Development of a multiple sclerosis functional composite as a clinical trial outcome measure

The primary clinical outcome measure for evaluating multiple sclerosis in c linical trials has been Kurtzke's expanded disability status scale (EDSS). New therapies appear to favourably impact the course of multiple sclerosis and render continued use of placebo control groups more difficult. Conseque ntly, future trials are likely to compare active treatment groups which wil l most probably require increased sample sizes in order to detect therapeut ic efficacy. Because more responsive outcome measures will be needed for ac tive arm comparison studies, the National Multiple Sclerosis Society's Advi sory Committee on Cinical Trials of New Agents in Multiple Sclerosis appoin ted a Task Force that was charged with developing improved clinical outcome measures. This Task Force acquired contemporary clinical trial and histori cal multiple sclerosis data for meta-analyses of primary and secondary outc ome assessments to provide a basis for recommending a new outcome measure. A composite measure encompassing the major clinical dimensions of arm, leg and cognitive function was identified and termed the multiple sclerosis fun ctional composite (MSFC). The MSFC consists of three objective quantitative tests of neurological function which are easy to administer. Change in thi s MSFC over the first year of observation predicted subsequent change in th e EDSS, suggesting that the MSFC is more sensitive to change than the EDSS, This paper provides details concerning the development and testing of the MSFC.