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Nucleic Acid Therapeutics Feb 2022The aim of this Phase 1/2, 2-part, multicenter trial was to report clinical safety and efficacy of long-term golodirsen treatment among ambulatory patients with exon 53... (Randomized Controlled Trial)
Randomized Controlled Trial
Long-Term Safety and Efficacy Data of Golodirsen in Ambulatory Patients with Duchenne Muscular Dystrophy Amenable to Exon 53 Skipping: A First-in-human, Multicenter, Two-Part, Open-Label, Phase 1/2 Trial.
The aim of this Phase 1/2, 2-part, multicenter trial was to report clinical safety and efficacy of long-term golodirsen treatment among ambulatory patients with exon 53 skip-amenable Duchenne muscular dystrophy (DMD). Part 1 was a 12-week, randomized, double-blind, placebo-controlled, dose-titration study followed by 9-week safety review. Part 2 was a 168-week, open-label evaluation of golodirsen 30 mg/kg. Part 1 primary endpoint was safety. Part 2 primary endpoints were dystrophin protein expression and 6-minute walk test (6MWT); secondary endpoints were percent predicted forced vital capacity (FVC%p) and safety. ambulation analyses used mutation-matched external natural history controls. All patients from Part 1 (golodirsen, = 8; placebo, = 4) plus 13 additional patients entered Part 2; 23 completed the study. Adverse events were generally mild, nonserious, and unrelated to golodirsen, with no safety-related discontinuations or deaths. Golodirsen increased dystrophin protein (16.0-fold; < 0.001) and exon skipping (28.9-fold; < 0.001). At 3 years, 6MWT change from baseline was -99.0 m for golodirsen-treated patients versus -181.4 m for external controls ( = 0.067), and loss of ambulation occurred in 9% versus 26% ( = 0.21). FVC%p declined 8.4% over 3 years in golodirsen-treated patients, comparing favorably with literature-reported rates. This study provides evidence for golodirsen biologic activity and long-term safety in a declining DMD population and suggests functional benefit versus external controls. Clinical Trial Registration number: NCT02310906.
Topics: Dystrophin; Exons; Humans; Muscular Dystrophy, Duchenne; Oligonucleotides; Walk Test
PubMed: 34788571
DOI: 10.1089/nat.2021.0043 -
Journal of Neuromuscular Diseases 2022Duchenne muscular dystrophy (DMD) is a rare, genetic disease caused by mutations in the DMD gene resulting in an absence of functional dystrophin protein. Viltolarsen,... (Clinical Trial)
Clinical Trial
BACKGROUND
Duchenne muscular dystrophy (DMD) is a rare, genetic disease caused by mutations in the DMD gene resulting in an absence of functional dystrophin protein. Viltolarsen, an exon 53 skipping therapy, has been shown to increase endogenous dystrophin levels. Herein, long-term (>2 years) functional outcomes in viltolarsen treated patients were compared to a matched historical control group.
OBJECTIVE
To evaluate long-term efficacy and safety of the anti-sense oligonucleotide viltolarsen in the treatment of patients with DMD amenable to exon 53 skipping therapy.
METHODS
This trial (NCT03167255) is the extension of a previously published 24-week trial in North America (NCT02740972) that examined dystrophin levels, timed function tests compared to a matched historical control group (Cooperative International Neuromuscular Research Group Duchenne Natural History Study, CINRG DNHS), and safety in boys 4 to < 10 years (N = 16) with DMD amenable to exon 53 skipping who were treated with viltolarsen. Both groups were treated with glucocorticoids. All 16 participants elected to enroll in this long-term trial (up to 192 weeks) to continue evaluation of motor function and safety.
RESULTS
Time to stand from supine and time to run/walk 10 meters showed stabilization from baseline through week 109 for viltolarsen-treated participants whereas the historical control group showed decline (statistically significant differences for multiple timepoints). Safety was similar to that observed in the previous 24-week trial, which was predominantly mild. There have been no treatment-related serious adverse events and no discontinuations.
CONCLUSIONS
Based on these results at over 2 years, viltolarsen can be a new treatment option for patients with DMD amenable to exon 53 skipping.
