Nusinersen safety and effects on motor function in adult spinal muscular atrophy type 2 and 3

Six-minute walk test as outcome measure of fatigability in adults with spinal muscular atrophy treated with nusinersen

INTRODUCTION/AIMS

Fatigue (subjective perception) and fatigability (objective motor performance worsening) are relevant aspects of disability in individuals with spinal muscular atrophy (SMA). The effect of nusinersen on fatigability in SMA patients has been investigated with conflicting results. We aimed to evaluate this in adult with SMA3.

METHODS

We conducted a multicenter retrospective cohort study, including adult ambulant patients with SMA3, data available on 6-minute walk test (6MWT) and Hammersmith Functional Motor Scale-Expanded (HFMSE) at baseline and at least at 6 months of treatment with nusinersen. We investigated fatigability, estimated as 10% or higher decrease in walked distance between the first and sixth minute of the 6MWT, at baseline and over the 14-month follow-up.

RESULTS

Forty-eight patients (56% females) were included. The 6MWT improved after 6, 10, and 14 months of treatment (p < 0.05). Of the 27 patients who completed the entire follow-up, 37% improved (6MWT distance increase ≥30 m), 48.2% remained stable, and 14.8% worsened (6MWT distance decline ≥30 m). Fatigability was found at baseline in 26/38 (68%) patients and confirmed at subsequent time points (p < 0.05) without any significant change over the treatment period. There was no correlation between fatigability and SMN2 copy number, sex, age at disease onset, age at baseline, nor with 6MWT total distance and baseline HFMSE score.

DISCUSSION

Fatigability was detected at baseline in approximately 2/3 of SMA3 walker patients, without any correlation with clinical features, included motor performance. No effect on fatigability was observed during the 14-month treatment period with nusinersen.

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.

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.

Evaluation of inpatient and emergency department healthcare resource utilization and costs pre- and post-nusinersen for the treatment of spinal muscular atrophy using United States claims

Aim: Nusinersen, administered by intrathecal injection at a dose of 12 mg, is indicated across all ages for the treatment of spinal muscular atrophy (SMA). Evidence on real-world healthcare resource use (HRU) and costs among patients taking nusinersen remains limited. This study aimed to evaluate real-world HRU and costs associated with nusinersen use through US claims databases. Patients & methods: Using the Merative™ MarketScan® Research Databases, patients with SMA receiving nusinersen were identified from commercial (January 2017 to June 2020) and Medicaid claims (January 2017 to December 2019). Those likely to have complete information on the date of nusinersen initiation and continuous enrollment 12 months pre- and post-index (first record of nusinersen treatment) were retained. Number and costs (US$ 2020) of inpatient admissions and emergency department (ED) visits, unrelated to nusinersen administration, were evaluated for 12 months pre- and post-nusinersen initiation and stratified by age: pediatric (<18 years) and adult (≥18 years). Results: Overall, 103 individuals treated with nusinersen were retained: 59 were pediatric (mean age [range]: 9 [1-17] years), and 44 were adults (30 [18-63] years). Inpatient admissions decreased by 41% for pediatrics and 67% for adults in the 12 months post-treatment versus the 12 months pre-treatment. Average inpatient admission costs per patient for the pediatric cohort decreased by 63% ($22,903 vs $8466) and by 79% ($13,997 vs $2899) for the adult cohort when comparing the 12 months pre-index with the 12 months post-index period. Total ED visits and ED visit costs decreased by 8% and 35%, respectively, for the overall cohort over the 12-month period pre- and post-index. Conclusion: Using US claims databases, nusinersen treatment in pediatric and adult patients was associated with reductions in HRU and costs over a 12-month period post-treatment initiation relative to the pre-treatment period.

Smartphone-Based Assessment of Mobility and Manual Dexterity in Adult People with Spinal Muscular Atrophy

Background

More responsive, reliable, and clinically valid endpoints of disability are essential to reduce size, duration, and burden of clinical trials in adult persons with spinal muscular atrophy (aPwSMA).

Objective

The aim is to investigate the feasibility of smartphone-based assessments in aPwSMA and provide evidence on the reliability and construct validity of sensor-derived measures (SDMs) of mobility and manual dexterity collected remotely in aPwSMA.

Methods

Data were collected from 59 aPwSMA (23 walkers, 20 sitters and 16 non-sitters) and 30 age-matched healthy controls (HC). SDMs were extracted from five smartphone-based tests capturing mobility and manual dexterity, which were administered in-clinic and remotely in daily life for four weeks. Reliability (Intraclass Correlation Coefficients, ICC) and construct validity (ability to discriminate between HC and aPwSMA and correlations with Revised Upper Limb Module, RULM and Hammersmith Functional Scale - Expanded HFMSE) were quantified for all SDMs.

Results

The smartphone-based assessments proved feasible, with 92.1% average adherence in aPwSMA. The SDMs allowed to reliably assess both mobility and dexterity (ICC > 0.75 for 15/22 SDMs). Twenty-one out of 22 SDMs significantly discriminated between HC and aPwSMA. The highest correlations with the RULM were observed for SDMs from the manual dexterity tests in both non-sitters (Typing, ρ= 0.78) and sitters (Pinching, ρ= 0.75). In walkers, the highest correlation was between mobility tests and HFMSE (5 U-Turns, ρ= 0.79).

Conclusions

This exploratory study provides preliminary evidence for the usability of smartphone-based assessments of mobility and manual dexterity in aPwSMA when deployed remotely in participants' daily life. Reliability and construct validity of SDMs remotely collected in real-life was demonstrated, which is a pre-requisite for their use in longitudinal trials. Additionally, three novel smartphone-based performance outcome assessments were successfully established for aPwSMA. Upon further validation of responsiveness to interventions, this technology holds potential to increase the efficiency of clinical trials in aPwSMA.

A Post-Marketing Surveillance Study of Nusinersen for Spinal Muscular Atrophy in Routine Medical Practice in China: Interim Results

INTRODUCTION

Spinal muscular atrophy (SMA) is a rare, autosomal recessive, neuromuscular disease that leads to progressive muscular weakness and atrophy. Nusinersen, an antisense oligonucleotide, was approved for SMA in China in February 2019. We report interim results from a post-marketing surveillance phase 4 study, PANDA (NCT04419233), that collects data on the safety, efficacy, and pharmacokinetics of nusinersen in children with SMA in routine clinical practice in China.

