Onasemnogene Abeparvovec-xioi: Gene Therapy for Spinal Muscular Atrophy

2020 ◽  
Vol 54 (10) ◽  
pp. 1001-1009 ◽  
Author(s):  
Debra Stevens ◽  
Melanie K. Claborn ◽  
Brooke L. Gildon ◽  
Tiffany L. Kessler ◽  
Cheri Walker
Keyword(s):  
Gene Therapy ◽  
Spinal Muscular Atrophy ◽  
English Language ◽  
Liver Toxicity ◽  
Muscular Atrophy ◽  
Data Extraction ◽  
Case Series ◽  
Survival Motor Neuron ◽  
Smn1 Gene ◽  
Smn Protein

Objective: To review the efficacy and safety of onasemnogene abeparvovec-xioi (Zolgensma) in the treatment of spinal muscular atrophy (SMA). Data Sources: An English-language literature search of PubMed, MEDLINE, and Ovid (1946 to December 2019) was completed using the terms onasemnogene, AVXS-101, and spinal muscular atrophy. Manufacturer prescribing information, article bibliographies, and data from ClinicalTrials.gov were incorporated in the reviewed data. Study Selection/Data Extraction: All studies registered on ClinicalTrials.gov were incorporated in the reviewed data. Data Synthesis: Onasemnogene is the first agent for SMA utilizing gene therapy to directly provide survival motor neuron 1 ( SMN1) gene to produce SMN protein. Four publications of 1 clinical trial, 1 comparison study of treatment effects, and 1 combination therapy case series have been published. Relevance to Patient Care and Clinical Practice: Onasemnogene is a one time dose approved by the Food and Drug Administration for SMA patients <2 years old who possess mutations in both copies of the SMN1 gene. Conclusion: Onasemnogene appears to be an efficacious therapy for younger pediatric patients with SMA type 1. Concerns include drug cost and potential liver toxicity. Long-term benefits and risks have not been determined.

scholarly journals Short-duration splice promoting compound enables a tunable mouse model of spinal muscular atrophy

2020 ◽  
Vol 4 (1) ◽  
pp. e202000889
Author(s):  
Anne Rietz ◽  
Kevin J Hodgetts ◽  
Hrvoje Lusic ◽  
Kevin M Quist ◽  
Erkan Y Osman ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Antisense Oligonucleotides ◽  
Muscular Atrophy ◽  
Survival Motor Neuron ◽  
Potential Drug ◽  
Transgenic Mouse Models ◽  
Fda Approval ◽  
Smn Protein

Spinal muscular atrophy (SMA) is a motor neuron disease and the leading genetic cause of infant mortality. SMA results from insufficient survival motor neuron (SMN) protein due to alternative splicing. Antisense oligonucleotides, gene therapy and splicing modifiers recently received FDA approval. Although severe SMA transgenic mouse models have been beneficial for testing therapeutic efficacy, models mimicking milder cases that manifest post-infancy have proven challenging to develop. We established a titratable model of mild and moderate SMA using the splicing compound NVS-SM2. Administration for 30 d prevented development of the SMA phenotype in severe SMA mice, which typically show rapid weakness and succumb by postnatal day 11. Furthermore, administration at day eight resulted in phenotypic recovery. Remarkably, acute dosing limited to the first 3 d of life significantly enhanced survival in two severe SMA mice models, easing the burden on neonates and demonstrating the compound as suitable for evaluation of follow-on therapies without potential drug–drug interactions. This pharmacologically tunable SMA model represents a useful tool to investigate cellular and molecular pathogenesis at different stages of disease.

Nusinersen: A Treatment for Spinal Muscular Atrophy

2018 ◽  
Vol 53 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Melanie K. Claborn ◽  
Debra L. Stevens ◽  
Cheri K. Walker ◽  
Brooke L. Gildon
Keyword(s):  
Clinical Practice ◽  
Spinal Muscular Atrophy ◽  
English Language ◽  
Muscular Atrophy ◽  
Data Extraction ◽  
Age Groups ◽  
Survival Motor Neuron ◽  
Phase Iii ◽  
Open Label ◽  
Tract Infections

