October 2019

Introduction In September 2018, Duchenne UK announced a grant of $162,600 to Duke University, in collaboration with Solid Biosciences, to support the development of a novel, minimally invasive biomarker to estimate lean muscle mass. Taking part in a clinical trial can be hugely demanding for families. Part of the reason for this can be because of the demands placed on boys. In some trials they have to undergo MRI scans (Magnetic Resonance Imaging) or muscle biopsies, which involves removing pieces of muscle under general anaesthetic. These procedures need to be done to understand what impact a drug may be having on the body. However our co-founder Alex Johnson co-authored a paper published last month looking at the impact of muscle biopsies in boys. In it, she found that patients generally found biopsies distressing due to the pain and scarring. Click here to read her paper. Duchenne UK wanted to help scientists examine less intrusive ways of looking at what’s going on in the body. This is why in 2018, we, along with solid biosciences, granted $162,600 to Duke University and University of California to develop a new way of measuring the impact a treatment might be having on muscle. The scientists are developing what are called biomarkers- a way to examine the biological processes and the body’s response to medicines. Biomarkers involve testing things like blood and urine rather than taking muscle, and so they potentially offer a much less intrusive way of measuring what is going on in muscle tissue.   Biomarkers Project Update: WHAT HAPPENED? Researchers took 10 boys with DMD and 9 healthy boys of a similar age and gave them an oral dose of a compound containing D₃creatine. They gathered samples of saliva and urine. HOW DID THE STUDY WORK? The D₃creatine mixes evenly with all the body’s natural creatine – 98% of which is in muscle. The body metabolises creatine and creates creatinine, which is excreted in urine. The more healthy muscle a boy has, the more creatinine will be seen in his urine. By looking at both creatine and D₃-creatinine in urine, scientists can get a good measure of the total amount of healthy muscle. For this determination, only a single urine sample is needed. WHAT WERE THE RESULTS? This new urine test method successfully showed what is known to be true – that healthy muscle mass in boys with DMD is much lower than that of healthy boys. In the three oldest subjects with DMD, muscle mass comprised less than 5% of body weight. This has been a very positive study. Researchers believe they may have the beginnings of a method of measuring total muscle mass in boys without having to use painful biopsies or expensive and uncomfortable MRI. One other interesting result noted by the researchers was that in DMD boys, these biomarker measurements of muscle mass mirrored the “rise time” – the longer it took for a boy to get up was related to the biomarkers showing reduced muscle mass. This is encouraging evidence of the potential value of this technique. WHAT NEXT? Duchenne UK and Solid Biosciences are now working with scientists at Duke and UCLA to see what next steps need to be done to increase our understanding of this work and to create an effective urine test that could be used in clinical trials. Researchers plan to continue their studies with more volunteers so they can further validate the data, with the purpose of creating an effective urine test. They would also like to see if, in a bigger sample size, there are further links between the biomarkers and the physical activity of boys. This D₃-creatine dilution method to measure muscle mass may be a non-invasive method to determine disease progression and therapeutic efficacy. We will update you on the progress of this important project. We would like to thank our partner charities and funds for supporting this project: Joining Jack, Help Harry, Jack’s Mission and Team Felix