The process of drug repurposing (DR), or drug repositioning, involves the identification of a novel clinical use for an existing drug, i.e. to treat disease(s) for which it was not originally intended. Despite the shorter overall development time and reduced cost (30-75%) for repurposed medicines compared to development of new medicines, there are major challenges due to the fragmented and siloed approaches in DR research and development, problems in securing financing, and difficultiess in defining the development path (value chain). Many DR projects originated from academia where there is a lack of understanding and institutional support from employers of all the translational steps and the substantial patient engagement needed to advance the specific project into practical applications. Furthermore, the reimbursement and health technology assessment (HTA) environment have impediments to efficient uptake of repurposed drugs, lacking a viable path to market for repurposed generic medicines and a European regulatory landscape that is not yet fully aligned to the specific needs of the DR process. However, repurposing has been particularly valuable in rare diseases. A 2017 study reported that among the US FDA approvals were 73 drugs which served the mass market before repositioning into the orphan space and 83 drugs have been approved for multiple orphan indications; eight drugs appear under both these categories . Source: IRDIRC REPURPOSING TASK FORCE