This study evaluates AAV9-U7 exon skipping therapy in the Dup2 mouse model of Duchenne muscular dystrophy (DMD). A single injection in adults restored up to 95% exon skipping, improving muscle structure and function. Neonatal treatment achieved 99% dystrophin-positive fibers and near-complete disease correction over six months. Findings suggest AAV9-based exon skipping provides long-lasting dystrophin restoration, supporting its potential as a clinical therapy for DMD exon 2 duplications.

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This open-label study evaluates casimersen and golodirsen in DMD patients with rare single exon duplications (exon 45 or 53). Over 48 weeks, dystrophin levels increased from 0.94% to 5.1%, with dystrophin-positive fibers rising from 14% to 50%. RT-PCR confirmed exon skipping, while pulmonary and cardiac functions remained stable. No major safety concerns emerged, but longer trials with larger cohorts are needed to assess long-term clinical benefits. These findings highlight exon skipping as a targeted therapy for rare DMD mutations.

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This phase 2, open-label trial evaluated AVI-4658 (PMO) therapy in 19 boys with Duchenne muscular dystrophy (DMD), assessing exon 51 skipping and dystrophin restoration. The drug was well tolerated, showing dose-dependent dystrophin expression, with significant improvements at higher doses. Increased dystrophin correlated with protein localization and reduced inflammation, though responses varied. Findings support AVI-4658 as a potential disease-modifying treatment, emphasizing the need for long-term trials to confirm clinical benefits.

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This study investigates how voluntary exercise impacts AAV-U7-mediated exon skipping therapy in D2-mdx mice with Duchenne muscular dystrophy (DMD). Exercise did not worsen muscle damage or reduce viral genome expression, though dystrophin-positive muscle area declined from 80% to 65%. Despite this, gene therapy remained effective, and muscle strength improved. Findings suggest exercise can be integrated into DMD treatments without major therapy disruption, though long-term effects need further study.

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This study explores direct reprogramming of DMD fibroblasts into myotubes as a non-invasive model for testing antisense oligonucleotide (AO)-mediated exon skipping. Using MyoD gene induction, researchers converted fibroblasts into muscle cells, then applied phosphorodiamidate morpholino oligomers (PMOs) to skip exons 45–55, restoring dystrophin expression. This scalable, reproducible method provides an alternative to muscle biopsies, advancing DMD drug development.

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Casimersen (AMONDYS 45™) is an FDA-approved antisense oligonucleotide therapy for Duchenne muscular dystrophy (DMD) patients whose mutations allow exon 45 skipping. This treatment increases dystrophin production, stabilizing muscle function. Approved in 2021, Casimersen has shown promising results in the ESSENCE trial, significantly boosting dystrophin levels. While it is not a cure, this therapy offers hope for approximately 8% of DMD patients with exon 45 mutations. Clinical trials continue to assess long-term benefits and potential side effects, particularly concerning kidney health.

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Casimersen (Amondys 45) is an FDA-approved exon 45 skipping therapy for Duchenne Muscular Dystrophy (DMD). Learn about its efficacy, side effects, and ongoing ESSENCE Phase III trial.

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