Drug Repurposing (DR): An Emerging Approach in Drug Discovery

Abstract

Drug repurposing (DR) (also known as drug repositioning) is a process of identifying new therapeutic use(s) for old/existing/available drugs. It is an effective strategy in discovering or developing drug molecules with new pharmacological/ therapeutic indications. In recent years, many pharmaceutical companies are developing new drugs with the discovery of novel biological targets by applying the drug repositioning strategy in drug discovery and development program. This strategy is highly efficient, time saving, low-cost and minimum risk of failure. It maximizes the therapeutic value of a drug and consequently increases the success rate. Thus, drug repositioning is an effective alternative approach to traditional drug discovery process. Finding new molecular entities (NME) by traditional or de novo approach of drug discovery is a lengthy, time consuming and expensive venture. Drug repositioning utilizes the combined efforts of activity-based or experimental and in silico-based or computational approaches to develop/identify the new uses of drug molecules on a rational basis. It is, therefore, believed to be an emerging strategy where existing medicines, having already been tested safe in humans, are redirected based on a valid target molecule to combat particularly, rare, difficult-to-treat diseases and neglected diseases.

The Protozoan Inhibitor Atovaquone Affects Mitochondrial Respiration and Shows In Vitro Efficacy Against Glucocorticoid-Resistant Cells in Childhood B-Cell Acute Lymphoblastic Leukaemia

“…The advantage of this approach is saving considerable amount of time (at least 2–3 times quicker ( 18 )) and money (3–10 times less on average ( 19 )), ultimately translating into saving more lives faster and at a lower cost. Encouraging examples of drug repositioning already in use or in clinical trials range from Aspirin in colorectal cancer ( 20 ), Metformin (for diabetes) and Daunorubicin (antibiotic) for various malignancies ( 20 , 21 ), retinoic acid (vitamin A) in acute promyelocytic leukaemia (APL) ( 22 ), a combination of retinoic acid and Tranylcypromine (TCP—anti-depressant) in acute myeloid leukaemia ( 23 ), and others.…”

Challenges and Opportunities for Drug Repositioning in Fibrodysplasia Ossificans Progressiva

“…Compared to the development of new drugs, drug repurposing has a number of advantages (summarized in Table 1 ). As less than 15% of new therapeutic compounds reach approval [ 116 ], drug repurposing substantially reduces the risk of failure, whilst also reducing costs in drug development and shortening the time to clinical implementation [ 117 , 118 ]. This is an attractive benefit for rare diseases such as FOP, with a very limited market.…”

Targeting the RdRp of Emerging RNA Viruses: The Structure-Based Drug Design Challenge

“…Since pharmacokinetic, toxicological, and safety data have already been collected for the repurposed drug in preclinical and early clinical trials, the risk of failure is considerably lower. Then, fewer investments are required, although depending on the phase and process of development achieved by the candidate drug [94]. There are many successful examples of drug repurposing/repositioning, including sildenafil, originally designed to treat angina pectoris, to date used for the treatment of erectile dysfunction [95].…”