Developing a brand-new drug takes an enormous amount of time, money and effort. Delays and barriers mean that translation of a promising molecule into an approved drug often takes more than 14 years. It is crucial to advance strategies to reduce this time frame, decrease costs and improve success rates.

Drug repurposing or re-positioning is one such strategy. Many agents, developed or approved for other uses have already been tested in humans, so detailed information is available on their pharmacology, formulation and potential toxicity. Because repurposing/repositioning builds upon previous research and development efforts, new candidate therapies could be ready for clinical trials quickly, speeding their review by Regulatory Authorities and, if approved, their integration into treatment for Duchenne.

Duchenne UK is funding a clinical trial to assess the safety and efficacy of Tamoxifen as a potential treatment for Duchenne Muscular Dystrophy.

Tamoxifen has been used to treat breast cancer since the 1980s. It is also used for hormonal disorders in pre-pubescent boys. Preliminary data in the DMD mouse model (Dorchies et al. 2013) demonstrated that Tamoxifen reduced fibrosis, increased the thickness of muscle fibres, and resulted in a delay in disease progression.

Duchenne UK is contributing £575,000 to the study and will fund one European trial site and two in the UK, along with the project manager for the study, based in Switzerland. Duchenne UK is working with the DMD Hub to support the trial sites in the UK for the Tamoxifen study.

The trial is being jointly funded by Duchenne UK, E-Rare, Duchenne Parent Project in Holland, and the Monaco Association against Muscular Dystrophy. The trial is due to begin in 2018.

Idebenone (Raxone®) is being developed for a number of mitochondrial and neuromuscular indications by the pharmaceutical company Santhera.

Raxone is approved in the EU for the treatment of visual impairment in adolescent and adult patients with Leber's Hereditary Optic Neuropathy (LHON).

In a phase III trial, Raxone significantly delayed the rate of lung function loss in Duchenne patients that were not taking concomitant steroids. Submission of a dossier to obtain marketing authorisation for Duchenne in the US and EU is expected soon.

Another example of a drug that has the potential to be re-purposed for Duchenne is simvastatin. In addition to cholesterol lowering effects, experiments in mice have shown that statins also have potent anti-inflammatory, anti-fibrotic and anti-oxidant effects. In addition, they are already approved for treatment of familial hyperlipidemia in children and a good safety profile has been established. Plans for a clinical trial to assess their effect in Duchenne are ongoing.

Several research groups are investigating other drugs that have the potential to be re-purposed for Duchenne. These include Rimeporide which was initially developed as a treatment for congestive heart failure and is now in phase 1 clinical trials.

The Debiopharm group, in collaboration with Solid Biosciences, are developing Alisporivir as a treatment for Duchenne. Alisporivir has already been tested in more than 1500 patients during development for hepatitis C and has demonstrated an acceptable safety profile. Alisporivir is able to prevent mitochondrial-dependent muscular cell death and has shown promising activity in preclinical models of Duchenne.