BACKGROUND and OBJECTIVE
Delandistrogene moxeparvovec is the first FDA-approved gene therapy for Duchenne muscular dystrophy (DMD) in patients aged four years and older. We report our single-center experience administering this treatment to a cohort of DMD patients.
METHODS
A retrospective chart review was performed on 21 DMD patients treated with delandistrogene moxeparvovec between September 2023 and October 2025. Data collected included demographics, pathogenic variants, steroid regimen before and after infusion, laboratory monitoring, adverse events, and motor function assessments.
RESULTS
Twenty-one patients aged 4–16 years received the infusion. Seventeen patients took prednisone/prednisolone and four patients were on deflazacort as their baseline steroid, and supplemental prednisolone was added at 1 mg/kg/day one day prior to the infusion. Most patients had exon deletions (including 3–7, 48–50, 51, 52, 53, 54, 55, and 62); three patients had duplications in exons 3–4, 45–52, and 51–62; other patients had nonsense variants (exons 12, 18, and 68). The most frequent side effects were gastrointestinal, reported in eight patients (vomiting, nausea, abdominal pain, or anorexia). Irritability, fatigue, hyperactivity, and sleep difficulties occurred in seven patients. Two patients developed transaminitis. Both required additional steroids (one received increased oral steroids, the other intravenous steroids), and sirolimus was added in one patient after two courses of intravenous steroids. One patient experienced infusion-related anaphylaxis leading to interruption of the infusion. Other serious adverse effects (myocarditis, immune-mediated myositis) were not observed. Eight patients have completed at least 12 months of follow-up to date.
CONCLUSIONS
Delandistrogene moxeparvovec was well tolerated in our cohort. Two patients developed acute liver injury without acute liver failure and were treated with steroids (2) and sirolimus (1). One patient had anaphylaxis during the infusion. Continued long-term monitoring remains essential to assess potential delayed or cumulative adverse effects and to further define the long-term safety profile of this gene therapy.