Single-center experience with intrathecal administration of Nusinersen in children with spinal muscular atrophy type 1

Correlations between clinical motor scores and CMAP in patients with type 2 spinal muscular amyotrophy treated with nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the degeneration of the anterior horn cells of the spinal cord. Nusinersen for the treatment of SMA has been covered by public healthcare in France since May 2017.

OBJECTIVE

Our aim was to investigate whether there is a correlation between clinical and compound motor action potential (CMAP) measurements in SMA patients treated with nusinersen after 3  years' follow-up.

METHOD

Motor skills were evaluated regularly between M0 and M36 using the Motor Function Measure (MFM) score. CMAP measurements were collected regularly between M0 and M22.

RESULTS

Data for 10 patients with SMA type 2 were collected and divided into two age groups (< 5 years and > 5 years). Motor function improved, but not significantly, regarding distal motor skills (D3) in both groups, and in axial and proximal motor function (D2) in the younger group. CMAP measurements improved in all patients. CMAP increased significantly for the median nerve, and this improvement correlated significantly with global MFM and with axial and proximal tone (D2).

CONCLUSION

Our study shows gain in distal motor function with nusinersen, especially in younger patients with SMA type 2. These results encourage the screening of SMA patients and treatment as early as possible. CMAP measurements of the median nerve show clear improvement in patients treated with nusinersen and could be performed as routine follow-up.

Feasibility analysis of intrathecal administration strategy of nusinersen based on Cobb angle in children with spinal muscular atrophy

AIM

This retro-prospective observational study described the experience in lumbar puncture procedures in children with spinal muscular atrophy (SMA) with and without neuromuscular scoliosis in a single center. The technical feasibility of intrathecal nusinersen administration was the main limiting factor.

STUDY DESIGN

A total of 457 technically successful intrathecal injections based on a hierarchical strategy in Cobb angle were reviewed in 81 SMA children aged 0.75-13.5 years who were referred for nusinersen injections in our hospital from October 2019 to December 2022.

RESULTS

Under local anesthesia, conventional lumbar puncture was performed on 47 patients without spinal deformity (Cobb angle of 0-10°) and 20 patients with moderate scoliosis (Cobb angle of 10-50°). Ultrasound-assisted lumbar puncture was performed on 12 patients with moderate scoliosis but lordosis. A combination of ultrasound imaging and three-dimensional CT under sedation was performed in the remaining 14 patients with severe scoliosis (Cobb angle >50°). No severe complications were found.

CONCLUSION

Cobb angle is an important basis for intrathecal administration of nusinersen. It is feasible and suitable to carry out intrathecal nusinersen injection under ultrasound combined with three-dimensional CT imaging for children with severe scoliosis.

Needleless inhaled anesthesia with sevoflurane: Advantages of a simplified approach for children with spinal muscular atrophy undergoing intrathecal administration of nusinersen

BACKGROUND

Intrathecal nusinersen administration, a fundamental step in the treatment of spinal muscular atrophy, is challenging in children.

AIMS

This retrospective monocentric analysis of prospectively collected data evaluated the feasibility of needleless general anesthesia exclusively with sevoflurane, without imaging guidance, for children undergoing nusinersen administration in a 24-month period.

METHODS

Clinical data included demographics, type of spinal muscular atrophy, presence and severity of scoliosis. Primary outcome was defined by the number of predefined sentinel adverse events related to anesthesia. Secondary outcomes were assessed by duration of the procedure, number of lumbar puncture attempts, and number of failures. Other measures included number and type of moderate, minor and minimal adverse events, as well as number and type of puncture-related adverse events.

RESULTS

116 patients (mean age: 8.7 (SD 6.9) years; with scoliosis: 49.1%) underwent 250 lumbar punctures; two cases of prolonged desaturation, considered as sentinel adverse events, (0.8%) were recorded during anesthesia (primary outcome). None of the patients underwent orotracheal intubation nor required an unplanned admission in the Pediatric Intensive Care Unit. No patient required an unplanned or prolonged hospitalization after the procedure. Mean number of puncture attempts was 1.6 (SD 1.3), and mean duration of the procedure was 14.1 (SD 8.3) minutes. No failure in the drug administration occurred (secondary outcomes).

CONCLUSION

In this single-center experience, needleless general anesthesia with inhaled sevoflurane without imaging guidance has been shown to be feasible for children with spinal muscular atrophy undergoing lumbar puncture for nusinersen administration.

