Abstract
Cancer is the second leading cause of death in the U.S., leading to the loss of over half a million lives in 2019 alone [1]. While there are many available treatments, one hallmark of lethal forms of cancer is the development of drug resistance. Drug resistance gives rise to an evolutionary arms race between cancer and pharmaceutical companies, which spend billions of dollars each year in research and development attempting to discover new and powerful therapies to treat drug-resistant forms of cancer. One main weakness of developing novel first-in-human therapies in oncology is the high failure rate in clinical trials, with success rates remaining less than 4% for these types of compounds [2]. This low success rate is due to two main factors: 1. lack of efficacy in the target disease, and/or 2. intolerable toxicity. A more promising approach is drug repurposing or repositioning, which is a strategy for enhancing the value of a drug already used in the clinic for other indications by utilizing it to target diseases other than those it was originally intended to treat. Repurposed drugs, which have a known mechanism of action and toxicological profile, provide a much stronger approach to treat cancers with similar biomarkers and disease mechanisms, due to the probability of higher success rates in clinical trials.