Sarepta's Elevidys (delandistrogene moxeparvovec)
A $3.2 million gene therapy, a failed confirmatory trial and deaths from liver failure
Elevidys is a one-time gene therapy for Duchenne muscular dystrophy (DMD), a fatal genetic muscle disease. Families describe it as the hope they waited decades for; critics describe it as a $3.2 million product approved over the objections of the FDA's own scientists, that failed its key confirmatory trial and was later linked to deaths from acute liver failure. This article covers the full arc from approval through the 2025 safety crisis.
Questions
What is Elevidys and how does it work?
A one-time $3.2 million infusion using an AAVrh74 vector to deliver a micro-dystrophin gene to muscle cells in boys with DMD — the first gene therapy for the disease and among the most expensive drugs ever sold at launch.
DMD is caused by mutations that prevent the body from producing dystrophin, a protein essential for muscle. It affects about 1 in 5,000 boys and causes progressive muscle loss, typically leading to death in early adulthood. Elevidys uses a modified adeno-associated virus (the AAVrh74 vector) to deliver a gene for a shortened version of dystrophin, called micro-dystrophin, to muscle cells. It is given once, by infusion. Sarepta set its wholesale price at $3.2 million, making it among the most expensive drugs ever sold. It generated $200.3 million in sales in 2023, its first year. Because the therapy uses high doses of viral vector, it carries risks common to AAV gene therapies, including immune reactions and liver injury.
Q2How was Elevidys first approved?
Accelerated approval in June 2023 for ambulatory boys aged 4–5 on an 8-6 advisory vote — with the FDA's clinical, pharmacology and statistics teams finding the data inadequate — because the biologics centre head overruled his review staff.
The FDA granted accelerated approval on June 22, 2023, for ambulatory boys aged 4 and 5. The basis was micro-dystrophin expression, which the FDA judged reasonably likely to predict benefit, rather than proven improvements in function. An FDA advisory committee had voted only 8-6 in favour. The FDA's own reviewers were more sceptical: briefing documents said micro-dystrophin levels only showed the gene was being expressed, rather than providing insight into a pharmacologic effect on the disease. According to a Health Affairs analysis, the clinical, pharmacology and statistics teams found the data not adequate to meet the threshold for approval. Peter Marks, head of the FDA's biologics centre, decided against the review team's recommendation and approved it.
Q3Did Elevidys pass its confirmatory trial?
No — the phase 3 EMBARK trial failed its primary motor-function endpoint (2.6 vs 1.9 points, not statistically significant), yet Sarepta's CEO called it evidence of effectiveness and the FDA later expanded the label anyway.
No. The phase 3 EMBARK trial enrolled 125 ambulatory boys aged 4 to 7 and measured change in the North Star Ambulatory Assessment (NSAA) motor score at 52 weeks. Treated boys improved by 2.6 points versus 1.9 points on placebo, a difference that was not statistically significant, so the trial failed its primary endpoint. Some functional measures, such as time to rise from the floor, favoured treatment, but those were not statistically significant either. Micro-dystrophin expression averaged 34.29% versus zero on placebo. Sarepta's CEO said the study "met the standard" to show evidence of effectiveness and that the drug "alters" the disease course. Critics noted the drug had now fallen short of its primary endpoint in two studies.
Q4Why was the 2024 label expansion controversial?
Despite EMBARK's failure, in June 2024 Peter Marks again overruled staff — granting traditional approval for ambulatory patients 4+ and accelerated approval for non-ambulatory patients — the group in which the first deaths later occurred.
In June 2024, despite the EMBARK result, the FDA converted Elevidys to traditional approval for ambulatory patients aged 4 and older, and granted accelerated approval for non-ambulatory patients, whose disease is more advanced. Once again, Marks bucked agency staff, relying on his own interpretation of secondary endpoints. ICER's chief medical officer, David Rind, wrote in JAMA that authorising therapies that fail their efficacy endpoints casts doubt on the accelerated approval pathway. The expansion to non-ambulatory patients proved significant because the first deaths later occurred in that group. Supporters argued that DMD is relentlessly fatal and that regulators should accept more uncertainty; critics argued this was the second time a single senior official had overruled reviewers on a Sarepta drug, following Exondys 51 in 2016.
Q5What deaths have been linked to Elevidys?
Three patients died from acute liver failure — two non-ambulatory DMD boys in March and June 2025, and a 51-year-old man in a related Sarepta gene therapy trial using the same AAVrh74 vector — prompting holds and boxed-warning requirements.
The first reported death, from acute liver failure in a non-ambulatory patient, was announced on March 18, 2025. A second non-ambulatory patient died from acute liver failure in June 2025, after which Sarepta paused dosing of non-ambulatory patients and its confirmatory ENVISION trial. The FDA said it was investigating both deaths. In July 2025 a 51-year-old man in a trial of a related Sarepta therapy, SRP-9004, which uses the same vector, also died of liver failure. Separately, an 8-year-old boy treated in Brazil died in June 2025; Brazilian regulators and later the FDA concluded that death was unrelated to Elevidys, with a CNBC reporter noting that Brazilian regulators had determined the boy likely died from flu intensified by immunosuppression.
Q6What was the July 2025 confrontation between Sarepta and the FDA?
On July 18, 2025 the FDA asked Sarepta to pause all Elevidys shipments — Sarepta initially refused, then reversed days later — while also confirming a third death it had reported to the FDA two weeks earlier but not disclosed publicly.
