Drug Repositioning in Cancer

The development of new therapeutic agents, in any kind of disease, requires either long time or high costs; indeed 10 15 years of research are required to market a drug, resulting in an overall cost of about 1.8 billion dollars [1]. In addition, drug development in oncology is very challenging due to cancer biological complexity, actually comprising several subtypes of diseases carrying different molecular features. Despite over the last decades a high number of drugs (cytotoxic, targeted agents and emergent immunotherapeutic approaches) have been developed [2], on average just one in fifteen drugs with an oncology indication entering phase I clinical trials is finally approved by the FDA [3]. In order to overcome these issues, the strategy of “drug repositioning” aims to apply “old” and well known drugs for the treatment of certain diseases (other than cancer) to new indications, thus allowing a good knowledge on their safety, pharmacology and toxicology. New effective cancer therapies may be ready in a cost-effective and fast way. The best-known example of successful drug repositioning in cancer is thalidomide. This drug was employed in 1950s to treat morning sickness and in 1961 discontinued to cause serious birth defects. Its anti-cancer properties were found later, from the observation made by Folkman and colleagues in 1994 that thalidomide inhibited the angiogenesis inducted by fibroblast growth factor 2 (FGF2) in vivo [4]. In May 2006, the US FDA’s approved the use of thalidomide in combination with dexamethasone for the treatment of newly diagnosed multiple myeloma [5].