Repositioning Old Drugs for New Battles: The Expanding Role of Drug Repurposing in Cancer, Inflammation, and Metabolic Disease.
Rofiyat Omolara Raji, Sodiq Balogun, Tawakalitu Bidemi Aliu, Kaosara Badmus · BIOMED natural and applied science · 2025
Drug repurposing has emerged as a powerful, cost-effective strategy for therapeutic innovation amid increasing global disease burdens and the limitations of traditional drug development, which is time-consuming, costly, and marked by high failure rates. This systematic review synthesizes the current landscape of drug repurposing, drawing from literature published between 2000 and 2025 across major biomedical databases. The review highlights mechanistic rationales, successful examples, computational and experimental approaches, and regulatory and ethical considerations. Repurposed drugs such as thalidomide, sildenafil, metformin, and minoxidil demonstrate the clinical potential of repositioning strategies guided by mechanistic insight, phenotypic screening, and real-world observations. The applications span oncology, infectious diseases, neurology, and cardiovascular medicine, where existing drugs have shown efficacy beyond their original indications. Emerging tools including artificial intelligence, network pharmacology, high-throughput screening, multi-omics integration, and real-world evidence from electronic health records are transforming how candidates are identified and validated. Despite these advances, challenges remain particularly intellectual property constraints, regulatory barriers, and limited commercial incentives for off-patent drugs. A coordinated approach involving regulatory innovation, ethical oversight, and public-private collaboration is essential to fully leverage repurposing as a path to safer, faster, and more affordable treatments for both common and neglected diseases.