MS brain lesion as seen on an MRI.
By obliterating the broken immune systems of patients with severe forms of multiple sclerosis and then seeding new, defect-free systems with transplanted stem cells, researchers can thwart the degenerative autoimmune disease, but that comes at a price.
In a small phase II study of 24 MS patients, treatment stopped or even reversed the disease in 70 percent of patients three years after transplant. Eight patients saw that improvement last for seven and a half years, researchers report in the Lancet. This means that some of those patients went from being wheelchair bound to walking and being active again. But to achieve that success, many suffered serious side effects, such as life-threatening infections and organ damage from toxicity caused by the harsh chemotherapy required to destroy the body’s immune system. One patient died from complications of treatment, representing a four percent mortality rate.
In addition, while the risks may be worth it for some patients with rapidly progressing forms of MS — a small percentage of MS patients — the researchers also caution that the trial was small and did not include a control group.
“Larger clinical trials will be important to confirm these results,” study co-author Mark Freedman of the University of Ottawa said in a statement. “Since this is an aggressive treatment, the potential benefits must be weighed against the risks of serious complications associated with it [this stem cell transplant]and this treatment should only be offered in specialized centers experienced in both the treatment of multiple sclerosis and stem cell therapy, or as part of a clinical trial,” he added.
Similar treatments have been used before in other studies, which also produced positive, though not as dramatic, results. Generally, researchers start by harvesting a patient’s hematopoietic stem cells, which give rise to the body’s immune system. Next, researchers use chemotherapy to push back the patient’s misbehaving immune system. In MS patients, faulty immune responses pull away the insulation of nerve cells in the brain and spinal cord, causing inflammation, lesions and nerve damage that eventually lead to physical and mental disability. The disease can progress in bouts over decades or continuously over months.
Now that that faulty immune system has been weakened, researchers can replace patients’ stem cells, which are precursors far enough away that they don’t carry the glitches that cause MS. Thus, they may be able to produce a faultless immune system.
Freedman and colleagues took this general treatment strategy a step further by not only pushing back the patient’s faulty immune system, but destroying it completely with a cocktail of powerful drugs.
“It’s important to emphasize that this is a very early study,” Stephen Minger, a stem cell biologist who was not involved in the study, told the BBC. “Nevertheless, the clinical results are really impressive, almost curative in some cases.”
Freedman added that future research will focus not only on replicating the results in larger trials, but also on figuring out how to make it safer for patients.
Lancet2016. DOI: 10.1016/S0140-6736(16)30169-6 (About DOIs).