The transitional phase of multiple sclerosis: Characterization and conceptual framework

Area of Science:

• Neuroimmunology
• Clinical Neurology
• Disease Progression

Background:

• The conversion from relapsing-remitting multiple sclerosis (RRMS) to secondary progressive multiple sclerosis (SPMS) is a gradual process, lacking a defined threshold.
• A transitional phase between RRMS and SPMS is hypothesized but poorly understood.
• Current understanding of transitional multiple sclerosis (MS) lacks characterization of patient properties, disease course, and therapeutic strategies.

Purpose of the Study:

• To review existing knowledge on the transitional phase of multiple sclerosis.
• To characterize patient properties, disease course, and therapeutic interventions relevant to transitional MS.
• To propose designs and criteria for a prospective clinical study in transitional MS patients.

Main Methods:

• Literature review of current evidence on transitional MS.
• Analysis of patient characteristics and disease progression in the transitional phase.
• Exploration of potential diagnostic markers and therapeutic targets.

Main Results:

• The conversion to SPMS is a continuum, suggesting a distinct transitional MS phase.
• Transitional MS is poorly defined regarding clinical features, pathogenesis, and diagnostic markers.
• Evidence for interventions delaying RRMS to SPMS conversion in this phase is limited.

Conclusions:

• The transitional phase of MS requires further investigation to improve patient management.
• Prospective studies are essential to define transitional MS and identify effective treatments.
• Better characterization of transitional MS could lead to earlier diagnosis and intervention, potentially delaying disease progression.