Mid- and long-term (at least 12 months) follow-up of patients with spinal muscular atrophy (SMA) treated with nusinersen, onasemnogene abeparvovec, risdiplam or combination therapies: A systematic review of real-world study data

Effect of Nusinersen on Respiratory and Bulbar Function in Children with Spinal Muscular Atrophy: Real-World Experience from a Single Center

BACKGROUND

Due to the limited data from clinical trials and real-world settings in the realm of nusinersen, there is a need for further evidence. This study seeks to assess the impact of nusinersen, when combined with standard care, on bulbar function, respiratory function, and the necessity for respiratory support among pediatric patients with spinal muscular atrophy (SMA).

METHODS

Prospective observational study, involving pediatric SMA patients (Types 1-3) undergoing nusinersen treatment at the Hospital Universitario Virgen del Rocío in Spain over at least 24 months. The cohort included 11 SMA type 1 patients, comprising 6 type 1b and 5 type 1c, 12 SMA type 2 patients, and 5 SMA type 3 patients.

RESULTS

Twenty-eight pediatric patients were enrolled with the majority being male (n = 20). Patients with type 1 were diagnosed and received treatment significantly earlier than those with types 2 and 3 (p < 0.001). Additionally, there was a longer period between diagnosis and the start of treatment in types 2 and 3 (p = 0.002). Follow-up revealed statistically improved functional and respiratory outcomes associated with earlier initiation of nusinersen treatment at 6, 12, and 24 months in all phenotypes. The ability to swallow and feed correctly remained unchanged throughout the study, with SMA type 1c patients maintaining oral feeding in contrast to patients with SMA type 1b. Notably, no deaths were recorded.

CONCLUSIONS

This study provides important insights into the real-world clinical progress of pediatric SMA patients and their response to nusinersen treatment, highlighting the significance of early intervention for better functional and respiratory outcomes.

Spinal muscular atrophy type 1 in the Caribbean: the first case report from the Dominican Republic

Spinal muscular atrophy (SMA) is a progressive genetic neuromuscular condition affecting spinal motor neurons. The underlying cause of SMA is deletions or mutations in the SMN gene. It is classified into five variants based on age and clinical manifestations of the patient. In this report, we present the case discovery of a four-month-old male patient with SMA type 1, presenting with generalized hypotonia and regression of acquired neurodevelopmental milestones. Our study aims to illustrate, through a case report, the clinical analysis, therapeutic interventions, and progression until the patient's demise. This aims to share the challenges in managing such patients and the strategies employed in their care plan. By documenting this case, our goal is to contribute to the understanding of SMA type 1 and emphasize the ongoing need for learning effective care strategies.

Comprehensive analysis of adverse events associated with onasemnogene abeparvovec (Zolgensma) in spinal muscular atrophy patients: insights from FAERS database

Onasemnogene Abeparvovec (Zolgensma) is a gene therapy for the treatment of Spinal Muscular Atrophy (SMA) with improved motor neuron function and the potential for a singular treatment. Information on its adverse drug reactions is mainly from clinical trials and real-world studies with extensive sample sizes are lacking. In this study, we analyzed the U.S. Food and Drug Administration's Adverse Event Reporting System (FAERS) database to assess the drug safety profile of Zolgensma. A total of 1951 adverse event reports associated with onasemnogene abeparvovec (Zolgensma), containing 778 import important medical event (IME) signals, were identified from the FAERS database, and multiple disproportionate analysis algorithms were used to determine the significance of these adverse events. This study identified 281 onasemnogene abeparvovec-related adverse events (AEs), including some significant adverse events not mentioned in the product labelling. Elevated liver enzymes, fever, vomiting, and thrombocytopenia were the most common adverse reactions. Most adverse events manifested within the initial month of onasemnogene abeparvovec use, especially the first 8 days, but some may still occur after 1 year of treatment. Sex-specific scrutiny revealed differing risk levels for adverse events among women and men. Thrombocytopenia and thrombotic microangiopathy are more common in patients weighing ≥8.5 kg, and changes in renal function need to be closely monitored if thrombotic microangiopathy occurs. The above findings provide valuable insights into optimizing the utilization of onasemnogene abeparvovec, improving its effectiveness, and minimizing potential side effects, thereby greatly facilitating its practical application in clinical settings.

Efficacy and safety of Nusinersen among children with spinal muscular atrophy from North India: A prospective cohort study (NICE-SMA study)

BACKGROUND

Intra-thecal Nusinersen has been approved for the treatment of Spinal muscular atrophy (SMA). Limited data is available regarding the efficacy and safety of Nusinersen in children with SMA type 2 and 3 from North India.

OBJECTIVE

To study the efficacy and safety of Nusinersen among children with SMA type 2 and 3 from North India compared to standard of care (SOC) over 12 months.

METHODS

Children with a genetically confirmed diagnosis of SMA and ≥2 copies of the SMN2 gene were screened for enrolment in prospective study design. Revised Hammersmith score (RHS) and revised upper limb module (RULM) were assessed every three months. Compound muscle action potentials (CMAPs) at median and ulnar nerves and quality of life (QOL) were performed at baseline and 12 months. Intra-thecal procedure-related and treatment-emergent side effects in children receiving Nusinersen therapy were recorded. Outcome measures at 6 and 12 months were compared between the Nusinersen and SOC groups.

RESULTS

Forty-two children with SMA, mean age of 85 ± 6 months, including 16 in the Nusinersen group and 26 in the SOC group, were enrolled. The mean RHS score in the Nusinersen group increased from the baseline of 35 ± 18 to 38.9 ± 19, and 39.9 ± 17 at 6 and 12 months (p value-0.001), in the SOC group increased from the baseline of 28.8 ± 15, to 29.6 ± 16, and 29.9 ± 17 at 6 and 12 months respectively (p value-0.35). The mean gain in the RHS score over 12 months in the Nusinersen group was significantly higher compared to the SOC group (p-value 0.02). RULM showed significant gain in the Nusinersen group compared to the SOC group over 12 months (p value 0.03). The median and ulnar nerve CMAPs, and QOL were similar in both the groups. A total of 119 intrathecal injections of Nusinersen were given. Most adverse events were mild and related to the intra-thecal procedure.

CONCLUSION

Intra-thecal Nusinersen therapy among children with late-onset SMA from North India over 12-month duration was associated with improvement in motor abilities as measured by RHS compared to SOC. Intra-thecal Nusinersen was safe and tolerated well.

Type I spinal muscular atrophy and disease modifying treatments: a nationwide study in children born since 2016

Background

The advent of disease-modifying treatments (DMT) has changed natural history in 5q Spinal muscular atrophy (SMA). The aim of this study was to report survival and functional aspects in all the Italian type I children born since 2016.

Methods

The study included all symptomatic children with type I SMA born since January 1st, 2016, when DMTs became available in Italy. All the Italian SMA referral centers provided data on survival and motor, respiratory, and nutritional status. To compare survival rate pre and post DMTs approval, we also included similar data from SMA I patients born between January 1st, 2010, and December 31st, 2015. A two-proportion z-test was conducted to compare the two cohorts. The significance level was set at p < .05.

Findings

241 infants (98%) had type I SMA. Mean follow-up was 3.48 years (SD 2.33). Among type I patients, 42/241 did not survive (25 untreated), while 199 were alive at last follow-up (all treated; mean treatment age 0.6 years), with 25 needing >16 h/day ventilation or tracheostomy with continuous invasive ventilation. 130 of the 199 survivors (65%) achieved independent sitting, and 175 (87.9%) did not require tube feeding.

Interpretation

Our study provides a picture of the 'new natural history' of type I SMA, confirming the impact of the new therapies on the progression of type I with longer survival r and has better motor, respiratory and nutritional.

Funding

This research was partially funded by grants from the Italian Ministry of Health.

Outcomes of early-treated infants with spinal muscular atrophy: A multicenter, retrospective cohort study

INTRODUCTION/AIMS

While prompt identification and treatment of infants with spinal muscular atrophy (SMA) can ameliorate outcomes, variability persists. This study assessed management and outcomes of early-treated infants with SMA.

METHODS

We analyzed retrospective data at 12 centers on infants with SMA treated at age ≤6 weeks from August 2018 to December 2023.