Objective: To review the efficacy and safety of nusinersen (Spinraza) in the treatment of spinal muscular atrophy (SMA). Data Sources: An English-language literature search of PubMed and MEDLINE (1946 to June 2018) was performed using the terms nusinersen, ISIS-SMN (Rx), and spinal muscular atrophy. Manufacturer prescribing information, abstracts, article bibliographies, and clinicaltrials.gov data were incorporated for additional materials. Study Selection/Data Extraction: All clinical trials of nusinersen were identified and analyzed in the review. Data Synthesis: Nusinersen is the first drug therapy approved for the treatment of SMA. It is a novel modified antisense oligonucleotide designed to treat SMA caused by mutations in chromosome 5q that lead to survival motor neuron protein deficiency. Nusinersen has been studied for safety, pharmacokinetics, and efficacy in both open-label and randomized controlled trials. The studies show improvement in motor function across SMA of all types. The most common adverse effects were respiratory tract infections, headache, back pain, constipation, and post–lumbar puncture syndrome. Relevance to Patient Care and Clinical Practice: Based on phase III trial data, nusinersen produced positive changes in the clinical course of patients with SMA. The acquisition and administration of nusinersen present a number of challenges in clinical practice. Its intrathecal delivery and costly price tag must be recognized. Conclusion: Nusinersen is safe and effective in patients with SMA. It was well tolerated across all studied age groups.

scholarly journals The First Orally Deliverable Small Molecule for the Treatment of Spinal Muscular Atrophy

2020 ◽  
Vol 15 ◽  
pp. 263310552097398
Author(s):  
Ravindra N Singh ◽  
Eric W Ottesen ◽  
Natalia N Singh
Keyword(s):  
Spinal Muscular Atrophy ◽  
Small Molecule ◽  
Muscular Atrophy ◽  
Survival Motor Neuron ◽  
Smn1 Gene ◽  
The Third ◽  
Splicing Silencer ◽  
Phenotypic Spectrum ◽  
Low Levels ◽  
Smn Protein

Spinal muscular atrophy (SMA) is 1 of the leading causes of infant mortality. SMA is mostly caused by low levels of Survival Motor Neuron (SMN) protein due to deletion of or mutation in the SMN1 gene. Its nearly identical copy, SMN2, fails to compensate for the loss of SMN1 due to predominant skipping of exon 7. Correction of SMN2 exon 7 splicing by an antisense oligonucleotide (ASO), nusinersen (Spinraza™), that targets the intronic splicing silencer N1 (ISS-N1) became the first approved therapy for SMA. Restoration of SMN levels using gene therapy was the next. Very recently, an orally deliverable small molecule, risdiplam (Evrysdi™), became the third approved therapy for SMA. Here we discuss how these therapies are positioned to meet the needs of the broad phenotypic spectrum of SMA patients.

scholarly journals Genomic Variability in the Survival Motor Neuron Genes (SMN1 and SMN2): Implications for Spinal Muscular Atrophy Phenotype and Therapeutics Development

2021 ◽  
Vol 22 (15) ◽  
pp. 7896
Author(s):  
Matthew E. R. Butchbach
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Muscular Atrophy ◽  
Survival Motor Neuron ◽  
Smn1 Gene ◽  
Spinal Motor Neurons ◽  
Copy Numbers ◽  
Smn Protein ◽  
High Degree

Spinal muscular atrophy (SMA) is a leading genetic cause of infant death worldwide that is characterized by loss of spinal motor neurons leading to muscle weakness and atrophy. SMA results from the loss of survival motor neuron 1 (SMN1) gene but retention of its paralog SMN2. The copy numbers of SMN1 and SMN2 are variable within the human population with SMN2 copy number inversely correlating with SMA severity. Current therapeutic options for SMA focus on increasing SMN2 expression and alternative splicing so as to increase the amount of SMN protein. Recent work has demonstrated that not all SMN2, or SMN1, genes are equivalent and there is a high degree of genomic heterogeneity with respect to the SMN genes. Because SMA is now an actionable disease with SMN2 being the primary target, it is imperative to have a comprehensive understanding of this genomic heterogeneity with respect to hybrid SMN1–SMN2 genes generated by gene conversion events as well as partial deletions of the SMN genes. This review will describe this genetic heterogeneity in SMA and its impact on disease phenotype as well as therapeutic efficacy.

