Assessment Study of Steroid Effect in Relapsing Multiple Sclerosis Subjects Treated With Glatiramer Acetate

One interim analysis was planned for possible early termination due to proven efficacy when 75% of the preplanned 500 (approx. 375 patients) recruited patients completed the entire study duration or early discontinued. In addition to the stopping rule already given for proven efficacy, the sponsor was also interested in examining the data for futility (i.e., absence of the desired treatment effect) with the view to terminating the trial if an "insufficient" effect of the treatment is seen. The reasons why the need for futility arose were: 1. Recruitment difficulties 2. Increasing dropout rate 3. Budgetary constraints The primary efficacy measure is defined as the percent change from baseline to termination (Month 36 or Early Termination) in normalized brain volume (Brain Atrophy) measured according to the SIENA (Structural Imaging Evaluation using Normalization of Atrophy) method. However, since not many patients had completed the entire study at the time of futility analysis, it was the sponsor's decision that the futility analysis be performed on patients with MRI scans at months 24 or 36 or at early termination visits - the latest available. Based on the recalculation of study power (probability is unconditioned on the interim result and provide the real power of the study if designed anew), conditional power (based on the interim results) and risk assessment of a false negative, the Data Monitoring Committee agreed that the study should be terminated early.