226thENMC International Workshop:. Towards validated and qualified biomarkers for therapy development for Duchenne muscular dystrophy 20-22 January 2017, Heemskerk, The Netherlands

Twenty-three participants from 6 countries (England; Germany; Italy; Sweden, The Netherlands; USA) attended the 226th ENMC workshop on Duchenne biomarkers “Towards validated and qualified biomarkers for therapy development for Duchenne Muscular Dystrophy.” The meeting was a follow-up of the 204th ENMC workshop on Duchenne muscular dystrophy biomarkers. The workshop was organized with the support of Parent Project Muscular Dystrophy (PPMD) and Marathon Pharmaceuticals, which provided travel support for participants from the US via an unrestricted grant to PPMD in addition to ENMC support. It was attended by representatives of academic institutions, industry working in the Duchenne muscular dystrophy field and patient representatives. 1.1. Background to the workshop 1.1.1. Biomarkers Biomarkers are defined as biological, measurable and quantifiable indicators of underlying biological processes. Different types of biomarkers can be distinguished: diagnostic biomarkers indicate the presence of disease, prognostic biomarkers correlate with predicted disease course, and therapeutic biomarkers are designed to predict or measure response to treatment [1]. Therapeutic biomarkers can indicate whether a therapy is having an effect. This type of biomarker is called a pharmacodynamics biomarker and can be used to e.g. show that a missing protein is restored after a therapy. Safety biomarkers assess likelihood, presence, or extent of toxicity as an adverse effect, e.g. through monitoring blood markers indicative of liver or kidney damage. Sometimes biomarkers can also be used as primary endpoints in clinical trials instead of functional outcome measures, and these are termed “surrogate endpoints”. In Europe [2,3] biomarkers can only be used as surrogate endpoints after going through a rigorous regulatory process to officially qualify them for this purpose. Similar pathways exist in the US, where the Food and Drug Administration (FDA) also supplies a process for qualification of biomarkers for other contexts of use.