scholarly journals Molecular Mechanisms of Neurodegeneration in Spinal Muscular Atrophy

2016 ◽  
Vol 10 ◽  
pp. JEN.S33122 ◽  
Author(s):  
Saif Ahmad ◽  
Kanchan Bhatia ◽  
Annapoorna Kannan ◽  
Laxman Gangwani
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Motor Neurons ◽  
Molecular Mechanisms ◽  
Muscular Atrophy ◽  
Survival Motor Neuron ◽  
Skeletal Muscle Atrophy ◽  
Spinal Motor Neurons ◽  
Low Levels ◽  
Smn Protein

Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease with a high incidence and is the most common genetic cause of infant mortality. SMA is primarily characterized by degeneration of the spinal motor neurons that leads to skeletal muscle atrophy followed by symmetric limb paralysis, respiratory failure, and death. In humans, mutation of the Survival Motor Neuron 1 (SMN1) gene shifts the load of expression of SMN protein to the SMN2 gene that produces low levels of full-length SMN protein because of alternative splicing, which are sufficient for embryonic development and survival but result in SMA. The molecular mechanisms of the (a) regulation of SMN gene expression and (b) degeneration of motor neurons caused by low levels of SMN are unclear. However, some progress has been made in recent years that have provided new insights into understanding of the cellular and molecular basis of SMA pathogenesis. In this review, we have briefly summarized recent advances toward understanding of the molecular mechanisms of regulation of SMN levels and signaling mechanisms that mediate neurodegeneration in SMA.

scholarly journals Self-oligomerization regulates stability of survival motor neuron protein isoforms by sequestering an SCFSlmb degron

2018 ◽  
Vol 29 (2) ◽  
pp. 96-110 ◽  
Author(s):  
Kelsey M. Gray ◽  
Kevin A. Kaifer ◽  
David Baillat ◽  
Ying Wen ◽  
Thomas R. Bonacci ◽  
...  
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Muscular Atrophy ◽  
Survival Motor Neuron ◽  
Protein Isoforms ◽  
Survival Motor Neuron Protein ◽  
Protein Levels ◽  
Motor Neuron Protein ◽  
Smn Protein ◽  
Oligomerization Domain

SMN protein levels inversely correlate with the severity of spinal muscular atrophy. The SCFSlmbE3 ligase complex interacts with a degron embedded within the C-terminal self-oligomerization domain of SMN. The findings elucidate a model whereby accessibility of the SMN degron is regulated by self-multimerization.

scholarly journals Spinal Muscular Atrophy Type B Awareness and Symptoms Prediction Using 3D Segmentation Process in MRI Images

2019 ◽  
pp. 312-318
Author(s):  
V. Manochithra ◽  
G. Sumithra
Keyword(s):  
Spinal Muscular Atrophy ◽  
Motor Neuron ◽  
Muscular Atrophy ◽  
Homozygous Deletion ◽  
Survival Motor Neuron ◽  
Molecular Testing ◽  
Prevention Measures ◽  
Neuron Loss ◽  
Motor Neuron Loss ◽  
Smn Protein

Spinal muscular atrophy (SMA) describes a group of disorders associated with spinal motor neuron loss. In this review we provide an update regarding the most common form of SMA, proximal or 5q SMA, and discuss the contemporary approach to diagnosis and treatment. Electromyography and muscle biopsy features of denervation were once the basis for diagnosis, but molecular testing for homozygous deletion or mutation of the SMN1 gene allows efficient and specific diagnosis. In combination with loss of SMN1, patients retain variable numbers of copies of a second similar gene, SMN2, which produce reduced levels of the survival motor neuron (SMN) protein that are insufficient for normal motor neuron function. Despite the fact that the understanding of how ubiquitous reduction of SMN protein leads to motor neuron loss remains incomplete, several promising therapeutics are now being tested in early phase clinical trials. This proposed model investigates the symptoms and scans readings from the initial MRI scan images of babies with mutation progress and SMN proteins formation benchmark values for this particular disorder SMA and further this segmented parameters are acquitted into the K-means clustering technique that predict the report with the disorder symptoms with MSE (mean square error) values that helps the babies in future to take prevention measures to overcome this problem.

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