Population-based assessment of nusinersen efficacy in children with spinal muscular atrophy: a 3-year follow-up study

Nusinersen (Spinraza®) improves survival of infants with hereditary proximal spinal muscular atrophy and motor function in children up to 12 years. Population-based assessments of treatment efficacy are limited and confined to select cohorts of patients. We performed a nationwide, population-based, single-centre cohort study in children with spinal muscular atrophy younger than 9.5 years at start of treatment in line with reimbursement criteria in the Netherlands. We assessed age-relevant motor function scores, the need for tube feeding, hours of ventilatory support and documented adverse events. We used linear mixed modelling to assess treatment effects. We compared motor function during treatment with natural history data and to individual trajectories of muscle strength and motor function before the start of treatment. We included 71 out of 72 Dutch children who were treated (median age 54 months; range 0–117) and followed them for a median of 38 months (range 5–52). We observed improvement of motor function in 72% and stabilization in another 18% of the symptomatic children, which differed from the natural disease course in a matched cohort of which we had previously collected natural history data. Longitudinal analysis showed that motor function improved up to a median of 24 months (range 12–30) of treatment after which it stabilized. Shorter disease duration at start of treatment resulted in better treatment efficacy (P < 0.01). Sixteen children (23%) achieved new motor milestones. Bulbar and respiratory function did not improve significantly during treatment. In 15 patients from whom treatment-naïve data were available, the pre-treatment trajectory of motor function decline changed to stabilization or improvement after the start of treatment. We documented 82 adverse events after 934 injections (9%) in 45 patients. None of the adverse events led to treatment discontinuation. Intrathecal nusinersen treatment is safe and improves or stabilizes motor function in 90% of young children with spinal muscular atrophy types 1c–3a. We did not observe improvement of respiratory and bulbar functions.

Disease Modifying Therapies for the Management of Children with Spinal Muscular Atrophy (5q SMA): An Update on the Emerging Evidence

SMA (5q SMA) is an autosomal recessive neuromuscular disease with an estimated incidence of approximately 1 in 11,000 live births, characterized by progressive degeneration and loss of α-motor neurons in the spinal cord and brain stem, resulting in progressive muscle weakness. The disease spectrum is wide, from a serious congenital to a mild adult-onset disease. SMA is caused by biallelic mutations in the SMN1 gene and disease severity is modified primarily by SMN2 copy number. Before the advent of specific disease altering treatments, SMA was the second most common fatal autosomal recessive disorder after cystic fibrosis and the most common genetic cause of infant mortality. Nusinersen, risdiplam, and onasemnogene abeparvovec are presently the only approved disease modifying therapies for SMA, and the aim of this review is to discuss their mode of action, effects, safety concerns, and results from real-world experience. All exert their action by increasing the level of SMN protein in lower motor neuron. Nusinersen and risdiplam by modifying the SMN2 gene product, and onasemnogene abeparvovec by delivering SMN1 gene copies into cells. All have an established clinical efficacy. An important feature shared by all three is that early intervention is associated with a better treatment outcome, such that in cases where treatment is initiated in an early pre-symptomatic period, it may result in normal - or almost normal - motor development. Thus, early diagnosis followed by swift initiation of treatment is fundamental for the treatment response and consequently long-term prognosis in SMA type 1, and probably SMA type 2. The same principle similarly applies to the milder phenotypes. All three therapies are relatively novel, with risdiplam being the latest addition. Except for nusinersen, real-world data are still scarce, and long-term data are quite naturally lacking.

Body mass index in type 2 spinal muscular atrophy: a longitudinal study

The aim of this retrospective study was to review body mass index (BMI) in a large cohort of Italian pediatric type 2 spinal muscular atrophy (SMA) patients, aged between 0 and 20 years and to establish possible differences in relation to a number of variables such as ventilation, motor function, and survival motor neuron 2 gene copies. Cross-sectional data were collected from 102 patients for a total of 344 visits. Standard growth charts for height and weight were used as reference, with age adjusted BMI calculated using the Center for Disease and Prevention Children's BMI Tool. In the 344 visits, weight ranged between 3.90 and 83 kg, and the BMI between 8.4 and 31.6 with a BMI/age z-scores <  - 2SD present in 28% and BMI/age z-scores >  + 2SD in 9% of the measurements. The BMI/age z-scores were relatively stable < 5 years of age with an increasing number of patients <  - 2SD after the age of 5, and a wider range of BMI/age z-scores after the age of 13. A difference on the BMI/age z-scores was found among the different age subgroups (< 5, 5-12, ≥ 13 years). A multivariate analysis in 58 patients with longitudinal assessments showed that baseline BMI/age z-scores and gender were significantly contributing to the changes while other variables were not.

CONCLUSION

Our results confirm that careful surveillance of weight and BMI/age z-scores is needed in type 2 SMA. Further studies, including assessments of chewing and swallowing and of lean/fat body mass, will help to better understand the possible mechanisms underlying weight issues.

WHAT IS KNOWN

• Feeding difficulties have been reported in a few studies and were invariably found in patients with type 1 SMA. • Type 2 SMA patients often have low BMI with a relevant number of patients requiring tube feeding.

WHAT IS NEW

• Reduction in BMI/age z-score overtime appeared to depend on baseline BMI/age z-score and gender. • Patients with a low BMI/age z-score were at higher risk of developing further reduction.

Respiratory outcome of spinal muscular atrophy type 1 patients treated with nusinersen

BACKGROUND

Respiratory failure is the leading cause of mortality in spinal muscular atrophy type 1 (SMA1) children. The current study aims to evaluate the effect of nusinersen treatment on respiratory outcome of the patients with SMA1.

