. 24 update.
While Boesen’s father is impressed with the results, the optimism of researchers inside and outside the study has been guarded. The trial is still in its early stages, and the sample size is small, said Paul Knoepfler, a cell biology professor and stem cell researcher at UC Davis, who is not involved in the SCiStar study.
"As a scientist, I still would want to wait for more data,” Knoepfler said. “It’s certainly interesting, but it’s still early. It’s a phase 2 trial.”
To address the issue of small sample size, Asterias is looking at historical data to determine the level of improvement for patients in similar circumstances who did not receive stem cell therapy. The company has said it found "a meaningful difference" in the recovery of its study patients compared to the norm.
Liu said one of the most important results is the lack of significant side effects or other negative outcomes resulting from the treatment to date.
"That’s very significant to me,” Liu said. “That’s the first thing you look for, is anyone hurt from this therapy.”
There was also a concern, he said, that some patients might regress over time, once the initial injection of stem cells wore off. That has yet to occur.
“No one has lost anything they’ve gained,” Liu said. “We were very happy to see that. This is all very promising."
The next step for the SCiStar trial will be to establish a control group, Cartt said.
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