Drug Repurposing as an Effective Drug Discovery Strategy: A Critical Review

Abdulaziz H Al Khzem,1 Saad M Wali2 1Department of Pharmaceutical Chemistry, College of Pharmacy, Imam Abdulrahman Bin Faisal University, Dammam, 31441, Eastern Province, Kingdom of Saudi Arabia; 2Pharmacology and Toxicology Department, College of Pharmacy, Umm Al-Qura University, Makkah, 24342, Kingdom of Saudi ArabiaCorrespondence: Saad M Wali, Pharmacology and Toxicology Department, College of Pharmacy, Umm Al-Qura University, Makkah, 24342, Kingdom of Saudi Arabia, Tel +966543800090, Email [email protected] Abdulaziz H Al Khzem, Department of Pharmaceutical Chemistry, College of Pharmacy, Imam Abdulrahman Bin Faisal University, Dammam, 31441, Eastern Province, Kingdom of Saudi Arabia, Email [email protected]: Drug repurposing, or repositioning, has emerged as a pivotal strategy in pharmaceutical research, offering a promising approach to uncover new therapeutic uses for existing drugs. While traditional de novo drug discovery typically requires 10– 17 years and investments exceeding $2 billion with only 11% of Phase I candidates reaching approval, drug repurposing can reduce development timelines to 3– 12 years at substantially lower costs, with approval rates reaching approximately 30% for de-risked compounds. The current review evaluates recent approaches, benefits, challenges and successful examples of drug repurposing. Relevant literature related to the advantages and obstacles associated with drug repurposing were reviewed. Additionally, the review demonstrates computational and data-driven methods, as well as traditional and novel examples of repurposed drugs across different therapeutic fields. Drug repurposing offers a faster and cost-effective approach to new therapies, particularly for critical conditions, such as rare diseases, neurodegenerative disorders and cancer. These advantages overcome the shortcomings of traditional drug development. Successful examples include the repurposing of dimethyl fumarate, chloroquine and daptomycin, which addressed a range of medical indications beyond the original drug uses. Collectively, these findings demonstrate that drug repurposing provides a viable solution for accelerating the process of drug discovery and addressing urgent medical needs. The integration of advanced computational methods and enhancing collaborative research projects would allow further expansion of treatment options and supporting timely solutions for critical and rare medical conditions.Keywords: drug repurposing, pharmaceutical chemistry, drug discovery, strategies, clinical applications