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Nature Reviews. Disease Primers Feb 2021Duchenne muscular dystrophy is a severe, progressive, muscle-wasting disease that leads to difficulties with movement and, eventually, to the need for assisted... (Review)
Review
Duchenne muscular dystrophy is a severe, progressive, muscle-wasting disease that leads to difficulties with movement and, eventually, to the need for assisted ventilation and premature death. The disease is caused by mutations in DMD (encoding dystrophin) that abolish the production of dystrophin in muscle. Muscles without dystrophin are more sensitive to damage, resulting in progressive loss of muscle tissue and function, in addition to cardiomyopathy. Recent studies have greatly deepened our understanding of the primary and secondary pathogenetic mechanisms. Guidelines for the multidisciplinary care for Duchenne muscular dystrophy that address obtaining a genetic diagnosis and managing the various aspects of the disease have been established. In addition, a number of therapies that aim to restore the missing dystrophin protein or address secondary pathology have received regulatory approval and many others are in clinical development.
Topics: Animals; Disease Models, Animal; Dystrophin; Humans; Muscular Dystrophy, Duchenne
PubMed: 33602943
DOI: 10.1038/s41572-021-00248-3 -
Journal of Neurology Aug 2023Duchenne muscular dystrophy (DMD) is a severe, progressive, muscle-wasting disease, characterized by progressive deterioration of skeletal muscle that causes rapid loss... (Review)
Review
Duchenne muscular dystrophy (DMD) is a severe, progressive, muscle-wasting disease, characterized by progressive deterioration of skeletal muscle that causes rapid loss of mobility. The failure in respiratory and cardiac muscles is the underlying cause of premature death in most patients with DMD. Mutations in the gene encoding dystrophin result in dystrophin deficiency, which is the underlying pathogenesis of DMD. Dystrophin-deficient myocytes are dysfunctional and vulnerable to injury, triggering a series of subsequent pathological changes. In this review, we detail the molecular mechanism of DMD, dystrophin deficiency-induced muscle cell damage (oxidative stress injury, dysregulated calcium homeostasis, and sarcolemma instability) and other cell damage and dysfunction (neuromuscular junction impairment and abnormal differentiation of muscle satellite). We also describe aberrant function of other cells and impaired muscle regeneration due to deterioration of the muscle microenvironment, and dystrophin deficiency-induced multiple organ dysfunction, while summarizing the recent advances in the treatment of DMD.
Topics: Humans; Muscular Dystrophy, Duchenne; Dystrophin; Muscle, Skeletal; Mutation; Neuromuscular Junction
PubMed: 37258941
DOI: 10.1007/s00415-023-11796-x -
Drugs Sep 2023Delandistrogene moxeparvovec (delandistrogene moxeparvovec-rokl; ELEVIDYS) is an adeno-associated virus (AAV) vector-based gene therapy designed to deliver a gene... (Review)
Review
Delandistrogene moxeparvovec (delandistrogene moxeparvovec-rokl; ELEVIDYS) is an adeno-associated virus (AAV) vector-based gene therapy designed to deliver a gene encoding a micro-dystrophin protein [i.e. a shortened (138 kDa) version of the dystrophin protein expressed in normal muscle cells (427 kDa)] to all muscles involved in the pathology of Duchenne muscular dystrophy (DMD). Developed by Sarepta Therapeutics, it is the first gene therapy to be approved (in June 2023 under the Accelerated Approval pathway) for the treatment of DMD in the USA, where it is indicated for ambulatory paediatric patients aged 4 through 5 years with DMD and a confirmed mutation in the dystrophin (DMD) gene. The recommended dose of delandistrogene moxeparvovec is 1.33 × 10 vector genomes per kg of body weight or 10 mL/kg body weight, administered as a single intravenous infusion. Delandistrogene moxeparvovec is undergoing clinical development in several countries/regions, including the EU and Japan. This article summarizes the milestones in the development of delandistrogene moxeparvovec leading to this first approval in the USA for the treatment of ambulatory paediatric patients aged 4 through 5 years with DMD and a confirmed mutation in the DMD gene.
