Treatment optimization in multiple sclerosis: how do we apply emerging evidence?

In the past years, the introduction of highly effective treatments has considerably expanded treatment options in relapsing remitting multiple sclerosis (RRMS). Not only the number of available treatment options has increased, but evidence has emerged that there is a limited window of opportunity to intervene effectively in multiple sclerosis (MS) patients, which appears to be critical for achieving favorable long–term outcomes [1,2]. Considering the important role of focal inflammation driving both acute and delayed neurodegeneration, a zero tolerance or no evidence of disease activity (NEDA) strategy suppressing all inflammatory activity should be the therapeutic aim [3]. This new emerging therapeutic strategy treating to target to achieve NEDA is in line with treatment concepts of other autoimmune diseases as rheumatoid arthritis where treatment algorithms aim to suppress as much joint inflammation as possible and to induce long-term remission for prevention of permanent end-organ damage. Effective and strategical interventions imply prompt treatment optimization, a switch of therapy in patients with suboptimal response or treatment failure with their current MS treatment. A suboptimal clinical response can be defined as occurring in patients receiving disease-modifying therapies (DMTs) for ≥1 year with one or more relapses or expanded disability status scale increase. However, it is not always easy but challenging to define suboptimal response respective treatment failures precisely: On treatment, the monitoring of MS disease activity is key to achieve optimal outcomes [4]. During treatment, it has to be defined whether the patient is a treatment responder or not [5]. For this treatment monitoring, clinical and especially MRI parameters as well as potentially other biomarkers can be applied: