On behalf of the Federal Ministry of Health (BMG), the German Institute for Quality and Efficiency in Health Care (IQWiG) examined whether specific methodological aspects have to be considered in the conduct, analysis and assessment of the certainty of results of studies on rare diseases. Within the framework of the same commission, the Institute also analysed the underlying studies for the approval of so-called orphan drugs, i.e. drugs for rare diseases, in Europe. 

The result: For a different approach than in more common diseases, there are neither scientific reasons nor specific designs and methods that would not also be relevant for more common diseases. This is the case for both drug and non-drug treatments. If compromises have to be made with regard to the reliability of the conclusions because of a particularly small number of participants, raising the significance level is preferable to a limitation of the external or even internal validity of the studies.

For more details, go to: https://www.iqwig.de/en/press/press-releases/press-releases/rare-diseases-no-reason-for-lower-demands-for-studies.6343.html