On 7th December 2010, we saw the release of important clinical information supporting the benefit of aspirin in preventing colorectal and other cancers. Truly, aspirin is a charmed drug. One of the oldest known therapeutics, this is now the third substantial therapeutic effect of the compound: first pain, then cardiovascular disease (stroke, myocardial infarction) and now cancer. One could hardly have scripted a group of clinical benefits of greater medical importance.
Of course, aspirin derives from the bark of the willow tree, the use of which to relieve headaches, pains and fevers was known to Hippocrates. Its isolated form was discovered in the early 19th Century. The fact that this clinical evidence in cancer prevention, despite being suspected for some time, has only surfaced nearly 200 years later, shows how long it can take for therapeutic substantiation even with a well known drug. Indeed, even today’s release, based on data from 25,000 patients, is published with the caveat that ‘further research is needed’.
Normally, drug repurposing as a commercial proposition needs to be guided towards a new, differentiated product — a new formulation, dose or presentation. In the case of aspirin, the research by the University of Oxford is supported by public funds, rather than towards capitalistic enterprise. The commercial benefit is limited to the increased sale of generic aspirin, particularly low-dose enteric coated versions (with reduced capacity to induce gastrointestinal bleeding). Indeed, this use may remain ‘off-label’ for quite a while despite the evidence in its support.
If more research of this kind can be performed without the need for a commercial endpoint, the opportunity for drug repurposed products in healthcare can only increase. The argument for funds from public, not-for-profit and charitable organisations needs to be made on the basis the resultant public good. Drug repurposing of older, generic medicines is almost always going to be cheaper than newer, patent protected medicines. And while there is often an argument for the superiority of newer products, it is more complicated in the case of aspirin. As we know, aspirin is a non-selective inhibitor of the cyclooxygenase (COX) enzyme; it is also well-known, that trials of a newer and more selective inhibitor of the COX-2 subtype turned out to uncover unwanted cardiovascular effects, and led to the dramatic withdrawal of Vioxxâ„¢ (rofecoxib).
The use of drug repurposed strategies to innovate products based on new uses of old medicines, without a commercial endpoint, is becoming a feature of a range of publicly and charitably funded trials. Such trials may actually involve more by way of re-analysis of old data than prospective evidence. The organisation Partnership for Cures raises funds for exactly this type of research, recombining and reusing old drugs and old data for various important diseases including orphan ones. Non-commercial organisations are able to bypass a frequent reason for not pursuing a drug repurposed project, the difficulty in defining a commercial return on product innovation. In so doing, they can realise the full advantages of repurposing, taking forward old generic products in the wider pursuit of enhanced, affordable healthcare for their stakeholders.