Topics: Humans; Child; Dystrophin; Muscular Dystrophy, Duchenne; Genetic Therapy; Mutation; Muscles; Muscle, Skeletal
PubMed: 37566211
DOI: 10.1007/s40265-023-01929-x -
Nature Reviews. Neurology Jul 2019Duchenne muscular dystrophy (DMD) is caused by the lack of functional dystrophin protein. Improvements in patient care and disease management have slowed down disease... (Review)
Review
Duchenne muscular dystrophy (DMD) is caused by the lack of functional dystrophin protein. Improvements in patient care and disease management have slowed down disease progression, but current treatments cannot stop the relentless loss of muscle tissue and function, which leads to premature death. Research is ongoing to develop effective therapies for DMD. Gene-addition, exon-skipping, stop codon readthrough and genome-editing therapies can restore the expression of partially functional dystrophin protein, whereas other therapeutic approaches aim to improve muscle function and quality by targeting pathways involved in the pathogenesis of DMD. This Review outlines important developments in these research areas and specifically focuses on new therapies that are in the clinical trial phase or have already been approved.
Topics: Anti-Inflammatory Agents; Dystrophin; Exons; Gene Editing; Genetic Therapy; Humans; Muscular Dystrophy, Duchenne
PubMed: 31147635
DOI: 10.1038/s41582-019-0203-3 -
The Lancet. Neurology Sep 2022Duchenne muscular dystrophy is an X-linked disease caused by the absence of functional dystrophin in the muscle cells. Major advances have led to the development of gene... (Review)
Review
Duchenne muscular dystrophy is an X-linked disease caused by the absence of functional dystrophin in the muscle cells. Major advances have led to the development of gene therapies, tools that induce exon skipping, and other therapeutic approaches, including treatments targeting molecular pathways downstream of the absence of functional dystrophin. However, glucocorticoids remain the only treatment unequivocally shown to slow disease progression, despite the adverse effects associated with their long-term use. Besides glucocorticoids, which are standard care, five compounds have received regulatory approval in some but not all jurisdictions, with further efficacy results being awaited. Several compounds with promising results in early-phase clinical trials have not met their efficacy endpoints in late-phase trials, but the clinical development of many other compounds is ongoing. The current landscape is complicated by the number of compounds in various stages of development, their various mechanisms of action, and their genotype-specific applicability. The difficulties of clinical development that arise from both the rarity and variability of Duchenne muscular dystrophy might be overcome in the future by use of sensitive biomarkers, natural history data, and ameliorated trial designs.
Topics: Dystrophin; Exons; Genetic Therapy; Genotype; Humans; Muscular Dystrophy, Duchenne
PubMed: 35850122
DOI: 10.1016/S1474-4422(22)00125-9 -
International Journal of Molecular... Feb 2022Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder with a prevalence of approximately 1 in 3500-5000 males. DMD manifests as... (Review)
Review
Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder with a prevalence of approximately 1 in 3500-5000 males. DMD manifests as childhood-onset muscle degeneration, followed by loss of ambulation, cardiomyopathy, and death in early adulthood due to a lack of functional dystrophin protein. Out-of-frame mutations in the dystrophin gene are the most common underlying cause of DMD. Gene editing via the clustered regularly interspaced short palindromic repeats (CRISPR) system is a promising therapeutic for DMD, as it can permanently correct DMD mutations and thus restore the reading frame, allowing for the production of functional dystrophin. The specific mechanism of gene editing can vary based on a variety of factors such as the number of cuts generated by CRISPR, the presence of an exogenous DNA template, or the current cell cycle stage. CRISPR-mediated gene editing for DMD has been tested both in vitro and in vivo, with many of these studies discussed herein. Additionally, novel modifications to the CRISPR system such as base or prime editors allow for more precise gene editing. Despite recent advances, limitations remain including delivery efficiency, off-target mutagenesis, and long-term maintenance of dystrophin. Further studies focusing on safety and accuracy of the CRISPR system are necessary prior to clinical translation.
Topics: Animals; CRISPR-Cas Systems; Disease Models, Animal; Dystrophin; Frameshift Mutation; Gene Editing; Humans; Male; Muscular Dystrophy, Duchenne; Reading Frames; Translational Research, Biomedical
PubMed: 35163754
DOI: 10.3390/ijms23031832 -
Nature Communications Dec 2021Genome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal...