METHODS

Participants enrolled in PANDA will be observed for 2 years following nusinersen treatment initiation. The primary endpoint is the incidence of adverse events (AEs)/serious AEs (SAEs) during the treatment period. Efficacy assessments include World Health Organization (WHO) Motor Milestones assessment, the Hammersmith Infant Neurological Examination (HINE), and ventilation support. Plasma and cerebrospinal fluid (CSF) concentrations of nusinersen are measured at each dose visit.

RESULTS

Fifty participants were enrolled as of the January 4, 2023, data cutoff: 10 with infantile-onset (≤ 6 months) and 40 with later-onset (> 6 months) SMA. All 50 participants have received at least one dose of nusinersen; 6 have completed the study. AEs were experienced by 45 (90%) participants and were mostly mild/moderate; no AEs led to nusinersen discontinuation or study withdrawal. Eleven participants experienced SAEs, most commonly pneumonia (n = 9); none were considered related to study treatment. Stability or gain of WHO motor milestone was observed and mean HINE-2 scores improved in both subgroups throughout the study. No serious respiratory events occurred, and no permanent ventilation support was initiated during the study. Pre-dose nusinersen CSF concentrations increased steadily through the loading-dose period, with no accumulation in plasma after multiple doses.

CONCLUSION

Nusinersen was generally well tolerated with an acceptable overall safety profile, consistent with the known safety of nusinersen. Efficacy, safety, and nusinersen exposure are consistent with prior observations. These results support continuing PANDA and evaluation of nusinersen in Chinese participants with SMA.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04419233.

Neurofilament light chain and profilin-1 dynamics in 30 spinal muscular atrophy type 3 patients treated with nusinersen

BACKGROUND AND PURPOSE

The aim was to investigate whether neurofilament light chain (NfL) and profilin-1 (PFN-1) might qualify as surrogate disease and treatment-response biomarkers by correlating their concentrations dynamic with clinical status in a cohort of 30 adult spinal muscular atrophy type 3 patients during nusinersen therapy up to 34 months.

METHODS

Neurofilament light chain was measured in cerebrospinal fluid at each drug administration with a commercial enzyme-linked immunosorbent assay (ELISA); PFN-1 concentrations were tested in serum sampled at the same time points with commercial ELISA assays. Functional motor scores were evaluated at baseline, at the end of the loading phase and at each maintenance dose and correlated to biomarker levels. The concurrent effect of age and clinical phenotype was studied.

RESULTS

Neurofilament light chain levels were included in the reference ranges at baseline; a significant increase was measured during loading phase until 1 month. PFN-1 was higher at baseline than in controls and then decreased during therapy until reaching control levels. Age had an effect on NfL but not on PFN-1. NfL was partially correlated to functional scores at baseline and at last time point, whilst no correlation was found for PFN-1.

CONCLUSION

Cerebrospinal fluid NfL levels did not qualify as an optimal surrogate treatment biomarker in adult spinal muscular atrophy patients with a long disease duration, whilst PFN-1 might to a greater extent represent lower motor neuron pathological processes. The observed biomarker level variation during the first 2 months of nusinersen treatment might suggest a limited effect on axonal remodeling or rearrangement.

Patients' Perceptions of Nusinersen Effects According to Their Responder Status

Background and Objective: Patients with spinal muscular atrophy (SMA) treated with a disease-modifying therapy (DMT) are often classified as responders or non-responders based on the attainment of a specific improvement threshold on validated functional scales. This categorization may significantly impact treatment reimbursement in some countries. The aim of this research is to evaluate the perception of treatments and their benefit by patients considered as responders or non-responders. Methods: In this non-commercial multicenter study, 99 post-symptomatically treated SMA type I-III patients with a median age of 11.2 (0.39-57.4) years at treatment initiation were stratified into three groups based on their treatment outcomes, i.e., those exhibiting clinically significant improvement (N = 41), those with non-clinically significant improvement (N = 18), or those showing no improvement (N = 40). Fifteen months after treatment, the initiation patients or patients' caregivers were assessed using a patient-rated scoring system based on the Patient Global Impression of Change (PGIC) scale, comprising 22 questions targeting important aspects and tasks in the daily life of patients with SMA. Results: We found no statistical difference in the patient perception of treatment benefits in 17 out of 22 domains across patient groups. Conclusions: Our results suggest that functional motor scales do not recapitulate patients' and patients' caregivers' experience of the effect of nusinersen treatment in SMA.

Risdiplam improves subjective swallowing quality in non-ambulatory adult patients with 5q-spinal muscular atrophy despite advanced motor impairment

BACKGROUND

5q-associated spinal muscular atrophy (SMA) is characterized by the progressive loss of motor neurons with consecutive weakness and atrophy of the limb, respiratory, and bulbar muscles. While trunk and limb motor function improve or stabilize in adults with SMA under nusinersen and risdiplam treatment, the efficacy on bulbar function in this age group of patients remains uncertain. However, it is important to assess bulbar dysfunction, which frequently occurs in the disease course and is associated with increased morbidity and mortality.

METHODS

Bulbar function was evaluated prospectively in 25 non-ambulatory adults with type 2 and 3 SMA before and 4 and 12 months after risdiplam treatment initiation using the Sydney Swallow Questionnaire (SSQ) and the bulbar subscore of the Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (b-ALSFRS-R). Extremity function was assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE) and Revised Upper Limb Module (RULM).

RESULTS

Subjective swallowing quality, measured with the SSQ, improved after 12 months of therapy with risdiplam. For the b-ALSFRS-R, a non-significant trend towards improvement was observed. The RULM score improved after 12 months of risdiplam therapy, but not the HFMSE score. HFMSE and RULM scores did not correlate with the SSQ but the b-ALSFRS-R score at baseline.

CONCLUSIONS

The improvement in subjective swallowing quality under risdiplam treatment, despite an advanced disease stage with severe motor deficits, strengthens the importance of a standardized bulbar assessment in addition to established motor scores. This may reveal relevant treatment effects and help individualize treatment decisions in the future.

'Reading the palm' - A pilot study of grip and finger flexion strength as an outcome measure in 5q spinal muscular atrophy

BACKGROUND

Innovative RNA modifying and gene replacement therapies are currently revolutionizing the therapeutic landscape in 5q-associated spinal muscular atrophy (SMA). In order to provide individual recommendations for choice of treatment and therapy (dis-) continuation, objective outcome measures are needed. The purpose of this study was to determine whether maximum isometric voluntary grip and finger flexion strength is a useful sensitive outcome measure in children and adult patients with SMA.

