There’s no slowing the momentum of Sarepta’s groundbreaking Duchenne muscular dystrophy (DMD) gene therapy Elevidys—not even the failure of a confirmatory trial.
On Thursday, the FDA expanded the label for Elevidys (delandistrogene moxeparvovec-rokl) to all DMD patients ages 4 and older. It’s a major boost for the first gene therapy to treat the inherited disorder, which received an accelerated approval a year ago—nearly to the date—but only for ambulatory boys ages 4 to 5.
Confirming the drug's functional benefits, the FDA has blessed Elevidys with traditional approval for ambulatory patients while granting accelerated approval for those who are non-ambulatory. Continued approval for non-ambulatory patients may be contingent upon verification of clinical benefit in a confirmatory trial.
“The (expansion) is a defining moment for the Duchenne community," Doug Ingram, Sarepta's CEO, said in a release. "Today also stands as a watershed occasion for the promise of gene therapy and a win for science."
The label expansion represents “a major milestone for Sarepta and the best possible outcome for the company,” William Blair analyst Tim Lugo wrote in a note to clients. It’s a “transformational” milestone for the company and for DMD patients, he added.
“Given the strength of the initial launch under the restricted label for 4- to 5-year-olds, we expect the expanded label will drive significant top-line growth for the company in the near term with a product revenue estimate of $3 billion in 2025 and $5 billion in 2027, before beginning to decline in 2028,” Lugo wrote.
The expansion comes eight months after Sarepta revealed that the EMBARK pivotal study failed to reach its primary endpoint, coming up short of statistical significance in the North Star Ambulatory Assessment (NSAA), which measures motor function.
Despite the result, Sarepta—which partners with Roche on the treatment—touted “clinically meaningful” effects seen across the secondary endpoints of the trial, such as a patient’s time to rise from the floor, the change in a 10-meter walk or run time and the quantity of dystrophin protein expression triggered by Elevidys.
When Sarepta revealed the results, Ingram said that the study—which included 125 patients ages 4 to 7 and compared Elevidys to placebo—showed that Elevidys “alters” the course of the disease and that the company would seek the “broadest possible label."
Investors didn’t buy Sarepta’s pitch as its share price tumbled by 41% on the day of the EMBARK topline reveal. Since then, however, investors regained faith in the treatment as it gained commercial success, raking in $334 million in sales in its first three quarters on the market.
It also likely eased investors' concerns when the FDA in February assigned the Elevidys expansion application a priority review and opted not to hold an advisory committee meeting as part of the review process.
Before the markets opened on Friday, Sarepta's shares were trading about 38% higher to $170. Before the EMBARK failure, Sarepta shares were worth about $110.
Sarepta had a bumpy ride to Elevidys’ initial approval. During its development, it was put on clinical hold in both 2018 and in 2021 because of safety concerns. Then last year, after an advisory committee voted 8-6 to recommend approval, the FDA delayed its decision on the treatment by a month.
The wait was much longer for Sarepta's senior advisor for medical affairs Jerry Mendell, M.D., who discovered Elevidys, and the company's chief scientific officer and R&D head Louise Rodino-Klapac, Ph.D.
“Today’s expansion of the Elevidys label represents the culmination of my 50-year pursuit of a treatment for Duchenne patients and, along with my colleague Dr. Louise Rodino-Klapac, a nearly 20-year effort to optimize and develop a gene therapy that could be safely and effectively delivered to muscle,” Mendell said in the release.
Elevidys delivers a micro-dystrophin-encoding gene into a patient’s muscle tissue to prompt production of the micro-dystophin protein, which is necessary for patients with the disease because they can’t make the protein properly on their own.
The lack of this protein leads to a progressive loss of muscle strength. Sarepta’s one-time treatment—which is priced at $3.2 million—is meant to change the disease trajectory to a milder form.
As for Sarepta's $1 billion-plus partnership with Roche, which was established in 2019, the Massachusetts-based company is responsible for regulatory approval and commercialization of Elevidys in the U.S., as well as manufacturing, while Roche is responsible for regulatory approval and commercialization of Elevidys in the rest of the world.