RESULTS

Sixty-six patients, 35 with two SMN2 copies and 31 with ≥3 SMN2 copies, were included. Twenty-five (38%, 22 with two SMN2 copies), had SMA findings before initial treatment which was onasemnogene abeparvovec in 47 (71%) and nusinersen in 19 (29%). Thirty-two received sequential or combination treatments, including 16 adding nusinersen or risdiplam due to SMA findings following onasemnogene abeparvovec. All sat independently. Compared to children with ≥3 SMN2 copies, those with two SMN2 copies were less likely to walk (23/34 [68%] vs. 31/31 [100%], p < .001) and less likely to walk on time (9/34 [26%] vs. 29/31 [94%], p < .001); one non-ambulatory child was <18 months old and was excluded from this analysis. No patients required permanent ventilation or exclusively enteral nutrition; six required nocturnal non-invasive ventilation and four utilized supplemental enteral nutrition, all with two SMN2 copies.

DISCUSSION

Early treatment of infants with SMA can improve outcomes as indicated by our cohort, all of whom sat independently and are without permanent ventilation. However, our study demonstrates ongoing disability in most children with two SMN2 copies despite early monotherapy and emphasizes the need for additional research, including earlier monotherapy, initial combination therapy, prenatal treatment, and non-SMN modifying treatments.

Identification of Biochemical Determinants for Diagnosis and Prediction of Severity in 5q Spinal Muscular Atrophy Using 1H-Nuclear Magnetic Resonance Metabolic Profiling in Patient-Derived Biofluids

This study explores the potential of 1H-NMR spectroscopy-based metabolic profiling in various biofluids as a diagnostic and predictive modality to assess disease severity in individuals with 5q spinal muscular atrophy. A total of 213 biosamples (urine, plasma, and CSF) from 153 treatment-naïve patients with SMA across five German centers were analyzed using 1H-NMR spectroscopy. Prediction models were developed using machine learning algorithms which enabled the patients with SMA to be grouped according to disease severity. A quantitative enrichment analysis was employed to identify metabolic pathways associated with disease progression. The results demonstrate high sensitivity (84-91%) and specificity (91-94%) in distinguishing treatment-naïve patients with SMA from controls across all biofluids. The urinary and plasma profiles differentiated between early-onset (type I) and later-onset (type II/III) SMA with over 80% accuracy. Key metabolic differences involved alterations in energy and amino acid metabolism. This study suggests that 1H-NMR spectroscopy based metabolic profiling may be a promising, non-invasive tool to identify patients with SMA and for severity stratification, potentially complementing current diagnostic and prognostic strategies in SMA management.

Nutrition outcomes of disease modifying therapies in spinal muscular atrophy: A systematic review

The nutritional implications of spinal muscular atrophy (SMA) are profound. Disease modifying therapies (DMT) have improved clinical outcomes. This review describes the impact of DMT on nutrition outcomes. A systematic search strategy was applied across seven databases until May 2023. Eligible studies measured nutrition outcomes in individuals with SMA on DMT (nusinersen, risdiplam or onasemnogene abeparvovec [OA]) compared to untreated comparators. Nutrition outcomes included anthropometry, feeding route, swallowing dysfunction, dietary intake, dietetic intervention, nutritional biochemistry, metabolism, gastrointestinal issues and energy expenditure. Articles retrieved were screened in duplicate, data were extracted and appraised systematically. Sixty three articles from 54 studies were included; 41% (n = 22) investigated nusinersen in pediatric participants with SMA type 1. Anthropometry (n = 18), feeding route (n = 39), and swallowing dysfunction (n = 18) were the most commonly reported outcomes. In combined pediatric and adult cohorts, BMI z-score remained stable post nusinersen therapy. The proportion of children with SMA requiring enteral nutrition was stable post nusinersen therapy. Ability to thrive at age 1.5 years was higher in children treated in early infancy with OA compared to historical controls. Significant heterogeneity existed across study population characteristics and outcome measures. Nusinersen may prevent deterioration in some nutrition outcomes; and OA in early infancy may be associated with improved nutrition outcomes. Timing of DMT initiation is an important consideration for future nutrition research. Studies investigating nutrition as a primary outcome of DMT, using consistent outcome measures are required for nutritional management strategies for this cohort to be appropriately tailored.

Type-1 spinal muscular atrophy cohort before and after disease-modifying therapies

BACKGROUND

 Spinal muscular atrophy (SMA-5q) is a neurodegenerative disease characterized by progressive muscle atrophy, hypotonia, and weakness, with SMA 1 presenting symptoms within the first 6 months of life. Disease-modifying therapies have been approved, with better outcomes with earlier treatment.

OBJECTIVE

 To describe the safety and clinical efficacy of disease-modifying therapies based on SMN1 and SMN2 gene strategies concerning motor, respiratory, and bulbar function. Patients with SMA 1 were divided into 2 groups: those exclusively on nusinersen (group 1) and those transitioning to onasemnogene abeparvovec (OA) (group 2).

METHODS

 Over 18 months, patients were assessed using the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) scale, developmental milestones, ventilation needs and duration, nutritional support needs, consistency of food, and signs of dysphagia. There were ten patients, divided between the groups; in group 1, the average age for starting nusinersen was 53.6 (12-115) months, and, in group 2, the age was 7 (1-12) months for nusinersen and 15.2 (10-19) months for OA.

RESULTS

 Our results indicate that 70% of patients reached some motor milestones, with group 1 increasing by 10.2 points on the CHOP-INTEND scale, while group 2 increased by 33 points. Additionally, 90% of the patients experienced no respiratory decline, and 30% maintained oral feeding. No serious adverse effects or deaths were recorded.

CONCLUSION

 Both groups showed improvement in motor function and stabilization of respiratory and bulbar function, with the difference between the groups possibly being related to the earlier treatment initiation. Thus, the present study provides valuable insights into the real-world safety and clinical efficacy of disease-modifying therapies for SMA 1 patients.

Gene therapy as an emerging treatment for Scn2a mutation-induced autism spectrum disorders

Autism spectrum disorder (ASD) is a complex neurological and developmental disorder that affects how a person acts, communicates, learns, and interacts with others. It affects the structure and function of the brain and nervous system. How ASD is caused remains uncertain and there is no effective treatment for this disorder. Searching for new technologies for treatment of this disorder becomes a priority. Genetic alterations have been implicated in the generation of this disorder. One of the most promising genes for potential treatment of ASD is sodium voltage-gated channel alpha subunit 2 gene (SCN2A). SCN2A, encoding the neuronal voltage-gated Na+ channel NaV1.2, is one of the most commonly affected loci linked to ASD. Here, we discuss the implications of loss of function (LOF) mutations in SCN2A and the potential efficacy of gene therapy by highlighting the usage of CRISPR restoration of various Scn2a-insufficiencies. Various therapeutics exist that can be extrapolated to address the needs of Scn2a LOF induced ASD. The current treatment that exists for ASD can be seen as outdated in comparison to the advent of new technologies that build upon CRISPR. Due to complications in treatment of ASD, genetic therapies may induce alterations such as insertion-deletion mutations, which may lead to further complications along with a negative public outlook on CRISPR technologies. Gene therapy can be applied to ASD but much work is yet to be done in order to address both biochemical and ethical considerations.

Type 1 spinal muscular atrophy treated with nusinersen in Norway, a five-year follow-up

BACKGROUND

New treatments for 5q spinal muscular atrophy (SMA) have led to changes in the disease phenotype. Questions about long-term efficacy, however, persist. We present the results from five-year follow-up of the first ten Norwegian patients with SMA type1 treated with nusinersen.

METHODS

- Ten patients referred to the expanded access program were included. Standardized assessments with Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND), the Hammersmith Infant Neurological Examination (HINE-2), compound muscle action potential (CMAP) examination and cerebrospinal fluid analysis of neurofilament light chain (cNfL) were performed.

RESULT

Age at baseline ranged from three months to 11 years and eight months. Nine patients were alive and continued to receive treatment at 62 months of follow-up. CHOP INTEND scores increased significantly up to 38 months. Any further increase from 38 to 50 months was not statistically significant, and scores remained almost unchanged from 50 to 62 months. HINE-2 scores increased but the difference from baseline never reached statistical significance. The youngest patients showed the best motor outcome. The changes in CMAP scores were not statistically significant. cNfL values were significantly reduced after 18 months compared with baseline; the largest difference occurred between baseline and 6 months. There was a significant negative correlation between log cNfL and CHOP INTEND (p = 0.042). Bulbar and respiratory function did not improve during the observation period.

