Research update from Dr. Jason White, lead researcher at the National Muscular Dystrophy Research Centre at the Murdoch Childrens Research Institute
To be perfectly frank, it has been a difficult time recently with what seems to be a stream of sobering news around multiple FDA decisions on drugs targeted at Duchenne Muscular Dystrophy (DMD). The next important date for the MD community is April 25th 2016, when the FDA Advisory Committee will consider Sarepta’s New Drug Application for eteplirsen. The Sarepta technology is different from others in its mode of delivery, which hopefully puts it in a better position compared to alternatives. Even though the news has not been what we would have hoped for, a number of valuable lessons have been learnt and will further help in development and application advances.
Other drugs continue to be developed aimed at combating the chronic inflammation associated with many of the muscular dystrophies. We are acutely aware of the need for such alternatives, but also must keep in mind the need for rigorous pre-clinical studies before considering clinical trials. All too often in this field we see exciting results presented that when translated to the clinic, just don’t hold up. Some of this relates to the fact that patients are not mice or fish and thus, the way the drug acts may be different, but sometimes this is a result of lack of scientific rigor in the laboratory; this is something we can and must control.
Some of the more interesting recent scientific reports are in the area of stems cells and a new and exciting technique referred to as gene editing. Recent research published in the prestigious scientific journal, Nature, describes DMD as a “stem cell disease”; what does this mean? This is a very important finding as it helps us understand, at a fundamental level, why muscle repair in DMD is compromised. We have known for some time it is the protein dystrophin which is missing in DMD and dystrophin provides structure and strength to muscle tissue; this new research describes a new role.
In muscle, there are precursor cells which respond to any injury to help rebuild the damaged areas of the tissue. Under normal circumstances, there are some of these cells which stay in reserve and these reserve cells express dystrophin. Thus in DMD, the ability of muscle to keep cells in reserve to repair the next area of injury is compromised. This research not only tells us a lot about how DMD muscle repairs itself, but also has implications for how we approach gene correction therapies.
A recent report from scientists in the USA, in the prestigious scientific journal Cell Stem Cell, describes the use of gene editing technology in stem cells. This is a new and exciting development which means the gene change can be specifically targeted in an individual patient. Some reports suggest this technology could be applicable in up to 60 per cent of patients. This new report uses a patient’s own cells (taken from the skin) and converts them into stems cells. The editing technology, which is very precise, called CRISPR/Cas9 is then used to “cut and paste” the affected part of the gene to correct it. While this is in essence a feasibility study it is also a significant step forward. The translation of these findings into the clinic will take some further work and optimisation -at least 10 years but this is a very significant and exciting step forward.
You can view the latest DMD research overview which has recently been updated.
If you would like to ask Dr. Jason White a question regarding research or any of the above information, please send your question through to email@example.com and MDA will endeavour to answers all questions of a general scientific basis. Any non-clinical questions specific to your own medical circumstance should be posed to your neurologist.