provides the opportunity to fulfil the gap for treatment of diseases with little or

no cure.

Keywords

Drug repositioning · FDA approved · Disease · Genomic approaches · Drug

target · In silico approaches · Computational · Artificial intelligence

5.1

Introduction

Drug development is a process wherein a new drug aimed to alleviate or treat disease

symptoms is introduced into the pharmaceutical market upon identification of a lead

compound via drug discovery. Discovery of lead compounds holding therapeutic

activity is traditionally found through classical and reverse pharmacological

approaches. The former involves the screening of natural products or chemical

libraries of synthetic small molecules in vitro or in vivo, whereas the latter relies

on high-throughput screening of large compound libraries against a cellular pathway

of interest. Across the recent years, drug discovery has shown a staggering decrease

in productivity because of its lengthy, risky, tedious, and financially straining

process. Statistics show that a conventional route from drug discovery to drug

delivery may cost a span of approximately 10–15 years with an average expense

of US$12 billion (Xue et al. 2018). Most drug leads fail to enter clinical trials due to

the lack of safety and efficacy. Some may go as far as phase II and III clinical trials

only for it to be retracted because of insufficient validation or suboptimal setup of

clinical trials (Everett 2015).

The United Nations General Assembly has recently designed a blueprint enlisting

the Sustainable Development Goals (SDGs) to be achieved by 2030. SDG 3 calls for

an improvement in health services to promote healthy lives and well-being amongst

citizens of all ages (The 17 Goals 2021). In alignment with rapid technology

advancements moving towards a digital era, we foresee a revolution in digital

healthcare. Consequently, there is a dire need to understand in depth how we may

establish a novel framework in drug development for long-term sustainability. An

increasingly popular trend currently is drug repositioning (DR). Evidently, a query

of publications associated with the term “drug repositioning” on PubMed began in

2006 with only 1 publication, followed by an exponential growth with up to more

than 1000 publications in 2021.

DR, synonymously known as drug repurposing, drug recycling, drug redirecting,

drug re-tasking, or drug reprofiling, is defined as measures looking into approved or

investigational drugs for new indications of other diseases aside from that originally

intended (Fig. 5.1). Instead of solely relying on top pharmaceutical industries, more

extensive collaboration and networking through the partnership of these industries,

biotechnology companies, and academia will encourage a wider exchange of infor-

mation while garnering financial support. Considering that these drugs have been

de-risked, the investment and cost in time may be reduced while reaping the benefits

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I. A. Farouk et al.