METHODS

In this non-interventional, longitudinal pilot study, we assessed grip and finger flexion strength on 39 patients with SMA II and III (n = 16 children, mean age = 10.0; n = 23 adults, mean age = 38.4) using the Weber hand and finger dynamometer HFD 200. Grip and finger flexion strength, clinical examinations and motor function scores (Revised Upper Limb Module, Hammersmith Functional Motor Scale Expanded) were assessed over a 12-month treatment period concurrent with the nusinersen treatment.

RESULTS

Grip and finger flexion strength was highly associated with motor function and disease severity, SMA type and SMN2 copy number. During nusinersen treatment, grip and finger flexion strength significantly increased in children and adults with SMA.

CONCLUSION

Grip and finger flexion strength measured with the HFD 200 is a promising sensitive outcome measure for SMA.

Molecular mechanisms and therapeutic strategies for neuromuscular diseases

Neuromuscular diseases encompass a heterogeneous array of disorders characterized by varying onset ages, clinical presentations, severity, and progression. While these conditions can stem from acquired or inherited causes, this review specifically focuses on disorders arising from genetic abnormalities, excluding metabolic conditions. The pathogenic defect may primarily affect the anterior horn cells, the axonal or myelin component of peripheral nerves, the neuromuscular junction, or skeletal and/or cardiac muscles. While inherited neuromuscular disorders have been historically deemed not treatable, the advent of gene-based and molecular therapies is reshaping the treatment landscape for this group of condition. With the caveat that many products still fail to translate the positive results obtained in pre-clinical models to humans, both the technological development (e.g., implementation of tissue-specific vectors) as well as advances on the knowledge of pathogenetic mechanisms form a collective foundation for potentially curative approaches to these debilitating conditions. This review delineates the current panorama of therapies targeting the most prevalent forms of inherited neuromuscular diseases, emphasizing approved treatments and those already undergoing human testing, offering insights into the state-of-the-art interventions.

Respiratory function in adult patients with spinal muscular atrophy treated with nusinersen - a monocenter observational study

Background/objective

Insufficiency of respiratory muscles is the most important reason for mortality in the natural history of SMA. Thus, improvement or stabilization of respiratory function by disease-modifying therapies (DMT) is a very important issue.

Methods

We examined respiratory function using forced vital capacity (FVC) in 42 adult SMA patients (2 SMA type 1, 15 SMA type 2, 24 SMA type 3, 1 SMA type 4, median age 37 years, range 17-61 years) treated with nusinersen for a median of 22.1 months (range 2.1 to 46.7 months). Change in FVC was assessed using mixed effects linear regression models.

Results

Baseline FVC differed significantly between SMA type 1 (4.0, 8.0%), 2 (median 22.0%, IQR 18.0-44.0), 3 (median 81.0%, IQR 67.0-90.8) and, respectively, type 4 (84.0%) patients reflecting the heterogeneity of respiratory impairment based on the SMA type in adulthood (p < 0.0001). FVC remained stable during follow-up (mean -0.047, 95% CI -0.115 to 0.020, p = 0.17); however, subgroup analysis showed an increase in FVC of type 2 patients (mean 0.144, 95% CI 0.086 to 0.202, p < 0.0001) and a decrease in FVC of type 3/4 patients (-0.142, 95% CI -0.239 to -0.044, p = 0.005).

Conclusion

The observed improvement in FVC in patients with SMA type 2 can be seen as a therapeutic response differing from the progressive decline typically seen in the spontaneous course. For SMA type 3/4 patients approaching normal spirometry at baseline, FVC may only be of limited use as an outcome parameter due to ceiling effects.

Neurodegeneration Biomarkers in Adult Spinal Muscular Atrophy (SMA) Patients Treated with Nusinersen

The objective of this study is to evaluate biomarkers for neurodegenerative disorders in adult SMA patients and their potential for monitoring the response to nusinersen. Biomarkers for neurodegenerative disorders were assessed in plasma and CSF samples obtained from a total of 30 healthy older adult controls and 31 patients with adult SMA type 2 and 3. The samples were collected before and during nusinersen treatment at various time points, approximately at 2, 6, 10, and 22 months. Using ELISA technology, the levels of total tau, pNF-H, NF-L, sAPPβ, Aβ40, Aβ42, and YKL-40 were evaluated in CSF samples. Additionally, plasma samples were used to measure NF-L and total tau levels using SIMOA technology. SMA patients showed improvements in clinical outcomes after nusinersen treatment, which were statistically significant only in walkers, in RULM (p = 0.04) and HFMSE (p = 0.05) at 24 months. A reduction in sAPPβ levels was found after nusinersen treatment, but these levels did not correlate with clinical outcomes. Other neurodegeneration biomarkers (NF-L, pNF-H, total tau, YKL-40, Aβ40, and Aβ42) were not found consistently changed with nusinersen treatment. The slow progression rate and mild treatment response of adult SMA types 2 and 3 may not lead to detectable changes in common markers of axonal degradation, inflammation, or neurodegeneration, since it does not involve large pools of damaged neurons as observed in pediatric forms. However, changes in biomarkers associated with the APP processing pathway might be linked to treatment administration. Further studies are warranted to better understand these findings.

A Real-World Study of Nusinersen Effects in Adults with Spinal Muscular Atrophy Type 2 and 3

BACKGROUND

Spinal muscular atrophy (SMA) is a progressive genetic disorder characterized by muscle weakness ultimately leading to pulmonary impairments that can be fatal. The recent approval of nusinersen, a disease-modifying therapy, substantially changed the prognosis for patients, particularly in children. However, real-world evidence about its long-term effectiveness in adults remains limited. This study aimed to document longitudinal data on motor function, pulmonary function and patient-reported outcome measures of Canadian adults with SMA type 2 and 3 treated with nusinersen.

METHODS

Outcomes from 17 patients were collected at the Institut de réadaptation en déficience physique de Québec during routine clinical visits over 36 months post nusinersen treatment, using the Hammersmith Functional Motor Scale Expanded for SMA (HFMSE), Revised Upper Limb Module (RULM), 6-Minute Walk Test (6MWT), Children's Hospital of Philadelphia Adult Test of Neuromuscular Disorders (CHOP-ATEND), SMA functional rating scale (SMAFRS), pulmonary function testing and subjective changes reported by patients.

