FDA Grants Full Approval to Elevidys for Duchenne Muscular Dystrophy

The FDA has converted the accelerated approval to Elevidys (delandistrogene moxeparvovec-rokl) to a full approval to treat ambulatory patients with Duchenne muscular dystrophy aged 4 years and older. The agency also granted accelerated approval to Elevidys for non-ambulatory patients.

Developed by Sarepta Therapeutics, Elevidys is a one-time therapy that delivers a gene to muscle that codes for a shortened, functional form of dystrophin, which is mutated in Duchenne muscular dystrophy. Duchenne causes the muscles in the body to become weak and damaged over time and is eventually fatal. The disease affects about 1 in 3,500 to 5,000 males born worldwide.

Doug Ingram

With this expansion, Elevidys is potentially available to about 80% to all diagnosed Duchenne patients, Doug Ingram, president and CEO of Sarepta, said in an investor call.

Elevidys launched with a wholesale acquisition cost (WAC) of $3.2 million. A cost-effectiveness analysis sponsored by Sarepta indicated the value of Elevidys between $5 million and $13 million compared with standard of care alone, with a willingness-to-pay threshold of $500,000. The analysis found that Elevidys increases quality of life and equal value of life years gained, a measure used to determine how much a treatment can extend life.

In its preliminary earnings release issued in January 2024, Elevidys’ net product revenue is expected to be $131.3 million for the fourth quarter of 2023 and $200.4 million for full-year 2023.

The full approval is supported by results from EMBARK, a phase 3 clinical study in patients with Duchenne between the ages of 4 through 7 years and data from ENDEAVOR, an open-label clinical study in patients with Duchenne in patients ages 2 years and older.

Topline results of EMBARK were announced in October 2023. In the study, Elevidys-treated patients improved 2.6 points on their North Star Ambulatory Assessment (NSAA) total score 52 weeks after treatment compared with 1.9 points in placebo-treated patients.

Related: FDA Sets Date for Full Approval, Broader Indication for Elevidys

Ingram said in the call that the company is working to satisfy the post marketing commitment with a confirmatory study ENVISION to assess Elevidys for non-ambulatory patients with Duchenne, as well as potentially extend to use of the gene therapy.

Sarepta has completed enrollment in the United States and is on track with enrollment outside the United States.

Sarepta has begun a study to clear antibodies with imlifidase, an enzyme that breaks down antibodies. Sarepta is also working on a plasmapheresis approach, a process that separates plasma from blood cells to filter out antibodies. Elevidys is not indicated for those with those with preexisting antibodies.

Ingram also mentioned the company is developing a newborn screening method to identify patients under than 4 years of age. Additionally, Sarapta is working with partner Roche on a study of patients as young as 3 months of age.

Elevidys is not indicated for patients with mutations in exon 8 or exon 9 in the DMD gene because of the risk for an immune response. Ingram said the company is working to better characterize this risk.