Disease modifying trials are becoming increasingly common in the field of Alzheimer's disease (AD) as the search for a treatment able to slow the progression of this disease continues. In this paper, we briefly discuss the methodological considerations for disease modifying trials that were addressed during three recent international task force meetings involving specialists in the field of AD trials. Topics covered included study design, the identification of appropriate outcomes, the use of biomarkers, and the identification of suitable study populations. We also provide an update on recent disease modifying trials which have enabled us to gain experience in the use of biomarkers and have helped to define suitable outcomes, and consider how they can help us to shape future perspectives for disease modifying trials.