ABSTRACT
The concept of drug repurposing excludes any structural modification of the drug. Instead, repositioning makes advantage of either the biological qualities for which the medication has already been licensed. Many of the drugs being studied for oncological repurposing, on the other hand, are either generic or low-cost. One of the most important aspects of drug repurposing is the use of in silico tools (data mining, machine learning, ligand-based, and structure-based approaches) to describe the factors connected with the complex interplay between diseases, drugs, and targets. Considering heterogeneity of cancer, drug development process for cancer is even more complicated. Undruggable target, chemo-resistance, tumor heterogeneity are major barriers for safe and effective cancer chemotherapy. Traditional drug discovery approach fails to provide effective solution. Drug repurposing has provided safe and cost-effective solution for cancer therapy. In silico methods also have the capability to repurpose the old and off-target compounds to increase the likelihood in selected patients and predict better response in tumours. In 2011, the FDA approved drugs vemurafenib and crizotinib were repurposed in metastatic melanoma and lung cancer respectively. In this 112chapter we had discussed about various drug repurposing approaches for cancer therapy along with its limitations.
