Pharmaceutical manufacturers incur tremendous expense and deal with considerable risk when developing new drugs, especially drugs to be used in cancer. For this reason, many researchers are interested in looking at FDA-approved drugs that could potentially be repositioned for use in cancer treatment. This allows the drugs to enter clinical trials rapidly and lets researchers rely on previous pharmacokinetic, toxicological, and safety data.
http://www.pharmacytimes.com/resource-centers/gastrointestinal/reuse-repurpose-reposition-old-drugs-new-uses
Reuse, Repurpose, Reposition: Old Drugs, New Uses