Whenever I give a talk on stem cells one of the questions I invariably get asked is “how do you know the cells are going where you want them to and doing what you want them to?”
The answer is pretty simple: you look. That’s what Asterias Biotherapeutics did in their clinical trial to treat people with spinal cord injuries. They used magnetic resonance imaging (MRI) scans to see what was happening at the injury site; and what they saw was very encouraging.
Asterias is transplanting what they call AST-OPC1 cells into patients who have suffered recent injuries that have left them paralyzed from the neck down. AST-OPC1 are oligodendrocyte progenitor cells, which develop into cells that support and protect nerve cells in the central nervous system, the area damaged in spinal cord injury. It’s hoped the treatment will restore connections at the injury site, allowing patients to regain some movement and feeling.
Taking a closer look
Early results suggest the therapy is doing just that, and now follow-up studies, using MRIs, are adding weight to those findings.
The MRIs – taken six months after treatment – show that the five patients given a dose of 10 million AST-OPC1 cells had no evidence of lesion cavities in their spines. That’s important because often, after a spinal cord injury, the injury site expands and forms a cavity, caused by the death of nerve and support cells in the spine, that results in permanent loss of movement and function below the site, and additional neurological damage to the patient.
Another group of patients, treated in an earlier phase of the clinical trial, showed no signs of lesion cavities 12 months after their treatment.
Positively encouraging
In a news release, Dr. Edward Wirth, the Chief Medical Officer at Asterias, says this is very positive:
“These new follow-up results based on MRI scans are very encouraging, and strongly suggest that AST-OPC1 cells have engrafted in these patients post-implantation and have the potential to prevent lesion cavity formation, possibly reducing long-term spinal cord tissue deterioration after spinal cord injury.”
Because the safety data is also encouraging Asterias is now doubling the dose of cells that will be transplanted into patients to 20 million, in a separate arm of the trial. They are hopeful this dose will be even more effective in helping restore movement and function in patients.
Jake Javier, participant in Asterias clinica trial
Starting a clinical trial is like taking a step into the unknown. It’s moving a potential therapy out of the lab and testing it in people. To reach this point the researchers have done a lot of work trying to ensure the therapy is safe. But that work was done in the lab, and on mice or other animals. Now it’s time to see what happens when you try it in the real world.
It can be quite nerve wracking for everyone involved: both the researchers, because years of hard work are at stake, and the patients, because they’re getting something that has never been tested in humans before; something that could, potentially, change their lives.
Today we got some good news about one clinical trial we are funding, the Asterias Biotherapeutics spinal cord injury trial. Asterias announced that its Data Monitoring Committee (DMC) has reviewed the safety data from the first two groups of patients treated and found no problems or bad side effects.
That’s an important first step in any clinical trial because it shows that, at the very least, the therapy is not going to make the patient’s condition any worse.
The big question now, is will it make their condition better? That’s something we’ll come back to at a later date when we have a better idea how the people treated in the trial are doing. But for now let’s take a deeper dive into the safety data.
Asterias – by the numbers
This current trial is a Phase 1/2a trial. The people enrolled have all experienced injuries in the C5-C7 vertebrae – that’s high up in the neck – and have essentially lost all feeling and movement below the injury site. All are treated between two weeks and one month after the injury was sustained.
The therapy involves transplants of Asterias’ AST-OPC1 cells which were made from human embryonic stem cells. The AST-OPC1 cells have been turned into oligodendrocyte progenitors, which are capable of becoming the kind of cells which help protect nerve cells in the central nervous system, the area damaged in spinal cord injury.
The first group of three patients in the Asterias trial was given 2 million cells. The second group of five patients received 10 million cells. The DMC said the safety data from those patients looked fine, that there were no signs of problems.
As Dr. Edward Wirth, the Chief Medical Officer at Asterias, said in a news release, this means the company can plan for its next phase:
“The positive safety data in the previous phase 1 study and in the ongoing phase 1/2a study gives us the confidence to now proceed to administration of 20 million cells, which based on our significant pre-clinical research is likely well within the dosing range where we would expect to see clinically meaningful improvement in these patients.”
Asterias is now looking to enroll 5-8 patients for this 20 million cell phase.
For people like Jake Javier this news is not about numbers or data, it’s personal. Earlier this summer Jake broke his neck at a pool party, celebrating graduating from high school. It left him paralyzed from the chest down with extremely limited use of his arms and hands. On July 7th Jake was enrolled in the Asterias trial, and had ten million cells transplanted into his neck.
It could be months, even as much as one year, before we know if those cells are having any beneficial effect on Jake. But at least for now we know they don’t seem to be having any negative effects.
“First do no harm” is the cardinal rule that all budding physicians are taught. This trial seems to be meeting that benchmark. Our hope now is that it will do a lot more, and truly make a difference in the lives of people like Jake.
As Randy Mills, CIRM’s President and CEO, said in a news release:
“I recently met with Jake and heard first-hand what he and his family are going through in the aftermath of his injury. But I also saw a young man with remarkable courage and determination. It is because of Jake, and the others who volunteer to take part in clinical trials, that progress is possible. They are true heroes.”
* On a side note, Roman Reed, a great champion of stem cell research and a patient advocate extraordinaire, helped make much of this story happen. He helped Jake enroll in the Asterias trial ,and the research that led to this therapy was pioneered by Dr. Hans Keirstead who was funded by the Roman Reed Spinal Cord Injury Research Act.