CONCLUSION

Our findings support previously reported results on efficacy and safety of nusinersen. All patients have shown improvement in motor function. The need of respiratory and nutritional support did not improve.

The Impact of Nusinersen Treatment on Respiratory Function in Patients with Spinal Muscular Atrophy: A Systematic Review

Background/Objectives: This systematic review evaluated the impact of nusinersen therapy on respiratory health and function in individuals with spinal muscular atrophy (SMA) and determined whether nusinersen improves pulmonary function, focusing on differences based on patient age and the timing of treatment initiation. Methods: A systematic search of PubMed, Ovid Medline, ScienceDirect, and Web of Science databases was conducted up to January 2024 in accordance with the PRISMA guidelines. Thirteen studies were included, comprising clinical trials, observational studies, and case series that focused on respiratory outcomes in SMA patients treated with nusinersen. The data on study design, participant characteristics, nusinersen intervention, respiratory outcomes, and adverse events were extracted. The Joanna Briggs Institute Critical Appraisal Tool was used to assess study quality. A narrative synthesis was conducted to address the heterogeneity of the studies. Results: This review found a general trend of improvement in pulmonary function, specifically in forced vital capacity (FVC), although the extent and duration of improvement varied across the studies. Peak cough flow (PCF) and peak expiratory flow (PEF) showed positive trends in some studies, although the results were not consistently significant. Respiratory function improvements were frequently observed, particularly in younger patients and those treated earlier. Conclusions: Nusinersen appears to enhance respiratory function and improve motor outcomes in SMA patients, especially with early treatment. However, further research is needed to fully understand its mechanisms and long-term effects on respiratory health in SMA.

Experiences and the psychosocial situation of parental caregivers of children with spinal muscular atrophy against the background of new treatment options: a qualitative interview study

BACKGROUND

Spinal muscular atrophy is a rare neurodegenerative disorder in children which leads untreated to muscle wasting, respiratory impairments, and a shortened life expectancy. Parents as primary caregivers are often physically and psychologically burdened. In recent years, new and promising treatment options have been approved, but it remains unclear if they have an impact on the psychosocial situation of affected families.

OBJECTIVES

The aim of this study was to explore the views and experiences of parents as informal caregivers of children with SMA in the course of the disease against the background of new treatment options (Spinraza® or Zolgensma®).

METHODS

We conducted qualitative interviews with 27 parents of children with SMA treated with Spinraza® and Zolgensma® from April to September 2020. The analysis was done using thematic analysis and reported according to the COREQ criteria.

RESULTS

The data analysis resulted in three main themes: a) caregiver burden and negative consequences for families, b) resources and protective aspects, c) psychosocial care needs. The results are discussed against the background of new treatment options and previous models of supportive care needs. Parental caregivers of affected children face multiple burdens in different stages of the child's disease progression.

CONCLUSION

Although new treatment options for SMA showed observable effects for most parents, the main caregiver burden and reported symptoms were attributable to the overburdening care tasks. To unburden families, more screening for unmet needs, family-centered help services, professional caregivers, childcare, and sufficient financial support are needed.

Acceptability, validity and responsiveness of inertial measurement units for assessing motor recovery after gene therapy in infants with early onset spinal muscular atrophy: a prospective cohort study

BACKGROUND

Onasemnogene abeparvovec gene replacement therapy (GT) has changed the prognosis of patients with spinal muscular atrophy (SMA) with variable outcome regarding motor development in symptomatic patients. This pilot study evaluates acceptability, validity and clinical relevance of Inertial Measurement Units (IMU) to monitor spontaneous movement recovery in early onset SMA patients after GT.

METHODS

Clinical assessments including CHOPINTEND score (the gold standard motor score for infants with SMA) and IMU measurements were performed before (M0) and repeatedly after GT. Inertial data was recorded during a 25-min spontaneous movement task, the child lying on the back, without (10 min) and with a playset (15 min) wearing IMUs. Two commonly used parameters, norm acceleration 95th centile (||A||_95) and counts per minute (||A||_CPM) were computed for each wrist, elbow and foot sensors.

RESULTS

23 SMA-patients were included (mean age at diagnosis 8 months [min 2, max 20], 19 SMA type 1, three type 2 and one presymptomatic) and 104 IMU-measurements were performed, all well accepted by families and 84/104 with a good child participation (evaluated with Brazelton scale). ||A||_95 and ||A||_CPM showed high internal consistency (without versus with a playset) with interclass correlation coefficient for the wrist sensors of 0.88 and 0.85 respectively and for the foot sensors of 0.93 and 0.91 respectively. ||A||_95 and ||A||_CPM were strongly correlated with CHOPINTEND (r for wrist sensors 0.74 and 0.67 respectively and for foot sensors 0.61 and 0.68 respectively, p-values < 0.001). ||A||_95 for the foot, the wrist, the elbow sensors and ||A||_CPM for the foot, the wrist, the elbow sensors increased significantly between baseline and the 12 months follow-up visit (respective p-values: 0.004, < 0.001, < 0.001, 0.006, < 0.001, < 0.001).

CONCLUSION

IMUs were well accepted, consistent, concurrently valid, responsive and associated with unaided sitting acquisition especially for the elbow sensors. This study is the first reporting a large set of inertial sensor derived data after GT in SMA patients and paves the way for IMU-based follow-up of SMA patients after treatment.

Real-world multidisciplinary outcomes of onasemnogene abeparvovec monotherapy in patients with spinal muscular atrophy type 1: experience of the French cohort in the first three years of treatment

BACKGROUND

Spinal muscular atrophy type 1 (SMA1) is the most severe and early form of SMA, a genetic disease with motor neuron degeneration. Onasemnogene abeparvovec gene transfer therapy (GT) has changed the natural history of SMA1, but real-world data are scarce.

METHODS

A French national expert committee identified 95 newly diagnosed treatment-naive SMA1 patients between June 2019 and June 2022. We prospectively report on children treated with GT as the first and only therapy who had more than one-year of follow-up.

RESULTS

Forty-six SMA1 patients received GT. Twelve patients received other treatments. Patients with respiratory insufficiency were oriented toward palliative care after discussion with families. Twenty-nine of the treated patients with more than 12 months of follow-up were included in the follow-up analysis. Among them, 17 had 24 months of follow-up. The mean age at treatment was 7.5 (2.1-12.5) months. Twenty-two patients had two SMN2 copies, and seven had three copies. One infant died in the month following GT due to severe thrombotic microangiopathy, and another died due to respiratory distress. Among the 17 patients with 24 months of follow-up, 90% required spinal bracing (15/17), three patients required nocturnal noninvasive ventilation, and two needed gastrostomy. Concerning motor milestones at the 24-month follow-up, all patients held their head, 15/17 sat for 30 s unassisted, and 12/17 stood with aid. Motor scores (CHOPINTEND and HINE-2) and thoracic circumference significantly improved in all patients.

CONCLUSIONS

Our study shows favorable motor outcomes and preserved respiratory and feeding functions in treatment-naive SMA1 infants treated by GT as the first and only therapy before respiratory and bulbar dysfunctions occurred. Nevertheless, almost all patients developed spinal deformities.

Long-term impact of nusinersen on motor and electrophysiological outcomes in adolescent and adult spinal muscular atrophy: insights from a multicenter retrospective study

BACKGROUND

5q spinal muscular atrophy (SMA) is a progressive autosomal recessive motor neuron disease.

OBJECTIVE

We aimed to assess the effects of nusinersen on motor function and electrophysiological parameters in adolescent and adult patients with 5q SMA.

METHODS

Patients with genetically confirmed 5q SMA were eligible for inclusion, and clinical data were collected at baseline (V1), 63 days (V4), 180 days (V5), and 300 days (V6). The efficacy of nusinersen was monitored by encompassing clinical assessments, including the Revised Upper Limb Module (RULM), Hammersmith Functional Motor Scale Expanded (HFMSE), 6-Minute Walk Test (6MWT), and percent-predicted Forced Vital Capacity in sitting position (FVC%) and Compound Muscle Action Potential (CMAP) amplitude. The patients were divided into "sitter" and "walker" subgroups according to motor function status.

