Good News: Eteplirsen-DMD (转载)
Matsuo M. IUBMB Life. 2002;53(3):147-52.
Duchenne and Becker muscular dystrophy (DMD/BMD) are X-linked muscular dystrophies. The isolation of the defective gene in DMD/BMD has led to a better understanding of the disease process and has promoted studies regarding the application of molecular therapy. The purpose of this review is to present the progress made in this area of research with particular reference to dystrophin Kobe. Based on the results from the molecular analysis of dystrophin Kobe, we propose a novel molecular therapeutic method for DMD in which antisense oligonucleotides transform DMD into a milder phenotype by inducing exon skipping. In addition, current proposals for the molecular therapy of DMD are discussed.
Genetic Diagnosis and Molecular Therapies for Duchenne Muscular Dystrophy.
Takeshima Y. Rinsho Byori. 2015 t;63(10):1194-201.
Duchenne muscular dystrophy (DMD) is the most common form of inherited muscle disease and is characterized by progressive muscle wasting, ultimately resulting in the death of patients in their twenties or thirties. DMD is characterized by a deficiency of the muscle dystrophin as a result of mutations in the dystrophin gene. Currently, no effective treatment for DMD is available. Promising molecular therapies which are mutation-specific have been developed. Transformation of an out-of-frame mRNA into an in-frame dystrophin message by inducing exon skipping is considered one of the approaches most likely to lead to success. We demonstrated that the intravenous administration of the antisense oligonucleotide against the splicing enhancer sequence results in exon skipping and production of the dystrophin protein in DMD case for the first time. After extensive studies, anti-sense oligonucleotides comprising different monomers have undergone clinical trials and provided favorable results, enabling improvements in ambulation of DMD patients. Induction of the read-through of nonsense mutations is expected to produce dystrophin in DMD patients with nonsense mutations, which are detected in 19% of DMD cases. The clinical effectiveness of gentamicin and PTC124 has been reported. We have demonstrated that arbekacin-mediated read-through can markedly ameliorate muscular dystrophy in vitro. We have already begun a clinical trial of nonsense mutation read-through therapy using arbekacin. Some of these drug candidates are planned to undergo submission for approval to regulatory agencies in the US and EU. We hope that these molecular therapies will contribute towards DMD treatment
Eteplirsen: First Global Approval.
Syed YY. Drugs. 2016;76(17):1699-1704.
Eteplirsen (Exondys 51) is an antisense oligonucleotide designed to induce exon 51 skipping that is developed by Sarepta Therapeutics. Intravenous eteplirsen has received accelerated approval from the US FDA for the treatment of Duchenne muscular dystrophy (DMD) in patients with a confirmed mutation of the DMD gene amenable to exon 51 skipping. Eteplirsen has orphan drug designation in the USA and EU, and rare paediatric disease designation in the USA for use in DMD. In the phase III PROMOVI trial, eteplirsen significantly increased dystrophin levels from baseline in muscle tissues of 12 evaluable patients with DMD after 48 weeks of treatment. This finding is supported by data from phase II trials. Long-term treatment with eteplirsen was associated with a decrease in the rate of decline in ambulation and pulmonary function in an open-label extension of a phase II trial. Eteplirsen was generally well tolerated in clinical trials. This article summarizes the milestones in the development of eteplirsen leading to this first approval for DMD
Exon skipping therapy for Duchenne muscular dystrophy.
Kole R, Krieg AM. Adv Drug Deliv Rev. 2015 ;87:104-7.
Duchenne muscular dystrophy (DMD) is caused mostly by internal deletions in the gene for dystrophin, a protein essential for maintaining muscle cell membrane integrity. These deletions abrogate the reading frame and the lack of dystrophin results in progressive muscle deterioration. DMD patients experience progressive loss of ambulation, followed by a need for assisted ventilation, and eventual death in mid-twenties. By the method of exon skipping in dystrophin pre-mRNA the reading frame is restored and the internally deleted but functional dystrophin is produced. Two oligonucleotide drugs that induce desired exon skipping are currently in advanced clinical trials.
Gene therapies that restore dystrophin expression for the treatment of Duchenne muscular dystrophy.
Robinson-Hamm JN2, Gersbach CA. Hum Genet. 2016; 135(9):1029-40.
Duchenne muscular dystrophy is one of the most common inherited genetic diseases and is caused by mutations to the DMD gene that encodes the dystrophin protein. Recent advances in genome editing and gene therapy offer hope for the development of potential therapeutics. Truncated versions of the DMD gene can be delivered to the affected tissues with viral vectors and show promising results in a variety of animal models. Genome editing with the CRISPR/Cas9 system has recently been used to restore dystrophin expression by deleting one or more exons of the DMD gene in patient cells and in a mouse model that led to functional improvement of muscle strength. Exon skipping with oligonucleotides has been successful in several animal models and evaluated in multiple clinical trials. Next-generation oligonucleotide formulations offer significant promise to build on these results. All these approaches to restoring dystrophin expression are encouraging, but many hurdles remain. This review summarizes the current state of these technologies and summarizes considerations for their future development.
Longitudinal effect of eteplirsen versus historical control on ambulation in Duchenne muscular dystrophy.
Mendell JR, Goemans N, Lowes LP, et al. Ann Neurol. 2016 ;79(2):257-71.
OBJECTIVE: To continue evaluation of the long-term efficacy and safety of eteplirsen, a phosphorodiamidate morpholino oligomer designed to skip DMD exon 51 in patients with Duchenne muscular dystrophy (DMD). Three-year progression of eteplirsen-treated patients was compared to matched historical controls (HC).
METHODS: Ambulatory DMD patients who were ≥7 years old and amenable to exon 51 skipping were randomized to eteplirsen (30/50mg/kg) or placebo for 24 weeks. Thereafter, all received eteplirsen on an open-label basis. The primary functional assessment in this study was the 6-Minute Walk Test (6MWT). Respiratory muscle function was assessed by pulmonary function testing (PFT). Longitudinal natural history data were used for comparative analysis of 6MWT performance at baseline and months 12, 24, and 36. Patients were matched to the eteplirsen group based on age, corticosteroid use, and genotype.
RESULTS: At 36 months, eteplirsen-treated patients (n = 12) demonstrated a statistically significant advantage of 151m (p < 0.01) on 6MWT and experienced a lower incidence of loss of ambulation in comparison to matched HC (n = 13) amenable to exon 51 skipping. PFT results remained relatively stable in eteplirsen-treated patients. Eteplirsen was well tolerated. Analysis of HC confirmed the previously observed change in disease trajectory at age 7 years, and more severe progression was observed in patients with mutations amenable to exon skipping than in those not amenable. The subset of patients amenable to exon 51 skipping showed a more severe disease course than those amenable to any exon skipping.
INTERPRETATION: Over 3 years of follow-up, eteplirsen-treated patients showed a slower rate of decline in ambulation assessed by 6MWT compared to untreated matched HC.