RESULTS

After 36 months, 9 patients showed motor function improvement. Changes beyond the minimal clinically important difference were seen for four patients on the HFMSE, four patients on the RULM and five patients on the 6MWT. Pulmonary function remained stable for most subjects. Subjective positive changes were reported in 88% of patients and five patients showed improvement in the SMAFRS.

CONCLUSION

This real-world study demonstrates the positive effects of nusinersen in adults with SMA types 2 and 3. Although stabilizing the patient's condition is considered therapeutic success, this study shows an improvement in motor function and subjective gains in several patients.

Assessment of the upper limb function, strength, and mobility in treatment-naive children with spinal muscular atrophy Types 2 and 3

INTRODUCTION/AIMS

Current upper limb assessments in pediatric spinal muscular atrophy (SMA) may not adequately capture change with disease progression. Our aim was to examine the relationship between motor function, strength, and hand/finger mobility of the upper limb in treatment-naïve children with SMA Types 2 and 3 to assess new methods to supplement current outcomes.

METHODS

The Revised Upper Limb Module (RULM), grip and pinch strength, and hand/finger mobility data were collected from 19 children with SMA Types 2 and 3 aged 5.2-16.9 years over a year.

RESULTS

A median loss between 0.5 and 2.5 points in the RULM was seen across all SMA subgroups with the biggest median loss recorded between 10 and 14 years of age. The grip strength loss was -0.06 kg (-4.69 to 3.49; IQR, 1.21); pinch improvement of 0.05 (-0.65 to 1.27; IQR, 0.48); hand/finger mobility test improvement of 4 points (-24 to 14; IQR, 6.75) for the whole cohort. Significant correlations were found between the RULM and grip strength (p < .001), RULM and pinch strength (p < .001), RULM and revised Brooke (p < .001), grip strength and pinch strength (p < .001).

DISCUSSION

The combined use of the RULM, dynamometry, and hand mobility provide insight about correlations between function and strength in children with SMA. The RULM and grip strength assessments captured a significant decline in upper limb function, whereas the pinch and finger/hand mobility showed an improvement over the course of 1 year and these results should be considered for future studies.

Effect of nusinersen treatment on quality of life and motor function in adult patients with spinal muscular atrophy

The aim of this study was to assess the effect of 4 loading doses of nusinersen on motor function and quality of life (QoL) in adult patients with spinal muscular atrophy (SMA). Twenty-one adult patients with genetically confirmed SMA who were treated with 4 loading doses of nusinersen were included in this study. All patients were evaluated with the Medical Research Council (MRC) scale, the Hammersmith Functional Motor Scale Expanded (HFMSE), and the Short Form Survey-36 (SF-36) at baseline (V1) and before the first nusinersen maintenance treatment, which was at the 15th month of treatment (V2). The SF-36 score was compared between the patients and 35 age-matched healthy controls. Of the twenty-one patients with a median age of 36 years, 10 were nonambulatory, and 11 were ambulatory. The physical component score and the mental component score of the SF-36 were significantly lower in the SMA patient group at baseline than in the healthy group. The median HFMSE scores significantly improved at V2 in both ambulatory and nonambulatory SMA patients (p < 0.05). The median MRC score significantly increased at V2 in the ambulatory SMA patient group (p = 0.04) but not in the nonambulatory SMA patient group (p = 0.19). There was a significant improvement in physical QoL in all the SMA patients at V2 (p = 0.02), but there was no significant improvement in mental QoL (p = 0.15). The loading nusinersen treatment significantly improved motor function scores, muscle strength, and physical QoL.

Multidisciplinary team meetings in treatment of spinal muscular atrophy adult patients: a real-life observatory for innovative treatments

BACKGROUND

In 2017, a new treatment by nusinersen, an antisense oligonucleotide delivered by repeated intrathecal injections, became available for patients with spinal muscular atrophy (SMA), whereas clinical trials had mainly involved children. Since 2020, the oral, selective SMN2-splicing modifier risdiplam has been available with restrictions evolving with time. In this peculiar context of lack of data regarding adult patients, many questions were raised to define the indications of treatment and the appropriate follow-up in this population. To homogenize access to treatment in France, a national multidisciplinary team meeting dedicated to adult SMA patients, named SMA multidisciplinary team meeting, (SMDTs) was created in 2018. Our objective was to analyze the value of SMDTs in the decision-making process in SMA adult patients and to provide guidelines about treatment.

METHODS

From October 2020 to September 2021, data extracted from the SMDT reports were collected. The primary outcome was the percentage of cases in which recommendations on validating treatment plans were given. The secondary outcomes were type of treatment requested, description of expectations regarding treatment and description of recommendations or follow-up and discontinuation. Data were analyzed using descriptive statistics. Comparisons between the type of treatment requested were performed using Mann-Whitney test or the Student t test for quantitative data and the Fisher's exact test or the χ2 test for qualitative data.

RESULTS

Cases of 107 patients were discussed at the SMDTs with a mean age of 35.3 (16-62). Forty-seven were SMA type 2, and 57 SMA type 3. Twelve cases were presented twice. Out of 122 presentations to the SMDTs, most of requests related to the initiation of a treatment (nusinersen (n = 46), risdiplam (n = 54), treatment without mentioning preferred choice (n = 5)) or a switch of treatment (n = 12). Risdiplam requests concerned significantly older patients (p = 0.002), mostly SMA type 2 (p < 0.0001), with greater disease severity in terms of motor and respiratory function compared to requests for nusinersen. In the year prior to presentation to the SMDTs, most of the patients experienced worsening of motor weakness assessed by functional tests as MFM32 or other meaningful scales for the most severe patients. Only 12% of the patients discussed had a stable condition. Only 49/122 patients (40.1%) expressed clear expectations regarding treatment. The treatment requested was approved by the SMDTs in 72 patients (67.2%). The most common reasons to decline treatment were lack of objective data on the disease course prior discussion to the SMDTs or inappropriate patient's expectations. Treatment requests were more likely to be validated by the SMDTs if sufficient pre-therapeutic functional assessment had been performed to assess the natural history (55% vs. 32%) and if the patient had worsening rather than stable motor function (p = 0.029). In patients with approved treatment, a-priori criteria to define a further ineffectiveness of treatment (usually after 14 months of treatment) were proposed for 67/72 patients.

