ABSTRACT
The recent emergence of interventions that effect some aspects of the disease process in multiple sclerosis (MS) has resulted in a resurgence of interest in the evaluation of these new agents in a way that produces clear, definitive results to guide patients, prescribers, and purchasers. This chapter addresses some of the complexities involved in undertaking studies to determine treatment effectiveness in MS. They are considered under three main headings: the disease process, identifying and measuring outcomes, and trial design. These headings are ordered in a logical fashion: it is impossible to identify outcome measurement without in-depth knowledge of the disease process and equally impossible to design a trial without a clear idea of the questions being asked and the outcomes that address those questions.
