**2. Drug repurposing in cancer therapy**

Effective, safe, and affordable cancer drugs are highly needed to reduce cancer mortality. The field of drug repurposing emerged in the early 1990s as an alternative to the conventional drug discovery model. This model entails targeting discovery and validation, lead identification by high-throughput screening, and lead optimization by medicinal chemistry. Drug repurposing surged to overcome the pharmaceutical industry's limited productivity regarding the number of approved drugs concerning the long time and huge money required to develop a drug. Classical drug discovery requires an average of 15 years of research, whereas drug development by repurposing is portended to be cheaper, faster, and safer. The significant advantage of drug repurposing is that the pharmacokinetics, pharmacodynamics, and toxicity profiles of drugs are, in general, well known; thus, its rapid translation into phase II and III clinical trials is feasible [9]. Among the different drugs currently studied under the focus of therapeutic repositioning, ivermectin is very promising. It has been shown to have antitumor effects *in vitro and in vivo* (**Figure 1**).
