Drug repurposing

Drug repurposing offers a quick, cheap, and accessible route to develop new treatments for rare diseases

Although there are over 7,500 rare diseases, only around 400 have licensed treatments. Due to the high cost of drug development and low patient population in any given rare disease, investing in research is often not financially viable for the pharmaceutical industry. This leaves millions of patients with no medication to ease their symptoms, and little hope of ever seeing one in their life time. Drug repurposing offers a route to accelerate the development of new treatments while lowering the cost of research.

What is drug repurposing?

Drug repurposing is like recycling. It takes existing drugs already approved for human use, and identifies new illnesses that they could treat. These ideas are then tested through a clinical trial to confirm their efficacy (effect) in the new patient population.

Any drug can be repurposed, but they generally fall into one of two categories:

1. Generic drugs – these are drugs that are no longer covered by a patent, and can be produced by a large number of pharmaceutical companies.

2. Patented drugs – legally, these drugs can only be produced by the single manufacturer who owns the patent, giving them control over the drug’s accessibility and price. The drug may be currently available on the market, or its development may have been halted before it ever reached patients.

Why is drug repurposing a good option for rare diseases?

Aside from eliminating the expensive process of discovering a completely new compound, the big advantage of repurposing is that you are working with what you know. We know something about the side effects of the drug, its effect on different age groups, and where it acts in the body. All of this can help to reduce the time and money spent on identifying treatments, and running clinical trials.

Due to the lower cost, repurposing trials are also ideal projects to be led by researchers or patient groups without involvement from the pharmaceutical industry. This can help to drive drug development in rare conditions that would otherwise be financially unappealing to industry.

BM Manifesto and drug repurposing

We believe drug repurposing has huge potential to deliver new treatments to underserved rare disease patient populations. We work to highlight great repurposing projects, to encourage patient engagement in research, and are investigating new funding models for generic drug repurposing projects.

Drug repurposing for rare diseases conference

Every year our annual conference highlights the best examples of drug repurposing for rare diseases.


This EU-funded project aims to develop a new repurposed therapy for a rare genetic skeletal condition.

Rare disease drug repurposing social impact bond

We are working to develop a new financial model for generic drug repurposing.

Patient group involvement in drug repurposing

Repurposing can bring hope to patients living with rare diseases. Over the past few years, a number of projects have emerged that are delivering new research and new treatments to rare disease patients.

Professor Timothy Barrett and Wolfram Syndrome UK

Wolfram syndrome is a rare genetic disease, characterised by dilute urine (diabetes insipidus), problems with blood sugar regulation (diabetes mellitus), severe visual impairment, deafness, and neurodegeneration. The symptoms develop in early childhood, diabetes mellitus being the most common early sign, followed by degeneration of the eyesight around the age of 10. There is currently no treatment for Wolfram syndrome.

In 2013, Prof Timothy Barrett from Birmingham Children’s Hospital identified a widely available generic drug – sodium valproate – that had potential to treat the condition. Prof Barrett and his colleagues managed to secure funding for a clinical trial to test the treatment’s real-life effect on patients. Beginning in 2018, the trial will be supported by the patient group Wolfram Syndrome UK, who are providing patient perspectives for the trial design and have raised money to financially support patients taking part in the trial.


The Alkaptonuria Society

Alkaptonuria is an ultra-rare genetic condition that causes the bones to turn black, and their surface to corrode. This leads to a form of severe early onset osteoarthritis, leaving patients in great pain and often requiring a number of joint replacements throughout life.

In the early 2000s, a US-based clinical trial to test a repurposed drug, nitisinone, in AKU proved inconclusive. While the drug was biochemically effective, patient benefit was not proved conclusively. The AKU Society, a UK-based patient organisation, felt that this was due to inappropriate ‘end points’ (measures that determine whether the treatment is successful or not) in the trial rather than a lack of efficacy. Since then the AKU Society have:

  • Performed the first autopsy on an AKU patient.
  • Developed their own metric of disease progression.
  • Developed the first mouse models for the disease.
  • Secured funding for a UK-based specialist centre for the treatment of alkaptonuria.
  • Formed an international collaboration to deliver a new clinical trial of nitisinone in AKU and secured EU funding to run a five-year phase 2 and phase 3 clinical trial

The consortium are now nearing the end of the phase three clinical trial, and have reported promising interim results. They hope to soon have the evidence to licence nitisinone for the treatment of AKU in the near future.

The LouLou Foundation and Healx

CDKL5 syndrome is a rare genetic disorder that causes severe neuro-developmental impairment and early onset seizures in children. According to NORD, ‘most cannot walk, talk or feed themselves, and many are confined to a wheelchair. Some may have scoliosis, visual impairment, gastrointestinal difficulties, respiratory and sleep problems.’

In order to tackle this devastating condition the LouLou Foundation worked with Healx, a Cambridge-based drug repurposing start-up, to identify new repurposing opportunities for the condition. Using ‘omic approaches and data mining, it took the Healx team less than six months to identify a potential new treatment for cdkl5 – in this case a generic anti-depressant.

The Tuberous Sclerosis Association and Novartis

Tuberous sclerosis is a rare, genetic, multi-organ condition that causes small growths to form in the body, most commonly in the brain, eyes, heart, kidney, skin, and lungs.

Basic research into the causes of the condition led researchers to propose the use of a drug known as rapamycin to treat the disease. While their initial experiments, funded in-part by the Tuberous Sclerosis Association (TSA) in the UK, were promising, they were unable to secure the research grants required to fund a fully fledged clinical trial. By opening up conversations with the pharmaceutical industry, both the academics and TSA were able to secure industry backing for a clinical trial. The drug has now been repurposed by the pharmaceutical company to treat multiple tuberous sclerosis related symptoms, and it has been reimbursed on the NHS in the UK under the name everolimus.

Would you like to learn more?

If you would like to learn more about drug repurposing as a strategy for your rare disease patient group, BM Manifesto has a number of different resources available.

The book Rare Diseases – Challenges and Opportunities for Social Entrepreneurs, edited by BM Manifesto’s co-founder Nick Sireau, includes a chapter focussing on drug repurposing. You can find out more about the book on our publications page.

Our e-learning portal includes an introductory course on drug repurposing for rare disease patient groups. Visit the portal to sign-up and start this course, along with many others designed to aid patient group development.

Videos of many of the talks at our past conferences can be accessed through our drug repurposing conference webpage.