Though demonstrating clear efficacy on a number of short-term clinical measures, these agents are not cures and most patients with MS continue to experience disease activity in spite of treatment. Over the last ten years, clinicians have become comfortable initiating therapy with DMT. Now, attention is focused on monitoring the results of a chosen therapy and deciding whether or not a patient is responding optimally to treatment. At present, however, clinicians lack criteria for defining optimal response to DMT as well as evidence-based recommendations on how to improve treatment outcomes for individual patients.