Although researchers haven't been able to identify the cause of MS with any certainty, there has been excellent progress in other areas of MS research—especially in development of new treatments to prevent exacerbations of the disease. New discoveries are constantly changing treatment options for patients.
Some researchers are investigating promising avenues for therapeutics, such as drugs that would protect myelin cells from damage or that could help them recover after an attack. Interfering with the inflammatory cells and substances involved in the development of MS lesions or keeping immune-system cells from crossing the blood-brain barrier could potentially thwart an attack.
There are many new treatments that have been shown to prevent the formation of new MS lesions in small studies. These treatments are now being tested in a large number of MS patients in Phase III clinical trials. These include injectable drugs called rituximab, ocrelizumab, daclizumab, and alemtuzumab and oral drugs such as cladribine, laquinimod, teriflunamide, and fumaric acid. There are also clinical trials being performed to determine whether combining two therapies is beneficial for preventing relapses.
Several studies have shown that destroying the immune system with chemotherapy and then replacing it with immune system stem cells obtained from the patient’s own blood can halt development of new MS lesions. This treatment appears to re-set the immune system so that it no longer attacks the brain. This strategy is being tested in clinical trials. Other studies are investigating whether transplanting stem cells derived from bone marrow, called mesenchymal stem cells, may be helpful in MS.
A 2009 study suggested that a condition called chronic cerebrospinal venous insufficiency (CCSVI), which results from abnormalities in veins leading from the brain, may contribute to the symptoms of MS. However, studies exploring a link between CCSVI and MS have been inconclusive. In 2012, the U.S. Food and Drug Administration (FDA) issued a warning that procedures to relieve CCSVI have been linked to serious complications, including strokes, cranial nerve damage, and death. Because the surgery is risky and the potential for benefit is highly uncertain, patients should only undergo the procedure as part of a properly controlled clinical study with appropriate safeguards and follow-up evaluations.
Other studies are trying to find ways to stop progression of the disease in MS patients with primary progressive MS or secondary progressive MS, and to restore neurological function in these individuals. Researchers are investigating whether symptoms that do not respond to FDA-approved immunomodulatory treatments may be caused by problems with the energy-producing parts of neuronal cells, called mitochondria. Investigators also are trying to develop ways to help brain cells called oligodendrocytes produce new myelin in order to strengthen or repair damaged cells of the brain and spinal cord.
Some experimental drugs can protect brain cells from dying or help brain cells produce new myelin in test tubes or animal models. However, in order to test these drugs as potential treatments in humans, researchers need accurate indicators, or biomarkers, so that the amount of neuronal cell death and cell repair, including remyelination, can be measured. These biomarkers would help to show whether an experimental treatment is working as intended. As the number of available treatment options for MS continues to grow, researchers are also trying to identify biomarkers that could help doctors determine whether or not an individual will respond well to any particular therapy, or, ideally, to select the optimal treatment for each person with MS. Other studies aim to develop better imaging tools to diagnose MS and test drugs.
Some researchers are working to develop improved animal models that closely resemble MS in humans. Currently available animal models share many of the same disease mechanisms and symptoms as MS, but they do not fully mimic the disease. This means that drugs that work well in animal models are often less successful in human clinical trials. Having a more accurate animal model would reduce the time and expense of testing therapies that may not prove to be successful in treating the human disease.
Reference: National Institute of Neurological Disorders and Stroke (NINDS)