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Drugs of Today (Barcelona, Spain : 1998) Oct 2019Duchenne muscular dystrophy is the most common lethal X-linked genetic disorder, characterized by progressive muscle loss, with cardiac and respiratory complications. It... (Review)
Review
Duchenne muscular dystrophy is the most common lethal X-linked genetic disorder, characterized by progressive muscle loss, with cardiac and respiratory complications. It is caused by a lack of dystrophin protein due to mutations in the DMD gene, which can disrupt the reading frame of the dystrophin primary transcript. Antisense oligonucleotides such as phosphorodiamidate morpholino oligomers (PMOs) can induce exon skipping during pre-mRNA splicing and restore the reading frame of the DMD primary transcript. The resulting dystrophin protein is internally deleted but partially functional. Viltolarsen, also known as NS-065/NCNP-01, is a PMO developed through comprehensive sequence optimization and is designed to skip exon 53 on the DMD primary transcript. Exclusion of exon 53 from the DMD primary transcript can treat 8-10% of DMD patients worldwide. This review paper summarizes the mechanism of action, pharmacokinetics and safety of viltolarsen from preclinical and clinical trials.
Topics: Clinical Trials as Topic; Dystrophin; Exons; Humans; Morpholinos; Muscular Dystrophy, Duchenne; Oligonucleotides; Oligonucleotides, Antisense; RNA Precursors
PubMed: 31720560
DOI: 10.1358/dot.2019.55.10.3045038 -
Drugs Nov 2016Eteplirsen (Exondys 51) is an antisense oligonucleotide designed to induce exon 51 skipping that is developed by Sarepta Therapeutics. Intravenous eteplirsen has... (Review)
Review
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.
Topics: Clinical Trials, Phase II as Topic; Clinical Trials, Phase III as Topic; Drug Approval; Humans; Morpholinos; Muscular Dystrophy, Duchenne; Oligonucleotides, Antisense; United States; United States Food and Drug Administration
PubMed: 27807823
DOI: 10.1007/s40265-016-0657-1 -
Journal of the American Chemical Society Sep 2020This Article outlines the optimized chemical synthesis and preliminary biochemical characterization of a new oligonucleotide analogue called thiophosphoramidate...
This Article outlines the optimized chemical synthesis and preliminary biochemical characterization of a new oligonucleotide analogue called thiophosphoramidate morpholinos (TMOs). Their rational design hinges upon integrating two well-studied pharmacophores, namely, phosphorothioates (pS) and morpholinos, to create morpholino-pS hybrid oligonucleotides. Our simple synthesis strategy enables the easy incorporation of morpholino-pS moieties and therapeutically relevant sugar modifications in tandem to create novel oligonucleotide (ON) analogues that are hitherto unexplored in the oligotherapeutics arena. Exclusively TMO-modified ONs demonstrate high stability toward 3'-exonuclease. Hybridization studies show that TMO chimeras consisting of alternating TMO and DNA-pS subunits exhibit higher binding affinity toward complementary RNA relative to the canonical DNA/RNA duplex (∼10 °C). Oligonucleotides that consist entirely of TMO linkages also show higher RNA binding affinity but do not recruit ribonuclease H1 (RNase H1). Chimeric TMO analogues demonstrate high gene silencing efficacy, comparable to that of a chimeric 2'-OMe-pS/pO control, during bioassay screens designed to evaluate their potential as microRNA inhibitors of hsa-miR-15b-5p in HeLa cells.
