Orphan drugs: major development challenges at the clinical stage.

Biotechnology has provided powerful tools to assist in research and development (R&D) for rare diseases. However, orphan drug development presents several major challenges and obstacles, such as low disease prevalence, disease severity, small and heterogeneous patient populations, difficulties in patient recruitment, and limited knowledge of the natural history of disease, among others. Several strategies can be used to plan for and overcome these clinical and regulatory challenges, namely improved clinical trial design, improved patient recruitment, and closer collaboration with the regulatory authorities and with patient associations. As growth in the orphan drug market is expected over the next few years, improving its relevance in the global pharmaceutical market, further challenges might present themselves in the development of orphan drugs.