Multiple Sclerosis Journal | 2021
Towards an objective classification of multiple sclerosis
Abstract
The classification of MS into clinically isolated syndrome, relapsing–remitting (RRMS), secondary progressive (SPMS) and primary progressive is based on a retrospective recollection of medical history. New descriptors of ‘active’ and ‘progressive’ introduced in 2013 provide a better understanding of the clinical status of each phenotype.2 However, lack of clear and objective boundaries or biological distinction across these phenotypes has introduced a misalignment in clinical practice and across research studies. This issue is also a challenge for pharmaceutical regulators, as treatments for ‘progressive’ MS are becoming increasingly available.3 Such ambiguity has been more challenging in RRMS while transitioning to a progressive course because an ‘SPMS’ label can drastically change how patients are treated.