RESULTS

54 patients were screened, divided into "sitter" (N = 22) and "walker" (N = 32), with the mean age at baseline of 27.03 years (range 13-53 years). The HFMSE in the walker subgroup increased significantly from baseline to V4 (mean change +2.32-point, P = 0.004), V5 (+3.09, P = 0.004) and V6 (+4.21, P = 0.005). The patients in both the sitter and walker subgroup had no significant changes in mean RULM between V1 and the following time points. Significant increases in CMAP amplitudes were observed in both upper and lower limbs after treatment. Also, patients with RULM ≥ 36 points showed significant CMAP improvements. Our analysis predicted that patients with CMAP amplitudes of trapezius ≥ 1.76 mV were more likely to achieve significant motor function improvements.

CONCLUSIONS

Nusinersen effectively improves motor function and electrophysiological data in adolescent and adult patients with SMA. This is the first report on the CMAP amplitude changes in the trapezius after treatment in patients with SMA. The CMAP values effectively compensate for the ceiling effect observed in the RULM, suggesting that CMAP could serve as an additional biomarker for evaluating treatment efficacy.

Real-World Data in Children with Spinal Muscular Atrophy Type 1 on Long-Term Ventilation Receiving Gene Therapy: A Prospective Cohort Study

Patients with spinal muscular atrophy type 1 (SMA-1) requiring invasive ventilation can be eligible for gene therapy if they tolerate at least 8 h off ventilation per day. We aimed to assess the short-term safety and efficacy of gene therapy (onasemnogene abeparvovec; Zolgensma) on respiratory function in SMA-1 patients ventilated via tracheostomy pre-gene therapy. A prospective cohort study included 22 patients. Patients were weaned off ventilation for at least 8 h daily by optimizing ventilator settings and duration, using cough augmentation, managing excessive airway secretions, enhancing nutrition, screening for respiratory bacterial colonization, and treating infections. Gene therapy was administered at a median age of 26 (Q1: 18, Q3: 43) months with a mean follow-up period of 7.64 (SD: 6.50) months. Gene therapy was safe and effective in resolving paradoxical breathing, improving cough ability, reducing airway secretions, and enhancing CHOP-INTEND scores. The clinical assessment and management implemented pre-gene therapy were effective in safely weaning patients for at least 8 h off ventilation daily. Gene therapy at a late age was safe and effective over the short-term period; however, long-term follow-up is recommended. In conjunction with gene therapy, high-quality clinical care is beneficial and should be paired with gene therapy.

Newborn Screening for Spinal Muscular Atrophy: Variations in Practice and Early Management of Infants with Spinal Muscular Atrophy in the United States

In the United States (U.S.), newborn screening (NBS) for spinal muscular atrophy (SMA) is implemented by individual states. There is likely variation in the practice patterns of state NBS programs and among the providers caring for newborns with SMA. This is a prospective, descriptive, observational study that seeks to quantify and describe practice patterns and heterogeneities in state NBS programs and provider practices in the U.S. We surveyed U.S. state NBS programs and care providers of newborns with SMA. Thirty states and 41 practitioners responded. NBS program practices vary by state. Most (74%) state programs provide results to both primary care and specialist providers and also defer confirmatory SMA testing to those providers. Two states had relatively high rates of false-positive or inclusive results. The total birth prevalence of SMA was 1:13,862. Most providers were in tertiary care centers (90%) and were child neurologists (81%) and/or had fellowship training in Neuromuscular Medicine or Electromyography (76%). All providers see new referrals in less than a week, but many do not initiate treatment until >3 weeks of age (39%), with most commonly reported delays related to insurance processes. Most (81%) prefer onasemnogene abeparvovec-xioi (OA) as the treatment of choice, mainly due to perceived efficacy and the route/frequency of administration. NBS practice patterns in the U.S. vary by state but overall yielded the predicted birth prevalence of positive results. Providers evaluate these newborns urgently, but many do not initiate therapy until after 3 weeks of age. Treatment delays are mainly related to insurance processes.

Unveiling the adverse events of Nusinersen in spinal muscular atrophy management based on FAERS database

This study aims to collect and analyze adverse event (AE) reports related to Nusinersen from the FAERS database. The study employed a combination of signal quantification techniques, including the Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and Multi-item Gamma Poisson Shrinker (MGPS), to enhance the accuracy of signal detection and reduce the risk of false positives or negatives. Between the first quarter of 2017 and the third quarter of 2023, the FAERS database collected a total of 11,485,105 drug AE reports, of which 5772 were related to Nusinersen. Through signal mining analysis, 218 preferred term (PT) signals involving 27 system organ classes (SOCs) were identified. The study discovered AEs related to metabolism and nutrition disorders, psychiatric disorders, and cardiac disorders SOCs, which were not mentioned in the product information. Additionally, complications directly related to the intrathecal administration of Nusinersen, such as increased CSF pressure, positive CSF red blood cell count, and AEs related to the method of drug use, such as neuromuscular scoliosis and cerebrospinal fluid reservoir placement, were highlighted. Notably, AEs related to renal function abnormalities, such as abnormal Urine protein/creatinine ratio and protein urine presence, showed higher frequency and signal strength. The findings of this study emphasize the importance of comprehensive safety monitoring in the clinical application of Nusinersen. These results are significant for guiding future clinical practices, improving disease management strategies, and developing safer treatment protocols.

Functional and Structural Changes in Patients with Spinal Muscular Atrophy Treated in Poland during 12-Month Follow-Up: A Prospective Cohort Study

Background: In recent years, rapid advances in diagnosis and treatment have been observed in spinal muscular atrophy (SMA) patients. The introduction of modern therapies and screening tests has significantly changed the clinical picture of the disease. The previous classification has, therefore, been replaced by new phenotypes: non-sitters, sitters, and walkers, defined by the patient's functional level. However, despite the change in the clinical picture of the disease, patients still suffer from accompanying structural disorders such as scoliosis or joint contractures. Their presence also significantly affects the acquisition of subsequent motor skills. Due to this, monitoring structural changes and ensuring therapists are aware of improvements or declines in patient functionality are essential components of clinical practice. This study aims to compare the assessment of structural and functional changes after a 12-month follow-up in SMA patients who have already experienced the effects of the disease and are now receiving modern therapy. Methods: We present a study of 34 SMA patients being treated with modern therapies and tested twice 12 months apart. The participants were tested using structural measurements and validated scales such as The Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) and Hammersmith Functional Motor Scale-Expanded (HFMSE). Results: During the 12-month follow-up, patients showed deteriorating, non-statistically significant structural changes. We also proved that patients showed a trend toward functional improvement. Analyzing the individual scale items, we distinguished which participants obtained the maximum score for a given parameter and no longer had an opportunity to improve during the second examination. Conclusions: Our study proved that most patients improved overall motor function. The examination of structural measurements should become a standard in the evaluation of SMA patients.

Polysomnography findings and respiratory muscle function in infants with early onset spinal muscular atrophy after gene replacement as monotherapy: A prospective study

BACKGROUND

Gene replacement therapy (onasemnogene abeparvovec) is associated with an improvement of the prognosis of children with spinal muscular atrophy, but information on long-term respiratory outcome is scarce. The aim of this study was to report the polysomnography findings and respiratory muscle function of infants with treatment-naive spinal muscular atrophy type 1 and 2 up to 24 months after onasemnogene abeparvovec monotherapy.

METHODS

A clinical and motor evaluation, respiratory muscle function testing, and polysomnography were performed repeatedly.

RESULTS

Fifteen spinal muscular atrophy patients (1 presymptomatic, 7 type 1b, 6 type 1c, and 1 type 2) were included at a median age of 8.6 months (range 3.8-12.6) and followed for 24 months. The thoracic over head circumference ratio was close to normal at baseline (median 1.00 (range 0.90-1.05)) and increased significantly over time. All polysomnography and nocturnal gas exchange parameters were within normal ranges at baseline (median apnea-hypopnea index 2.5 events/hour (range 0.4-5.3)) and follow-up. The inspiratory muscle strength was normal at baseline but tended to slightly decrease over time and the expiratory muscle strength was low at any time especially for patients with recurrent respiratory infections (median (range) at baseline in cmH2O: crying esophageal pressure 54 (30-110), crying transdiaphragmatic pressure 65 (35-107), gastric pressure during maximal cough 26 (10-130), esophageal pressure during maximal cough 61 (38-150)). Only 3 patients required noninvasive ventilation.

CONCLUSION

A continuous respiratory monitoring of spinal muscular atrophy patients during the first years of life following onasemnogene abeparvovec monotherapy seems recommended despite the normality of polysomnography parameters.