METHODS

In this retrospective, single-center study, 52 SMA1 patients treated with nusinersen were included in the analysis. Patients were divided into two groups based on their age at the time of their first nusinersen treatment (Group 1: ≤6 months, Group 2: >6 months). Respiratory outcome on the 180th day of treatment is defined as the type of ventilation support (spontaneous breathing, noninvasive ventilation (NIV), and tracheostomized or intubated on invasive mechanical ventilation). Demographic data, respiratory outcome, and Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scores were obtained from medical records.

RESULTS

On the 180th day of treatment, 46 of the 52 (88.4%) children were alive. Prevalence of the mortality was similar in both groups (P = 0.65). The comparison of respiratory outcome in patients between group 1 and group 2 was as follows: spontaneous breathing, 7 (43.7%) versus 4 (13.3%) (P = 0.03); NIV <16 h/day, 3 (18.7%) versus 4 (13.3%) (P = 0.68); invasive mechanical ventilation, 6 (37.5%) versus 22 (73.3%) (P = 0.01). There were no patients using NIV ≥16 h/day. There were significant improvements in Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders scores of the patients at day 180 in comparison with the baseline (P < 0.001).

CONCLUSIONS

Early initiation of nusinersen treatment in SMA1 patients may alter the disease's natural course.

Spinal muscular atrophy: from rags to riches

The aim of this paper is to provide a short history of spinal muscular atrophy, from the first descriptions of the disease to the impact of the most recent therapeutical advances on the disease course. The paper provides an overview of how the field has progressed over the years after the availability of care recommendations and, more recently of the new therapies. The paper also highlights the new challenges related to the interpretation of the efficacy of the new therapies and how these are likely to affect several aspects such as the classification of spinal muscular atrophy. We will also discuss the need for further work to better define possible new phenotypes and new methods of assessments and how these should be reflected in the care recommendations. The results in presymptomatic patients will finally highlight the need for neonatal screening.

Effect of the COVID-19 Pandemic on Children With SMA Receiving Nusinersen: What Is Missed and What Is Gained?

Nusinersen is the first oligonucleotide-based drug that is approved for the treatment of spinal muscular atrophy. In January 2020, the WHO declared COVID-19 a pandemic and nusinersen-provider centers had to postpone planned infusions for some children along with other related interventions. Considering the important contribution that the intrathecal infusions and other support activities could have on the quality of life of spinal muscular atrophy patients and their families, this emergency could have a relevant impact on the course of the pathology. The present work aims to assess the clinical and social issues that arise for spinal muscular atrophy children in care at the referral pediatric palliative care Centre of Padua (Veneto) from a delay in nusinersen infusions, resulting from the contingent COVID-19 restrictions. This evaluation has been carried out in both the short and long term after the first lockdown period and can be considered as a "proxy" of a situation of a possible delay in administration or management of infusions, due to other different causes.

Evaluation of Metabolic Effects of Nusinersen in Patients with Spinal Muscular Atrophy

Nusinersen is the first disease-modifying therapy for spinal muscular atrophy (SMA), but there are few data on potential long-term endocrinological and metabolic systemic effects of this novel treatment as well as metabolic alterations in SMA itself. In this retrospective and multicentric study, we analyzed anthropometric, endocrinological, and motor function data of 81 pediatric and adult patients with SMA1 to 3 undergoing treatment with nusinersen. In 39 patients (51%), we observed a slight increase in body mass index (BMI) centiles under treatment with nusinersen, especially in patients with SMA2 and in pediatric patients between 3.1 and 12 years. A correlation to the SMN2 copy number or motor function was not found. Additionally, length centiles decreased significantly under treatment. The results of longitudinal endocrinological assessments were interpreted as not clinically significant in most patients; in three patients, the signs of an altered glucose metabolism were present. Our study indicates a putative effect of treatment with nusinersen on BMI, which might be due to a conjoint effect of weight gain and reduction of height velocity, without evidence of correlation to increased muscle function. Further studies need to address specific effects of targeted therapies such as nusinersen or onasemnogene abeparvovec on body composition including fat and muscle mass.

Nusinersen in pediatric and adult patients with type III spinal muscular atrophy

Objective

We report longitudinal data from 144 type III SMA pediatric and adult patients treated with nusinersen as part of an international effort.

Methods

Patients were assessed using Hammersmith Functional Motor Scale Expanded (HFMSE), Revised Upper Limb Module (RULM), and 6‐Minute Walk Test (6MWT) with a mean follow‐up of 1.83 years after nusinersen treatment.

Results

Over 75% of the 144 patients had a 12‐month follow‐up. There was an increase in the mean scores from baseline to 12 months on both HFMSE (1.18 points, p = 0.004) and RULM scores (0.58 points, p = 0.014) but not on the 6MWT (mean difference = 6.65 m, p = 0.33).

When the 12‐month HFMSE changes in the treated cohort were compared to an external cohort of untreated patients, in all untreated patients older than 7 years, the mean changes were always negative, while always positive in the treated ones. To reduce a selection bias, we also used a multivariable analysis. On the HFMSE scale, age, gender, baseline value, and functional status contributed significantly to the changes, while the number of SMN2 copies did not contribute. The effect of these variables was less obvious on the RULM and 6MWT.

