In the past decades we have seen the rise and fall of a number of promising therapies for Duchenne muscular dystrophy. Despite huge efforts in the field only a few have made it through approval by regulatory agencies. Two main reasons of failure are :1) a limited efficacy of the compounds in development and 2) issues in trial design (the selection of outcome measures and endpoints, selection of patient population). In this seminar we will discuss the issues in clinical development in DMD and explore how we could potentially improve clinical trial design.