Spinal Muscular Atrophy Therapy Research Articles

SMN depletion impairs skeletal muscle formation and maturation in a mouse model of SMA.

Spinal muscular atrophy (SMA) is characterized by low levels of the ubiquitously expressed Survival Motor Neuron (SMN) protein, leading to progressive muscle weakness and atrophy. Skeletal muscle satellite cells play a crucial role in muscle fiber maintenance, repair, and remodelling. While the effects of SMN depletion in muscle are well documented, its precise role in satellite cell function remains largely unclear. Using the Smn2B/- mouse model, we investigated SMN-depleted satellite cell biology through single fiber culture studies. Myofibers from Smn2B/- mice were smaller in size, shorter in length, had reduced myonuclear domain size, and reduced sub-synaptic myonuclear clusters-all suggesting impaired muscle function and integrity. These changes were accompanied by a reduction in the number of myonuclei in myofibers from Smn2B/- mice across all disease stages examined. Although the number of satellite cells in myofibers was significantly reduced, those remaining retained their capacity for myogenic activation and proliferation. These findings support the idea that a dysregulated myogenic process could be occurring as early in muscle stem cells during muscle formation and maturation in SMA. Targeting those pathways could offer additional options for combinatorial therapies for SMA.

Potential biomarkers of the effectiveness of pathogenetic therapy of spinal muscular atrophy in adults

The review summarizes and systematizes data on the prognostic significance of various biomarkers in determining the effectiveness of pathogenetic therapy for spinal muscular atrophy. The review includes a clinical case of a patient with type 3 spinal muscular atrophy. The case illustrates that a decrease in the level of heavy chains of neurofilaments in the cerebrospinal fluid of the patient during the use of pathogenetic therapy with nusinersen positively correlated with an improvement in motor function, assessed by standard functional scales.

Efficacy of Nusinersen Treatment in Type 1, 2, and 3 Spinal Muscular Atrophy: Real-World Data from a Single-Center Study

Background: Spinal muscular atrophy (SMA) is an inherited neuromuscular disease characterized by progressive muscle weakness and atrophy due to the absence of the survival motor neuron 1 (SMN1) gene. SMA is classified into types 0 through 4 based on the age of symptom onset and the severity of motor function decline. Recent advances in SMA treatment, including nusinersen, onasemnogene abeparvovec, and risdiplam, have significantly improved the prognosis of SMA patients. This study evaluated the safety and efficacy of nusinersen in pediatric patients with SMA types 1, 2, and 3 in a real-world clinical setting. Methods: This prospective observational single-center study assessed the treatment effects of nusinersen in 23 pediatric patients with genetically confirmed SMA over a 22-month observation period. All the participants received intrathecal loading doses of 12 mg of nusinersen on days 1, 14, 28, and 63, followed by maintenance doses every four months. Functional assessments were conducted using the CHOP-INTEND scale. Data were collected during routine patient visits, including clinical laboratory tests and vital sign parameters, and adverse events were recorded. The inclusion criteria were defined by the national reimbursement program for nusinersen treatment in Poland. Results: Initially, 37 patients ranging from 1 month old to 18 years old were included, but 23 were ultimately observed due to changes in treatment regimens or assessment scales. The patients showed significantly improved CHOP-INTEND scores over the 22-month period. At 6 months, the average increase was 4.2 points, continuing to 17.8 points at 22 months. By the end of the study, 100% of patients showed either stabilization or improvement, with significant clinical improvements observed in several patients. Nusinersen was generally well-tolerated, with post-lumbar puncture headache and lower back pain being the most common adverse events. Conclusions: Nusinersen treatment significantly enhances motor function in pediatric patients with SMA types 1, 2, and 3. This study demonstrates the importance of early and sustained treatment, with most patients showing the continuous improvement or stabilization of motor function. These findings support the use of nusinersen as an effective therapy for SMA; however, further research is needed to understand the long-term outcomes and optimize treatment strategies.

