Normally in the business of curing what ails, the global pharmaceutical market has been battling to cure its own ills for a number of years now. The increasingly harsh global drug pricing environment coupled with rapid generic erosion in many of the largest and therefore most lucrative markets means that pharmaceutical companies are facing a double-edged sword of declining profitability and falling productivity.
Drug repositioning should not be confused with traditional life cycle management strategies which look to develop new formulations (such as combination therapies or different methods of administration) and approvals for related indications as a way to prolong a drug's life. By comparison, drug repositioning requires an innovative approach to drug development. In fact, it relies on an element of molecular redundancy, such that either a biological target functions in several physiological pathways, or drugs have multiple uncharacterized off-target effects.
Drug repositioning has several advantages over traditional discovery: reduced cost, risk and time to market. Repositioning is also ideally placed to meet much of the unmet need that exists in treating rarer diseases, which can often be neglected by the traditional de novo approach which is focused on drug discovery for the 'masses'.
At best, a molecule has only a one in 5,000 chance of approval, with just three out of 10 drugs that actually reach the market providing a return on the R&D investment. It is also estimated that 90% of all drugs entering clinical trials are discontinued, more often due to issues associated with efficacy than safety. This implies most pharmaceutical companies are sitting on an enormous backlog of drugs which could potentially be re-developed. Viagra, Pfizer's anti-impotence drug actually began life as a treatment for angina but showed poor efficacy during clinical trials. All was not lost for Pfizer however, as the drug's anti-impotence properties serendipitously came to light during the clinical process and Viagra went on to become a blockbuster seller.
Eli Lilly's drug duloxetine serves as a good example of drug repositioning by informed insight. Initially in development as an antidepressant (receiving marketing approval for this indication in the US in 2003, where it was launched under the name Cymbalta a year later), Eli Lilly also investigated its efficacy in treating stress urinary incontinence (SUI). Following successful clinical trials, Eli Lilly succeeded in obtaining marketing approval for the drug for SUI, making it the first in class.
Although drug repositioning offers considerable advantages over conventional drug discovery, the regulatory and intellectual property issues associated with it require special attention. Most leading pharmaceutical companies lack the resources to reposition drugs effectively and have looked outside to smaller companies, leading to a burgeoning industry dedicated to this development approach. The many companies now involved in repositioning are using a variety of technologies and methodologies aimed at systemizing drug repositioning in a young and highly fragmented industry. With the value that repositioning brings, Datamonitor believes that the leading drug makers are likely to incorporate this strategy into their own development process, changing the dynamics of the repositioning industry going forward.
Last updated on: 27/08/2010 11:40:18