Learn The BasicsThe first-line therapy for Duchenne muscular dystrophy (DMD) is corticosteroids. However, these do not address the underlying cause of the disease and only aim to delay its progression.
Surgery may also be an option for some patients.
There are also disease-modifying therapies that address the underlying cause of DMD or promote the production of muscle tissue. These include ataluren, exon-skiping drugs, gene therapy and histone deacetylases (HDAC) inhibitors.
Additionally, there are experimental therapies that are currently being developed for patients with DMD.
Corticosteroids
Corticosteroids have been used for more than 20 years to treat patients with DMD.
The two main corticosteroids used in this patient group are prednisone and deflazacort.
Research has shown that these therapies can improve lung function, delay the development of scoliosis, reduce the incidence and progression of heart muscle disease and reduce mortality.
However, they are associated with many side effects such as weight gain, suppression of growth, delayed puberty, brittle bones, mood changes, excess hair growth, acne and cataracts.
Surgery
Some patients may benefit from surgical interventions to relieve contractures and correct scoliosis.
Some patients may also need to undergo a surgical procedure called a tracheostomy to insert an invasive ventilator to aid in breathing in the later stages of the disease.
Ataluren
One disease-modifying therapy that addresses the underlying cause of DMD is called ataluren.
In some cases, DMD is caused by a mutation in the DMD gene that introduces a premature stop signal in the genetic code. This causes the protein-making machinery of the cell to prematurely stop reading the instructions contained in the gene. This means that the protein made from the gene is shorter than normal and cannot function.
Ataluren is called a stop signal read-through drug. It “covers up” the premature stop signal to allow the protein-making machinery to continue reading the rest of the information necessary to make a functional protein.
Ataluren is approved for use in the European Union and is marketed under the brand name Translarna. It is not yet approved by the U.S. Food and Drug Administration.
Exon-skipping drugs
Some patients may have mutations in the DMD gene, which disrupt the reading frame of the gene. Exon skipping aims to mask the area that causes this disruption and restore the reading frame of the gene to ensure a protein that can still function is made by the cells.
Several exon-skipping drugs have been approved for the treatment of DMD. These include Exondys 51 (eteplirsen), Vyondys 53 (golodirsen), Amondys (casimersen) and Viltepso (viltolarsen). Each of these drugs is only suitable for patients with a certain type of mutation.
Gene therapy
Gene therapy aims to deliver a healthy copy of the DMD gene to the body so cells can make a functional protein based on the instructions contained in this gene.
There is currently one gene therapy approved for the treatment of DMD called Elevidys (delandistrogene moxeparvovec-rokl).
HDAC Inhibitors
HDAC inhibitors aim to increase myogenesis or the formation of new muscle tissue.
Research has shown that HDAC inhibitors block the formation of scar and fat tissue caused by muscle degeneration and promote muscle regeneration in patients with DMD.
Givinostat (Duvyzat) is an HDAC inhibitor approved by the FDA for the treatment of patients with DMD older than six years of age.
Experimental therapies and clinical trials
Experimental therapies for DMD include myoblast transplantation, stem cell therapy and other gene therapies like fordadistrogene movaparvovec, rAAVrh74.MCK.GALGT2, SGT-001 and RGX-202.
Other experimental therapies include EDG-5506, a small molecule drug that aims to stop muscle damage, pamrevlumab, an antibody to combat scar tissue formation, rimeporide to reduce inflammation and scar tissue formation and ifetroban to improve heart function.
All of these experimental therapies are currently being tested in clinical trials.