Interpretation

Our results expand the available data on the effect of Nusinersen on type III patients, so far mostly limited to data from adult type III patients.

Lumbar Puncture Opening Pressure in Patients with Spinal Muscular Atrophy

The announcement of a hydrocephalus as a possible side effect in patients with spinal muscular atrophy (SMA) receiving the drug nusinersen, promoted major concern and warrants further evaluation. In this retrospective monocentric study, we analyzed clinical data, lumbar puncture opening pressure (LOP) measurement, and ophthalmologic and neuroimaging results in 34 patients with SMA types 1 to 3 undergoing treatment with nusinersen. None of the patients reported symptoms indicative of increased intracranial pressure. In our cohort, the LOP was >20 cm H₂O in 25 patients (70.5%), and within this group ≥28 cm H₂O in 12 patients (35.3%), in two patients, it was increased prior to treatment initiation. Signs of increased intracranial pressure in ophthalmological assessments or brain imaging were only seen in one patient. We did not identify a correlation between increased LOP and SMA type, scoliosis, or age of the patients; however, it was slightly higher in patients receiving sedation. Our results raise the question whether the LOP is generally increased in SMA as part of the underlying disease, if so, what the etiology is, and whether the increased LOP needs to be treated.

Post-dural puncture headache-a single-centre analysis in paediatric patients with and without SMA

AIM

To gather epidemiologic data on post-dural puncture headache (PDPH) after diagnostic or therapeutic lumbar puncture (LP) in children and adolescents with SMA as well as in a cohort of paediatric patients without SMA.

METHODS

We performed a retrospective, single-centre analysis via chart review and questionnaire. Patients were identified using the German procedure classification. Respective charts and SMArtCARE documentation forms (SMA patients) were reviewed concerning documentation of headaches fulfilling criteria of the IHS-classification for PDPH of 2004. Non-SMA patients received additional questionnaires.

RESULTS

We identified a total of 218 LPs in 95 patients. Of those 141 were performed in 22 patients with known SMA (mean age SMA patients 9.2 years; non-SMA patients 11.4 years). Following chart review, IHS criteria for PDPH were fulfilled in 6.9% of all procedures (3.5% in SMA patients; 13.0% in non-SMA patients; p = 0.008). Data from questionnaires of non-SMA patients confirmed this result (position dependent headache within 72 h after intervention in 13.0% of procedures).

CONCLUSION

The prevalence of PDPH after therapeutic LPs in our cohort of SMA patients was significantly lower than after LPs in the general paediatric cohort. Data of this retrospective analysis show a similar overall prevalence of PDPH in paediatric patients as reported in bigger adult cohorts.

Pediatric SMA patients with complex spinal anatomy: Implementation and evaluation of a decision-tree algorithm for administration of nusinersen

The approval of nusinersen for the treatment of spinal muscular atrophy (SMA) has significantly changed the natural history of the disease. Nevertheless, scoliosis secondary to axial muscle weakness occurs at some point in most of patients with SMA and a conventional posterior interlaminar approach for intrathecal administration of nusinersen can be particularly challenging to perform in patients with severe scoliosis and/or previous spine fusion surgeries. We developed a protocol for the administration of nusinersen in pediatric patients, which includes a decision-tree algorithm that categorizes patients according to the estimated technical difficulty for the intrathecal administration. Complex spine patients were defined as those with a Cobb angle greater than 50° and/or a history of spinal surgery, while the rest of patients were considered non-complex. Nusinersen was successfully administered through a conventional non-CT-guided lumbar puncture in all 14 non-complex spine patients (110 out of 110 procedures; 100%). The feasibility of the intrathecal injection in the 15 complex spine patients was assessed by 3D CT. Administration was considered unfeasible in 7 out of these 15 patients according to imaging. In the 8 complex spine patients in whom the administration was considered feasible, conventional non-CT-guided lumbar punctures were successful only in 19 out of 53 procedures (36%). The remaining 34 procedures (64%) were guided by CT scan, all successful. Our work demonstrates that a cut-off point of 50° in Cobb angle and history of spinal surgery can reliably be used to anticipate the need for CT guidance in nusinersen administration.

Do we always need to treat patients with spinal muscular atrophy? A personal view and experience

Background

We report the clinical outcomes observed in our patients with SMA type 1 or 2 receiving nusinersen, and we comment on the ethical implications of this treatment, in line with our results and those reported by Audic et al. in their analysis published in the Orphanet Journal of Rare Diseases.

Methods

We analyzed records of all children with a genetically diagnosed SMA and clinically confirmed diagnosis of SMA Type 1 or 2 to whom nusinersen was offered. Follow-up lasted 30 months.

Results

Among the 17 children with SMA type 1, 6 interrupted treatment with nusinersen due to adverse events or lack of efficacy. Of the remaining 11 patients, 9 are responding to therapy, though multidisciplinary complex care is still required. All those children started nusinersen at a very early age.