CONCLUSIONS

In the context of costly treatments with few controlled studies in adults with SMA, in whom assessment of efficacy can be complex, SMDTs are 'real-world observatories' of great interest to establish national recommendations about indications of treatment and follow-up.

Monitoring Nusinersen Treatment Effects in Children with Spinal Muscular Atrophy with Quantitative Muscle MRI

BACKGROUND

Spinal muscular atrophy (SMA) is caused by deficiency of survival motor neuron (SMN) protein. Intrathecal nusinersen treatment increases SMN protein in motor neurons and has been shown to improve motor function in symptomatic children with SMA.

OBJECTIVE

We used quantitative MRI to gain insight in microstructure and fat content of muscle during treatment and to explore its use as biomarker for treatment effect.

METHODS

We used a quantitative MRI protocol before start of treatment and following the 4th and 6th injection of nusinersen in 8 children with SMA type 2 and 3 during the first year of treatment. The MR protocol allowed DIXON, T2 mapping and diffusion tensor imaging acquisitions. We also assessed muscle strength and motor function scores.

RESULTS

Fat fraction of all thigh muscles with the exception of the m. adductor longus increased in all patients during treatment (+3.2%, p = 0.02). WaterT2 showed no significant changes over time (-0.7 ms, p = 0.3). DTI parameters MD and AD demonstrate a significant decrease in the hamstrings towards values observed in healthy muscle.

CONCLUSIONS

Thigh muscles of children with SMA treated with nusinersen showed ongoing fatty infiltration and possible normalization of thigh muscle microstructure during the first year of nusinersen treatment. Quantitative muscle MRI shows potential as biomarker for the effects of SMA treatment strategies.

Assessing the Assisted Six-Minute Cycling Test as a Measure of Endurance in Non-Ambulatory Patients with Spinal Muscular Atrophy (SMA)

Assessing endurance in non-ambulatory individuals with Spinal Muscular Atrophy (SMA) has been challenging due to limited evaluation tools. The Assisted 6-Minute Cycling Test (A6MCT) is an upper limb ergometer assessment used in other neurologic disorders to measure endurance. To study the performance of the A6MCT in the non-ambulatory SMA population, prospective data was collected on 38 individuals with SMA (13 sitters; 25 non-sitters), aged 5 to 74 years (mean = 30.3; SD = 14.1). The clinical measures used were A6MCT, Revised Upper Limb Module (RULM), Adapted Test of Neuromuscular Disorders (ATEND), and Egen Klassifikation Scale 2 (EK2). Perceived fatigue was assessed using the Fatigue Severity Scale (FSS), and effort was assessed using the Rate of Perceived Exertion (RPE). Data were analyzed for: (1) Feasibility, (2) Clinical discrimination, and (3) Associations between A6MCT with clinical characteristics and outcomes. Results showed the A6MCT was feasible for 95% of the tested subjects, discriminated between functional groups (p = 0.0086), and was significantly associated with results obtained from RULM, ATEND, EK2, and Brooke (p < 0.0001; p = 0.029; p < 0.001; p = 0.005). These findings indicate the A6MCT's potential to evaluate muscular endurance in non-ambulatory SMA individuals, complementing clinician-rated assessments. Nevertheless, further validation with a larger dataset is needed for broader application.

Differential impact on motor unit characteristics across severities of adult spinal muscular atrophy

OBJECTIVE

To test the hypotheses that decomposition electromyography (dEMG) motor unit action potential (MUAP) amplitude and firing rate are altered in SMA; dEMG parameters are associated with strength and function; dEMG parameters are correlated with traditional electrophysiological assessments.

METHODS

Ambulatory and non-ambulatory adults with SMA on nusinersen and healthy controls were enrolled. MUAPs were decomposed from multielectrode surface recordings during 30-s maximum contraction of the abductor digiti minimi (ADM). Isometric strength, upper limb function, patient-reported function, and standard electrophysiologic measures of the ADM (compound muscle action potential [CMAP], single motor unit potential [SMUP], motor unit number estimation [MUNE]) were collected.

RESULTS

dEMG MUAP amplitudes were higher in ambulatory versus control and non-ambulatory groups and were higher in controls versus non-ambulatory SMA. In contrast, dEMG firing rates were higher in ambulatory versus non-ambulatory and control groups but similar between non-ambulatory and control. dEMG parameters showed moderate to strong positive correlation with strength and function whereas CMAP and MUNE better correlated with function than strength. SMUP did not correlate with strength, function, or dEMG MUAP amplitude. dEMG parameters show overall good test-retest reliability.

INTERPRETATION

dEMG provided reliable, noninvasive measure of MUAP amplitude size and firing rate and revealed divergent patterns across disease severity in adults with SMA. Firing rate enhancement, as seen in milder SMA, may provide a therapeutic avenue for improving function in more severe SMA, where firing rates appear preserved. MUAP amplitude size and firing rate, quantified with dEMG, may be promising monitoring biomarker candidates for noninvasive assessment of SMA.

Assessing Prevalence and Characteristics of Oro-bulbar Involvement in Children and Adults with SMA Type 2 and 3 Using a Multimodal Approach

Bulbar and jaw muscles are impaired in patients with Spinal Muscular Atrophy (SMA) but the assessment of their severity and progression are limited by the lack of age-appropriate and disease-specific measures. We investigated mastication and swallowing in children and adults with SMA, sitters and walkers. In a 2-year multicentre cross-sectional prospective study, lip and tongue strength (Iowa Oral Performance Instrument), chewing and swallowing (Test of Masticating and Swallowing Solids), active mouth opening (aMMO) were compared to age-appropriate normative data. The perceived burden of oro-bulbar involvement (SMA-Health Index) was recorded. 78 patients were included, 45 children (median age 7.4 years),22 adults (median age 26.8 years) on nusinersen and 11 untreated (median age 32.7 years). Forty-three percent children had reduced mouth opening, 50% had prolonged total time to eat. These issues were more prominent in sitters than in walkers (p = 0.019, p = 0.014). Sixty-six percent needed increased swallows for bolus clearance. Nusinersen treated adults had median aMMO, tongue strength and total time at TOMASS values within normal range (z score: -1.40, -1.22, -1.32, respectively) whereas untreated adults had reduced aMMO (z score: -2.68) and tongue strength (z score: -2.20). Only a minority of children (2/17) and treated adults (5/21) reported burden in swallowing or mastication compared to all untreated adults (5/5). After 16 months, mastication and swallowing were stable in treated children and adults, whether sitters or walkers. The reported multimodal approach to assess oro-bulbar functions demonstrate that swallowing and mastication are impaired in SMA despite patients' perception. These results suggest a trend towards stabilization of oro-bulbar function in patients on long-term treatment with nusinersen.