Oral functions in adult persons with spinal muscular atrophy compared to a healthy control group: a prospective cross-sectional study with a multimodal approach

BackgroundOral function tests have been shown to reliably detect impaired bulbar function in adults with spinal muscular atrophy (SMA). Although not routinely recorded, it is known that persons with SMA are affected to varying degrees. Detecting differences in bite and tongue force, endurance, and maximum mouth opening has become particularly promising since the introduction of causal therapy for SMA. This study aimed to compare oral function among adult persons with SMA with different SMA types, walking abilities, and treatment status to a healthy control group.MethodsData from oral function tests conducted on 58 persons with SMA and 45 healthy individuals were analyzed. Differences in oral function between SMA subgroups were pairwise tested and compared to the healthy control group using Wilcoxon rank sum tests.ResultsIn an overall comparison, three out of five oral function tests revealed lower values for the SMA group compared to the control group. Subgroup analyses indicated lower scores for most oral function tests in non-ambulatory, untreated patients with SMA type 2 compared to controls. Ambulatory, treated patients with SMA type 3 achieved strength and endurance values comparable to those of healthy individuals.ConclusionsThe impairment of oral function varies across persons with SMA. Routine measurement of oral function is warranted to determine individual bulbar involvement stages. Further evaluation should be scheduled if indicators such as restricted maximum mouth opening arise.Trial registration DRKS, DRKS00015842. Registered 30 July 2019, https://drks.de/register/de/trial/DRKS00015842/preview.

138P Long-term motor responses to disease-modifying therapies in spinal muscular atrophy (SMA) adults: a prospective study

138P Long-term motor responses to disease-modifying therapies in spinal muscular atrophy (SMA) adults: a prospective study

130P Real-life outcome data on Risdiplam therapy for spinal muscular atrophy

130P Real-life outcome data on Risdiplam therapy for spinal muscular atrophy

154VP Usage of disease modifying therapies in spinal muscular atrophy and existing disparities: a population-based study from the MDA MOVR database

154VP Usage of disease modifying therapies in spinal muscular atrophy and existing disparities: a population-based study from the MDA MOVR database

Onasemnogene abeparvovec gene therapy for spinal muscular atrophy: A cohort study from the United Arab Emirates.

Spinal muscular atrophy (SMA) manifests with progressive motor neuron degeneration, leading to muscle weakness. Onasemnogene abeparvovec is a US Food and Drug Administration-approved gene replacement therapy for SMA. This study aimed to present short-term data of children in the United Arab Emirates (UAE) treated with onasemnogene abeparvovec, particularly in the context of children requiring invasive ventilatory support via tracheostomy. A retrospective analysis was performed on 60 children who received onasemnogene abeparvovec. All these children received corticosteroids. They were followed up for up to 3 months. Motor function assessments were performed before and after the gene therapy. Comprehensive clinical evaluations, including pulmonary functions, were performed at baseline and the 3-month mark. Forty-three percent were male, and the mean age at the time of infusion was 29.6 months (SD ± 17.2). The mean weight was 10.1 kg (SD 2.6). All children demonstrated marked improvements in motor function within 3 months of gene therapy administration. No adverse effects attributable to corticosteroid therapy were observed. Positive clinical outcomes, including increased ventilator-free intervals, reduced antibiotic dependency, and fewer hospital admissions, were reported among children with invasive ventilation via tracheostomy. This study demonstrates the favorable tolerability and promising responses to onasemnogene abeparvovec in invasively ventilated pediatric patients. Early improvements in motor function, as observed within 3 months post-treatment, suggest its potential as a viable therapeutic option for this vulnerable patient population.

159P Acute liver failure failure post gene therapy in spinal muscular atrophy

159P Acute liver failure failure post gene therapy in spinal muscular atrophy

144P Gene therapy for Spinal Muscular Atrophy amid the dengue outbreak in Brazil: a case report

144P Gene therapy for Spinal Muscular Atrophy amid the dengue outbreak in Brazil: a case report

Clinicogenetic characterization and response to disease-modifying therapies in spinal muscular atrophy: real-world experience from a reference center in Southern Brazil