Just 31 years old, Richard Lajara thought he was going to die.
Richard Lajara, the 4th participant in Geron’s stem cell-based clinical trial for spinal cord injury.
On September 9, 2011 he slipped on some rocks at a popular swimming hole and was swept down a waterfall headfirst into a shallow, rocky pool of water. Though he survived, the fall left him paralyzed from the waist down due to a severed spinal cord.
Patient Number Four
At that same time period, Geron Inc. had launched a clinical trial CIRM helped fund testing the safety of a stem cell-based therapy for spinal cord injury (SCI). It was the world’s first trial using cells derived from human embryonic stem cells and Lajara was an eligible candidate. Speaking to CIRM’s governing Board this past summer for a Spotlight on Disease seminar, he recalled his decision to participate:
“When I participated with the Geron study, I was honored to be a part of it. It was groundbreaking and the decision was pretty easy. I understood that it was very early on and I wasn’t looking for any improvement but laying the foundation [for future trials].”
A few months after his treatment, Geron discontinued the trial for business reasons. Lajara was devastated and felt let down. But this year the therapy got back on track with the announcement in June by Asterias Biotherapeutics that they had treated their first spinal cord injury patient after having purchased the stem cell assets of Geron.
Getting Hope Back on Track
Dr. Jane Lebkowski, Asterias’ President of R&D and Chief Scientific Officer, also spoke at the Spotlight on Disease seminar to provide an overview and update on the company’s clinical trial. A video recording of Lebkowski’s and Lajara’s presentations is now available on our web site and posted here:
As Dr. Lebkowski explains in the video, Asterias didn’t have to start from scratch. The Geron study data showed the therapy was well tolerated and didn’t cause any severe safety issues. In that trial, five people (including Richard Lajara) with injuries in their back received an injection of two million stem cell-derived oligodendrocyte progenitor cells into the site of spinal cord damage. The two million-cell dose was not expected to show any effect but was focused on ensuring the therapy was safe.
Oligodendrocyte Precursors: Spinal Cord Healers
As the former Chief Scientific Officer at Geron, Lebkowski spoke first hand about why the oligodendrocyte precursor was the cell of choice for the clinical trial. Previous animal studies showed that oligodendrocyte progenitors, a cell type normally found in the spinal cord, have several properties that make them ideal cells for treating SCI: first, they help stimulate the growth of damaged neurons, the cell type responsible for transmitting electrical signals from the brain to the limbs.
Second, the oligodendrocytes produce myelin, a protein that acts as an insulator of neurons, very much like the plastic covering on a wire. In many spinal cord injuries, the nerves are still intact but lose their myelin insulation and their ability to send signals. Third, the oligodendrocytes release other proteins that help reduce the size of cysts that often form at the injury site and damage neurons. In preclinical experiments, these properties of oligodendrocyte progenitors improved limb movement in spinal cord-severed rodents.
Together, the preclinical animal studies and the safety data from the Geron clinical trial helped Asterias win approval from the Food and Drug Administration (FDA) to start their current trial, also funded by CIRM, this time treating patients with neck injuries instead of back injuries.
The Asterias trial is a dose escalation study with the first group of three patients again receiving two million cells. The trial was designed such that if this dose shows a good safety profile in the neck, as it did in the Geron trial in the back, then the next cohort of five patients will receive 10 million cells. In fact, Asterias reported in August that the lower dose was not only safe but also showed some encouraging results in one of the patients. And just two days ago Asterias announced their data monitoring committee recommended to begin enrolling patients for the 10 million cell dose. If all continues to go well with safety, the dose will be escalated to 20 million cells in the third cohort of five patients. While two million cells was a very low safety dose, Asterias anticipates seeing some benefit from the 10 and 20 million cell doses.
Changing Lives by Increasing Independence
Does Lebkowski’s team expect the patients to stand up out of their wheelchairs post-treatment? No, but they do hope to see a level of improvement that could dramatically increase quality of life and decrease the level of care needed. Specifically, they are looking to see a so-called “two motor level improvement.” In her talk Lebkowski explained this quantitative measure with the chart below:
“If a patient is a C4 [meaning their abilities are consistent with someone with a spinal cord injury at the fourth cervical, or neck, bone] they will need anywhere from 18 to 24 hours of attendant care for daily living. If we could improve their motor activity such that they become a C6, that is just two motor levels, what you can see is independence tremendously increases and we go from 18 to 24 hour attendant care to having attendant care for about four hours of housework.”
Small improvements in movement abilities can be life changing for people with spinal cord injuries.
It’s so exciting the field is at a point in time that scientists like Dr. Lebkowski are discussing real stem cell-based clinical trials that are underway in real patients who could achieve real improvements in their lives that otherwise would not be possible.
And we have people like Richard Lajara to thank. I think Dr. Oswald Stewart, the Board’s spinal cord injury patient advocate, summed it up well when speaking to Lajara at the meeting:
“Science and discovery and translation [into therapies] doesn’t happen without people like you who are willing to put yourselves on the line to move things forward. Thank you for being in that first round of people testing this new therapy.”
Whenever I give a talk on stem cells one of the questions I invariably get asked is “how do you know the cells are going where you want them to and doing what you want them to?”
The Stem Cellar 