Finding hidden treasures in old drugs: the challenges and importance of licensing generics.

Identifying new indications for existing drugs creates new therapeutic options while bypassing much of the costs and time involved with bringing a new drug to market. The rediscovery of a generic drug, however, is a challenging pursuit because there is no formal regulatory approach and a lack of economic interest by pharmaceutical companies. This played a part in the re-registration of thioguanine as a rescue drug for the treatment of patients with inflammatory bowel disease in The Netherlands. In this article, we aim to underline the importance of drug rediscovery, the difficulties of this procedure in Europe and we attempt to suggest conceivable solutions.