Eighteen patients with SMA type 2 received nusinersen; five required treatment interruption. The other 13 patients are still on nusinersen therapy, and 6 are responders. Among the seven non-responders, only two met the inclusion criteria of the pivotal trial.

Conclusions

Our analysis further supports the findings reported in the study by Audic et al. We believe that a wider use of nusinersen in clinical practice would require a comprehensive assessment of its actual benefits weighed against the discomfort caused to patients, as well as the identification of the patients who may obtain the best benefits from this treatment.

Type I SMA "new natural history": long-term data in nusinersen-treated patients

Objective

The aim of this paper was to report the 2‐year follow‐up in type I patients treated with Nusinersen and to assess whether possible changes in motor function are related to the subtype, age, or SMN2 copy number.

Methods

Sixty‐eight patients, with ages ranging from 0.20 to 15.92 years (mean: 3.96; standard deviation: +3.90) were enrolled in the study. All patients were assessed using the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) and the developmental section of the Hammersmith Infant Neurological Examination (HINE‐2) at the time they started treatment and 12 and 24 months after that.

Results

For both CHOP and HINE‐2 repeated measures analysis of variance showed a significant difference (P < 0.001) between baseline and 12 months, 12 months and 24 months, and baseline and 24‐month scores for the whole group. When age subgroups (<210 days, <2 years, 2–4 years, 5–11 years, 12–18 years) were considered, on the CHOP INTEND the difference was significant between baseline and 24 months in all age subgroups. On the HINE‐2, the difference between baseline and 24 months was significant in all the subgroups before the age of 4 years. Age was predictive of changes on both scales (P < 0.05), whereas SMN2 copy number and decimal classification were not.

Interpretation

Our results suggest that some improvement of motor function can be observed even after the first year of treatment. This is more obvious in the infants treated in the first 2 years but some improvement can also be found in older children.

Administration of nusinersen via paramedian approach for spinal muscular atrophy

OBJECTIVE

To assess the success rate, procedure time, and adverse events of intrathecal administration of nusinersen via the paramedian approach in adolescents and adults with spinal muscular atrophy (SMA) associated with scoliosis.

METHODS

Seven patients with genetically confirmed SMA (age, 12-40 years) were included. Intrathecal administration of nusinersen was performed via paramedian approach using fluoroscopy after determination of the largest interlaminal foramen among L2-L3, L3-L4, or L4-L5 by three-dimensional computed tomography. We measured the times for preparation, positioning, and puncture, and the total time of stay. Adverse effects of intrathecal administration were noted.

RESULTS

Intrathecal administration via paramedian approach was successful for all 38 opportunities. The median total time of stay was 44.0 min (interquartile range, 37.3-50.0 min). The total time of stay was significantly longer in patients with SMA type 1 than in those with SMA type 2, but was not different according to the severity of scoliosis. Adverse effects included oxygen supplementation, headache, and back pain. Sedation was correlated with oxygen supplementation and headache.

CONCLUSIONS

Intrathecal administration of nusinersen via the paramedian approach had the advantages of a high success rate and short procedure time with fewer adverse events in SMA patients associated with scoliosis.

Early experiences of nusinersen for the treatment of spinal muscular atrophy: Results from a large survey of patients and caregivers

Background

This study aimed to examine the early experience of nusinersen for spinal muscular atrophy (SMA) from the patient and caregiver perspective.

Methods

A 54‐item online survey was administered to adult patients and caregivers of pediatric patients diagnosed with SMA.

Results

Overall, respondents (56 patients and 45 caregivers) were satisfied with nusinersen. Satisfaction was highest on changes in energy, stamina, and motor function and lowest on treatment administration and overall time commitment. Differences were noted for treatment effect sustained over time as reported by adult patients vs caregivers reporting on behalf of pediatric patients. Respondents reported insurance approval as a key barrier to access, particularly among adult patients.

Conclusions

Despite therapeutic advances, there remain significant unmet needs for SMA. Challenges with administration and barriers to access potentially limit the number of patients treated or delay treatment. Continued efforts are needed to develop more treatment options and to improve access to treatments.

Spinal muscular atrophy - insights and challenges in the treatment era

Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease caused by deletion or mutation of SMN1. Four subtypes exist, characterized by different clinical severities. New therapeutic approaches have become available in the past few years, dramatically changing the natural history of all SMA subtypes, including substantial clinical improvement with the severe and advanced SMA type 1 variant. Trials have now demonstrated that phenotypic rescue is even more dramatic when pre-symptomatic patients are treated, and emerging real-world data are demonstrating the benefits of intervention even in the chronic phase of the condition. Here, we critically review how the field is rapidly evolving in response to the new therapies and questions that the new treatments have posed, including the effects of treatment at different ages and stages of disease, new phenotypes and long-term outcomes in patients who would not have survived without treatment, and decisions of who to treat and when. We also discuss how the outcomes associated with different timing of therapeutic intervention are contributing to our understanding of the biology and pathogenesis of SMA.