Genome editing therapy for Duchenne muscular dystrophy (DMD) holds great promise, however, one major obstacle is delivery of the CRISPR-Cas9/sgRNA system to skeletal muscle tissues. In general, AAV vectors are used for in vivo delivery, but AAV injections cannot be repeated because of neutralization antibodies. Here we report a chemically defined lipid nanoparticle (LNP) system which is able to deliver Cas9 mRNA and sgRNA into skeletal muscle by repeated intramuscular injections. Although the expressions of Cas9 protein and sgRNA were transient, our LNP system could induce stable genomic exon skipping and restore dystrophin protein in a DMD mouse model that harbors a humanized exon sequence. Furthermore, administration of our LNP via limb perfusion method enables to target multiple muscle groups. The repeated administration and low immunogenicity of our LNP system are promising features for a delivery vehicle of CRISPR-Cas9 to treat skeletal muscle disorders.
Topics: Animals; CRISPR-Associated Protein 9; CRISPR-Cas Systems; Disease Models, Animal; Dystrophin; Exons; Gene Editing; Genetic Therapy; Humans; Liposomes; Mice; Muscle, Skeletal; Muscular Dystrophy, Duchenne; Nanoparticles; Neuromuscular Diseases; RNA, Messenger
PubMed: 34880218
DOI: 10.1038/s41467-021-26714-w -
Neuromuscular Disorders : NMD Oct 2021Duchenne muscular dystrophy (DMD) is a severe X-linked disease characterized by progressive muscle weakness. It is caused by a variety of DMD gene pathogenic variations... (Review)
Review
Duchenne muscular dystrophy (DMD) is a severe X-linked disease characterized by progressive muscle weakness. It is caused by a variety of DMD gene pathogenic variations (large deletions or duplications, and small mutations) which leads to the absence or to a decreased amount of dystrophin protein. The allelic Becker muscular dystrophy is characterized by later onset and milder muscle involvement, and other rarer phenotypes might also be associated, such as dilated cardiomyopathy, cognitive impairment, and other neurological signs. Following the identification of the genetic cause and the disease pathophysiology, innovative personalized therapies emerged. These can be categorized into two main groups: (1) therapies aiming at the restoration of dystrophin at the sarcolemma; (2) therapeutics dealing with secondary consequences of dystrophin deficiency. In this review we provide an overview about DMD genotype-phenotype correlation, and on main approaches to restore dystrophin as stop codon read-through, exon skipping, vector-mediated gene therapy, and genome-editing strategies, some of these are based on approved orphan drugs. Finally, we present the clinical potential of novel strategies combining therapies to correct the genetic defect and other approaches, targeting secondary downstream pathological cascade due to dystrophin deficiency.
Topics: Dystrophin; Exons; Genetic Therapy; Humans; Muscular Dystrophy, Duchenne; Mutation; Phenotype; Sarcolemma
PubMed: 34736624
DOI: 10.1016/j.nmd.2021.08.004 -
Neurology May 2020To report safety, pharmacokinetics, exon 53 skipping, and dystrophin expression in golodirsen-treated patients with Duchenne muscular dystrophy (DMD) amenable to exon 53... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To report safety, pharmacokinetics, exon 53 skipping, and dystrophin expression in golodirsen-treated patients with Duchenne muscular dystrophy (DMD) amenable to exon 53 skipping.
METHODS
Part 1 was a randomized, double-blind, placebo-controlled, 12-week dose titration of once-weekly golodirsen; part 2 is an ongoing, open-label evaluation. Safety and pharmacokinetics were primary and secondary objectives of part 1. Primary biological outcome measures of part 2 were blinded exon skipping and dystrophin protein production on muscle biopsies (baseline, week 48) evaluated, respectively, using reverse transcription PCR and Western blot and immunohistochemistry.