Respiratory function in a large cohort of treatment-naïve adult spinal muscular atrophy patients: a cross-sectional study

Due to poor data in literature, we aimed to investigate the respiratory function in a large cohort of naïve Italian adult (≥18 years) SMA patients in a multi-centric cross-sectional study. The following respiratory parameters were considered: forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and need for non-invasive ventilation (NIV). We included 145 treatment-naïve adult patients (SMA2=18, SMA3=125; SMA4=2), 58 females (40 %), with median age at evaluation of 37 years (range 18-72). Fifty-six (37 %) and 41 (31 %) patients had abnormal (<80 %) values of FVC and FEV1, respectively. Fourteen (14 %) patients needed NIV, started at median age of 21 (range 4-68). Motor function, measured by Hammersmith Functional Motor Scale Expanded and Revised Upper Limb Module as well as SMA2, loss of walking ability, surgery for scoliosis, use of NIV, and cough assisting device (CAD) were all significantly associated to lower FVC and FEV1 values, while no association with age at baseline, disease duration, gender or 6 min walking test was observed, except for a correlation between FVC and age in SMA3 walkers (p < 0.05). In conclusion, respiratory function in adult SMA patients is relatively frequently impaired, substantially stable, and significantly correlated with motor function and disease severity.

SMN deficiency perturbs monoamine neurotransmitter metabolism in spinal muscular atrophy

Beyond motor neuron degeneration, homozygous mutations in the survival motor neuron 1 (SMN1) gene cause multiorgan and metabolic defects in patients with spinal muscular atrophy (SMA). However, the precise biochemical features of these alterations and the age of onset in the brain and peripheral organs remain unclear. Using untargeted NMR-based metabolomics in SMA mice, we identify cerebral and hepatic abnormalities related to energy homeostasis pathways and amino acid metabolism, emerging already at postnatal day 3 (P3) in the liver. Through HPLC, we find that SMN deficiency induces a drop in cerebral norepinephrine levels in overt symptomatic SMA mice at P11, affecting the mRNA and protein expression of key genes regulating monoamine metabolism, including aromatic L-amino acid decarboxylase (AADC), dopamine beta-hydroxylase (DβH) and monoamine oxidase A (MAO-A). In support of the translational value of our preclinical observations, we also discovered that SMN upregulation increases cerebrospinal fluid norepinephrine concentration in Nusinersen-treated SMA1 patients. Our findings highlight a previously unrecognized harmful influence of low SMN levels on the expression of critical enzymes involved in monoamine metabolism, suggesting that SMN-inducing therapies may modulate catecholamine neurotransmission. These results may also be relevant for setting therapeutic approaches to counteract peripheral metabolic defects in SMA.

Cerebrospinal Fluid Proteomic Changes after Nusinersen in Patients with Spinal Muscular Atrophy

Disease-modifying treatments have transformed the natural history of spinal muscular atrophy (SMA), but the cellular pathways altered by SMN restoration remain undefined and biomarkers cannot yet precisely predict treatment response. We performed an exploratory cerebrospinal fluid (CSF) proteomic study in a diverse sample of SMA patients treated with nusinersen to elucidate therapeutic pathways and identify predictors of motor improvement. Proteomic analyses were performed on CSF samples collected before treatment (T0) and at 6 months (T6) using an Olink panel to quantify 1113 peptides. A supervised machine learning approach was used to identify proteins that discriminated patients who improved functionally from those who did not after 2 years of treatment. A total of 49 SMA patients were included (10 type 1, 18 type 2, and 21 type 3), ranging in age from 3 months to 65 years. Most proteins showed a decrease in CSF concentration at T6. The machine learning algorithm identified ARSB, ENTPD2, NEFL, and IFI30 as the proteins most predictive of improvement. The machine learning model was able to predict motor improvement at 2 years with 79.6% accuracy. The results highlight the potential application of CSF biomarkers to predict motor improvement following SMA treatment. Validation in larger datasets is needed.

Preliminary insights into RNA in CSF of pediatric SMA patients after 6 months of nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a rare autosomal-recessive neurodegenerative disorder caused by mutations in survival motor neuron 1 (SMN1) gene, and consequent loss of function of SMN protein, which results in progressive loss of lower motor neurons, and muscular wasting. Antisense oligonucleotide (ASO) nusinersen (Spinraza®) modulates the pre-mRNA splicing of the SMN2 gene, allowing rebalance of biologically active SMN. It is administered intrathecally via lumbar puncture after removing an equal amount of cerebrospinal fluid (CSF). Its effect was proven beneficial and approved since 2017 for SMA treatment. Given the direct effect of nusinersen on RNA metabolism, the aim of this project was to evaluate cell-free RNA (cfRNA) in CSF of SMA patients under ASOs treatment for biomarker discovery.

METHODS

By RNA-sequencing approach, RNA obtained from CSF of pediatric SMA type 2 and 3 patients was processed after 6 months of nusinersen treatment, at fifth intrathecal injection (T6), and compared to baseline (T0).

RESULTS

We observed the deregulation of cfRNAs in patients at T6 and we were able to classify these RNAs into disease specific, treatment specific and treatment dependent. Moreover, we subdivided patients into "homogeneous" and "heterogeneous" according to their gene expression pattern. The "heterogeneous" group showed peculiar activation of genes coding for ribosomal components, meaning that in these patients a different molecular effect of nusinersen is observable, even if this specific molecular response was not referable to a clinical pattern.

CONCLUSIONS

This study provides preliminary insights into modulation of gene expression dependent on nusinersen treatment and lays the foundation for biomarkers discovery.

Safety and effectiveness of nusinersen, a treatment for spinal muscular atrophy, in 524 patients: results from an interim analysis of post-marketing surveillance in Japan

PURPOSE

Nusinersen is an antisense oligonucleotide approved for the treatment of spinal muscular atrophy (SMA). A post-marketing surveillance (PMS) has been ongoing (August 2017-August 2025) in all patients in Japan who were administered nusinersen intrathecally in real-world clinical settings. We report the interim analysis results for safety and effectiveness.

