Top 5 Most-Read DMD Articles of 2023

The first gene therapy to treat Duchenne muscular dystrophy (DMD), delandistrogene moxeparvovec, was approved in June by the FDA, and our write-up on that approval is this year’s top DMD article at AJMC.com, the website of The American Journal of Managed Care^®. Other top content for this year are a second FDA approval, this time for the novel corticosteroid, vamorolone (Agamree; Santhera Pharmaceuticals); an orphan drug designation for an investigational DMD agent; a case report of a potential link between transgene therapy for DMD and a patient death; and the high cost of care to treat DMD.

Here are your top DMD articles for 2023, and please visit our DMD page for plenty of other clinical content on the genetic disorder.

5. FDA Approves Vamorolone to Treat Duchenne Muscular Dystrophy

In November, the FDA approved the new drug application for the novel corticosteroid treatment from Santhera Pharmaceuticals, to be marketed as Agamree for patients aged 2 years and older. Data from the VISION-DMD study (NCT03439670) supported the application, and showed the primary end point of time-to-stand velocity was met. In contrast with current standard-of-care corticosteroids, vamorolone also had a favorable safety and tolerability profile. The treatment also received orphan drug and pediatric rare disease designations in 2023.

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4. Avidity Biosciences Gains FDA Orphan Drug Designation for Patients With DMD

Antibody oligonucleotide conjugate 1044 (AOC 1044) is an investigational agent currently being evaluated to treat DMD with mutations amenable to exon 44 skipping. In this interview on the designation, Sarah Boyce, president and CEO at Avidity Biosciences, pulls back the curtain on the science behind AOC 1044, discusses the benefits of an orphan drug designation for increasing treatment access, and addresses how Avidity is working to enroll more minority patients in trials of rare disease, of which DMD is one.

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3. Case Report of Patient Death Following High-Dose Gene Therapy for DMD

Following administration of a high-dose transgene therapy meant to upregulate cortical dystrophin as a custom CRISPR–transactivator therapy, recombinant adeno-associated virus serotype 9 (rAAV9), a 27-year-old male patient who had been living with DMD since age 5.5 years died. Investigators point to an innate immune reaction that brought on fatal acute respiratory distress syndrome as the cause of death. Signs of distress first appeared the day after the treatment was delivered, and included premature ventricular contractions and falling platelet counts. Mutations in the dystrophin gene are to blame for DMD, and this report’s authors cite challenges to treatment effectiveness being high rAAV doses needed and the gene’s large size.

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2. Exon-Skipping Therapy for DMD Linked to High Care Costs, Health Care Resource Utilization

This study compared health care costs and utilization rates of exon-skipping therapy for DMD compared with branded or generic glucocorticoid treatment or no treatment among patients aged 13 to 19 years. With the study’s index date being day of DMD treatment initiation or diagnosis date if not on treatment, postindex pharmacy spend was exponentially higher among the 43 patients who received exon-skipping therapy: $648,869 vs $66,218 seen for branded glucocorticoid treatment (172 patients), $2809 seen for generic glucocorticoid treatment (149 patients), and $688 for no treatment (68 patients). All-cause office and outpatient visits were also highest for the patients who received exon-skipping therapy.

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1. FDA Approves Delandistrogene Moxeparvovec, First Gene Therapy to Treat Duchenne Muscular Dystrophy

In June, the FDA approved delandistrogene moxeparvovec-rokl (Elevidys, Sarepta Therapeutics) to treat ambulatory patients aged 4 through 5 years who have a confirmed mutation in the DMD gene. The approval is based on evidence from the SRP-9001-102 and SRP-9001-103 clinical trials. Officials at Sarepta say the treatment addresses the root cause of DMD “by delivering a gene that codes for a shortened form of dystrophin to muscle cells, known as Elevidys micro-dystrophin.” At the time this article was written, topline results from the phase 3 confirmatory EMBARK trial were expected in late 2023; those results were released in October.

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