RESULTS
Twelve patients were randomized to receive golodirsen (n = 8) or placebo (n = 4) in part 1. All from part 1 plus 13 additional patients received 30 mg/kg golodirsen in part 2. Safety findings were consistent with those previously observed in pediatric patients with DMD. Most of the study drug was excreted within 4 hours following administration. A significant increase in exon 53 skipping was associated with ∼16-fold increase over baseline in dystrophin protein expression at week 48, with a mean percent normal dystrophin protein standard of 1.019% (range, 0.09%-4.30%). Sarcolemmal localization of dystrophin was demonstrated by significantly increased dystrophin-positive fibers (week 48, < 0.001) and a positive correlation (Spearman = 0.663; < 0.001) with dystrophin protein change from baseline, measured by Western blot and immunohistochemistry.
CONCLUSION
Golodirsen was well-tolerated; muscle biopsies from golodirsen-treated patients showed increased exon 53 skipping, dystrophin production, and correct dystrophin sarcolemmal localization.
CLINICALTRIALSGOV IDENTIFIER
NCT02310906.
CLASSIFICATION OF EVIDENCE
This study provides Class I evidence that golodirsen is safe and Class IV evidence that it induces exon skipping and novel dystrophin as confirmed by 3 different assays.
Topics: Administration, Intravenous; Adolescent; Child; Dose-Response Relationship, Drug; Double-Blind Method; Dystrophin; Fluorescent Antibody Technique; Humans; Male; Muscle, Skeletal; Muscular Dystrophy, Duchenne; Oligonucleotides; Sequence Deletion
PubMed: 32139505
DOI: 10.1212/WNL.0000000000009233 -
Annals of Neurology Nov 2023Delandistrogene moxeparvovec is approved in the USA for the treatment of ambulatory patients (4-5 years) with Duchenne muscular dystrophy. ENDEAVOR (SRP-9001-103;...
Delandistrogene Moxeparvovec Gene Therapy in Ambulatory Patients (Aged ≥4 to <8 Years) with Duchenne Muscular Dystrophy: 1-Year Interim Results from Study SRP-9001-103 (ENDEAVOR).
OBJECTIVE
Delandistrogene moxeparvovec is approved in the USA for the treatment of ambulatory patients (4-5 years) with Duchenne muscular dystrophy. ENDEAVOR (SRP-9001-103; NCT04626674) is a single-arm, open-label study to evaluate delandistrogene moxeparvovec micro-dystrophin expression, safety, and functional outcomes following administration of commercial process delandistrogene moxeparvovec.
METHODS
In cohort 1 of ENDEAVOR (N = 20), eligible ambulatory males, aged ≥4 to <8 years, received a single intravenous infusion of delandistrogene moxeparvovec (1.33 × 10 vg/kg). The primary endpoint was change from baseline (CFBL) to week 12 in delandistrogene moxeparvovec micro-dystrophin by western blot. Additional endpoints evaluated included: safety; vector genome copies; CFBL to week 12 in muscle fiber-localized micro-dystrophin by immunofluorescence; and functional assessments, including North Star Ambulatory Assessment, with comparison with a propensity score-weighted external natural history control.
RESULTS
The 1-year safety profile of commercial process delandistrogene moxeparvovec in ENDEAVOR was consistent with safety data reported in other delandistrogene moxeparvovec trials (NCT03375164 and NCT03769116). Delandistrogene moxeparvovec micro-dystrophin expression was robust, with sarcolemmal localization at week 12; mean (SD) CFBL in western blot, 54.2% (42.6); p < 0.0001. At 1 year, patients demonstrated stabilized or improved North Star Ambulatory Assessment total scores; mean (SD) CFBL, +4.0 (3.5). Treatment versus a propensity score-weighted external natural history control demonstrated a statistically significant difference in least squares mean (standard error) CFBL in North Star Ambulatory Assessment, +3.2 (0.6) points; p < 0.0001.
INTERPRETATION
Results confirm efficient transduction of muscle by delandistrogene moxeparvovec. One-year post-treatment, delandistrogene moxeparvovec was well tolerated, and demonstrated stabilized or improved motor function, suggesting a clinical benefit for patients with Duchenne muscular dystrophy. ANN NEUROL 2023;94:955-968.
Topics: Male; Humans; Muscular Dystrophy, Duchenne; Dystrophin; Genetic Therapy; Infusions, Intravenous; Muscle Fibers, Skeletal
PubMed: 37539981
DOI: 10.1002/ana.26755