Brazilian version of the Hammersmith Functional Motor Scale Expanded: cross-cultural adaptation and validation

BACKGROUND

 The Hammersmith Functional Motor Scale Expanded (HFMSE) has been widely used to assess the motor function of patients with spinal muscular atrophy (SMA) older than 2 years, with the ability to sit and/or walk.

OBJECTIVE

 To translate, cross-culturally adapt and validate the HFMSE to Brazilian Portuguese.

METHODS

 The translation process and cross-cultural adaptation followed international guidelines recommendations. The reliability and applicability of the Brazilian version consisted of the application of the HFMSE (in Brazilian Portuguese) to 20 patients with types 2 and 3 SMA. Two examiners assessed the participants for interrater reliability, through the analysis of Kappa reliability agreement (k) and intraclass correlation coefficient (ICC).

RESULTS

 The HFMSE was successfully translated and cross culturally adapted to Brazilian Portuguese. Twenty participants with types 2 and 3 SMA were enrolled in the study (type 2 = 6; type 3 = 14). The ICC for the total score showed very high reliability (ICC =1.00), and the reliability of each of the items individually was considered excellent (Kappa > 0.80).

CONCLUSION

 The Brazilian version of the HFMSE proved to be valid and reliable for the evaluation of SMA patients older than 2 years with the ability to sit and/or walk.

Preemptive dual therapy for children at risk for infantile-onset spinal muscular atrophy

OBJECTIVE

Compare efficacy of gene therapy alone (monotherapy) or in combination with an SMN2 augmentation agent (dual therapy) for treatment of children at risk for spinal muscular atrophy type 1.

METHODS

Eighteen newborns with biallelic SMN1 deletions and two SMN2 copies were treated preemptively with monotherapy (n = 11) or dual therapy (n = 7) and followed for a median of 3 years. Primary outcomes were independent sitting and walking. Biomarkers were serial muscle ultrasonography (efficacy) and sensory action potentials (safety).

RESULTS

Gene therapy was administered by 7-43 postnatal days; dual therapy with risdiplam (n = 6) or nusinersen (n = 1) was started by 15-39 days. Among 18 children enrolled, 17 sat, 15 walked, and 44% had motor delay (i.e., delay or failure to achieve prespecified milestones). Those on dual therapy sat but did not walk at an earlier age. 91% of muscle ultrasounds conducted within 60 postnatal days were normal but by 3-61 months, 94% showed echogenicity and/or fasciculation of at least one muscle group; these changes were indistinguishable between monotherapy and dual therapy cohorts. Five children with three SMN2 copies were treated with monotherapy in parallel: all sat and walked on time and had normal muscle sonograms at all time points. No child on dual therapy experienced treatment-associated adverse events. All 11 participants who completed sensory testing (including six on dual therapy) had intact sural sensory responses.

INTERPRETATION

Preemptive dual therapy is well tolerated and may provide modest benefit for children at risk for severe spinal muscular atrophy but does not prevent widespread degenerative changes.

An updated systematic review on spinal muscular atrophy patients treated with nusinersen, onasemnogene abeparvovec (at least 24 months), risdiplam (at least 12 months) or combination therapies

OBJECTIVE

This systematic review provides an update on outcomes for patients with spinal muscular atrophy (SMA) type 1 to 4 treated with approved therapeutics, including the most recent, risdiplam, for an observation period of up to 48 months.

METHODS

A systematic literature search was conducted in July 2023 in four databases. Selected publications were assessed for internal validity and risk of bias by two authors and relevant data were extracted into standardised tables. Results were summarised narratively as substantial heterogeneity of studies prevents meaningful quantitative analysis.

RESULTS

Twenty observational studies and one RCT were included in the analysis, fifteen studies on nusinersen, one on onasemnogene abeparvovec and two on risdiplam. Evidence supports the effectiveness of the therapies in motor function improvement for up to 48 months of follow-up in the SMA types specified in their respective indications. Better results were observed with earlier treatment initiation and higher baseline function. Whilst motor improvement was consistently observed, regardless of SMA type or treatment used, we noted no significant improvements in respiratory and nutritional outcomes. Quality of life endpoints were rarely investigated. Adverse events were common but seldom classified as treatment-related except for post-lumbar puncture syndrome, which was frequently reported across nusinersen studies.

CONCLUSION

The treatment of SMA with the new therapies changes the disease phenotype with changes in motor function far exceeding any improvement in respiratory and nutritional function. Questions persist on long-term efficacy, potential regressions, impact on quality of life and social functioning, therapy duration, and discontinuation indicators.

Integrated Approaches and Practical Recommendations in Patient Care Identified with 5q Spinal Muscular Atrophy through Newborn Screening

In recent years, significant progress has been made in 5q Spinal Muscular Atrophy therapeutics, emphasizing the importance of early diagnosis and intervention for better clinical outcomes. Characterized by spinal cord motor neuron degeneration, 5q-SMA leads to muscle weakness, swallowing difficulties, respiratory insufficiency, and skeletal deformities. Recognizing the pre-symptomatic phases supported by screening and confirmatory genetic tests is crucial for early diagnosis. This work addresses key considerations in implementing 5q-SMA screening within the Brazilian National Newborn Screening Program and explores Brazil's unique challenges and opportunities, including genetic tests, time-to-patient referral to specialized centers, program follow-up, and treatment algorithms. We aim to guide healthcare professionals and policymakers, facilitating global discussions, including Latin American countries, and knowledge-sharing on this critical subject to improve the care for newborns identified with 5q SMA.

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.

Dysfunction of proprioceptive sensory synapses is a pathogenic event and therapeutic target in mice and humans with spinal muscular atrophy

Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by a varying degree of severity that correlates with the reduction of SMN protein levels. Motor neuron degeneration and skeletal muscle atrophy are hallmarks of SMA, but it is unknown whether other mechanisms contribute to the spectrum of clinical phenotypes. Here, through a combination of physiological and morphological studies in mouse models and SMA patients, we identify dysfunction and loss of proprioceptive sensory synapses as key signatures of SMA pathology. We demonstrate that SMA patients exhibit impaired proprioception, and their proprioceptive sensory synapses are dysfunctional as measured by the neurophysiological test of the Hoffmann reflex (H-reflex). We further show that loss of excitatory afferent synapses and altered potassium channel expression in SMA motor neurons are conserved pathogenic events found in both severely affected patients and mouse models. Lastly, we report that improved motor function and fatigability in ambulatory SMA patients and mouse models treated with SMN-inducing drugs correlate with increased function of sensory-motor circuits that can be accurately captured by the H-reflex assay. Thus, sensory synaptic dysfunction is a clinically relevant event in SMA, and the H-reflex is a suitable assay to monitor disease progression and treatment efficacy of motor circuit pathology.

Genetic therapies and respiratory outcomes in patients with neuromuscular disease

PURPOSE OF REVIEW

Genetic therapies made a significant impact to the clinical course of patients with spinal muscular atrophy and Duchenne muscular dystrophy. Clinicians and therapists who care for these patients want to know the changes in respiratory sequelae and implications for clinical care for treated patients.

RECENT FINDINGS

Different genetic therapy approaches have been developed to replace the deficient protein product in spinal muscular atrophy and Duchenne muscular dystrophy. The natural history of these conditions needed to be understood in order to design clinical trials. Respiratory parameters were not the primary outcome measures for the clinical trials. The impact of these therapies is described in subsequent clinical trial reports or real-world data.

SUMMARY

Genetic therapies are able to stabilize or improve the respiratory sequelae in patients with spinal muscular atrophy and Duchenne muscular dystrophy. Standardized reporting of these outcomes is needed to help inform the future revisions of clinical standards of care and practice guidelines.

Efficacy and safety of onasemnogene abeparvovec for the treatment of patients with spinal muscular atrophy type 1: A systematic review with meta-analysis

BACKGROUND

Onasemnogene abeparvovec has been approved for the treatment of spinal muscular atrophy 5q type 1 in several countries, which calls for an independent assessment of the evidence regarding efficacy and safety.

OBJECTIVE

Conduct a meta-analysis to assess the efficacy and safety of onasemnogene abeparvovec in patients diagnosed with SMA type 1, based on the available evidence.

METHODS

This article results from searches conducted on databases up to November 2022. Outcomes of interest were global survival and event-free survival, improvement in motor function and treatment-related adverse events. Risk of bias assessment and certainty of evidence were performed for each outcome. Proportional meta-analysis models were performed when applicable.

