Design and analysis of clinical trials for small rare disease populations.

The mostly unmet need as well as the pressure to show efficacy of new therapies to treat rare diseases contrasts with the limited possibility to use traditional statistical methods to design and analyse clinical trials in this setting.
Within this paper, we will refer to the current state of design and analysis methods, as well as practical conditions to be considered when conducting a clinical trial for rare diseases. We will embed the research of the IDeAl project within this setting and give some first recommendations to improve the methodology for clinical trials in rare diseases.