**7. Discussion**

Currently, various efforts to facilitate the discovery of drug repurposing candidates for cancer and a large number of drug candidates do exist [51]. As an example, the Repurposing Drugs in Oncology (ReDO) Project, which is initiated by a non-profit international collaboration of researchers, clinicians, and cancer patient advocates whose goal is to find efficacious, minimally toxic, and affordable cancer treatments identified a total of 268 drugs that matched the following two criteria: i) the drug is licensed for non-cancer indications in at least one country in the world, and ii) the drug is the subject of one or more peer-reviewed publications showing a specific anticancer effect based on *in vitro*, *in vivo*, or clinical research in one or more malignancies. According to these criteria, ivermectin can be a potential repurposing candidate for cancer. Ivermectin has extensive preclinical *in vitro* and *in vivo* anticancer data and is thus an ideal candidate for clinical trials. An especially promising feature with ivermectin is that its anti-cancer concentration *in vitro* should be attainable clinically, inexpensively, and without undue toxicity.