RESULTS

Four reports of three open-label, non-comparative clinical trials covering 67 patients were included. Meta-analyses of data available in a 12-month follow-up estimate a global survival of 97.56% (95%CI: 92.55 to 99.86, I2 = 0%, n = 67), an event-free survival of 96.5% (95%CI: 90.76 to 99.54, I2 = 32%, n = 66) and a CHOP-INTEND score ≥ 40 points proportion of 87.28% (95%CI: 69.81 to 97.83, I2 = 69%, n = 67). Proportion of 52.64% (95%CI: 27.11 to 77.45, I2 = 78%, n = 67) of treatment-related adverse events was estimated.

CONCLUSION

The results indicate a potential change in the natural history of type 1 SMA, but the methodological limitations of the studies make the real extent of the technology's long-term benefits uncertain.

Communicative development inventory in type 1 and presymptomatic infants with spinal muscular atrophy: a cohort study

OBJECTIVE

The aim of this study was to assess early language acquisitions in treated individuals with spinal muscular atrophy (SMA) type 1 and in infants identified by newborn screening (NBS).

METHODS

Parents of SMA individuals aged between 8 and 36 months were asked to fill in the MacArthur-Bates Communicative Development Inventory (MB-CDI) that assesses comprehension, gesture and expressive skills. A follow-up assessment was performed in 21 of the 36.

RESULTS

The MB-CDI was completed by parents of 24 type 1 and 12 infants identified by NBS. Comprehension skills were preserved in 81% of the type 1 SMA and in 87% infants identified by NBS. Gesture abilities were <5th centile in 55% of the type 1 SMA and in none of those identified by NBS. Lexical expressions were <5th centile in more than 80% type 1 SMA and in 50% of infants identified by NBS. At follow-up, despite an increase in lexical expression skills, the scores remained below the fifth centile in 43% type 1 SMA and in 86% of infants identified by NBS.

CONCLUSIONS

These results suggest that language and communication development may follow a similar pattern to that observed in motor function with the possibility to develop skills (eg, ability to say clear words) that are not usually present in untreated infants but with a level of performance that does not reach that of their typically developing peers.

Global Risdiplam Compassionate Use Program for Patients with Type 1 or 2 Spinal Muscular Atrophy

PURPOSE

Spinal muscular atrophy (SMA) is a genetic neuromuscular disease causing progressive muscle weakness and reducing life expectancy. Risdiplam (Evrysdi; Genentech/F. Hoffmann-La Roche Ltd, Basel, Switzerland) is a drug approved for use in the treatment of patients with SMA. The ongoing global risdiplam Compassionate Use Program (CUP), initiated in November 2019, is the largest CUP in SMA, currently providing access to risdiplam for >2000 patients with type 1 or 2 SMA in 59 countries. Here, the challenges and learnings from the risdiplam CUP are presented.

METHODS

Enrolled patients (aged ≥2 months) had type 1 or 2 SMA and no alternative treatment options (ie, they were not medically eligible for approved SMA treatments, were unable to continue their SMA treatment due to medical reasons, were at risk for lack/loss of SMA treatment efficacy, or did not qualify for/had no access to SMA treatment within a clinical trial). Requests were made by the treating physicians via an end-to-end system.

FINDINGS

The risdiplam CUP highlighted the importance of collaborating with patient advocacy groups early to learn about patients' perspectives on unmet medical needs, understanding the sometimes-unique nature of local regulations and requirements, and adapting physician- and patient-eligibility criteria. Key learnings were obtained from enrolling patients from low- to middle-income countries and from countries without dedicated Compassionate Use regulations, and from operating the CUP during the coronavirus disease 2019 pandemic.

IMPLICATIONS

The risdiplam CUP experience was successful in many ways and may help to design and implement future CUPs in rare diseases, as well as patients living in countries or in circumstances in which access to innovative treatments is a challenge.

Nusinersen induces detectable changes in compound motor action potential response in spinal muscular atrophy type 1 patients with severe impairment of motor function

BACKGROUND

Most long-term affected spinal muscular atrophy (SMA) type 1 patients have severe impairment of motor function and are dependent on mechanical ventilation with tracheostomy. The efficacy and safety of nusinersen in these patients have not been established.

METHODS

We retrospectively evaluated the efficacy of intrathecal nusinersen treatment in patients with SMA type 1 who continued treatment for at least 12 months. There were three patients enrolled in our study (3, 4 and 16 years of age) who had severe impairment of gross motor function without head control or the ability to roll over. All three needed mechanical ventilation with tracheostomy and tube feeding. Motor function was assessed using the Children s Hospital of Philadelphia infant test of neuromuscular disorders (CHOP-INTEND) and the caregivers' evaluations. Concurrently, we examined nerve conduction longitudinally and compared compound motor action potential (CMAP) amplitudes.

RESULTS

All patients continued nusinersen administration without significant adverse events for more than three years. While CHOP-INTEND scores did not remarkably increase, according to the caregivers, all three patients had improved finger or facial muscle movements that enabled them to make their intentions understood. Some CMAPs before treatment were not identified but became traces after nusinersen administration.

CONCLUSIONS

The improvement in motor function that leads to smoother communication could be a basis for continuing nusinersen treatment. Currently available motor function scorings are not efficient for assessing therapeutic interventions in SMA patients with medical care complexity. Longitudinal nerve conduction studies could be an objective indicator.

Early treatment of type II SMA slows rate of progression of scoliosis

BACKGROUND

Type II spinal muscular atrophy (SMA) often leads to scoliosis in up to 90% of cases. While pharmacological treatments have shown improvements in motor function, their impact on scoliosis progression remains unclear. This study aims to evaluate potential differences in scoliosis progression between treated and untreated SMA II patients.

METHODS

Treatment effect on Cobb's angle annual changes and on reaching a 50° Cobb angle was analysed in treated and untreated type II SMA patients with a minimum 1.5-year follow-up. A sliding cut-off approach identified the optimal treatment subpopulation based on age, Cobb angle and Hammersmith Functional Motor Scale Expanded at the initial visit. Mann-Whitney U-test assessed statistical significance.

RESULTS

There were no significant differences in baseline characteristics between the untreated (n=46) and treated (n=39) populations. The mean Cobb angle variation did not significantly differ between the two groups (p=0.4). Optimal cut-off values for a better outcome were found to be having a Cobb angle <26° or an age <4.5 years. When using optimal cut-off, the treated group showed a lower mean Cobb variation compared with the untreated group (5.61 (SD 4.72) degrees/year vs 10.05 (SD 6.38) degrees/year; p=0.01). Cox-regression analysis indicated a protective treatment effect in reaching a 50° Cobb angle, significant in patients <4.5 years old (p=0.016).

CONCLUSION

This study highlights that pharmacological treatment, if initiated early, may slow down the progression of scoliosis in type II SMA patients. Larger studies are warranted to further investigate the effectiveness of individual pharmacological treatment on scoliosis progression in this patient population.

Cost-effectiveness of spinal muscular atrophy newborn screening based on real-world data in Belgium

The objective of the study was to assess the cost-effectiveness of real-world spinal muscular atrophy newborn screening followed by treatment. We modeled the lifetime cost-effectiveness of the spinal muscular atrophy newborn screening followed by treatment (screening) compared to treatment without screening (no screening) from the Belgian healthcare perspective. Real-world data, including quality of life, costs, and motor development data, were collected on 12 patients identified by screening and 43 patients identified by their symptoms. "Screening" was associated with slightly higher healthcare costs (€ 6,858,061 vs. € 6,738,120) but more quality-adjusted life years (QALY) (40.95 vs. 20.34) compared to "no screening", leading to an incremental cost-effectiveness ratio of € 5,820 per QALY gained. "Screening" was dominant from a societal perspective (negative incremental costs: € -14,457; incremental QALY = 20.61), when incorporating the burden on caregivers (negative incremental costs = € -74,353; incremental QALY = 27.51), and when the treatment was chosen by the parents (negative incremental costs = € -2,596,748; incremental QALY = 20.61). Spinal muscular atrophy newborn screening coupled with early treatment is thus cost-effective compared with late treatment following clinical diagnosis and is dominant when societal perspective, caregiver burden, and treatment based on parental preference were considered.

