The use of knowledge graphs for drug repurposing: From classical machine learning algorithms to graph neural networks

Drug repurposing, the development of new therapeutic indications for existing drugs, is a promising strategy in drug development. Computational methods and artificial intelligence may be used to identify new drug repurposing candidates. Knowledge graph (KG) based methods have emerged as powerful tools for modeling and predicting drug-disease relationships, because of their intuitive way of exploiting biomedical knowledge and data. This review provides an overview of computational drug repurposing methods based on KGs. The motivation for adopting KG-based knowledge representations, traditional machine learning and deep learning approaches are discussed, followed by an analysis of selected tools, their construction, link prediction capabilities, and inherent advantages and limitations.