Kris Boesen, a 20-year-old from Bakersfield, California, was paralysed from the neck down after a car crash in March 2016. A few weeks later he received ten million experimental stem-cell-derived cells, called AST-OPC1, injected directly into his damaged cervical spinal cord at Keck Medical Center of USC. Three months on he could feed himself, use a phone, write his name and drive a motorised wheelchair.
His recovery was real and remarkable, but it came from an early-stage clinical trial, not an approved cure. This article explains what happened to him, what the trial was testing, what the wider results showed, and what the story does and does not mean for people living with spinal cord injury.
The crash and the prognosis
On 6 March 2016, shortly before his 21st birthday, Boesen’s car fishtailed on a wet road, hit a tree and slammed into a telephone pole. The impact caused a severe injury to the cervical spine, the part of the spinal cord in the neck that controls breathing, the arms and the hands.
Doctors told his parents he would probably be paralysed from the neck down for life. At the time he was a sports car enthusiast studying to become a life insurance broker. Injuries like his are usually treated with surgery that stabilises the spine, which protects against further damage but does little to bring back movement or feeling.
The SCiStar trial and AST-OPC1
Boesen’s family agreed to enrol him in SCiStar, a Phase 1/2a clinical trial run by Asterias Biotherapeutics of Fremont, California. The trial was testing AST-OPC1, cells grown from embryonic stem cells and turned into oligodendrocyte progenitor cells. In the healthy nervous system, oligodendrocytes make myelin, the insulating layer around nerve fibres, and support nerve cells. In laboratory studies the cells released growth factors, encouraged new blood vessels and helped re-insulate nerves.
Timing was strict. Patients had to be between 18 and 69 and receive the injection 14 to 30 days after injury. Boesen first had to come off a ventilator, which the team managed in five days instead of the usual three weeks or so. In early April 2016 a surgical team led by Dr Charles Liu, director of the USC Neurorestoration Center, injected 10 million cells. Keck was the first centre in California to treat a patient in the trial and one of six US sites. Some reprints of this story wrongly give the year as 2018.
Liu described the gap the trial was trying to fill: standard spinal surgery “does very little to restore motor or sensory function.”
What changed for Kris
The first signs of improvement came about two weeks after surgery, not three as some reports said. He left hospital roughly six weeks after the operation and continued rehabilitation at home in Bakersfield.
By 90 days his motor function had improved by up to two spinal cord levels. In everyday terms, that meant he could eat on his own, use a mobile phone, write his name, operate a motorised wheelchair and hug his family and friends. Sensation and strength in his arms and hands had also returned to a degree.
Boesen was clear about what he had hoped for: “All I’ve wanted from the beginning was a fighting chance.” He also said that if there was any chance of walking again, he would do whatever it took. His doctors, however, declined to predict how much more he would recover.
What the wider trial showed
Boesen was one of 25 people treated in SCiStar. Three received a low safety dose of 2 million cells, and the other 22 received 10 to 20 million. According to results reported in 2019, after 12 months 21 of those 22 patients, about 95%, had recovered at least one motor level on at least one side, and 7, about 32%, had recovered two or more levels. The sponsor reported no serious side effects linked to the cells, and MRI scans showed no harmful changes.
These numbers are encouraging but need careful reading. The study was open-label and single-arm, meaning everyone got the treatment and there was no comparison group. People with spinal cord injuries often regain some function naturally in the first year, especially with intensive rehabilitation, so it is impossible to say how much of the improvement came from the cells. The trial’s main purpose was to test safety and dosing, not to prove the treatment works.
The therapy, now called OPC1, passed to Lineage Cell Therapeutics. In December 2020 the company said it was reviewing options for a later-stage, comparative trial and working on better manufacturing and delivery methods. That kind of controlled study is what will be needed before regulators could approve it.
Myths about stem cell treatments
- “Stem cells cured him.” Boesen regained important arm and hand function, but he remained a wheelchair user, and the treatment is still experimental.
- “He was the first person ever treated with stem cells for paralysis.” He was the first patient in California treated in this specific trial. Other spinal cord cell trials, including earlier work with the same cell line, came before.
- “Stem cells will soon cure Parkinson’s, diabetes and cancer.” Researchers are testing cell therapies for many diseases, and some blood stem cell transplants are long-established treatments. But for most conditions, cell therapies are still in trials, and no single stem cell treatment cures them all.
- “Clinics that sell stem cell injections offer the same thing.” Many private clinics market unproven products outside clinical trials. Legitimate research is registered, closely monitored and usually free for participants.
Anyone considering a stem cell treatment should talk to a doctor, ideally a spinal cord injury specialist, and check whether the treatment is part of a registered clinical trial.
Why one patient’s story still matters
A single case cannot prove a therapy works, but stories like Boesen’s show why such trials exist. Regaining the use of the hands can mean the difference between needing help for every meal and living with real independence. That is why researchers, patients and funders such as the California Institute for Regenerative Medicine, which supported SCiStar, continue to invest in careful, controlled studies.
His story is also a reminder of how much depends on fast, coordinated care: the rapid ventilator weaning, the narrow injection window and the rehabilitation team at Rancho Los Amigos National Rehabilitation Center all played a part alongside the cells themselves.
Sources: Keck Medicine of USC / HSC News, 9 September 2016, California Institute for Regenerative Medicine, May 2019: one-year SCiStar results, Lineage Cell Therapeutics, December 2020: SCiStar and OPC1 update.
COMMENTS