Rare disease, as the name suggests, affects a small proportion of the population and appears with low prevalence. The limited number of patients impedes development of new therapies, reducing the pool of clinical trial candidates and the size of the end market. A surprising figure is that the average rare disease has a population below 100. According to the National Institutes for Health, there are ~7,000 identified rare diseases; however, most do not have any approved treatment. The agency...