Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system which leads to the formation of focal confluent lesions of primary demyelination in the white and gray matter and to diffuse damage and neurodegeneration in the entire brain. MS is the leading cause of non-traumatic neurological disability in young adults. In the majority of patients multiple sclerosis starts with a relapsing remitting course
(RRMS), which may at later times transform into secondary progressive disease (SPMS).
In about 10% of patients the relapsing remitting disease is skipped and the patients
show progression from the onset, the so called primary progressive MS (PPMS). Despite these distinctions, all clinical forms of MS appear to reflect the same underlying disease process. And although inflammation is typically associated with relapses, and neurodegeneration with progression, it is now recognized that both pathologies are present in essentially all patients across the entire disease continuum.
Siponimod is a selective S1P modulator that is approved for relapsing forms of MS including
active SPMS. Ocrelizumab, cladribine, and ozanimod can also be used for patients with active SPMS. Ocrelizumab is the only approved disease-modifying therapy for the treatment of PPMS.
An increase number of trials and diversity of therapeutic approaches for progressive MS provides hope for future effective therapy.