Sarepta Therapeutics on Wednesday called the launch of the gene therapy for Duchenne muscular dystrophy “exceptional” but the company does not expect to see significant growth in the first half of 2024 due to its currently limited patient pool.
Pictured: Sarepta sign on a brick building/courtesy Sarepta Therapeutics
Sarepta Therapeutics in its fourth-quarter and full-year 2023 earnings report on Wednesday touted the strong market demand for its Duchenne muscular dystrophy gene therapy Elevidys (delandistrogene moxeparvovec-rokl), which has brought in just over $200 million since its launch in mid-2023.
In the fourth quarter, Elevidys hit a net product revenue of $131.2 million, up approximately 90% from its nearly $70 million sales during its first few months on the market.
Elevidys is the first-ever FDA-approved gene therapy for Duchenne muscular dystrophy (DMD), clearing the regulatory gauntlet in June 2023. The treatment works by delivering a functional copy of the dystrophin gene into the patients’ muscle tissues, which addresses the genetic root of DMD. Mutations to this gene lead to the muscle weakness and developmental delay associated with the disease.
The gene therapy was approved under the FDA’s accelerated pathway—meaning Sarepta needs to run a confirmatory Phase III study to keep it on the market—and is authorized to treat patients aged four to five years old.
Sarepta CEO Doug Ingram in an investor call on Wednesday called Elevidys’ launch “exceptional,” noting that its commercial performance so far has been “particularly impressive and reflects first-in-class launch excellence” despite being limited to only four- and five-year-olds, which comprise a minority of Duchenne patients.
Still, the company was quick to caution analysts against overly optimistic projections based on Elevidys’ initial performance. With its currently limited patient pool, Elevidys will face several “unique executional challenges that are relevant moving forward,” Sarepta Chief Commercial Officer Dallan Murray said during the call.
Most Duchenne patients are diagnosed at an average age of five, which is already at the upper range of Elevidys’ current label. The age restriction also gives patients and their families “a very short time window” to learn about the disease and to secure access to doses.
“We do not expect to see significant additional growth within the existing population through the first half of this year,” Murray said.
Sarepta has filed a supplemental Biologics License Application (sBLA) with the FDA that not only seeks traditional approval for Elevidys but also proposes an expanded label covering DMD patients across all age groups. The regulator accepted the supplement application in February 2024 and indicated that it does not intend to hold an advisory committee meeting.
The FDA’s target action date for the sBLA is June 21, 2024.
While it awaits the verdict, Sarepta is preparing to respond to the greater anticipated patient demand driven by a broader label. “By the time of label expansion, we expect to have cleared the way for those older patients to get dosed as rapidly as possible upon eligibility,” Murray said during Wednesday’s call.
Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at tristan@tristanmanalac.com or tristan.manalac@biospace.com.