Topics: HeLa Cells; Humans; MicroRNAs; Molecular Structure; Morpholinos; Phosphates
PubMed: 32866014
DOI: 10.1021/jacs.0c04335 -
Drug Design, Development and Therapy 2017Duchenne muscular dystrophy is a fatal neuromuscular disorder affecting around one in 3,500-5,000 male births that is characterized by progressive muscular... (Review)
Review
Duchenne muscular dystrophy is a fatal neuromuscular disorder affecting around one in 3,500-5,000 male births that is characterized by progressive muscular deterioration. It is inherited in an X-linked recessive fashion and is caused by loss-of-function mutations in the gene coding for dystrophin, a cytoskeletal protein that stabilizes the plasma membrane of muscle fibers. In September 2016, the US Food and Drug Administration granted accelerated approval for eteplirsen (or Exondys 51), a drug that acts to promote dystrophin production by restoring the translational reading frame of through specific skipping of exon 51 in defective gene variants. Eteplirsen is applicable for approximately 14% of patients with mutations. This article extensively reviews and discusses the available information on eteplirsen to date, focusing on pharmacological, efficacy, safety, and tolerability data from preclinical and clinical trials. Issues faced by eteplirsen, particularly those relating to its efficacy, will be identified. Finally, the place of eteplirsen and exon skipping as a general therapeutic strategy in Duchenne muscular dystrophy treatment will be discussed.
Topics: Animals; Humans; Morpholinos; Muscular Dystrophy, Duchenne
PubMed: 28280301
DOI: 10.2147/DDDT.S97635 -
Methods in Molecular Biology (Clifton,... 2017Differing from the conventional direct-targeting strategy in which a probe or payload is directly loaded onto a targeting molecule that binds to the native target,...
Differing from the conventional direct-targeting strategy in which a probe or payload is directly loaded onto a targeting molecule that binds to the native target, pretargeting is an improved targeting strategy. It converts the native target to an artificial target specific for a secondary targeting molecule loaded with the probe or payload (effector). The effector is small and does not accumulate in normal tissues, which accelerates the targeting process and generates high target to nontarget ratios. DNA/cDNA analogs can serve as the recognition pair, i.e., the artificial target and the secondary targeting effector. Morpholino oligomers are so far the most investigated and the most successful DNA/cDNA analog recognition pairs for pretargeting. Herein, we describe the pretargeting principles, the pretargeting strategy using Morpholino oligomers, and the preclinical success so far achieved.
Topics: Animals; Gene Targeting; Gene Transfer Techniques; Immunoconjugates; Isotope Labeling; Mice; Morpholinos; Single Photon Emission Computed Tomography Computed Tomography; Tissue Distribution
PubMed: 28364242
DOI: 10.1007/978-1-4939-6817-6_14 -
Chembiochem : a European Journal of... Mar 2021A novel class of nucleotide analogues with a dioxane ring as central scaffold has been developed. Synthetic routes in two diastereomeric series were realized, and the...
A novel class of nucleotide analogues with a dioxane ring as central scaffold has been developed. Synthetic routes in two diastereomeric series were realized, and the final thymidine analogues were synthesized with common functionalities for the automated oligonucleotide synthesis. The chemical space of the initially derived nucleotides was expanded by changing the central dioxane to analogous morpholine derivatives. This opens up the possibility for further derivatization by attaching different substituents at the morpholine nitrogen. The novel nucleotide building blocks were incorporated into double-stranded RNA sequences, and their hybridization properties investigated by melting-temperature analysis. Both scaffolds, dioxanes and morpholines, had an equal impact on double-strand stability, but T values differed depending on the chirality in the six-membered ring.
Topics: Dioxanes; Morpholinos; Nucleic Acid Hybridization; RNA, Double-Stranded; Stereoisomerism; Thymidine; Transition Temperature
PubMed: 33112485
DOI: 10.1002/cbic.202000693 -
Methods in Molecular Biology (Clifton,... 2019Morpholino antisense oligonucleotides are used as routine tools in developmental biology to investigate gene function during early embryogenesis. These chemically...
Morpholino antisense oligonucleotides are used as routine tools in developmental biology to investigate gene function during early embryogenesis. These chemically modified oligos contain morpholine ring connected with phosphorodiamidate linkages as backbone but carry unmodified nucleobases. In this chapter, we describe the methods to further modify the nucleobases using palladium-catalyzed cross-coupling reactions. The key reactions used are halogenations of the nucleobases in suitable position and subsequent Pd-catalyzed Sonogashira and Suzuki reactions. The sequential synthetic steps are described in detail in this chapter, and the examples are shown in tables.
