Despite the broadening range of available treatments, the response of multiple sclerosis patients to disease-modifying therapies remains quite heterogeneous, thus a scheme is required in order to flag individuals achieving a suboptimal treatment response, so that they may switch to a different, possibly more effective disease-modifying therapy. There are several treatment outcomes that can be defined as surrogate markers for continued treatment efficacy and can be used for optimizing disease-modifying therapy. As no single marker is validated, we must make use of all available potential surrogates to help predict the future course of the disease. Only by putting all of the outcome measures together can a true picture be derived that will indicate an optimal response to treatment.
Keywords: disease progression; disease-modifying therapy; multiple sclerosis; optimization; surrogate markers.