A clinical pharmacology-regulatory perspective on the approval of drugs for rare diseases.

Orphan drugs or drugs for rare diseases represents a particular regulatory conundrum. There is a desperate need for effective therapies for these patients, who have been historically underserved by the drug development community. However, there is also a need to make sure these therapies are both safe and effective. In response, the US Food and Drug Administration (FDA) has evolved new approaches to facilitate drug development in this area.