A study was published this week showing that rats improved function after receiving transplants of Neuralstem, Inc.'s human neural stem cells three days after a spinal cord contusion injury (at L3). The study, "Amelioration of Motor/Sensory Dysfunction and Spasticity in a Rat Model of Acute Lumbar Spinal Cord Injury by Human Neural Stem Cell Transplantation
," was led by Martin Marsala, M.D., of the University of California, San Diego (UCSD) School of Medicine.
The human cells in this experiment -- they call them NSI-566 cells -- are derived from a single, legally aborted fetus; these are the same ones used by Neuralstem in 15 patients in an ALS safety trial. They are also the same ones set for clinical trial in chronic SCI, which we will get to in a minute.
In all cases, the cells are injected into the exposed spinal cord in several locations; so far, they appear to be safe. For the ALS trial, the company reported earlier this month that the procedure “was found to be safe, well-tolerated, and promising for other spinal cord conditions.”
The company also notes that some of the patients benefited from the cell transplants. A 39-year-old man with ALS, Ted Herada, got two sets of stem cell transplants. After the first, in 2011, he was recovered a meaningful degree of function, then declined. A year later, he got more cells. Neuralstem reports that Ted recently completed 2.5 -mile fundraising ALS walk in Atlanta, “still going strong past finish line.” He is “Living a normal life: walking, climbing stairs, hands stronger again, increased dexterity.”
Says Principal Investigator Eva L. Feldman, M.D., University of Michigan, from a release
, “Although this phase of the trial was not powered to demonstrate efficacy, we appear to have interrupted the progression of the disease in one subgroup of patients. We are anxious to move to future trial phases to examine therapeutic efficacy.”
Indeed, a Phase II trial with much larger cell dosage has been approved. From the company:
The Phase II trial is designed to treat up to 15 ambulatory ALS patients, in five different dosing cohorts, advancing up to a maximum of 40 direct injections and 400,000 cells per injection, based on safety. This compares to a maximum of 15 injections of 100,000 cells each, directly into the gray matter of the spinal cord, in the completed Phase I trial. The first 12 Phase II patients will receive injections in the cervical region of the spinal cord only, where the stem cells could help preserve breathing function; the final three patients will receive both cervical and lumbar injections.
And yes, as we reported in January a clinical trial is being prepped for chronic spinal cord injury
-- for those one to two years post. It is expected to begin enrolling patients this summer as centers and institutional approvals are lined up. The company hasn't released any information about the trial but a look at the trial detail at clinicaltrial.gov
shows that several centers have been identified:
• Crawford Research Institute at the Shepherd Center in Atlanta. Former Reeve Foundation International Research Consortium on Spinal Cord Injury Associate Keith Tansey, M.D., Ph.D. is listed as principal investigator for the study. (keith_tansey@Shepherd.org).
• University of Miami
• Thomas Jefferson University Hospital, Philadelphia
• Medical College of Wisconsin, Milwaukee
• Karl Johe, the chairman and chief medical officer of Neuralstem, announced this week that UCSD Medical School would also be one of the trial centers. For more about this site, contact Adrienne Rebollo, firstname.lastname@example.org.
I spoke with Johe: “The dogma has been that human cell transplants to the spinal cord were not feasible. First, the environment is too hostile, due to necrosis and inflammation. Second, there is no way to overcome this. We have shown here [in the acute rats], however, that our human cells integrate into the animals. Most of the stem cells die. Some survive and they proliferate in the injured area; they continue to divide until they fill the cavity. At that point they begin to differentiate into neural tissue.”
According to Marsala, the 556 cells appear to be doing two things: stimulating host neuron regeneration and partially replacing the function of lost neurons. “Grafted spinal stem cells are a rich source of different growth factors which can have a neuroprotective effect and can promote sprouting of nerve fibers of the host neurons. We have also demonstrated that grafted neurons can develop contacts with the host neurons and, to some extent, restore the connectivity between centers, above and below the injury, which are involved in motor and sensory processing.”
Johe said his 566 cells appear to reduce the size of injury. “Our studies with MRI show that the surface area of scar is much, much less. The stem cells also appear to stabilize the injury – the cells restore the integrity of the tissue. The fact the animals showed reduced spasticity is a sign of reduced secondary damage," said Johe.
“Rats often recover spontaneously,” said Johe, “so it is difficult to demonstrate a functional benefit; but the animals in our study have more accurate foot placement and better coordination of limb movement.”
Chronic SCI Trial
Johe wasn't able to predict when this trial would commence – this summer, he hopes. He acknowledged that there has been great interest – the word chronic is extremely rare in SCI trials.
Johe thinks his stem cells are versatile and robust enough to make a difference in both acute and chronic SCI, stroke, even brain cancer. Stem cells, he said, are not like drugs, which might target a specific process or action. “Stem cells are more like a shotgun – they offer many possible actions and mechanisms. A plethora of effects will be required for a reconstructive treatment in the spinal cord.”
Here's a summary of the chronic trial, from a release
This open-label, multi-site study will enroll up to eight patients with thoracic spinal cord injuries (T2-T12) who have an American Spinal Injury Association AIS-A level of impairment, between one and two years post injury. These patients exhibit no motor or sensory function in the relevant segments at and below the injury, and are considered to be in complete paralysis. Study patients will receive six injections in, or around, the injury site: the first four patients will receive 100,000 cells per injection; the second four patients, 200,000 cells per injection. All NSI-566 SCI patients will receive post-surgery physical therapy, as well as immunosuppressive therapy, which will be for three months, as tolerated. The trial study period will end six months post-surgery for each patient. The primary objective of the study is to determine the safety and toxicity of NSI-566 for the treatment of paralysis and related symptoms due to SCI. The secondary objectives are to evaluate graft survival in the transplant site by MRI, as well as the effectiveness of transient immunosuppression.
It is anticipated that each individual medical center will handle its own recruitment. We'll pass along more information as it is available.