The primary objective of this study is to determine whether DAC HYP, when compared to placebo, is effective in reducing the rate of relapses between baseline and Week 52. The secondary objectives are to determine whether DAC HYP is effective in reducing the number of new gadolinium (Gd)-enhancing lesions, reducing the number of new or newly-enlarging T2 hyperintense lesions, reducing the proportion of participants with relapses, and improving quality of life.