FDA approves Sarepta’s gene therapy for Duchenne muscular dystrophy

Published: Jun 23, 2023

By Heather McKenzie

BioSpace

Sarepta’s Elevidys, approved Thursday as the first gene therapy for Duchenne muscular dystrophy, has been priced at $3.2 million per patient, making it one of the world’s most expensive medicines.

The price, announced Thursday following the FDA’s decision, is second in the U.S. only to that of uniQure and CSL Behring’s hemophilia B therapy Hemgenix, approved late last year, which costs $3.5 million per patient, according to BioPharma Dive.

On a conference call, Sarepta CEO Doug Ingram said the price reflected a “conservative” approach to valuing the therapy’s benefits to patients and their families, BioPharma Dive reported. Sarepta expects that discounts through Medicaid or a 340B program will make the net price of Elevidys about 20% lower than its gross cost.

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Original story published June 22

Sarepta’s Elevidys, approved Thursday, is now one of the world’s most expensive medicines. 

In a decision the gene therapy space and Duchenne muscular dystrophy community has been eagerly anticipating, the FDA on Thursday approved Elevidys (delandistrogene moxeparvovec-rokl) as the first-ever gene therapy for DMD.

Elevidys—formerly SRP-9001—was greenlit under the FDA’s accelerated approval pathway for ambulatory patients 4 to 5 years of age with a confirmed mutation in the DMD gene.

Elevidys delivers a functional copy of the dystrophin gene into a patient’s muscle tissues. In DMD, mutations in this gene manifest as the hallmark muscle weakness and developmental delay. DMD, also known as Duchenne, strikes primarily young boys and is uniformly fatal.

The verdict came just three weeks after the FDA’s initial target action date of May 29. The regulator informed Sarepta on May 24 that it required “modest additional time to complete the review, including final label negotiations and postmarketing commitment discussions.”

Sarepta previewed the patient population it ultimately secured, saying the FDA had indicated that—subject to the completion of the BLA review—it was working toward potentially granting an accelerated approval for SRP-9001 in DMD patients 4 to 5 years of age.

The label is narrower than the one Sarepta sought in its original label and initial revenue for Elevidys could be limited, as there are about 400 children in this age group with DMD in any given year, a Sarepta spokesperson told BioPharma Dive.

Sharon Hesterlee, chief research officer at the Muscular Dystrophy Association, told Endpoints News that the approval provides a “clear regulatory path” and is helpful for other companies in this space who want to develop a gene therapy for DMD.

In a statement, Sarepta CEO Doug Ingram called the approval “a watershed moment for the treatment of Duchenne.”

Elevidys is the “first and only gene therapy approved for Duchenne, and this approval brings us closer to our goal of bringing forward a treatment that provides the potential to alter the trajectory of this degenerative disease,” he said.

Debra Miller, CEO of the patient advocacy group CureDuchenne, called the decision an important milestone “that keeps us on a path toward identifying truly transformative treatments for those living with Duchenne muscular dystrophy.” 

Despite the optimistic tone Sarepta struck when announcing the PDUFA delay, the approval was anything but secured.

On May 12, the FDA’s Cellular, Tissue, and Gene Therapies Advisory Committee voted 8-6 to grant the gene therapy accelerated approval.

Sarepta had sought accelerated approval of SRP-9001 based on the expression of its proprietary micro-dystrophin after 12 weeks of therapy as a surrogate endpoint “reasonably likely to predict clinical benefit.”

However, in briefing documents published prior to the adcomm meeting, the FDA stated that measurement of levels of this in micro-dystrophin in muscle tissue “only provides information about expression of the transgene product in cells transduced by SRP-9001, rather than insight into a pharmacologic effect on a biomarker in the pathway of the disease.”

The regulator also had safety concerns and pointed to a clinical hold placed on Sarepta’s IND application in August 2021 after a 9-year-old subject was hospitalized and required respiratory support due to muscle weakness following treatment with SRP-9001.

Sarepta will need to back up its initial data with the results of the Phase III EMBARK trial that is currently ongoing.

“We recognize that many in the community will be disappointed due to the narrow age range specified,” Miller said, adding that the organization is hopeful the trial “will demonstrate efficacy and safety to support an expanded age range, and eventually expand to include non-ambulatory individuals.” 

Heather McKenzie is a senior editor at BioSpace, focusing on neuroscience, oncology and gene therapy. You can reach her at [email protected]. Follow her on LinkedIn and Twitter @chicat08.

Editor’s Note: The story has been updated with Elevidys’ price and additional details.

Source: BioSpace