Age and baseline values predict 12 and 24-month functional changes in type 2 SMA

The aim of this retrospective study was to establish the range of functional changes at 12 and 24-month in 267 type 2 Spinal Muscular Atrophy (SMA) patients with multiple assessments. We included 652 Hammersmith Functional Motor Scale Expanded (HFMSE) assessments at 12 month- and 305 at 24 month- intervals. The cohort was subdivided by functional level, Survival of Motor Neuron copy number and age. Stable scores (± 2 points) were found in 68% at 12 months and in 55% at 24 months. A decrease ≥2 points was found in 21% at 12 months and in 35% at 24 months. An increase ≥2 points was found in 11% at 12 months and 9.5% at 24 months. The risk of losing ≥2 points increased with age and HFMSE score at baseline both at 12 and 24-month. For each additional HFMSE point at baseline, the relative risk of a >2 point decline at 12 months increases by 5% before age 5 years (p = 0.023), by 8% between 5 and 13 (p<0.001) and by 26% after 13 years (p = 0.003). The combination of age and HFMSE scores at baseline increased the ability to predict progression in type 2 SMA.

Effects of nusinersen after one year of treatment in 123 children with SMA type 1 or 2: a French real-life observational study

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder characterized by degeneration of the anterior horn cells of the spinal cord. Nusinersen has been covered by public healthcare in France since May 2017. The aim of this article is to report results after 1 year of treatment with intrathecal nusinersen in children with SMA types 1 and 2 in France. Comparisons between treatment onset (T0) and after 1 year of treatment (Y1) were made in terms of motor function and need for nutritional and ventilatory support. Motor development milestone achievements were evaluated using the modified Hammersmith Infant Neurologic Examination-Part 2 (HINE-2) for patients under 2 years of age and Motor Function Measure (MFM) scores for patients over 2 years of age.

RESULTS

Data on 204 SMA patients (type 1 or 2) were retrospectively collected from the 23 French centers for neuromuscular diseases. One hundred and twenty three patients had been treated for at least 1 year and were included, 34 of whom were classified as type 1 (10 as type 1a/b and 24 as type 1c) and 89 as type 2. Survival motor Neuron 2 (SMN2) copy numbers were available for all but 6 patients. Patients under 2 years of age (n = 30), had significantly higher HINE-2 scores at year 1 than at treatment onset but used more nutritional and ventilatory support. The 68 patients over 2 years of age evaluated with the Motor Function Measure test had significantly higher overall scores after 1 year, indicating that their motor function had improved. The scores were higher in the axial and proximal motor function (D2) and distal motor function (D3) parts of the MFM scale, but there was no significant difference for standing and transfer scores (D1). No child in either of the two groups achieved walking.

CONCLUSION

Nusinersen offers life-changing benefits for children with SMA, particularly those with more severe forms of the disorder. Caregiver assessments are positive. Nevertheless, patients remain severely disabled and still require intensive support care. This new treatment raises new ethical challenges.

Intrathecal delivery of nusinersen in individuals with complicated spines

BACKGROUND

The treatment of spinal muscular atrophy (SMA) with nusinersen requires intrathecal medication administration, which can be challenging in individuals with complicated spines. This retrospective case series reviews the nusinersen treatment experience at one academic medical center with children and adults with SMA and complicated spines.

METHODS

Twenty medical records of individuals receiving nusinersen were reviewed and administration methods summarized and assessed.

RESULTS

Ten children and 10 adults were treated, and 55% had complicated spines. In total, 163 treatments were given, 91 in those with complicated spines. In the complicated spines, 74% of treatments were done by means of fluoroscopic lumbar puncture, 22% by means of intrathecal Ommaya reservoir, 3% by means of palpation, and < 1% by means of computed tomography-guided transforaminal approach.

CONCLUSIONS

A large majority of individuals with complicated spines can receive intrathecal nusinersen using fluoroscopic guidance in the lumbar region. Other delivery methods are available but less frequently used.

Longitudinal natural history of type I spinal muscular atrophy: a critical review

Background

The advent of new therapies in spinal muscular atrophy (SMA) has highlighted the need to have natural history data for comparison. Natural history studies using structured assessments in type I however are very limited. We identified and reviewed all the existing longitudinal history data in infants with type I SMA first assessed before the age of 7 months with the Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND).

Main text

Three longitudinal natural history studies, two performed in the United States and one in Italy, were identified. The different study design of these three studies made it possible for the cumulative dataset to include the full spectrum of severity; from infants with neonatal onset to those with a milder phenotype that were not always included in the individual natural history studies. The cumulative analysis confirmed that, even in a larger cohort, there was never an improvement on the CHOP INTEND over time. This was true for all the infants, irrespective of their age or baseline CHOP INTEND scores. Infants with neonatal onset had low CHOP INTEND scores and a fast decline. The relatively large number of patients allowed us to calculate the rate of progression in subgroups identified according to SMN2 copy number and baseline CHOP INTEND scores.