Real-World Outcomes in Patients with Spinal Muscular Atrophy Treated with Onasemnogene Abeparvovec Monotherapy: Findings from the RESTORE Registry

Background

Long-term, real-world effectiveness and safety data of disease-modifying treatments for spinal muscular atrophy (SMA) are important for assessing outcomes and providing information for a larger number and broader range of SMA patients than included in clinical trials.

Objective

We sought to describe patients with SMA treated with onasemnogene abeparvovec monotherapy in the real-world setting.

Methods

RESTORE is a prospective, multicenter, multinational, observational registry that captures data from a variety of sources.

Results

Recruitment started in September 2018. As of May 23, 2022, data were available for 168 patients treated with onasemnogene abeparvovec monotherapy. Median (IQR) age at initial SMA diagnosis was 1 (0-6) month and at onasemnogene abeparvovec infusion was 3 (1-10) months. Eighty patients (47.6%) had two and 70 (41.7%) had three copies of SMN2, and 98 (58.3%) were identified by newborn screening. Infants identified by newborn screening had a lower age at final assessment (mean age 11.5 months) and greater mean final (SD) CHOP INTEND score (57.0 [10.0] points) compared with clinically diagnosed patients (23.1 months; 52.1 [8.0] points). All patients maintained/achieved motor milestones. 48.5% (n = 81/167) experienced at least one treatment-emergent adverse event (AE), and 31/167 patients (18.6%) experienced at least one serious AE, of which 8/31 were considered treatment-related.

Conclusion

These real-world outcomes support findings from the interventional trial program and demonstrate effectiveness of onasemnogene abeparvovec over a large patient population, which was consistent with initial clinical data and published 5-year follow-up data. Observed AEs were consistent with the established safety profile of onasemnogene abeparvovec.

Carrier screening for spinal muscular atrophy in 22913 Chinese reproductive age women

BACKGROUND

To determine the carrier frequency of, and evaluate a carrier screening program for, spinal muscular atrophy (SMA) in reproductive age women in Shenzhen area.

METHODS

A staged screening procedure was used to perform carrier screening for SMA in 22,913 Chinese reproductive age women between 2019 and 2022 in Shenzhen area of China. First, the copy number of exon 7 in the SMN1 gene were detected in women of reproductive age using real-time quantitative polymerase chain reaction. If SMA carriers were detected, their spouses were then recommended to test. Prenatal diagnosis was carried out in couples who were both carriers.

RESULTS

A total of 389 women were found to be SMA carriers (1.70%, 95% CI: 1.53%-1.87%), indicating the carrier prevalence was approximately 1:59. Despite the proportion of nonpregnant women increased from 37.96% in 2019 to 58.18% in 2022 (p < 0.05) among the 22,913 reproductive age women, the recall rate of spouses was still not high (62.21%, 95% CI: 57.39%-67.03%). Eight partners were found to be SMA carriers and two fetuses were determined to have SMA with no copies of the SMN1 gene.

CONCLUSION

Although the acceptability and awareness of SMA carrier screening in Chinese population has increased in recent years, it still fails to reach the ideal expectation. Our experience may provide a basis for and facilitate the popularization of SMA carrier screening in Shenzhen area.

Efficacy of risdiplam in spinal muscular atrophy: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to assess the efficacy and safety of risdiplam on motor and respiratory function in spinal muscular atrophy (SMA). We systematically searched Medline, Scopus, Web of Science, and the Cochrane Library from inception to March 2023. We included pre-post studies that determined the effect of risdiplam on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), the 32-item Motor Function Measure (MFM32), the Revised Upper Limb Module (RULM), the Hammersmith Functional Motor Scale - Expanded (HFMSE), respiratory function, and the proportion of risdiplam-related adverse events in a population with SMA (phenotypes 1 and 2/3). Meta-analyses were also performed where possible. Eleven studies were included. After 12 months of treatment, 57% of participants with SMA1 achieved a CHOP-INTEND score ≥ 40 points, and more than half were able to feed orally and had head control. In SMA2/3, MFM32, RULM, and HFMSE increased by 2.09 (1.17, 3.01), 1.73 (1.25, 2.20), and 1.00 (0.40, 1.59) points, respectively. Efficacy on respiratory function in SMA2/3 was inconsistent. Finally, 16% of participants experienced adverse events, but serious adverse events could not be quantified due to a lack of cases. The limited available evidence suggests that risdiplam is an effective and safe drug for the treatment of SMA. In addition, long-term clinical benefit may be partly determined by the stage of disease at which treatment is initiated.

Motor fiber function in spinal muscular atrophy-analysis of conduction velocity distribution

Objectives

The motor neuron survival protein, which is deficient in spinal muscular atrophy (SMA), performs numerous cellular functions. Currently, SMA is believed to be a multi-organ disease, including lesion of various structures of the central and peripheral nervous systems. Motor nerve damage, especially in milder SMA types, is controversial. This prompted the conduct of the electrophysiological studies in adults with SMA types 2 and 3 presented in this paper.

Methods

The study group consisted of 44 adult patients with SMA types 2 and 3. All patients underwent neurological examination with Hammersmith Functional Motor Scale-Expanded (HFMSE) assessment. Standard electrophysiological studies in the ulnar nerve and conduction velocity distribution (CVD) tests were performed in all patients and controls.

Results

A prolongation of the distal latency and lowering of the motor potential amplitude with no changes in CVD were found in the whole patient group. There were no dependencies on the number of gene copies. Patients with low HFSME value had slower standard conduction velocity, CVD in upper and median quartiles, and narrower CVD spread; in milder SMA, CVD spread was greater than in controls.

Interpretation

The significant reduction in motor response amplitude in SMA seems to be primarily related to motor neuron loss and directly proportional to its severity. The coexisting rearrangement in the peripheral nerve structure is present in SMA, and this could be partially caused by a coexisting demyelinating process. Nerve remodeling mainly affects large fibers and occurs in more severe SMA types with significant disability.

Evaluation of the therapeutic efficacy and tolerability of current drug treatments on the clinical outcomes of paediatric spinal muscular atrophy type 1: A systematic review

Spinal muscular atrophy (SMA) is a severe hereditary lower motor neuron disorder characterised by degeneration of alpha motor neurons in the spinal cord, resulting in progressive weakness and paralysis of proximal muscles. A systematic literature search was carried out by using PRISMA guidelines and searching through different databases that could provide findings of evidence on the health outcomes of the approved therapies for the management of paediatric SMA type 1 regarding efficacy with follow-up in terms of motor and respiratory functions and the tolerability and incidence of adverse drug reactions (ADRs) post-treatment from real-world publications. Half of the publications (50%) had a prospective observational design. Eight studies (66.7%) assessed nusinersen, and three studies (25%) assessed onasemnogene abeparvovec with a duration of follow-up ranging from 6 months to 3 years to evaluate the motor and respiratory functions using different assessment tools, hospitalisation rates, and the tolerability and incidence of ADRs post-treatment. The three currently approved treatments for SMA type 1 provided good support and health outcomes in terms of motor function, respiratory outcomes, reduction of hospitalisations, and improvement of survival. Nevertheless, uncertainties regarding continued improvement after long-term illness and the generalizability of results are still unknown.

Systematic Literature Review of the Natural History of Spinal Muscular Atrophy: Motor Function, Scoliosis, and Contractures

BACKGROUND AND OBJECTIVES

Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder associated with continuous motor function loss and complications, such as scoliosis and contractures. Understanding the natural history of SMA is key to demonstrating the long-term outcomes of SMA treatments. This study reviews the natural history of motor function, scoliosis, and contractures in patients with SMA.

METHODS

Electronic databases were searched from inception to June 27, 2022 (Embase, MEDLINE, and Evidence-Based Medicine Reviews). Observational studies, case-control studies, cross-sectional studies, and case series reporting on motor function (i.e., sitting, standing, and walking ability), scoliosis, and contracture outcomes in patients with types 1-3 SMA were included. Data on study design, baseline characteristics, and treatment outcomes were extracted. Data sets were generated from studies that reported Kaplan-Meier (KM) curves and pooled to generate overall KM curves.

RESULTS

Ninety-three publications were included, of which 68 reported on motor function. Of these, 10 reported KM curves (3 on the probability of sitting in patients with types 2 and 3 SMA and 8 on the probability of walking/ambulation in patients with type 3 SMA). The median time to loss of sitting (95% CI) was 14.5 years (14.1-31.5) for the type 2 SMA sitter population (their maximum ability was independent sitting). The median time to loss of ambulation (95% CI) was 13.4 years (12.5-14.5) for type 3a SMA (disease onset at age younger than 3 years) and 44.2 years (43.0-49.4) for type 3b SMA (disease onset at age 3 years or older). Studies including scoliosis and contracture outcomes mostly reported non-time-to-event data.