METHODS

This interim analysis was conducted using data collected from 524 patients whose case report forms were obtained at least once by May 30, 2022. Collected data included patient demographics and adverse events (AEs) for safety, and motor function assessments and Clinical Global Impressions of Improvement (CGI-I) for effectiveness.

RESULTS

Of the 524 patients in the safety analysis set, 522 patients who were diagnosed with SMA were included in the effectiveness analysis (infantile-onset SMA [n = 153, 29.3%], later-onset SMA [n = 369, 70.7%]). The median duration of treatment was 785.0 (range 1-1549) days. AEs occurred in 35.9% of patients (49.0% in infantile-onset SMA and 30.6% in later-onset SMA). Nusinersen treatment significantly improved Hammersmith Infant Neurological Examination scores in patients with infantile-onset SMA and Hammersmith Functional Motor Scale-Expanded scores in patients with later-onset SMA for up to nearly 3 years. Based on CGI-I assessments, 98.5-100% of patients receiving nusinersen 'improved' or remain 'unchanged'.

CONCLUSIONS

This interim analysis of the large-scale, all-case PMS in patients who were administered nusinersen in Japan supports the safety and effectiveness of nusinersen. The benefit-risk balance of nusinersen treatment remains favorable.

Impaired diaphragmatic motility in treatment-naive adult patients with spinal muscular atrophy improved during nusinersen treatment

INTRODUCTION/AIMS

The leading clinical feature of 5q-associated spinal muscular atrophy (SMA) is symmetric, proximal muscle weakness. Muscles involved in ventilation exhibit a specific pattern of denervation: intercostal muscles are severely atrophic, whereas the diaphragm muscle is less affected. The aim of this study was to investigate the involvement of diaphragmatic function by ultrasound imaging in adult patients with SMA and to quantify dynamics of diaphragmatic function during nusinersen treatment.

METHODS

Diaphragmatic thickness, thickening, and excursion during quiet breathing were assessed in 24 adult patients with SMA type 2 and 3 by diaphragm ultrasound imaging before and during nusinersen treatment and were correlated with spirometric parameters.

RESULTS

Diaphragm thickness was not reduced, but increased in a remarkable proportion of patients, whereas diaphragm thickening and excursion were reduced in about 20% to 30% of nusinersen-naive, adult patients with SMA types 2 and 3. During 26 months of nusinersen treatment, diaphragm thickening fraction and excursion improved.

DISCUSSION

Diaphragm ultrasound imaging can provide disease- and treatment-relevant information that is not identified during routine clinical assessments and may therefore be a valuable complementary outcome measure.

Multi-omics profiling of CSF from spinal muscular atrophy type 3 patients after nusinersen treatment: a 2-year follow-up multicenter retrospective study

Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in the SMN1 gene resulting in reduced levels of the SMN protein. Nusinersen, the first antisense oligonucleotide (ASO) approved for SMA treatment, binds to the SMN2 gene, paralogue to SMN1, and mediates the translation of a functional SMN protein. Here, we used longitudinal high-resolution mass spectrometry (MS) to assess both global proteome and metabolome in cerebrospinal fluid (CSF) from ten SMA type 3 patients, with the aim of identifying novel readouts of pharmacodynamic/response to treatment and predictive markers of treatment response. Patients had a median age of 33.5 [29.5; 38.25] years, and 80% of them were ambulant at time of the enrolment, with a median HFMSE score of 37.5 [25.75; 50.75]. Untargeted CSF proteome and metabolome were measured using high-resolution MS (nLC-HRMS) on CSF samples obtained before treatment (T0) and after 2 years of follow-up (T22). A total of 26 proteins were found to be differentially expressed between T0 and T22 upon VSN normalization and LIMMA differential analysis, accounting for paired replica. Notably, key markers of the insulin-growth factor signaling pathway were upregulated after treatment together with selective modulation of key transcription regulators. Using CombiROC multimarker signature analysis, we suggest that detecting a reduction of SEMA6A and an increase of COL1A2 and GRIA4 might reflect therapeutic efficacy of nusinersen. Longitudinal metabolome profiling, analyzed with paired t-Test, showed a significant shift for some aminoacid utilization induced by treatment, whereas other metabolites were largely unchanged. Together, these data suggest perturbation upon nusinersen treatment still sustained after 22 months of follow-up and confirm the utility of CSF multi-omic profiling as pharmacodynamic biomarker for SMA type 3. Nonetheless, validation studies are needed to confirm this evidence in a larger sample size and to further dissect combined markers of response to treatment.

Long-term nusinersen treatment across a wide spectrum of spinal muscular atrophy severity: a real-world experience

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive disorder caused by a biallelic mutation in the SMN1 gene, resulting in progressive muscle weakness and atrophy. Nusinersen is the first disease-modifying drug for all SMA types. We report on effectiveness and safety data from 120 adults and older children with SMA types 1c-3 treated with nusinersen.

METHODS

Patients were evaluated with the Hammersmith Functional Motor Scale Expanded (HFMSE; n = 73) or the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND; n = 47). Additionally, the Revised Upper Limb Module (RULM) and 6-minute walk test (6MWT) were used in a subset of patients. Patients were followed for up to 30 months of nusinersen treatment (mean, SD; 23, 14 months). Subjective treatment outcomes were evaluated with the Patients Global Impression-Improvement (PGI-I) scale used in all patients or caregivers at each follow-up visit.

RESULTS

An increase in the mean HFMSE score was noted at month 14 (T14) (3.9 points, p < 0.001) and month 30 (T30) (5.1 points, p < 0.001). The mean RULM score increased by 0.79 points at T14 (p = 0.001) and 1.96 points (p < 0.001) at month 30 (T30). The mean CHOP-INTEND increased by 3.6 points at T14 (p < 0.001) and 5.6 points at month 26 (p < 0.001). The mean 6MWT improved by 16.6 m at T14 and 27 m at T30 vs. baseline. A clinically meaningful improvement in HFMSE (≥ 3 points) was seen in 62% of patients at T14, and in 71% at T30; in CHOP INTEND (≥ 4 points), in 58% of patients at T14 and in 80% at T30; in RULM (≥ 2 points), in 26.6% of patients at T14 and in 43.5% at T30; and in 6MWT (≥ 30-meter increase), in 26% of patients at T14 and in 50% at T30. Improved PGI-I scores were reported for 75% of patients at T14 and 85% at T30; none of the patients reporting worsening at T30. Adverse events were mild and related to lumbar puncture.

