Why are all the new treatments evaluated for relapsing-remitting patients and not chronic-progressive?
At this time, treatments that would repair myelin and reverse the damage caused by MS are still in only the earliest theoretical stages, so no treatments that are currently in the pipeline are expected to significantly restore lost function. Given this, the treatments currently being investigated are for slowing or halting progression of MS symptoms. In order to study any treatment modality, some objective criteria for evaluating the efficacy must be devised. Chronic-progressive MS exhibits only a slow decline of function which is hard to quantify. Two scales in common use for assessing function are notoriously unreliable and nonreproducible rendering them not well suited for a clinical study. In contrast, in relapsing-remitting MS, a number of criteria are easily devised. The main feature of relapsing-remitting MS is the exacerbation. It is easy to form a well agreed upon definition of an exacerbation. This leads to criteria for assessing the treatment such as: number of exacerbations