DISCUSSION

The results demonstrate that a high degree of motor function loss is inevitable, affecting patients of all ages. In addition, data suggest that untreated patients with types 2 and 3 SMA remain at risk of losing motor milestones during late adulthood, and patients with types 3a and 3b SMA are at risk of loss of ambulation over time. These findings support the importance of stabilization of motor function development even at older ages. Natural history data are key for the evaluation of SMA treatments as they contextualize the assessment of long-term outcomes.

Role of circulating biomarkers in spinal muscular atrophy: insights from a new treatment era

Spinal muscular atrophy (SMA) is a lower motor neuron disease due to biallelic mutations in the SMN1 gene on chromosome 5. It is characterized by progressive muscle weakness of limbs, bulbar and respiratory muscles. The disease is usually classified in four different phenotypes (1-4) according to age at symptoms onset and maximal motor milestones achieved. Recently, three disease modifying treatments have received approval from the Food and Drug Administration (FDA) and the European Medicines Agency (EMA), while several other innovative drugs are under study. New therapies have been game changing, improving survival and life quality for SMA patients. However, they have also intensified the need for accurate biomarkers to monitor disease progression and treatment efficacy. While clinical and neurophysiological biomarkers are well established and helpful in describing disease progression, there is a great need to develop more robust and sensitive circulating biomarkers, such as proteins, nucleic acids, and other small molecules. Used alone or in combination with clinical biomarkers, they will play a critical role in enhancing patients' stratification for clinical trials and access to approved treatments, as well as in tracking response to therapy, paving the way to the development of individualized therapeutic approaches. In this comprehensive review, we describe the foremost circulating biomarkers of current significance, analyzing existing literature on non-treated and treated patients with a special focus on neurofilaments and circulating miRNA, aiming to identify and examine their role in the follow-up of patients treated with innovative treatments, including gene therapy.

Combination disease-modifying treatment in spinal muscular atrophy: A proposed classification

We sought to devise a rational, systematic approach for defining/grouping survival motor neuron-targeted disease-modifying treatment (DMT) scenarios. The proposed classification is primarily based on a two-part differentiation: initial DMT, and persistence/discontinuation of subsequent DMT(s). Treatment categories were identified: monotherapy add-on, transient add-on, combination with onasemnogene abeparvovec, bridging to onasemnogene abeparvovec, and switching to onasemnogene abeparvovec. We validated this approach by applying the classification to the 443 patients currently in the RESTORE registry and explored the demographics of these different groups of patients. This work forms the basis to explore the safety and efficacy profile of the different combinations of DMT in SMA.

Budget impact analysis: comparing the costs of nusinersen and risdiplam in the treatment of type 3 spinal muscular atrophy patients

OBJECTIVES

The aim of the budget impact analysis (BIA) was to determine the economic impact of introducing risdiplam in the treatment of type 3 spinal muscular atrophy (SMA) patients in a rare diseases reference centre on a 3-year time horizon, as compared with nusinersen.

METHODS

Public databases were used to estimate the target population. Two market scenarios were assessed over a 3-year time horizon: with nusinersen and with the introduction of risdiplam. Drug acquisition and administration costs were considered. BIA is calculated as the difference between scenarios with nusinersen - scenario with risdiplam.

RESULTS

The introduction of risdiplam would generate a 3-year saving of €3411.50. There could be a saving in the administration of risdiplam in the treatment of patients under the age of 2 with a weight of 5 kg (€26 382.08).

CONCLUSION

The BIA shows the overlapping costs of these therapies, although the oral administration of risdiplam could be a decisive factor for the therapeutical switch from nusinersen.

Spinal Muscular Atrophy: A (Now) Treatable Neurodegenerative Disease

Spinal muscular atrophy (SMA) is a progressive disease of the lower motor neurons associated with recessive loss of the SMN1 gene, and which leads to worsening weakness and disability, and is fatal in its most severe forms. Over the past six years, three treatments have emerged, two drugs that modify exon splicing and one gene therapy, which have transformed the management of this disease. When treated pre-symptomatically, many children show normal early motor development, and the benefits extend from the newborn period to adulthood. Similar treatment approaches are now under investigation for rare types of SMA associated with genes beyond SMN1.

Biomarkers in 5q-associated spinal muscular atrophy-a narrative review

5q-associated spinal muscular atrophy (SMA) is a rare genetic disease caused by mutations in the SMN1 gene, resulting in a loss of functional SMN protein and consecutive degeneration of motor neurons in the ventral horn. The disease is clinically characterized by proximal paralysis and secondary skeletal muscle atrophy. New disease-modifying drugs driving SMN gene expression have been developed in the past decade and have revolutionized SMA treatment. The rise of treatment options led to a concomitant need of biomarkers for therapeutic guidance and an improved disease monitoring. Intensive efforts have been undertaken to develop suitable markers, and numerous candidate biomarkers for diagnostic, prognostic, and predictive values have been identified. The most promising markers include appliance-based measures such as electrophysiological and imaging-based indices as well as molecular markers including SMN-related proteins and markers of neurodegeneration and skeletal muscle integrity. However, none of the proposed biomarkers have been validated for the clinical routine yet. In this narrative review, we discuss the most promising candidate biomarkers for SMA and expand the discussion by addressing the largely unfolded potential of muscle integrity markers, especially in the context of upcoming muscle-targeting therapies. While the discussed candidate biomarkers hold potential as either diagnostic (e.g., SMN-related biomarkers), prognostic (e.g., markers of neurodegeneration, imaging-based markers), predictive (e.g., electrophysiological markers) or response markers (e.g., muscle integrity markers), no single measure seems to be suitable to cover all biomarker categories. Hence, a combination of different biomarkers and clinical assessments appears to be the most expedient solution at the time.

Innovating spinal muscular atrophy models in the therapeutic era

Spinal muscular atrophy (SMA) is a severe, monogenetic, neuromuscular disease. A thorough understanding of its genetic cause and the availability of robust models has led to the development and approval of three gene-targeting therapies. This is a unique and exciting development for the field of neuromuscular diseases, many of which remain untreatable. The development of therapies for SMA not only opens the door to future therapeutic possibilities for other genetic neuromuscular diseases, but also informs us about the limitations of such treatments. For example, treatment response varies widely and, for many patients, significant disability remains. Currently available SMA models best recapitulate the severe types of SMA, and these models are genetically and phenotypically more homogeneous than patients. Furthermore, treating patients is leading to a shift in phenotypes with increased variability in SMA clinical presentation. Therefore, there is a need to generate model systems that better reflect these developments. Here, we will first discuss current animal models of SMA and their limitations. Next, we will discuss the characteristics required to future-proof models to assist the field in the development of additional, novel therapies for SMA.

Real-Life Outcome After Gene Replacement Therapy for Spinal Muscular Atrophy: A Multicenter Experience

BACKGROUND

Onasemnogene abeparvovec-xioi (OA) has been available since 2019 as a gene replacement therapy for individuals with spinal muscular atrophy (SMA) under age two years. We aim to expand upon the sparse knowledge about its safety and clinical efficacy.

METHODS

The clinical outcome data of all the individuals with SMA who were treated with gene therapy in four tertiary hospitals in Israel were retrieved and analyzed.

RESULTS

The study participants included 25 individuals who received the gene therapy between age 11 days and 23 months and whose median follow-up duration was 18.0 (interquartile range [IQR], 12.4 to 18.3) months. Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scores increased by a median (IQR) of 13 (8 to 20) points at the last follow-up compared with baseline. None of the patients experienced regression in motor abilities after gene therapy, which was generally well tolerated. There was gradual improvement in motor function, especially among presymptomatic patients (P ≤ 0.001) whose disease duration was shorter (≤8 months) before receiving gene therapy (P ≤ 0.001) and who did not experience recurrent infections and illnesses in the months following treatment (P ≤ 0.001).

CONCLUSIONS

OA was well tolerated and led to favorable functional motor outcomes at six to 24 months after treatment initiation. Better progress in motor function was observed in individuals who received OA earlier and who were presymptomatic, irrespective of the SMN2 copy number or type. Our results further strengthen the clinical efficacy of OA and reinforce the importance of early recognition of SMA via newborn screening programs.