According to a story from BioSpace, the US Food and Drug Administration (FDA) has recently approved the drug golodirsen (marketed as Vyondys 53) as a treatment for Duchenne muscular dystrophy that is linked to certain rare mutations. The drug was approved under Accelerated Approval protocols and is expected to be useful for around eight percent of Duchenne muscular dystrophy patients.
About Duchenne Muscular Dystrophy (DMD)
Duchenne muscular dystrophy is a neuromuscular disease, and it is one of the more severe types of muscular dystrophy. It is characterized by progressive muscle weakness that usually begins around age four and worsens quickly. As an X-linked genetic disease, boys are mostly affected, with girls only occasionally displaying mild symptoms. The disease is caused by mutations of the dystrophin gene. Symptoms of Duchenne muscular dystrophy include falling, abnormal walking posture, eventual loss of walking ability, muscle fiber deformities, intellectual disability (not in all cases), enlargement of the tongue and calf muscles, skeletal deformities, muscle atrophy, heart abnormalities, and difficulty with breathing. Treatment includes a variety of medications and therapies that can help alleviate symptoms and slow disease progression. Lifespan is usually into the thirties with good care. Better treatments for this disease are urgently needed. To learn more about Duchenne muscular dystrophy, click here.
Vyondys 53 and Accelerated Approval
It is important to take into consideration that Vyondys 53 was approved under Accelerated Approval. This is a program from the FDA that can allow for drugs developed for severe, life-threatening illnesses that appear to offer signficant advantages over currently available therapies to be approved more rapidly. These drugs may be approved with data based on a “surrogate endpoint.” This is a statistical measure that does not prove clinical impact, but instead merely predicts its likelihood. A therapy that is cleared with Accelerated Approval must still continue to undergo clinical testing to prove clinical benefit before it is permanently approved.
Vyondys 53 is a therapy that utilizes a special approach called exon skipping in order to allow for improved production of dystrophin, which is deficient in Duchenne muscular dystrophy patients. The drug “skips” exon 53 in order to address the underlying cause of the disorder. However, only certain patients possess mutations that can be skipped.
Hopefully continued testing of Vyondys 53 will more decisively confirm its positive impact on patients.