MS is a complex disease. One of several reasons for this is that people experience MS in very different ways and face highly variable courses. There are different forms of MS, such as relapsing-remitting, primary progressive, secondary progressive and progressive relapsing MS. In 1996, the US National MS Society (NMSS) Advisory Committee on Clinical Trials in Multiple Sclerosis established standardized definitions for each MS type in order to provide clarity and ensure consistency on a global scale.
The definitions quickly became a standard part of medical practice and research. However, it was soon recognized that the descriptions would require modifications in the future, as some of them lacked biological support and were heavily based on subjective views of MS experts. They recognized that advancements in imaging and biological markers would allow for the various MS types to be further defined
I recently read an interesting article in Neurology, in which the authors discussed a new way of looking at the different types of MS. In 2012, The Advisory Committee (now jointly supported by NMSS and the European Committee for Treatment and Research in MS) joined other MS researchers to re-examine the original definitions and look to new evidence from techniques that were not available in 1996. The Committee determined that while the crux of the definitions should be maintained, the descriptions needed to be updated to better reflect the full range of clinical characteristics of MS. The definitions were finalized in 2013 and were presented for future research strategies.
Re-defining the types of MS
One of the major points discussed by the Committee when they convened in 2012 was the incorporation of disease activity, as detected by the relapses and imaging scan results, and disease progression into the definitions of MS. Including these factors would result in more meaningful descriptions for both relapsing and progressive forms of MS. The experts agreed that disease activity should be assessed annually. Further work is needed to determine how often individuals with progressive MS should undergo brain imaging.
Secondary progressive MS (SPMS) was discussed, but there was not much change to its definition. This is because to date, there lacks criteria for determining the conversion from RRMS to SPMS. The experts agreed that further research is required to generate data that could help to accurately identify the point of transition to progressive MS.
New disease courses
Some of you may have heard of clinically isolated syndrome (CIS). People who are diagnosed with CIS display an isolated episode of inflammatory demyelination, a characteristic feature of MS, but may or may not go on to develop MS. CIS was not included in the original MS clinical descriptions, but is now recognized as the first clinical presentation which may lead to MS, and has been included in the spectrum of types of MS.
A less commonly known condition called radiologically isolated syndrome (RIS) was discussed in the paper as well. RIS may raise suspicions of MS due to demyelination incidentally found in imaging results, but clinical signs or symptoms are not present. So while people with RIS should be followed due to the risk of developing MS, RIS should not be considered part of the clinical course of MS.
The Committee clarified certain terms traditionally used to describe MS. For instance, it was suggested that the term “confirmed” should be used instead of “sustained” when describing worsening disability. They also suggested that the term “worsening” should be used in the place of “progressing,” especially for those with relapsing forms of MS. You can imagine how confusing it might be describing how an individual’s RRMS course is progressing!
Finally, the experts cautioned against the use of the terms “benign” and “malignant” when describing MS, because, as many of you may know, the severity and activity of MS can change unexpectedly and significantly.
What does this all mean?
You may be wondering what impact these changes will have. Well for one, research will be affected dramatically. When clinical trials are being designed, researchers take into account the type of MS they are studying in order to optimize treatment and accurately measure improvements or adverse effects. Clearer descriptions are also needed to help researchers determine who would be eligible for a particular clinical trial.
The updated clinical descriptions will have a significant impact on clinical care. The addition of biological markers which are highly specific to the different types of MS will help physicians to better communicate with their patients, by being able to explain if and how their disease is progressing. The new descriptions will also allow them to select the most appropriate and effective treatment regimen and make informed decisions about switching treatments when a person’s disease course has changes.
Overall, these modifications will help to more clearly define MS, as well as serve as a sound framework for future research and healthcare.
It is my hope that these revisions will be implemented by Canadian researchers and neurologists. As always, the MS Society is proud to support high quality research that will improve diagnosis and treatment of MS, and ultimately lead to a cure.