To date, clear clinical, imaging, pathological or immunological criteria have to be established in order to mark the transition from recurrent multiple sclerosis (RRMS) to secondary progressive multiple sclerosis (SPMS). In a study recently published in Neurology, a research team called for effective tools that would allow early identification of SPMS so that, when combined with available therapies, they could lead to improved long-term outcomes in patients with the disease.
According to the study’s investigators, new research suggested that SPMS and RRMS “are part of a disease continuum with an indistinct border”. However, the underlying mechanisms in the transition from RRMS to SPMS are less clear.
Some research suggested that the transition may be associated with cortical demyelination and diffuse white matter damage, as these variables tend to increase with the duration of RRMS.
The study’s researchers emphasized that the transformation of the relapsing-remitting state into a secondary progressive disorder is clear evidence of the progression of the disability. In addition, therapies that aim to reduce the progression of disability in RRMS have not historically been effective in patients with SPMS, at least until recently.
The ORATORIO study (ClinicalTrials.gov Identifier: NCT01194570), which investigated the monoclonal antibody ocrelizumab, is currently the only clinical study that has met its primary efficacy endpoint of reducing confirmed disability progression in patients with primary progressive multiple sclerosis.
Inflammation is also a major issue in multiple sclerosis (MS), and research has focused on understanding its wide-ranging roles in the disease. Based on the current literature, the study’s researchers suggested that disease-modifying therapies (DMTs) are required to control inflammation in the central nervous system (CNS) in addition to combating acute peripherally-mediated inflammation.
Given that recent studies demonstrate the key role of chronically active lesions in disease progression, “the fact that these lesions are present in patients receiving DMTs that target peripherally-mediated inflammation reinforces the notion that new treatments are directly targeting the CNS – Must target processes that contribute to progressive MS, ”the study researchers concluded.
Disclosure: This clinical study was supported by Novartis Pharma AG. Several study authors stated links with the pharmaceutical industry. For a full list of the author’s disclosures, see the original reference.
Cree BAC, Arnold DL, Chataway J, et al. Secondary Progressive Multiple Sclerosis: New Findings. Published online June 4, 2021. Neurology. doi: 10.1212 / WNL.0000000000012323