Multiple sclerosis (MS) research in recent years has identified an increasing number of potential therapeutic products that can be evaluated. The ultimate goal of a drug development program is to establish that the drug has a favorable effect upon the patient and has risks that are acceptable in light of the benefit. The Kurtzke Expanded Disability Status Scale (EDSS) is employed as the chief physical disability measure in development programs for many of the currently available therapies. An important aspect of drug development is determining what drug benefits should be claimed in the approved drug labeling. Biomarkers have the potential to be informative on a number of different aspects of biological responses in much shorter time and fewer patients, and contribute to feasible and successful drug development. An important aspect of efficient and informative drug development programs is selection of appropriate end-points for each study in the clinical development program.