On July 18, 2025, the FDA announced clinical holds on Sarepta's limb-girdle gene therapy trials, revoked the AAVrh74 platform technology designation, and asked Sarepta to stop shipping Elevidys. Sarepta initially said it would not comply, then reversed days later. BioPharma Dive described it as a highly unusual standoff. Transparency was a major issue: Sarepta had reported the third death to the FDA on July 3 but not to the public, disclosing it only after the fact, and analysts questioned why it had gone unmentioned on a recent investor call. CEO Doug Ingram said pausing was painful but necessary. The FDA's biologics chief, Vinay Prasad, said the agency would not allow products whose harms are greater than benefits.
Q7What restrictions now apply to Elevidys?
As of September 2026, Elevidys is approved only for ambulatory patients aged 4+ with confirmed DMD mutations (excluding exon 8/9 deletions), carries a boxed liver-failure warning, and is not authorised in Europe.
On July 28, 2025 the FDA recommended Sarepta resume shipments for ambulatory patients, while non-ambulatory patients remained on hold. A November 14, 2025 label update added a boxed warning for acute serious liver injury and acute liver failure and removed eligibility for non-ambulatory patients entirely. As of September 2026, Elevidys is approved only for ambulatory patients aged 4 and older with a confirmed DMD mutation, excluding those with exon 8 or 9 deletions. The European Medicines Agency refused EU authorisation. In practice, treatment centres must now monitor patients closely for liver injury after infusion. Sarepta had also been working on an enhanced immunosuppressive regimen including sirolimus aimed at making the therapy safer for non-ambulatory patients.
Q8How did Elevidys affect Sarepta as a business?
Sarepta cut 36% of its workforce in July 2025, partner Roche paused shipments in multiple countries, and the loss of the AAVrh74 platform technology designation was a setback for efforts to speed development of multiple products from a single vector.
Elevidys is Sarepta's most important product, so the safety crisis had severe business consequences. In July 2025 Sarepta announced a restructuring that would cut about 36% of its workforce, or roughly 500 employees. Its partner Roche, which markets Elevidys outside the US, paused shipments in several countries whose approvals relied on the FDA's decisions, and also in Brazil. The removal of the non-ambulatory indication narrowed the eligible population, and the boxed warning adds to the monitoring burden for treatment centres. For the wider gene therapy field, the loss of the platform designation was a setback for efforts to speed development of multiple products using a single, previously characterised vector.
Q9What is the case for and against Elevidys?
Supporters cite a fatal disease with no alternatives and biological activity on secondary measures; critics — including a Health Affairs analysis titled "Unsafe, Not Effective, $3.2 Million Per Dose" — cite two primary-endpoint failures, two regulatory overrides and deaths linked to treatment.
Supporters, including many DMD families and clinicians, argue that without treatment boys with DMD lose the ability to walk and die young, that micro-dystrophin expression shows the therapy is biologically active, and that secondary measures suggest it modifies the disease course. They argue regulators must accept more uncertainty for fatal rare diseases. Critics, including a Health Affairs analysis titled "Unsafe, Not Effective, $3.2 Million Per Dose", argue that it failed its primary endpoint twice, was approved by one official overriding review teams, has caused deaths, and is priced at a level that strains payers without proven functional benefit. They argue accelerated approval only works when surrogate endpoints reliably predict outcomes that matter to patients. Longer-term follow-up data will be decisive.
Q10What was Sarepta's regulatory track record before Elevidys?
Exondys 51 in 2016 set the template: Janet Woodcock overruled both her review team and a 7-6 advisory vote, two reviewers resigned, and the confirmatory trial deadline was missed — a pattern critics say Elevidys repeated on a larger scale.
Elevidys followed a contested precedent. Sarepta's first DMD drug, Exondys 51, was approved in 2016 on data from 12 boys after the FDA's drug centre director, Janet Woodcock, overruled her review team and an advisory committee that had voted 7-6 against. The FDA's acting chief scientist said this might be the first time a centre director had overruled both a review team and advisory committee on effectiveness, and two review team members resigned. Sarepta then missed the original November 2020 deadline for Exondys 51's confirmatory trial. Elevidys itself faced a long road, including clinical holds in 2018 and 2021, before its 2023 accelerated approval. Critics see a pattern of senior officials giving Sarepta latitude that reviewers opposed; supporters see regulators appropriately responding to an urgent unmet need.
Q11What does Elevidys mean for future drug approvals?
Elevidys is now a reference case for accelerated-approval reform alongside Exondys 51 and Aduhelm — and the FDA's 2025 interventions, plus a 9-3 advisory vote against another DMD therapy in August 2026, suggest a more sceptical posture is spreading across the field.
Elevidys has become a reference case in the debate over the FDA's accelerated approval pathway and the role of senior officials in overriding scientific staff. It sits alongside Sarepta's own Exondys 51 and Biogen's Aduhelm as examples critics cite when arguing that surrogate endpoints have been accepted too readily. At the same time, the FDA's actions in 2025, including the platform designation revocation and the request to halt shipments, suggest a more interventionist posture under current leadership. In August 2026 an FDA advisory committee voted 9-3 against another DMD therapy, deramiocel, indicating scepticism is spreading across the field. For patients, the practical question is whether benefits in ambulatory boys will be borne out over time, and whether liver risks can be managed.