The Barriers To Drug Repurposing

Hand of female African American nurse giving pills to elderly female patient.

Research institutions, physicians, and philanthropic organizations agree that drug repurposing offers a faster, cheaper and less risky development process than starting from scratch, making it essential to the advancement of modern medicine and patient impact.
But if it’s so beneficial, why isn’t more being done?

Lack of Financial Incentives

Industry and investors rightfully focus on areas where they can make a profit from their drug discovery investments. Drug repurposing, especially for rare and neglected diseases, does not ordinarily provide the same economic returns as does new drug development, with its patent protections and secured market exclusivity (1).

The result is that much of the financial burden for drug repurposing research falls to philanthropy – often to groups of patients and their supporters desperately seeking treatments to unsolved diseases. Even though drug repurposing development costs are much lower than for new drug development, the costs and complexity to bring a repurposed drug to patients is often beyond their financial resources, and beyond their capabilities.

Undermines Existing Markets

Industry often avoids supporting the repurposing of generic drugs, even with the promise of novel and patentable new uses. If the repurposed drug works in the new disease indication using its available formulation and doses, there is no current method for the company to charge a higher price for the new disease indication, while patients continue to pay a lower price for the old disease indication.  The low cost and wide availability of the repurposed drug can reduce a company’s chance to profit from the repurposing, and so they avoid getting started, even though it will help patients (2).  They can’t afford to do otherwise under the current payment system.

Until a new payment system is implemented that allows a company to reasonably recoup its investment on repurposing a generic drug, none of this generic drug repurposing will take place in the pharmaceutical industry.

Legal and Intellectual Property Issues

There are a number of legal and intellectual property (patent) barriers to drug repurposing.  First, many of the potential repurposing uses are already known in the scientific literature or in clinical practice.  Even through they have not been proven to work through clinical testing, they can no longer be patented, since there has already been public disclosure.  This lack of patentability reduces the chances of making a profit.  No profit, no incentive.

Second, even if you can secure a “method of use” patent, meaning you are the first to discover a new use for an old generic drug, you still might not be able to profit from it.  If the generic drug is widely available from many manufacturers, a physician could prescribe another manufacturer’s drug, and you wouldn’t see the profit, even though you hold the patent.

A third hurdle is that a lot of the new ideas for drug repurposing come from physicians in private practice.  Most practicing physicians do not have the time, expertise or legal support to hurdle the legal barriers, and so those repurposing opportunities often remain unvalidated and confined to  few clinical practices.

Still a Risky Business

Drug repurposing is not risk-free. Although the process starts from a much more favourable position that does de novo research, repurposed drugs still need to be shown to work. Repurposed drugs may have a significantly lower failure rate than for “new” drugs, but they still have the potential to fail in clinical trials and even after reaching the market (4).  Even though it’s 10-30% success rate far exceeds the success rate of new drug development, most drug repurposing will fail.

Scientists Rewarded for Originality

Scientists are trained to focus on finding “new” solutions (de-novo research). Original discoveries lead to highly ranked publications, and longer term funding. Philanthropies and their science advisors have historically followed this lead, and selected and funded primarily de-novo research.

1. Shineman D.W., Alam J., Anderson M., Black S.E., Carman A.J., Cummings J.L., Dacks P.A., Dudley J.T., Frail D.E., Green A., Lane R.F., Lappin D., Simuni T., Stefanacci R.G., Sherer T., and Fillit H.M. (2014). Overcoming obstacles to repurposing for neurodegenerative disease. Annals of Clinical and Translational Neurology 1(7): 512-518. [Link here]
2. Roin B.N. (2014). Solving the problem of new uses by creating incentives for private industry to repurpose off-patent drugs. Harvard Law School. [Link here]
3. Roundtable on Translating Genomic-Based Research for Health; Board on Health Sciences Policy, Institute of Medicine. Washington DC: National Academies Press (US); 2014 Aug 8. [Link here]
4. Thayer A.M. (2012). Drug repurposing. Chemical & Engineering News 90(40): 15-25. [Link here]