ObjectiveSpinal Muscular Atrophy linked to chromosome 5q (SMA) is an autosomal recessive neurodegenerative disease characterized by progressive proximal muscle atrophy and weakness. This study addresses the scarcity of research on novel disease-modifying therapies for SMA in Latin America by reporting a real-world experience in Southern Brazil. MethodologyThis is a single-center historical cohort that included all patients diagnosed with spinal muscular atrophy at a Regional Reference Service for rare diseases. ResultsEighty-one patients were included, of whom 7 died during follow-up. Of the remaining 74 patients, 5.4 % were classified as pre-symptomatic, 24.3 % with SMA type 1, 28.4 % with type 2, 36.5 % with type 3, and 5.4 % with type 4. The mean follow-up time ranged from 1.8 years for pre-symptomatic cases to 8.7 years for SMA types 2 and 3. Approximately 42 % of these patients received specific disease-modifying therapy, of these, 96.8 % received Nusinersen, with 19.4 % transitioning to gene therapy using Onasemnogene Abeparvovec, and 6.4 % starting Risdiplam. Most patients with SMA type 1 were on disease-modifying treatment, whereas only slightly over a third of patients with type 2 and about 10 % of type 3 were receiving such treatments. Among treated patients, 80 % demonstrated improvement in motor performance during the follow-up, with a lesser therapeutic response being associated with late initiation of treatment and low motor function scores at baseline. ConclusionThis real-world study reinforces the effectiveness of disease-modifying therapies for SMA in Brazil within the context of low- and middle-income countries, which is greater the earlier and the better the patient's functional status.

Current Treatment Process and Challenges for Spinal Muscular Atrophy (SMA)

Spinal muscular atrophy (SMA) presents as a pediatric neuromuscular disorder resulting from mutations in the survival motor neuron 1(SMN1) gene, with an incidence of approximately 10-13 per 100,000 live births. This condition manifests primarily through muscle weakness and atrophy, particularly affecting the proximal limb muscles. A homozygous deletion of exon 7 in the SMN1 gene is the most common genetic mutation in SMA and serves as a sensitive diagnostic marker. This article comprehensively explores various aspects of SMA, including its types, diagnostic methods, and management strategies. Pulmonary care, gastrointestinal (GI) management, nutritional supplementation, orthopedic spinal care, and physiotherapy play crucial roles in delaying disease progression. Current pharmacological treatments for SMA are diverse and evolving. Notable among them is Zolgensma (formerly AVXS-101 or Onasemnogene abeparvovec), a gene replacement therapy utilizing an adeno-associated virus vector to boost functional SMN protein levels. Sodium vanadate, a phosphatase inhibitor, and risdiplam (RO703406) are agents that modulate SMN2 splicing to augment the production of functional SMN protein. Riluzole acts as a neuroprotective agent by preventing SMN deficiency, while reldesemtive (CK-2127107) is under development as a muscle-enhancing therapy to ameliorate skeletal muscle function during fatigue. While pharmacological therapies for SMA are advancing, a holistic approach involving comprehensive multidisciplinary care, encompassing pulmonary support, proper nutritional supplementation, and adept orthopedic management, significantly contributes to the effective management of SMA.

Recent Progress in Gene-Targeting Therapies for Spinal Muscular Atrophy: Promises and Challenges.

Spinal muscular atrophy (SMA) is a severe genetic disorder characterized by the loss of motor neurons, leading to progressive muscle weakness, loss of mobility, and respiratory complications. In its most severe forms, SMA can result in death within the first two years of life if untreated. The condition arises from mutations in the SMN1 (survival of motor neuron 1) gene, causing a deficiency in the survival motor neuron (SMN) protein. Humans possess a near-identical gene, SMN2, which modifies disease severity and is a primary target for therapies. Recent therapeutic advancements include antisense oligonucleotides (ASOs), small molecules targeting SMN2, and virus-mediated gene replacement therapy delivering a functional copy of SMN1. Additionally, recognizing SMA's broader phenotype involving multiple organs has led to the development of SMN-independent therapies. Evidence now indicates that SMA affects multiple organ systems, suggesting the need for SMN-independent treatments along with SMN-targeting therapies. No single therapy can cure SMA; thus, combination therapies may be essential for comprehensive treatment. This review addresses the SMA etiology, the role of SMN, and provides an overview of the rapidly evolving therapeutic landscape, highlighting current achievements and future directions.

Gene therapy for spinal muscular atrophy: perspectives on the possibility of optimizing SMN1 delivery to correct all neurological and systemic perturbations.

Gene therapy for spinal muscular atrophy: perspectives on the possibility of optimizing SMN1 delivery to correct all neurological and systemic perturbations.

U1 snRNA interactions with deep intronic sequences regulate splicing of multiple exons of spinal muscular atrophy genes.