Topics: Catalysis; Cross-Linking Reagents; Molecular Structure; Morpholinos; Oligonucleotides, Antisense; Palladium
PubMed: 31016698
DOI: 10.1007/978-1-4939-9216-4_7 -
Neuromuscular Disorders : NMD Jun 2023Eteplirsen is FDA-approved for the treatment of Duchenne muscular dystrophy (DMD) in exon 51 skip-amenable patients. Previous studies in boys > 4 years of age indicate...
Eteplirsen is FDA-approved for the treatment of Duchenne muscular dystrophy (DMD) in exon 51 skip-amenable patients. Previous studies in boys > 4 years of age indicate eteplirsen is well tolerated and attenuates pulmonary and ambulatory decline compared with matched natural history cohorts. Here the safety, tolerability and pharmacokinetics of eteplirsen in boys aged 6-48 months is evaluated. In this open-label, multicenter, dose-escalation study (NCT03218995), boys with a confirmed mutation of the DMD gene amenable to exon 51 skipping (Cohort 1: aged 24-48 months, n = 9; Cohort 2: aged 6 to < 24 months, n = 6) received ascending doses (2, 4, 10, 20, 30 mg/kg) of once-weekly eteplirsen intravenously over 10 weeks, continuing at 30 mg/kg up to 96 weeks. Endpoints included safety (primary) and pharmacokinetics (secondary). All 15 participants completed the study. Eteplirsen was well tolerated with no treatment-related discontinuations, deaths or evidence of kidney toxicity. Most treatment-emergent adverse events were mild; most common were pyrexia, cough, nasopharyngitis, vomiting, and diarrhea. Eteplirsen pharmacokinetics were consistent between both cohorts and with previous clinical experience in boys with DMD > 4 years of age. These data support the safety and tolerability of eteplirsen at the approved 30-mg/kg dose in boys as young as 6 months old.
Topics: Male; Humans; Child, Preschool; Infant; Muscular Dystrophy, Duchenne; Morpholinos; Exons; Mutation; Dystrophin
PubMed: 37207382
DOI: 10.1016/j.nmd.2023.03.008 -
Clinical Pharmacology and Therapeutics Jan 2016The development of genetic and molecular biology tools permitting the connection of specific genes to their functions has accelerated our understanding of molecular... (Review)
Review
The development of genetic and molecular biology tools permitting the connection of specific genes to their functions has accelerated our understanding of molecular pathways underlying health and disease. The resulting gains in knowledge have propelled gene targeting to the forefront of promising therapeutic strategies. Here we discuss the uniquely powerful and adaptable approach of morpholino-driven modification of normal and mutant gene expression as a pathway to health.
Topics: Animals; Disease; Drug Carriers; Gene Expression; Gene Targeting; Genetic Engineering; Humans; Models, Genetic; Morpholinos; Preventive Medicine
PubMed: 26474085
DOI: 10.1002/cpt.276 -
Chemical Communications (Cambridge,... May 2023To ensure specificity of small interfering RNAs (siRNAs), the antisense strand must be selected by the RNA-induced silencing complex (RISC). We have previously...
To ensure specificity of small interfering RNAs (siRNAs), the antisense strand must be selected by the RNA-induced silencing complex (RISC). We have previously demonstrated that a 5'-morpholino-modified nucleotide at the 5'-end of the sense strand inhibits its interaction with RISC ensuring selection of the desired antisense strand. To improve this antagonizing binding property even further, a new set of morpholino-based analogues, Mo2 and Mo3, and a piperidine analogue, Pip, were designed based on the known structure of Argonaute2, the slicer enzyme component of RISC. Sense strands of siRNAs were modified with these new analogues, and the siRNAs were evaluated and in mice for RNAi activity. Our data demonstrated that Mo2 is the best RISC inhibitor among the modifications tested and that it effectively mitigates sense strand-based off-target activity of siRNA.
Topics: Animals; Mice; RNA, Small Interfering; RNA-Induced Silencing Complex; Morpholinos
PubMed: 37144553
DOI: 10.1039/d3cc01143g