Conclusion

A detailed understanding of the existing data is important, as it will be difficult to acquire new systematic longitudinal history data because of the availability of disease modifying therapies. The cumulative findings in this review help to better understand the variability of natural history data in untreated patients and will be of use for comparison to the real world patients treated with the recently approved therapies that have shown encouraging results in clinical trials.

Nusinersen as a Therapeutic Agent for Spinal Muscular Atrophy

The reduction of survival motor neuron (SMN) protein causes spinal muscular atrophy (SMA), an autosomal recessive neuromuscular disease. Nusinersen is an antisense oligonucleotide, approved by the FDA, which specifically binds to the repressor within SMN2 exon 7 to enhance exon 7 inclusion and augment production of functional SMN protein. Nusinersen is the first new oligonucleotide-based drug targeting the central nervous system for the treatment of SMA. This review of nusinersen will discuss its action mechanism, cellular uptake, trafficking mechanisms, and administration approaches to cross the blood-brain barrier. Furthermore, nusinersen clinical trials will be assessed in terms of pharmacokinetics, tolerability and safety, the clinical outcomes of multiple intrathecal doses, and a discussion on the primary and secondary endpoints.

Nusinersen in type 1 spinal muscular atrophy: Twelve-month real-world data

OBJECTIVE

The aim of the study was to report 12-month changes after treatment with nusinersen in a cohort of 85 type I spinal muscular atrophy patients of ages ranging from 2 months to 15 years and 11 months.

METHODS

All patients were assessed using the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) and the Hammersmith Infant Neurological Examination-Section 2 (HINE-2).

RESULTS

Two of the 85 patients had 1 SMN2 copy, 61 had 2 copies, and 18 had 3 copies. In 4 patients the SMN2 copy number was not available. At baseline, the mean CHOP INTEND scores ranged between 0 and 52 (mean = 15.66, standard deviation [SD] = ±13.48), and the mean HINE-2 score was between 0 and 5 (mean = 0.69, SD = ±1.23). There was a difference between baseline and the 12-month scores on both the CHOP INTEND and the HINE-2 for the whole group (p < 0.001), the subgroups with 2 SMN2 copies (p < 0.001), and those with 3 SMN2 copies (p < 0.001). The difference was found not only in patients younger than 210 days at baseline (p < 0.001) but also in those younger than 5 years on the CHOP INTEND and younger than 2 years on the HINE-2.

INTERPRETATION

Our results, expanding the age range and the severity of type I patients treated with nusinersen over 1 year, provide additional data on the range of efficacy of the drug that will be helpful in making an informed decision on whether to start treatment in patients of different ages and severity. ANN NEUROL 2019;86:443-451.

Intrathecal administration of nusinersen in adolescent and adult SMA type 2 and 3 patients

Spinal muscular atrophy is a genetic motor neuron disease that leads to progressive muscular atrophy and muscle weakness. In December 2016, the Food and Drug Administration, and in June 2017, the European Medicines Agency approved the antisense oligonucleotide nusinersen for treatment of spinal muscular atrophy. Nusinersen has to be repeatedly administered intrathecally. Due to the clinical features of SMA, the application of the ASO by lumbar puncture can be challenging in symptomatic patients considering the frequently observed scoliosis, previous spine fusion surgeries, joint contractures, and respiratory insufficiency. To evaluate safety and feasibility of the intrathecal treatment in adolescent and adult SMA type 2 and 3 patients, we analyzed 93 lumbar punctures, monitored number of lumbar puncture attempts, duration of the procedure, injection site, and needle length. Oxygen saturation during the intervention, medication for sedation and local anesthesia, adverse events related to lumbar punctures, and macroscopic analysis of CSF were recorded. Moreover, we analyzed the use of CT-scans for performing lumbar punctures and its associated radiation exposure. Performing lumbar puncture for the intrathecal administration of nusinersen in adolescent and adult patients with later-onset SMA is feasible and safe, even in patients with complex spinal anatomies and respiratory insufficiency. To guarantee the quality of the procedure, we recommend establishing an experienced interdisciplinary team consisting of neurologists and/or neuropediatricians, anesthesiologists, orthopedic surgeons, and/or neuroradiologists.

Intrathecal nusinersen treatment for SMA in a dedicated neuromuscular clinic: an example of multidisciplinary and integrated care

Nusinsersen is now available in Italy for all SMA types. We describe the experience with intrathecal treatment with nusinersen in 50 patients with SMA at the NEMO Center (NEuroMuscular Omniservice Clinical Center) in Milan, a neuromuscular patient-centered clinic hosted within Niguarda Hospital, a National Public General Hospital. Our results indicate that the pathway of care described outweighs the burden due to the repeated intrathecal injections. Irrespective of age and severity, the treatment is feasible, accessible, and replicable provided that there is a multidisciplinary team having experience and training in SMA.

A comprehensive institutional overview of intrathecal nusinersen injections for spinal muscular atrophy

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal-recessive neuromuscular disorder resulting in progressive muscle weakness. In December 2016, the U.S. Food and Drug Administration approved the first treatment for SMA, a drug named nusinersen (Spinraza) that is administered intrathecally. However many children with SMA have neuromuscular scoliosis or spinal instrumentation resulting in challenging intrathecal access. Therefore alternative routes must be considered in these complex patients.

