Medicines take a lot of time and money to develop, and the world of global pharmaceuticals pour billions of pounds and years of development time into compounds that have treatment potential, only to either not be demonstrably effective or feature considerable side effects.
As a result, when treating new diseases or rarer conditions, it is best to not only look at new drugs and compounds but medicines that are already in use and have been approved and deemed safe.
This concept is known as drug repositioning and has found success in treating difficult to manage or rare diseases.
Benefits Of Drug Repositioning
Because the side effects and health implications of an already-approved medicine are published and well-known, this can reduce the number of clinical trial phases the repositioned medication needs to go through to be approved for a new use, reducing the costs and time to market.
This also allows the researchers to move quickly into focusing on treating the disease in question rather than focusing on the medicine’s effects.
As well as this, because the medicine is already being produced, existing supply chains can enable it to be quickly formulated and distributed, as well as potential combinations with other medications.
With advances in human genomics as well as medical AI, drug repositioning can be undertaken with less of a need for serendipitous results compared to previous cases, and with fewer drug compounds left to discover, repositioning plays a vital role in managing and tackling diseases.
Examples Of Repositioned Medication
The most famous example of a repositioned drug is sildenafil, which whilst deemed relatively ineffective for angina it was developed for turned out to be very effective at dealing with pulmonary hypertension and erectile dysfunction, becoming the first-line treatment for the latter.
Another fascinating case of successful repositioning is the case of thalidomide, a highly controversial medication that was offered as a treatment for the wrong condition.
Thalidomide was initially an over-the-counter medication used to treat morning sickness, insomnia and anxiety. Whilst it did stop morning sickness, a common symptom of pregnancy, it was found to have a horrifying side effect.
Between its initial launch in 1957 and removal from the West German market in 1961, it was believed to have caused 2000 deaths and over 10,000 birth defects.
However, whilst the medication led to changes in drug regulation, it would also be an example of effective repositioning as well in 1964.
Jacob Sheskin, an Israeli doctor, gave thalidomide to a patient who was critically ill with leprosy, and despite the ban on the use of the treatment in the country, it helped the patient considerably, who managed to sleep soundly and got out of bed without help once he awakened.
Whilst it is not the first-line medicine of choice for leprosy with clofazimine not having as many side effects, it is an example of a medicine that was taken off the market before being put back on due to its ability to treat other conditions.
One final major example was zidovudine, which was initially designed as a cancer treatment, but due to a lack of knowledge of how cancers developed, the anti-retroviral treatment was shelved as a cancer treatment.
However, when HIV was first identified as a retrovirus in 1983, zidovudine, also known as azidothymidine or AZT, would be approved as one of the first treatments for HIV, albeit in controversial circumstances.