New Life for Old Drugs

jaynelawrenceby Professor Jayne Lawrence, Chief Scientific Advisor, Royal Pharmaceutical Society

BBC News online is today reporting that existing drugs used for treatment of motor neurone disease, asthma and heart disease are being tested as possible treatments for advanced multiple sclerosis (MS).

Although not a new idea, the concept of ‘new life for old drugs’ is rapidly gaining currency.   As our understanding of how our bodies work, and how they are affected by disease processes, grows ever-more sophisticated, it is increasingly being realised that drugs have effects on more than one disease. 

The results can be good or bad – the question is how to uncover promising new effects in a systematic way. Computer modelling and improved in vitro screening methods are aiding greatly in this search, along with the emergence of systems biology and a growing database of genetic information.

Taking a drug from discovery through to formulation as a medicine and clinical trials is an expensive, complex and lengthy process with a great many hurdles. Indeed, it’s estimated that out of 10,000 potential new drug molecules discovered, only 1 (and maybe none) will actually make it to market as a medicine. Currently, taking a drug from discovery to an approved medicine takes around 12 years and costs between £50 million to £1billion.  Re-using an existing drug for a new purpose can save several years and up to 40% of the cost.

I’m delighted to hear about new trials breathing new life into old drugs.

Drugs which have already found new uses include:

Aspirin: Originally used as a pain killer, aspirin now used for a variety of diseases/conditions such as, lowering the risk of heart attack, strokes and other blood flow problems

Thalidomide: Withdrawn from use in 1961 for causing severe birth defects but approved in 1998 for treatment of complications associated with leprosy and, more recently, bone marrow cancer

Sildenafil citrate: More famously known as Viagra – which was originally developed to treat high blood pressure, but ended up being used to treat impotence and now also for a form of high blood pressure which affects the blood vessels supplying the lungs. 

It’s likely that many other drugs will find new life in the coming years with patients suffering from rare and orphan diseases standing to gain much from drug re-use.

A related process is drug rescue, where drugs that were abandoned before they could be approved by the licensing agencies are screened to see if they can treat diseases other than the ones for which they were originally developed.

Both the re-use of drugs, and drug rescue, should provide a fertile source of new treatments in the coming years.