Disease modification in multiple sclerosis: Issues with relevance to clinical trial designs in Alzheimer's disease

The last 13 years have witnessed introduction of disease-modifying drugs (DMDT) in the multiple sclerosis (MS) field. This remarkable occurrence has not only ushered in an era of therapeutic optimism, it has stimulated change in how the pathogenesis of MS is viewed, how clinical studies should be conducted, and how outcome should be measured. These issues are in a stage of evolution at the time of this writing, but many have great relevance to development of DMDT in Alzheimer's disease (AD).