Orphan drugs: the regulatory environment.

The definition of a rare disease is not universal and depends on the legislation and policies adopted by each region or country. The main objective of this article is to describe and discuss the legal framework and the regulatory environment of orphan drugs worldwide. Some reflections and discussions on the need for specific orphan drug legislation or policies are described at length. Furthermore, some aspects of the history of each region in respect of the orphan drug legislation evolution are outlined. This article describes and compares the orphan drug legislation or policies of the following countries or regions: United Sates of America (US), European Union (EU), Japan, Australia, Singapore, Taiwan and Canada. The incentives described in the orphan drug legislations or policies, the criteria for designation of orphan status and the authorisation process of an orphan drug are also described and compared. The legislations and policies are to some extent similar but not the same. It is important to understand the main differences among all available legislative systems to improve the international collaboration in the field of orphan drugs and rare diseases.