Exploring the potential of drug repurposing / Serendipia

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Drug repurposing is a little like recycling. It is the process of finding new therapeutic uses for drugs that already exist, rather than creating something new.

This makes drug repurposing an effective strategy to discover existing drug molecules with new pharmacological or therapeutic indications.

The drugs that can be repurposed range from substances that are already used for specific illnesses or conditions, old drugs that aren’t used anymore, drugs that didn’t meet their primary endpoint in clinical trials, and shelved drugs.

It has been estimated that it costs approximately $1 billion to bring a drug from the laboratory to market, and this can take as many as 12 years. Additionally, when the costs of failed projects are considered, the real cost rises to about $2.6 billion.

Taking this into account, as well as pressure on revenues from generics as patents begin to expire, the interest in drug repurposing has unsurprisingly grown significantly.

Those involved in drug repurposing, also known as drug repositioning or drug reprofiling, range from charities, academic institutions, biopharmaceutical companies, and government divisions.

In theory, drug repurposing should cut down the time it takes to get a drug to market to as few as one to three years, as well as reduce the cost and risk involved.

Less time, money, and resources are needed to discover new uses for existing drugs, but how does drug repurposing work in reality?

How are repurposed drugs found?

In many cases, repurposed drugs are discovered completely by accident. When drugs are in clinical trials, many side effects are reported. These side effects are often negative, but sometimes they may prove themselves to be useful.

There are several famous examples of this, one being sildenafil. Sildenafil was first tested clinically for hypertension. During clinical trials, patients reported a rather interesting side effect that seemed worth noting. 

This side effect − persistent erections during the clinical trials − led sildenafil to be repurposed as Viagra for the treatment of erectile disfunction.

The same compound drug has also been further repurposed under a different dosing schedule as Revatio for pulmonary arterial hypertension. More recently, it is being explored for the treatments of certain types of cancers.

These discoveries don’t always happen by luck, some drugs fail in what they were first intended for, such as thalidomide. It was developed in the 1950s as a sedative and treatment for morning sickness in pregnant women, but was quickly withdrawn once serious birth defects in newborn babies became clear.

A closer look at the chemical structure of the compound demonstrated that thalidomide was in fact an effective treatment for leprosy. Even more recently the drug has been approved for the treatment of multiple myeloma. 

Final thoughts 

 In theory, drug repurposing is a great idea. It can offer a faster, cheaper, and more effective way of discovering new drugs that could potentially save many lives, particularly those with hard-to-treat cancers and rare diseases. However, it can be hard to fund for a number of reasons, such as scepticism and a lack of financial incentive. A system is needed to allow drug repurposing to be a more viable option, such as through collaboration, and technological advancements. If this happens, there is huge potential to find new treatments in the future by repurposing the tools already at pharma’s disposal. Más