What are the new drugs for Duchenne muscular dystrophy?

The new drugs approved by the FDA for the treatment of Duchenne muscular dystrophy (DMD) are:

• Amondys 45 (casimersen)
• Elevidys (delandistrogene moxeparvovec)
• Emflaza (deflazacort)
• Exondys 51 (eteplirsen)
• Viltepso (viltolarsen)
• Vyondys 53 (golodirsen)

Duchenne muscular dystrophy (DMD) is a genetic disease that causes progressive weakness and loss of skeletal and heart muscles.

DMD primarily affects males starting in early childhood, usually between the ages of 2 and 3. It leads to worsening muscle weakness and eventual premature death in the second or third decade of life due to heart problems and lung failure.

DMD is caused by mutations in the DMD gene. When a gene exon is missing (for example, exon 51 or 53), cells do not have the proper instructions to make dystrophin, which leads to a type of muscle damage that causes DMD. Dystrophin helps to strengthen and protect muscles. If needed, your doctor can test you for the DMD gene mutation.

How is Duchenne muscular dystrophy (DMD) treated?

Corticosteroids (glucocorticoids) are the foundation of treatment in DMD. These medicines are beneficial as they can help improve motor skills, muscle strength, lung function, and delay the loss of the ability to walk unaided. They may also help to reduce the risk of scoliosis and improve heart function and survival, although not all studies have found an association.

Newer agents called antisense oligonucleotides are now approved by the FDA. Antisense oligonucleotides are small pieces of DNA that are used to "mask" (cover up) the exon that needs to be skipped when making the dystrophin protein. This allows the rest of the gene to be be pieced together correctly.

It is estimated that about 8% of patients with DMD have a genetic mutation amenable to exon 53 skipping of the dystrophin gene, and about 13% of patients have a mutation amenable to exon 51 skipping.

Not all patients respond to, or are candidates for antisense oligonucleotides. They are not a cure for DMD, but may help improve muscle symptoms. Many of these drugs received accelerated approval by the FDA and still require clinical trials to confirm their clinical benefit in DMD.

In June 2023, the first gene therapy for DMD was approved called Elevidys. Elevidys is designed to treat the underlying cause of DMD by delivering a gene that codes for a functional shortened dystrophin (called Elevidys micro-dystrophin) into the muscle tissue.

The medications below have been approved by the FDA for the treatment of Duchenne muscular dystrophy:

Amondys 45 (casimersen) Injection

• FDA Approved: February 25, 2021
  Company: Sarepta Therapeutics

Amondys 45 is an antisense oligonucleotide for the treatment of patients with Duchenne muscular dystrophy (DMD) who have genetic mutations that are amenable to skipping exon 45 of the Duchenne gene.

Viltepso (viltolarsen) Injection

• FDA Approved: August 12, 2020
• Company: NS Pharma, Inc.

Viltepso is an antisense oliogonucleotide indicated for the treatment of Duchenne muscular dystrophy (DMD) in patients who have a confirmed mutation of the DMD gene that is amenable to exon 53 skipping.

Vyondys 53 (golodirsen) Injection

• FDA Approved: December 12, 2019
• Company: Sarepta Therapeutics

Vyondys 53 is an antisense oligonucleotide indicated for the treatment of DMD in patients with a confirmed mutation of the DMD gene amenable to exon 53 skipping.

Emflaza (deflazacort) Tablets and Oral Suspension

• FDA Approved: February 9, 2017
• Company: PTC Therapeutics, Inc.

Emflaza is a glucocorticoid indicated for the treatment of DMD in patients 2 years of age and older. Prednisone is also a glucocorticoid that is used in the treatment of DMD. Deflazacort is a derivative of prednisone.

Exondys 51 (eteplirsen) Injection

• FDA Approved: September 19, 2016
• Company: Sarepta Therapeutics

Exondys 51 is an antisense oligonucleotide indicated for the treatment of DMD in patients with a confirmed mutation of the DMD gene amenable to exon 51 skipping.

Elevidys (delandistrogene moxeparvovec) Injection

• FDA Approved: June 22, 2023
• Company: Sarepta Therapeutics

Elevidys was FDA-approved as the first gene therapy for DMD. Elevidys is an adeno-associated virus vector-based gene therapy indicated for the treatment of ambulatory pediatric patients aged 4 through 5 years with Duchenne muscular dystrophy (DMD) with a confirmed mutation in the DMD gene. Elevidys should not be used in patients with any deletion in exon 8 and/or exon 9 in the DMD gene.