A new treatment for Duchenne muscular dystrophy (DMD) has recently been approved by the FDA. The therapy is called viltolarsen and it was created by Nippon-Shinyaku and the National Center of Neurology and Psychiatry in Japan.
This therapy was based on the work of Toshifumi Yokota who is a professor of medical genetics at the University of Alberta.
DMD is a rare genetic disease that causes the muscles in the body to slowly weaken. The disease is caused by the absence of a protein called dystrophin. This protein is responsible for keeping cells intact.
When researchers first began studying DMD, they tried to use DNA to restore thee proteins that patients were missing. Unfortunately, this approach proved dangerous in animal models. The therapy was toxic to the cells of the animals and this lead to a dangerous immune response. Although the immune system is meant to protect the body, an overzealous immune response can prove just as dangerous as the condition you’re trying to treat.
Now, researchers have turned to synthetic molecules that resemble DNA but are not DNA. These are called antisense oligonucleotides. These DNA-like molecules are more stable than DNA itself and are less likely to cause a severe immune response. This is because they bind to RNA and DNA in a different way. Viltolarsen is one of these molecules.
Viltolarsen was first approved in Japan. Then, just this past August it was officially approved in the United States. Currently, it is in the process of review in Canada.
This therapy was not designed to treat all forms of muscular dystrophy. It instead concentrates on a certain DMD gene mutation which effects approximately 10% of DMD patients. Of course, this is just the starting point.
In 2009, these researchers first showed that DNA-like molecules were able to restore protein production. What viltolarsen does is customize the molecules to a specific gene mutation- in this case, one that causes DMD.
Researchers are hopeful that this therapy could be expanded to aid other forms of DMD. In fact, they are optimistic that 90% of DMD patients could respond to this form of therapy. The trick is just customizing each molecule to fit the unique form of the rare disease.
Further, this research shows that the medical field is continuing to recognize the importance of precision medicine. A one-size-fits-all approach doesn’t work for all conditions. Especially for rare diseases, custom approaches targeting specific mutations is continuing to prove the most promising option for patients.
You can read more about this therapy here.