Drug repurposing provides solutions to some of these challenges by offering a route that takes less time to complete, requiring less financial investment into research and development and ultimately lowering the cost of a drug for patients. Key benefits of drug repurposing include:

• Removal of the need for de novo drug discovery and candidate synthesis since a compound already exists.
•  As the pharmacokinetic characteristics of the drug are already well understood it is possible to match compounds that act on a known biochemical pathway, to a disease where the pathway in question is affected. It is therefore likely that only a few candidates will need to be screened, rather than several thousands.
• As the drug will probably have been used in a variety of populations (e.g. of different ages), there is already likely to be a good understanding of the safety profile. Therefore, the need for safety trials is reduced (with the caveat that dose/formulation changes will need to be thoroughly tested). 
•  Drug repurposing tends to have a high likelihood of success and typically more repurposed drugs will advance to market than those being developed using the traditional de novo route. This further decreases the overall cost of repurposed treatments as less time and money has been spent working on therapies that were ultimately unsuccessful.

Whilst there is a perception that drug repurposing is not as exciting or innovative as de novo drug discovery, the key benefit of drug repurposing is that it allows therapies to be delivered to patients far more quickly, which is crucial for the multitude of rare diseases for which there are no treatments available.