Multiple sclerosis halted by treatment with chemotherapy and stem cell transplant

Canada has the highest rate of multiple sclerosis in the world with an estimated 100-140 case per 100,000 people while in the US there are approximately 57-78  cases per 100,000 people. Multiple sclerosis seems to more often affect people in countries that live further away from the equator. It typically diagnosed between the ages of 20 and 40 but you can get the disease at any age. Multiple sclerosis is an autoimmune disease caused by the body attacking the insulating sheath (called myelin) that surrounds the neurons in the brain. This constant attack causes scars or lesions to form around the neurons and effectively shorts out the signals that are being sent. Inflammation is a big part of the disease, as it is with autoimmune diseases, and so has become the primary target for current treatments and therapies. These include steroid injections and injections with specific antibodies used to target problematic inflammation in a more targeted way. One treatment is becoming increasingly investigated for its use in multiple sclerosis is isolating stem cells from a patient, weakening their immune system, and then transplanting them back in to try and restart the faulty immune system. This type of treatment is already approved for use in cancers of the blood and in other blood disorders like sickle cell anemia and thalassemia. The problem with these treatments is that while they have relatively short lived benefits for the patients (reduced relapses for example) the disease inevitably reactivates. For such an invasive and intense treatment, short lived benefits aren’t going to be good enough. However, a group of Canadian researchers based in Ottawa recently published a clinical trial in the Lancet showing that using a modified methods for stem cell transplant, multiple sclerosis patients are free of symptoms and disease progression for at least 3 years.

The difference between this treatment regime and the ones tried before is that the team completely destroyed the patient’s immune system before resetting it while previous treatments have only tried to weaken it. 24 patients with multiple sclerosis had bone marrow taken and then were treated with a combination of three chemotherapeutic drugs, two of which are commonly used to treat cancer (busulfan and cyclophosphamide) and the other which is used to prevent organ rejection by immune cells (anti-thymocyte globulin). In treating the patients with these drugs, the immune system, including the cells that attacked the myelin in the brain, was completely wiped out. Next, the researchers took bone marrow stem cells and put it back into these patients to repopulate their immune system. Bone marrow stem cells, also called haematopoietic stem cells, are the cells from which your red and white blood cells come from. They then followed the patients for at least 3 years to look for signs of disease progression, relapse, and a change in their disability score. Before the treatment, the patients had around 1.2 relapses in their disease per year while after the treatment (between 4 and 13 years) there were no relapses in any of the patients. Before the treatment, there were 93 brain lesions (or scars) detected in total and after the treatment there was only 1 new lesion detected. Finally, multiple sclerosis patients typically show a faster rate of decline in their brain function but following this treatment the patients had rates of decline that were normal for their age and some of the patients were able to return to work or school and get off disability insurance. The results were truly remarkable.

Now for the down sides of this treatment. 1) This is a truly invasive and intense treatment that is likely only going to be applicable to the patients whose disease is severe and unable to be controlled by other forms of treatment. 2) One patients from the study died due to complications in the procedure. Since the immune system is being completely killed off, any infection that a patient may get prior to their immune system being repopulated could be fatal since they have nothing to fight it off. Still, for the patients who have no other option, a chance that this could help them may be outweighed by the risks. 3) This is still a relatively small study with only 24 participants and no control group for comparison. We don’t know if the recovery we are seeing here is truly remarkable or is just marginally better than current immune-suppressive treatments. We need more research with larger trials to determine the safety of the procedure and we need refinement to reduce the risks associated with it. This research suggests that in an autoimmune disease like multiple sclerosis, it is not enough to just turn down the faulty immune system before resetting it. We need to do the IT fix, did you try turning it off and on again.


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