Topics: Dystrophin; Humans; Male; Muscular Dystrophy, Duchenne; Oligonucleotides; Oligonucleotides, Antisense
PubMed: 35634851
DOI: 10.3233/JND-220811 -
Human Gene Therapy May 2023Duchenne muscular dystrophy (DMD) is a debilitating genetic disorder that results in progressive muscle degeneration and premature death. DMD is caused by mutations in... (Review)
Review
Duchenne muscular dystrophy (DMD) is a debilitating genetic disorder that results in progressive muscle degeneration and premature death. DMD is caused by mutations in the gene encoding dystrophin protein, a membrane-associated protein required for maintenance of muscle structure and function. Although the genetic mutations causing the disease are well known, no curative therapies have been developed to date. The advent of genome-editing technologies provides new opportunities to correct the underlying mutations responsible for DMD. These mutations have been successfully corrected in human cells, mice, and large animal models through different strategies based on CRISPR-Cas9 gene editing. Ideally, CRISPR-editing could offer a one-time treatment for DMD by correcting the genetic mutations and enabling normal expression of the repaired gene. However, numerous challenges remain to be addressed, including optimization of gene editing, delivery of gene-editing components to all the muscles of the body, and the suppression of possible immune responses to the CRISPR-editing therapy. This review provides an overview of the recent advances toward CRISPR-editing therapy for DMD and discusses the opportunities and the remaining challenges in the path to clinical translation.
Topics: Mice; Humans; Animals; Muscular Dystrophy, Duchenne; CRISPR-Cas Systems; Genetic Therapy; Exons; Dystrophin; Gene Editing; Disease Models, Animal
PubMed: 37060194
DOI: 10.1089/hum.2023.053 -
Precise correction of Duchenne muscular dystrophy exon deletion mutations by base and prime editing.Science Advances Apr 2021Duchenne muscular dystrophy (DMD) is a fatal muscle disease caused by the lack of dystrophin, which maintains muscle membrane integrity. We used an adenine base editor...
Duchenne muscular dystrophy (DMD) is a fatal muscle disease caused by the lack of dystrophin, which maintains muscle membrane integrity. We used an adenine base editor (ABE) to modify splice donor sites of the dystrophin gene, causing skipping of a common DMD deletion mutation of exon 51 (∆Ex51) in cardiomyocytes derived from human induced pluripotent stem cells, restoring dystrophin expression. Prime editing was also capable of reframing the dystrophin open reading frame in these cardiomyocytes. Intramuscular injection of ∆Ex51 mice with adeno-associated virus serotype-9 encoding ABE components as a split-intein trans-splicing system allowed gene editing and disease correction in vivo. Our findings demonstrate the effectiveness of nucleotide editing for the correction of diverse DMD mutations with minimal modification of the genome, although improved delivery methods will be required before these strategies can be used to sufficiently edit the genome in patients with DMD.
Topics: Animals; CRISPR-Cas Systems; Dystrophin; Exons; Gene Editing; Humans; Induced Pluripotent Stem Cells; Mice; Muscular Dystrophy, Duchenne; Sequence Deletion
PubMed: 33931459
DOI: 10.1126/sciadv.abg4910 -
Human Gene Therapy Apr 2021Duchenne muscular dystrophy (DMD) is a rare, X-linked, fatal, degenerative neuromuscular disease caused by mutations in the gene. More than 2,000 mutations of the gene...
Duchenne muscular dystrophy (DMD) is a rare, X-linked, fatal, degenerative neuromuscular disease caused by mutations in the gene. More than 2,000 mutations of the gene are responsible for progressive loss of muscle strength, loss of ambulation, and generally respiratory and cardiac failure by age 30. Recently, gene transfer therapy has received widespread interest as a disease-modifying treatment for all patients with DMD. We designed an adeno-associated virus vector (rAAVrh74) containing a codon-optimized human micro-dystrophin transgene driven by a skeletal and cardiac muscle-specific promoter, MHCK7. To test the efficacy of rAAVrh74.MHCK7.micro-dystrophin, we evaluated systemic injections in (dystrophin-null) mice at low (2 × 10 vector genome [vg] total dose, 8 × 10 vg/kg), intermediate (6 × 10 vg total dose, 2 × 10 vg/kg), and high doses (1.2 × 10 vg total dose, 6 × 10 vg/kg). Three months posttreatment, specific force increased in the diaphragm (DIA) and tibialis anterior muscle, with intermediate and high doses eliciting force outputs at wild-type (WT) levels. Histological improvement included reductions in fibrosis and normalization of myofiber size, specifically in the DIA, where results for low and intermediate doses were not significantly different from the WT. Significant reduction in central nucleation was also observed, although complete normalization to WT was not seen. No vector-associated toxicity was reported either by clinical or organ-specific laboratory assessments or following formal histopathology. The findings in this preclinical study provided proof of principle for safety and efficacy of systemic delivery of rAAVrh74.MHCK7.micro-dystrophin at high vector titers, supporting initiation of a Phase I/II safety study in boys with DMD.
Topics: Animals; Disease Models, Animal; Dystrophin; Genetic Therapy; Humans; Mice; Mice, Inbred mdx; Muscle, Skeletal; Muscular Dystrophy, Duchenne
PubMed: 33397205
DOI: 10.1089/hum.2019.255 -
Nature Communications Aug 2023Duchenne muscular dystrophy is caused by mutations in the DMD gene, leading to lack of dystrophin. Chronic muscle damage eventually leads to histological alterations in...