The U1 small nuclear RNA (snRNA) forms ribonucleoprotein particles (RNPs) such as U1 snRNP and U1-TAF15 snRNP. U1 snRNP is one of the most studied RNPs due to its critical role in pre-mRNA splicing in defining the 5' splice site (5'ss) of every exon through direct interactions with sequences at exon/intron junctions. Recent reports support the role of U1 snRNP in all steps of transcription, namely initiation, elongation, and termination. Functions of U1-TAF15 snRNP are less understood, though it associates with the transcription machinery and may modulate pre-mRNA splicing by interacting with the 5'ss and/or 5'ss-like sequences within the pre-mRNA. An anti-U1 antisense oligonucleotide (ASO) that sequesters the 5' end of U1 snRNA inhibits the functions of U1 snRNP, including transcription and splicing. However, it is not known if the inhibition of U1 snRNP influences post-transcriptional regulation of pre-mRNA splicing through deep intronic sequences. We examined the effect of an anti-U1 ASO that sequesters the 5' end of U1 snRNA on transcription and splicing of all internal exons of the spinal muscular atrophy (SMA) genes, SMN1 and SMN2. Our study was enabled by the employment of a multi-exon-skipping detection assay (MESDA) that discriminates against prematurely terminated transcripts. We employed an SMN2 super minigene to determine if anti-U1 ASO differently affects splicing in the context of truncated introns. We observed substantial skipping of multiple internal exons of SMN1 and SMN2 triggered by anti-U1 treatment. Suggesting a role for U1 snRNP in interacting with deep intronic sequences, early exons of the SMN2 super minigene with truncated introns were resistant to anti-U1 induced skipping. Consistently, overexpression of engineered U1 snRNAs targeting the 5'ss of early SMN1 and SMN2 exons did not prevent exon skipping caused by anti-U1 treatment. Our results uncover a unique role of the U1 snRNA-associated RNPs in splicing regulation executed through deep intronic sequences. Findings are significant for developing novel therapies for SMA based on deep intronic targets.

Recent Advance in Disease Modifying Therapies for Spinal Muscular Atrophy

Abstract Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease characterized by progressive weakness and atrophy of skeletal muscles. With homozygous survival motor neuron 1 (SMN1) gene mutation, all SMA patients have at least one copy of the SMN2 gene, which provides an opportunity for drug targeting to enhance SMN expression. Current three disease modifying drugs, including nusinersen, onasemnogene abeparvovec, and risdiplam, have demonstrated impressive effectiveness in SMA treatment. Nusinersen is an antisense oligonucleotide targeting SMN2 pre-messenger RNA (mRNA) to modify alternative splicing and is effective in SMA children and adults, administrating via intermittent intrathecal injection. Onasemnogene abeparvovec is an adeno-associated viral vector carrying human SMN1 gene, featuring intravenous injection once in a lifetime for SMA patients less than 2 years of the age. Risdiplam is a small molecule also targeting SMN2 pre-mRNA and is effective in SMA children and adults with administration via oral intake once per day. Patients with SMA should receive these disease modifying therapies as soon as possible to not only stabilize disease progression, but potentially obtain neurological improvement. The development in these therapies has benefited patients with SMA and will potentially provide insight in future drug discovery for other neurodegenerative diseases.

Disproportionality Analysis of Nusinersen in the Food and Drug Administration Adverse Event Reporting System: A Real-World Postmarketing Pharmacovigilance Assessment

BackgroundNusinersen is the first drug for precise targeted therapy of spinal muscular atrophy, a rare disease that occurs in one of 10,000 to 20,000 live births. Therefore, thorough and comprehensive reports on the safety of nusinersen in large, real-world populations are necessary. This study aimed to mine the adverse event (AE) signals related to nusinersen through the Food and Drug Administration Adverse Event Reporting System (FAERS) database. MethodsWe extracted reports of AEs with nusinersen as the primary suspect from FAERS between December 2016 and March 2023. Reporting odds ratio (ROR) and Bayesian confidence propagation neural network (BCPNN) were used for AE signal detection. ResultsWe extracted a total of 4807 suspected AE cases with nusinersen as the primary suspect from the FAERS database. Among them, 106 positive signals were obtained using the ROR and BCPNN. The highest frequency reported systemic organ class was general disorders and administration site conditions. Common clinical AEs of nusinersen were detected in the FAERS database, such as pneumonia, vomiting, back pain, headache, pyrexia, and post–lumbar puncture syndrome. In addition, we identified potential unexpected serious AEs through disproportionality analysis, including sepsis, seizure, epilepsy, brain injury, cardiorespiratory arrest, and cardiac arrest. ConclusionsAnalyzing large amounts of real-world data from the FAERS database, we identified potential new AEs of nusinersen by disproportionate analysis. It is advantageous for health care professionals and pharmacists to concentrate on effectively managing high-risk AEs of nusinersen, improve medication levels in clinical settings, and uphold patient medication safety.

