Drug repurposing: an emerging approach to lifesaving care

How drug repurposing has the potential to deliver life-saving treatments to rare diseases, at a fraction of the cost.

What is drug repurposing?

Drug repurposing, also known as drug repositioning, is emerging as a low-cost, low-risk, highly efficient means of capturing value in the drug discovery process. It involves finding new pharmacological or therapeutic indications for existing drugs that have already been approved by regulatory agencies. Not only does this circumvent the exorbitant costs and resources required to develop a new drug from scratch, it also means that, in an instance when an existing drug is found to have useful applications for other diseases, patients are able to access the benefits of effective care much faster than with traditional drug discovery processes. 

Over the last five years, drug repurposing has gained significant momentum, with the drug repurposing market estimated to grow to a value of $46 851.5 million by 2028, expanding at a CAGR of 5.4% year on year. There are approximately 10 000 known diseases, but only 2500 are paired with FDA-approved drugs. This presents a major opportunity for pharmaceutical organizations, particularly in the realm of rare diseases, diseases in children and pregnant women, and neglected tropical diseases – many of which could be addressed by existing drugs.

In this article, we’ll take a closer look at drug repurposing, and how it has the potential to deliver lifesaving care to patients across the globe, while delivering major returns to the pharmaceutical industry.

A doctor saves his own life

In the early 2010s, Dr. David Fajgenbaum, at the time a medical student at the University of Pennsylvania, became gravely ill with idiopathic multicentric Castleman disease. The disease is characterized by deadly cytokine storms – flares of immune-signaling cells which cause the immune system to attack the body. Determined to save his own life, Falgenbaum set out to find a new treatment approach, examining his own medical records. He noticed that a protein called vascular endothelial growth factor (VEGF) was spiking at 10 times the normal level. He consulted with his doctor and request a prescription for Sirolimus, an approved immunosuppressant usually prescribed to transplant patients. Years later, he remains relapse-free.

Since then, Fajgenbaum has founded a number of organizations dedicated to finding treatments for the 7000 rare diseases affecting over 400 million people around the world, using repurposed drugs.


A number of repurposed drugs have gone on to become blockbusters in the pharmaceutical market. Most famously, Sildenafil, originally developed to treat angina pectoris and hypertension, was repurposed into Viagra, one of Pfizer’s most successful drugs of all time. Other examples include Minoxidil, which led to Rogaine, and Wellbutrin, which delivered the smoking cessation drug Zyban. 

The advantages of drug repurposing

Repurposing a drug has two main advantages over the traditional drug development process: faster time to market and significantly lower cost of development. The average drug development process takes approximately 10-16 years on average, as opposed to 3-12 years for a repurposed drug – a saving of about 5-7 years of average R&D time. It only costs about $1.6 billion to develop a new drug using a drug repositioning strategy, as opposed to the average $12 billion it costs to develop a new drug from scratch. Chances of success and approval are also much higher – 45% of the failure rate of traditional new drug discovery processes can be attributed to safety and toxicity concerns, a factor not relevant in already-approved drugs targeted for repurposing. Overall, about 30% of repurposed drugs make it through to patients – 20% more than new drugs. 

How AI is accelerating drug repurposing efforts

Researchers are increasingly deploying AI’s ability to process immense data sets and discover and examine complex relationships between data to identify and predict the success of repurposing candidates. In one recent example, researchers used AI to try and identify existing medications that may be effective for the treatment of COVID-19. In just 48 hours, the system had identified baricitinib, a rheumatoid arthritis drug, as the most likely candidate. The drug went on to gain FDA approval for the treatment of adult COVID-19.

Accelerating R&D through AI-enabled insights management

Drug repurposing is one example of how researchers use existing data to create major value in the drug discovery process. 

For R&D teams throughout the pharmaceutical industry, the need to monitor the ever-increasing volume of data emerging across the industry every day is mission-critical to research success. 

By monitoring millions of data points in real-time, many of which are invisible to traditional search methods, Similari’s AI-enabled insights management platform allows you to offload up to 90% of your manual data monitoring time, keeping you absolutely up to date with all the latest developments in your specific arena of inquiry, and allowing you to optimize decision-making, resource allocation and research efforts across the board. 

Find out how Similari will change the way you work by trying a free demo today.

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