Duchenne muscular dystrophy is caused by mutations in the DMD gene, leading to lack of dystrophin. Chronic muscle damage eventually leads to histological alterations in skeletal muscles. The identification of genes and cell types driving tissue remodeling is a key step to developing effective therapies. Here we use spatial transcriptomics in two Duchenne muscular dystrophy mouse models differing in disease severity to identify gene expression signatures underlying skeletal muscle pathology and to directly link gene expression to muscle histology. We perform deconvolution analysis to identify cell types contributing to histological alterations. We show increased expression of specific genes in areas of muscle regeneration (Myl4, Sparc, Hspg2), fibrosis (Vim, Fn1, Thbs4) and calcification (Bgn, Ctsk, Spp1). These findings are confirmed by smFISH. Finally, we use differentiation dynamic analysis in the D2-mdx muscle to identify muscle fibers in the present state that are predicted to become affected in the future state.
Topics: Animals; Mice; Muscular Dystrophy, Duchenne; Transcriptome; Mice, Inbred mdx; Muscle, Skeletal; Dystrophin; Disease Models, Animal
PubMed: 37582915
DOI: 10.1038/s41467-023-40555-9 -
Human Mutation Apr 2015Analyzing the type and frequency of patient-specific mutations that give rise to Duchenne muscular dystrophy (DMD) is an invaluable tool for diagnostics, basic...
Analyzing the type and frequency of patient-specific mutations that give rise to Duchenne muscular dystrophy (DMD) is an invaluable tool for diagnostics, basic scientific research, trial planning, and improved clinical care. Locus-specific databases allow for the collection, organization, storage, and analysis of genetic variants of disease. Here, we describe the development and analysis of the TREAT-NMD DMD Global database (http://umd.be/TREAT_DMD/). We analyzed genetic data for 7,149 DMD mutations held within the database. A total of 5,682 large mutations were observed (80% of total mutations), of which 4,894 (86%) were deletions (1 exon or larger) and 784 (14%) were duplications (1 exon or larger). There were 1,445 small mutations (smaller than 1 exon, 20% of all mutations), of which 358 (25%) were small deletions and 132 (9%) small insertions and 199 (14%) affected the splice sites. Point mutations totalled 756 (52% of small mutations) with 726 (50%) nonsense mutations and 30 (2%) missense mutations. Finally, 22 (0.3%) mid-intronic mutations were observed. In addition, mutations were identified within the database that would potentially benefit from novel genetic therapies for DMD including stop codon read-through therapies (10% of total mutations) and exon skipping therapy (80% of deletions and 55% of total mutations).
Topics: Databases, Genetic; Dystrophin; Humans; Muscular Dystrophy, Duchenne; Mutation; Registries
PubMed: 25604253
DOI: 10.1002/humu.22758 -
Journal of Neuromuscular Diseases 2023Duchenne muscular dystrophy (DMD) is caused by DMD gene mutations, resulting in absence of functional dystrophin protein. Viltolarsen, an exon 53 skipping therapy,...
BACKGROUND
Duchenne muscular dystrophy (DMD) is caused by DMD gene mutations, resulting in absence of functional dystrophin protein. Viltolarsen, an exon 53 skipping therapy, significantly increased dystrophin levels in patients with DMD. Presented here are completed study results of > 4 years of functional outcomes in viltolarsen-treated patients compared to a historical control group (Cooperative International Neuromuscular Research Group Duchenne Natural History Study [CINRG DNHS]).
OBJECTIVE
To evaluate the efficacy and safety of viltolarsen for an additional 192 weeks in boys with DMD.
METHODS
This phase 2, open-label, 192-week long-term extension (LTE) study (NCT03167255) evaluated the efficacy and safety of viltolarsen in participants aged 4 to < 10 years at baseline with DMD amenable to exon 53 skipping. All 16 participants from the initial 24-week study enrolled into this LTE. Timed function tests were compared to the CINRG DNHS group. All participants received glucocorticoid treatment. The primary efficacy outcome was time to stand from supine (TTSTAND). Secondary efficacy outcomes included additional timed function tests. Safety was continuously assessed.
RESULTS
For the primary efficacy outcome (TTSTAND), viltolarsen-treated patients showed stabilization of motor function over the first two years and significant slowing of disease progression over the following two years compared with the CINRG DNHS control group which declined. Viltolarsen was well tolerated, with most reported treatment-emergent adverse events being mild or moderate. No participants discontinued drug during the study.
CONCLUSIONS
Based on the results of this 4-year LTE, viltolarsen can be an important treatment strategy for DMD patients amenable to exon 53 skipping.
