Does Initiation of Disease Modifying Therapy in Patients With Radiologically Isolated Syndrome Reduce their Risk of Conversion to Multiple Sclerosis? A Critically Appraised Topic.

Background: Radiologically Isolated Syndrome (RIS) is defined as incidentally found MRI abnormalities that are radiographically indistinguishable from multiple sclerosis (MS) and is considered a presymptomatic disease state of MS. Age <37 years, infratentorial or spinal cord lesions, gadolinium-enhancing lesions on index imaging, and positive cerebrospinal fluid oligoclonal bands have been identified as risk factors for conversion to MS. There are no existing guidelines regarding the role of disease-modifying therapy (DMT) in RIS patients.

Objective: The objective of this study was to critically assess the current evidence regarding the impact of initiating DMT for patients with RIS on the time to first clinical attack of MS.

Methods: The objective was addressed through the development of a structured critically appraised topic. This included a clinical scenario with a clinical question, literature search strategy, critical appraisal, results, evidence summary, commentary, and bottom-line conclusions. Participants included consultant and resident neurologists, medical librarian, and content experts in the field of neuroimmunology.

Results: A multicenter, prospective, randomized, double-blind, placebo-controlled trial was chosen for critical appraisal. This trial examined the impact of treatment with dimethyl fumarate (DMF) versus placebo on the risk of conversion from RIS to MS over a 96-week study period. Patients in the DMF arm were found to have an 82% reduction in risk of clinical attack. DMF patients also had a smaller number of new/newly enlarging T2 hyperintense lesions compared with placebo. No subgroup analyses were performed to elucidate risk factors for conversion.

Conclusions: While initiation of DMT in RIS does appear to reduce the time to first clinical attack of MS, the risk factors that should prompt initiation of DMT in this patient population require further study.