Differing Impact of Disease-Modifying Therapy on Relapse and Progression

Abstract

The artificial distinction between relapsing remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS) can lead to substantial difficulties in decisions on disease-modifying therapy (DMT) at this stage of multiple sclerosis (MS). There is not a simple transition between the two; patients may demonstrate background progression with superimposed relapses for many years. Progressive disease almost certainly starts some years before clinical acknowledgement; once it is identified, clinicians face a dilemma about the use of highly effective DMT. The influence of highly effective therapy on relapses and medium-term outcomes in early disease is well established; however, disentangling efficacy in terms of relapses and progression at this later stage is more complex.