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In November 2025 the Food and Drug Administration (FDA) announced the addition of a boxed warning, the agency’s most prominent safety warning, to the labeling for delandistrogene moxeparvovec-rokl (ELEVIDYS), a gene therapy for Duchenne muscular dystrophy. First approved in 2023, the gene therapy has been linked to two deaths from acute liver failure in patients treated with the product who were unable to walk.[1]
Delandistrogene moxeparvovec-rokl is an adeno-associated virus vector-based...
In November 2025 the Food and Drug Administration (FDA) announced the addition of a boxed warning, the agency’s most prominent safety warning, to the labeling for delandistrogene moxeparvovec-rokl (ELEVIDYS), a gene therapy for Duchenne muscular dystrophy. First approved in 2023, the gene therapy has been linked to two deaths from acute liver failure in patients treated with the product who were unable to walk.[1]
Delandistrogene moxeparvovec-rokl is an adeno-associated virus vector-based gene therapy that is administered as a single intravenous infusion. The liver toxicity may be related to a massive immune response to the viral vector.[2] As of July 2025 more than 900 patients 4 years of age and older had received the therapy.[3]
The updated labeling[4] limits use of the treatment to ambulatory patients 4 years of age and older who have a confirmed mutation in the Duchenne muscular dystrophy gene and no preexisting liver impairment. The revised labeling also advises weekly liver function tests for at least three months after treatment and weekly testing for cardiac injury for one month following treatment.
Although they are a step in the right direction, the enhanced safety warnings do not address two fundamental problems with delandistrogene moxeparvovec-rokl. First, the evidence that the gene therapy is clinically effective is not convincing. Second, the therapy costs more than $3 million per treatment.[5] In 2023 and 2024, Public Citizen’s Health Research Group repeatedly urged the FDA not to approve the therapy, because of concerns about safety, effectiveness and inadequate clinical trials.[6]
The boxed warning follows a brief pause of all shipments of the gene therapy in July 2025, which the FDA reversed 10 days later for reasons that were inadequately explained.[7] To further determine the risk of severe liver injury, the FDA is requiring the manufacturer to conduct a postmarketing observational study. The study will enroll 200 patients with Duchenne muscular dystrophy, follow the patients for at least 12 months after administration of delandistrogene moxeparvovec-rokl, and periodically assess their liver function. Although the study is needed, it is unlikely to answer the underlying questions of whether the gene therapy is clinically effective and whether the FDA should ever have approved it.
References
[1] FDA News Release. FDA approves new safety warning and revised indication that limits use for Elevidys following reports of fatal liver injury. November 14, 2025. https://www.fda.gov/news-events/press-announcements/fda-approves-new-safety-warning-and-revised-indication-limits-use-elevidys-following-reports-fatal. Accessed December 1, 2025.
[2] Feuerstein A, Mast J. Sarepta Therapeutics’ Duchene therapy faces ‘arduous’ task back to market, senior FDA official says. Statnews. July 22, 2025. https://www.statnews.com/2025/07/22/fda-sarepta-elevidys-muscular-dystrophy-drug/. Accessed December 1, 2025.
[3] Gilbert D. Biotech pauses trial after second patient death linked to gene therapy. Washington Post. June 16, 2025. https://www.washingtonpost.com/business/2025/06/16/sarepta-elevidys-duchenne-patient-death/. Accessed December 1, 2025.
[4] Elevidys. Prescribing Information. https://www.elevidys.com/pi. Accessed December 1, 2025.
[5] Rind DM. The FDA and gene therapy for Duchenne muscular dystrophy. JAMA 2024;331(20):1705-1706.
[6] Steinbrook R. Outrage of the Month: Patient deaths from a Duchene muscular dystrophy gene therapy. Public Citizen Health Letter. August 2025. https://www.citizen.org/article/outrage-of-the-month-patient-deaths-from-a-duchenne-muscular-dystrophy-gene-therapy/. Accessed December 1, 2025.
[7] Ibid.
[8] FDA News Release. FDA approves new safety warning and revised indication that limits use for Elevidys following reports of fatal liver injury. November 14, 2025. https://www.fda.gov/news-events/press-announcements/fda-approves-new-safety-warning-and-revised-indication-limits-use-elevidys-following-reports-fatal. Accessed December 1, 2025.
