Precision medicine for rare diseases: The times they are A-Changin'

The greatest challenge of current biomedicine is to identify curative therapies for every disease in a personalized way so that every individual gets benefit. To that end, however, we need fully understand mechanisms of disease that will drive the design of novel therapies and innovative approaches. For rare diseases (RDs) which individually affect low numbers of people (< 1:2000), but together, affect 300 million (∼10% of the world population) the constraints are greater. This is because: 1) there is limited knowledge on RD physiopathology; 2) the low number of patients strongly limits clinical trials; 3) there is low commercial interest by pharma; 4) when specific drugs reach the market, their high cost precludes their reaching all those who need them. Several possibilities that can help mitigate these barriers are discussed here, including orphan drug designation, drug repurposing, break-down into theratypes (as currently in place for Cystic Fibrosis), or novel precision-medicine-based approaches.