OBJECTIVE

To investigate routes of drug access, we reviewed our institutional experience of administering intrathecal nusinersen in all children with spinal muscular atrophy regardless of spinal anatomy or instrumentation.

MATERIALS AND METHODS

We reviewed children with SMA who were referred for intrathecal nusinersen injections from March to December 2017 at our institution. In select children with spinal hardware, spinal imaging was requested to facilitate pre-procedure planning. Standard equipment for intrathecal injections was utilized. All children were followed up by their referring neurologist.

RESULTS

A total of 104 intrathecal nusinersen injections were performed in 26 children with 100% technical success. Sixty procedures were performed without pre-procedural imaging and via standard interspinous technique. The remaining 44 procedures were performed in 11 complex (i.e. neuromuscular scoliosis or spinal instrumentation) patients requiring pre-procedural imaging for planning purposes. Nineteen of the 44 complex procedures were performed via standard interspinous technique from L2 to S1. Twenty-two of the 44 complex procedures were performed using a neural-foraminal approach from L3 to L5. Three of the 44 complex procedures were performed via cervical puncture technique. There were no immediate or long-term complications but there was one child with short-term complications of meningismus and back pain at the injection site.

CONCLUSION

Although we achieved 100% technical success in intrathecal nusinersen administration, our practices evolved during the course of this study. As a result of our early experience we developed an algorithm to assist in promoting safe and effective nusinersen administration in children with spinal muscular atrophy regardless of SMA type, abnormal spinal anatomy and complex spinal instrumentation.

Glial Activation and Central Synapse Loss, but Not Motoneuron Degeneration, Are Prevented by the Sigma-1 Receptor Agonist PRE-084 in the Smn2B/- Mouse Model of Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is characterized by the loss of α-motoneurons (MNs) with concomitant muscle denervation. MN excitability and vulnerability to disease are particularly regulated by cholinergic synaptic afferents (C-boutons), in which Sigma-1 receptor (Sig1R) is concentrated. Alterations in Sig1R have been associated with MN degeneration. Here, we investigated whether a chronic treatment with the Sig1R agonist PRE-084 was able to exert beneficial effects on SMA. We used a model of intermediate SMA, the Smn2B/- mouse, in which we performed a detailed characterization of the histopathological changes that occur throughout the disease. We report that Smn2B/- mice exhibited qualitative differences in major alterations found in mouse models of severe SMA: Smn2B/- animals showed more prominent MN degeneration, early motor axon alterations, marked changes in sensory neurons, and later MN deafferentation that correlated with conspicuous reactive gliosis and altered neuroinflammatory M1/M2 microglial balance. PRE-084 attenuated reactive gliosis, mitigated M1/M2 imbalance, and prevented MN deafferentation in Smn2B/- mice. These effects were also observed in a severe SMA model, the SMNΔ7 mouse. However, the prevention of gliosis and MN deafferentation promoted by PRE-084 were not accompanied by any improvements in clinical outcome or other major pathological changes found in SMA mice.

Preliminary Safety and Tolerability of a Novel Subcutaneous Intrathecal Catheter System for Repeated Outpatient Dosing of Nusinersen to Children and Adults With Spinal Muscular Atrophy

BACKGROUND

Many patients with spinal muscular atrophy (SMA) who might benefit from intrathecal antisense oligonucleotide (nusinersen) therapy have scoliosis or spinal fusion that precludes safe drug delivery. To circumvent spinal pathology, we designed a novel subcutaneous intrathecal catheter (SIC) system by connecting an intrathecal catheter to an implantable infusion port.

METHODS

Device safety and tolerability were tested in 10 SMA patients (age, 5.4 to 30.5 y; 80% with 3 copies of SMN2); each received 3 sequential doses of nusinersen (n=30 doses). Pretreatment disease burden was evaluated using the Revised Hammersmith Scale, dynamometry, National Institutes of Health pegboard, pulmonary function testing, electromyography, and 2 health-related quality of life tools.

RESULTS

Device implantation took ≤2 hours and was well tolerated. All outpatient nusinersen doses were successfully administered via SIC within 20 minutes on the first attempt, and required no regional or systemic analgesia, cognitive distraction, ultrasound guidance, respiratory precautions, or sedation. Cerebrospinal fluid withdrawn from the SIC had normal levels of glucose and protein; cerebrospinal fluid white blood cells were slightly elevated in 2 (22%) of 9 specimens (median, 1 cell/µL; range, 0 to 12 cells/µL) and red blood cells were detected in 7 (78%) specimens (median, 4; range, 0 to 2930 cells/µL).

DISCUSSION

Preliminary observations reveal the SIC to be relatively safe and well tolerated in SMA patients with advanced disease and spinal fusion. The SIC warrants further study and, if proven effective in larger trials of longer duration, could double the number of patients able to receive nusinersen worldwide while reducing administration costs 5- to 10-fold.