2024 update: European consensus statement on gene therapy for spinal muscular atrophy

Spinal muscular atrophy (SMA) is one of the most common genetic diseases and was, until recently, a leading genetic cause of infant mortality. Three disease-modifying treatments have dramatically changed the disease trajectories and outcome for severely affected infants (SMA type 1), especially when initiated in the presymptomatic phase. One of these treatments is the adeno-associated viral vector 9 (AAV9) based gene therapy onasemnogene abeparvovec (Zolgensma®), which is delivered systemically and has been approved by the European Medicine Agency for SMA patients with up to three copies of the SMN2 gene or with the clinical presentation of SMA type 1. While this broad indication provides flexibility in patient selection, it also raises concerns about the risk-benefit ratio for patients with limited or no evidence supporting treatment.In 2020, we convened a European neuromuscular expert working group to support the rational use of onasemnogene abeparvovec, employing a modified Delphi methodology. After three years, we have assembled a similar yet larger group of European experts who assessed the emerging evidence of onasemnogene abeparvovec's role in treating older and heavier SMA patients, integrating insights from recent clinical trials and real-world evidence. This effort resulted in 12 consensus statements, with strong consensus achieved on 9 and consensus on the remaining 3, reflecting the evolving role of onasemnogene abeparvovec in treating SMA.

Gene replacement therapy for spinal muscular atrophy: safety and preliminary efficacy in a Brazilian cohort.

Spinal muscular atrophy (SMA) is a motor neuron disease associated with progressive muscle weakness, ventilatory failure, and reduced survival. Onasemnogene abeparvovec is the first gene replacement therapy (GT) approved to treat this condition. An observational retrospective study was conducted to assess adverse events and efficacy of GT in SMA patients. Forty-one patients with SMA (58.5% females and 80.1% SMA type 1) were included. The mean age at GT dosing was 18 (±6.4) months. Thirty-six patients (87.8%) were under previous treatment with nusinersen, and 10 (24.4%) continued nusinersen after GT. Mean CHOP-INTEND increased 13 points after 6 months and this finding did not differ between groups according to nusinersen maintenance after GT (p = 0.949). Among SMA type 1 patients, 14 (46.6%) reached the ability to sit alone. Liver transaminases elevation at least two times higher than the upper limit of normal value occurred in 29 (70.7%) patients. Thrombocytopenia occurred in 13 (31.7%) patients, and one presented thrombotic microangiopathy. Older age (>2 years) was associated with more prolonged use of corticosteroids (p = 0.021). GT is effective in SMA patients, combined nusinersen after GT did not appear to add gain in motor function and older age is associated with prolonged corticosteroid use.

Sleep and sleep-related breathing disorders in patients with spinal muscular atrophy: a changing perspective from novel treatments?

Spinal Muscular Atrophy (SMA) is an inherited neuromuscular disorder characterized by progressive muscle weakness and atrophy, resulting from the degeneration of motor neurons in the spinal cord. A critical aspect of SMA is its impact on respiratory function. As the disease progresses, respiratory muscles, in particular intercostal muscles, become increasingly affected, leading to breathing difficulties and respiratory failure. Without intervention, many children with SMA type 1 die from respiratory failure before their second year of life. While assisted ventilation has improved survival, it often results in ventilator dependence. The development of new SMN-augmenting therapies has renewed optimism, but their long-term impact on respiratory function is uncertain, and non-invasive respiratory support remains an important part of SMA management. Despite the importance of respiratory support in SMA, knowledge regarding sleep disorders in this population is limited. This review aims to synthesize existing literature on sleep and sleep-related breathing disorders in patients with SMA, with a focus on SMA type 1. We summarize evidence of sleep-disordered breathing and respiratory failure in SMA, as well as outcomes and survival benefits associated with non-invasive or invasive ventilation with or without pharmacological therapies. We also discuss current knowledge regarding the effects of novel disease-modifying therapies for SMA on respiratory function and sleep. In conclusion, optimal care for children with SMA requires a multidisciplinary approach that includes neurology and respiratory specialists. This review highlights the importance of monitoring sleep and respiratory function in SMA, as well as the potential benefits and challenges associated with assisted ventilation combined with new therapies.