ABSTRACT
Drug repurposing is a growing purposeful strategy to identify new uses for pharmaceutical entities at any stage of their commercial or developmental life. Drug repurposing is a directed strategy to identify new uses for existing drugs, to be embarked upon at any stage in their developmental or clinical life. This chapter discusses the "concept of branching the development of an active pharmaceutical ingredient, at any stage of the life cycle and regardless of the success or misfortune it has encountered so far, to serve a therapeutic purpose that is significantly different from the originally intended one". A substantial advantage of drug repurposing is the ability to obtain so-called "method-of-use" patents, which are designed to promote the discovery of the secondary uses of compounds. Drug repurposing is a particularly attractive approach for rare diseases, for both scientific and commercial reasons; the term "rare-purposing" has even been trademarked by the company Healx Limited which is focused entirely on this strategy.