Topics: Male; Humans; Muscular Dystrophy, Duchenne; Dystrophin; Oligonucleotides; Glucocorticoids
PubMed: 37005891
DOI: 10.3233/JND-221656 -
Circulation. Genomic and Precision... Oct 2023Variants in the gene, that encodes the cytoskeletal protein, dystrophin, cause a severe form of dilated cardiomyopathy (DCM) associated with high rates of heart...
BACKGROUND
Variants in the gene, that encodes the cytoskeletal protein, dystrophin, cause a severe form of dilated cardiomyopathy (DCM) associated with high rates of heart failure, heart transplantation, and ventricular arrhythmias. Improved early detection of individuals at risk is needed.
METHODS
Genetic testing of 40 male probands with a potential X-linked genetic cause of primary DCM was undertaken using multi-gene panel sequencing, multiplex polymerase chain reaction, and array comparative genomic hybridization. Variant location was assessed with respect to dystrophin isoform patterns and exon usage. Telomere length was evaluated as a marker of myocardial dysfunction in left ventricular tissue and blood.
RESULTS
Four pathogenic/likely pathogenic variants were found in 5 probands (5/40: 12.5%). Only one rare variant was identified by gene panel testing with 3 additional multi-exon deletion/duplications found following targeted assays for structural variants. All of the pathogenic/likely pathogenic variants involved dystrophin exons that had percent spliced-in scores >90, indicating high levels of constitutive expression in the human adult heart. Fifteen variant-negative probands (15/40: 37.5%) had variants in autosomal genes including , , , and . Myocardial telomere length was reduced in patients with DCM irrespective of genotype. No differences in blood telomere length were observed between genotype-positive family members with/without DCM and controls.
CONCLUSIONS
Primary genetic testing using multi-gene panels has a low yield and specific assays for structural variants are required if -associated cardiomyopathy is suspected. Distinguishing X-linked causes of DCM from autosomal genes that show sex differences in clinical presentation is crucial for informed family management.
Topics: Adult; Humans; Male; Female; Dystrophin; Comparative Genomic Hybridization; Pedigree; Genotype; Phenotype; Adaptor Proteins, Signal Transducing; Apoptosis Regulatory Proteins
PubMed: 37671549
DOI: 10.1161/CIRCGEN.123.004221 -
Circulation Nov 2021Loss of dystrophin protein causes Duchenne muscular dystrophy (DMD), characterized by progressive degeneration of cardiac and skeletal muscles, and mortality in...
BACKGROUND
Loss of dystrophin protein causes Duchenne muscular dystrophy (DMD), characterized by progressive degeneration of cardiac and skeletal muscles, and mortality in adolescence or young adulthood. Although cardiac failure has risen as the leading cause of mortality in patients with DMD, effective therapeutic interventions remain underdeveloped, in part, because of the lack of a suitable preclinical model.
METHODS
We analyzed a novel murine model of DMD created by introducing a 4-bp deletion into exon 4, one of the exons encoding the actin-binding domain 1 of dystrophin (referred to as mice). Echocardiography, microcomputed tomography, muscle force measurement, and histological analysis were performed to determine cardiac and skeletal muscle defects in these mice. Using this model, we examined the feasibility of using a cytidine base editor to install exon skipping and rescue dystrophic cardiomyopathy in vivo. AAV9-based CRISPR/Cas9-AID (eTAM) together with AAV9-sgRNA was injected into neonatal mice, which were analyzed 2 or 12 months after treatment to evaluate the extent of exon skipping, dystrophin restoration, and phenotypic improvements of cardiac and skeletal muscles.
RESULTS
mice recapitulated many aspects of human DMD, including shortened life span (by ≈50%), progressive cardiomyopathy, kyphosis, profound loss of muscle strength, and myocyte degeneration. A single-dose administration of AAV9-eTAM instituted >50% targeted exon skipping in the transcripts and restored up to 90% dystrophin in the heart. As a result, early ventricular remodeling was prevented and cardiac and skeletal muscle functions were improved, leading to an increased life span of the mice. Despite gradual decline of AAV vector and base editor expression, dystrophin restoration and pathophysiological rescue of muscular dystrophy were long lasted for at least 1 year.
CONCLUSIONS
Our study demonstrates the feasibility and efficacy to institute exon skipping through an enhanced TAM (eTAM) for therapeutic application(s).
Topics: APOBEC Deaminases; Animals; CRISPR-Cas Systems; Cardiomyopathies; Dependovirus; Dystrophin; Exons; Genetic Vectors; Humans; Mice; Mice, Inbred mdx; Muscular Dystrophy, Duchenne
PubMed: 34698513
DOI: 10.1161/CIRCULATIONAHA.121.054628