FDA Grants Approval for the First Disease-Modifying Drug for Duchenne Muscular Dystrophy
In the 1860’s, Duchenne Muscular Dystrophy (DMD) was first identified by Guillaume Benjamin Amand Duchenne, a French neurologist. It wasn’t until over a hundred years later, in 1986, that a cause for this disease was defined; a mutated gene on the X chromosome. A year later in 1987, researchers further discovered that a lack of the protein dystrophin in muscle cells caused muscles to become weak and easily damaged.
Duchenne Muscular Dystrophy symptoms typically appear in children between the ages of three and five. These symptoms begin by impacting the muscles within the hips, pelvic region, thighs, and shoulders. As the child ages, the skeletal muscles of the arms, legs, and trunk of the body are affected. Often children with DMD have enlarged calves. During the teenage years, respiratory and heart muscles become impacted. This disease is prominent in males, but sporadically can impact females.
Prior to advances in cardiac and respiratory care, children with DMD did not live past their teenage years. Medical advances have helped increase the life expectancy. Now most children are able to live until their early 30’s or, in some cases, up to their 40’s and 50’s.
In addition to advances in cardiac and respiratory care, we now have access to Exondys 51, which is the first FDA approved drug to aid in treatment for DMD as of September 19, 2016. Exondys 51 or previously known as Eteplirsen, is an exon skipping drug used to treat specific DMD mutations that affect the production of dystrophin, an essential protein involved in muscle function. Exons are cellular structures that make up the RNA. Each of these exons contain a code for a specific set of amino acids, also known as the building blocks of protein. Due to exon deletion found in some DMD mutations, the translation of genetic code for dystrophin protein is interrupted. Exon skipping aims to “skip over” a specific exon in the RNA in order to realign the genetic code of dystrophin, thereby promoting the production of a functional yet shorter form of dystrophin.
Though this treatment became recently available, there are health care facilities already utilizing this treatment, such as the University of Florida. UF Health administered the first treatment session in the United States for a young male who was nine years old. Although there is not yet a cure for DMD, the new treatment Exondys 51 is believed to have positive results. In clinical trials, this treatment has shown to increase dystrophin protein production in skeletal muscle and lessen severe muscle weakness and atrophy. Exondys 51 may be the stepping-stone to further development of more effective and more advanced treatments for patients with DMD.
Exondys 51 (eteplirsen). (2016). Retrieved October 11, 2016, from http://musculardystrophynews.com/exondys-51-eteplirsen-sarepta-therapeutics
Muscular Dystrophy Association Inc. (2016). Duchenne Muscular Dystrophy. Retrieved from https://www.mda.org/disease/duchenne-muscular-dystrophy
UF Health. (2016, Oct. 7). First Commercial Duchenne Muscular Dystrophy Therapy in US Administered at UF Health. Retrieved from https://ufhealth.org/news/2016/first-commercial-duchenne-muscular-dystrophy-therapy-us-administered-uf-health
U.S. Food and Drug Administration. (2016, Sept. 29). FDA Grants Accelerated Approval To First Drug For Duchenne Muscular Dystrophy. Retrieved from http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm521263.htm