CONCLUSIONS

In our study, nusinersen led to continuous functional improvement over 30-month follow-up and was well tolerated by adults and older children with a wide spectrum of SMA severity.

Feasibility and tolerability of multimodal peripheral electrophysiological techniques in a cohort of patients with spinal muscular atrophy

OBJECTIVE

Electrophysiological techniques are emerging as an aid in identifying prognostic or therapeutic biomarkers in patients with spinal muscular atrophy (SMA), but electrophysiological assessments may be burdensome for patients. We, therefore, assessed feasibility and tolerability of multimodal peripheral non-invasive electrophysiological techniques in a cohort of patients with SMA.

METHODS

We conducted a single center, longitudinal cohort study investigating the feasibility and tolerability of applying multimodal electrophysiological techniques to the median nerve unilaterally. Techniques consisted of the compound muscle action potential scan, motor nerve excitability tests, repetitive nerve stimulation and sensory nerve action potential. We assessed tolerability using the numeric rating scale (NRS), ranging from 0 (no pain) to 10 (worst possible pain), and defined the protocol to be tolerable if the NRS score ≤ 3. The protocol was considered feasible if it could be performed according to test and quality standards.

RESULTS

We included 71 patients with SMA types 1-4 (median 39 years; range 13-67) and 63 patients at follow-up. The protocol was feasible in 98% of patients and was well-tolerated in up to 90% of patients. Median NRS score was 2 (range 0-6 at baseline and range 0-4 at follow-up (p < 0.01)). None of the patients declined follow-up assessment.

CONCLUSIONS

Multimodal, peripheral, non-invasive, electrophysiological techniques applied to the median nerve are feasible and well-tolerated in adolescents and adults with SMA types 1-4.

SIGNIFICANCE

Our study supports the use of non-invasive multimodal electrophysiological assessments in adolescents and adults with SMA types 1-4.

Decision-making and challenges within the evolving treatment algorithm in spinal muscular atrophy: a clinical perspective

INTRODUCTION

The clinical application of disease modifying therapies has dramatically changed the paradigm of the management of people with spinal muscular atrophy (SMA), from sole reliance on symptomatic care directed toward the downstream consequences of muscle weakness, to proactive intervention and even preventative care.

AREAS COVERED

In this perspective, the authors evaluate the contemporary therapeutic landscape of SMA and discuss the evolution of novel phenotypes and the treatment algorithm, including the key factors that define individual treatment choice and treatment response. The benefits achieved by early diagnosis and treatment through newborn screening are highlighted, alongside an appraisal of emerging prognostic methods and classification frameworks to inform clinicians, patients, and families about disease course, manage expectations, and improve care planning. A future perspective of unmet needs and challenges is provided, emphasizing the key role of research.

EXPERT OPINION

SMN-augmenting therapies have improved health outcomes for people with SMA and powered the practice of personalized medicine. Within this new proactive diagnostic and treatment paradigm, new phenotypes and different disease trajectories are emerging. Ongoing collaborative research efforts to understand the biology of SMA and define optimal response are critical to refining future approaches.

Caregivers' Expectations on Possible Functional Changes following Disease-Modifying Treatment in Type II and III Spinal Muscular Atrophy: A Comparative Study

Background: The primary aim of this study was to explore current caregivers' expectations on possible functional changes following treatment in comparison to data obtained in the pre-pharmacological era. Methods: A questionnaire, previously used in 2016, was administered to caregivers of type II and III SMA patients of age between 3 and 71 years, and to patients over the age of 13 years. The questionnaire focuses on (1) caregivers and patients expectations, (2) meaningfulness of the changes observed on the functional motor scales, and (3) their willingness to be enrolled in a clinical trial. A comparative study was performed with data obtained using the same questionnaire soon before the advent of disease-modifying therapies. Results: We administered the questionnaire to 150 caregivers. When comparing current caregiver data to those obtained in 2016, the most obvious differences were related to disease perception over the last year (stability: 16.5% in 2016 vs. 43.6% in 2022; deterioration 70.5% vs. 12.8%, and improvement: 12.9% vs. 43.6%) and expectations from clinical trials with higher expectations in 2022 compared to 2016 (p < 0.001). Forty-five of the 150 in the current study were caregivers of patients above the age of 13. In these 45 the questionnaire was also administered to the patient. No difference was found in responses between patients and their caregivers. Conclusions: Both carers and patients reported that even small changes on functional scales, similar to those reported by clinical studies and real-world data, are perceived as meaningful. Comparing the recent responses to those obtained in 2016, before pharmacological treatment was available, we found significant changes in caregivers' perception with increased expectations. These findings will provide a better understanding of the patients' expectations and facilitate discussion with regulators.

Adverse events in the treatment of spinal muscular atrophy in children and adolescents with nusinersen: A systematic review and meta-analysis

Objectives

To systematically analyze adverse events (AEs) in treatment of spinal muscular atrophy (SMA) with Nusinersen in children and adolescents.

Methods

The study is registered on PROSPERO (CRD42022345589). Databases were searched and literature relating to Nusinersen in the treatment of spinal muscular atrophy in children from the start of database establishment to December 1, 2022, was retrospectively analyzed. R.3.6.3 statistical software was used, and random effects meta-analysis was performed to calculate weighted mean prevalence and 95% confidence intervals (CI).

Results

In total, 15 eligible studies were included, with a total of 967 children. Rate of definite Nusinersen-related AEs was 0.57% (95% CI: 0%-3.97%), and probable Nusinersen-related AEs 7.76% (95% CI: 1.85%-17.22%). Overall rate of AEs was 83.51% (95% CI: 73.55%-93.46%), and serious AEs 33.04% (95% CI: 18.15%-49.91%). For main specific AEs, fever was most common, 40.07% (95% CI: 25.14%-56.02%), followed by upper respiratory tract infection 39.94% (95% CI: 29.43%-50.94%), and pneumonia 26.62% (95% CI: 17.99%-36.25%).The difference in overall AE rates between the two groups (Nusinersen group and placebo group) was significant (OR = 0.27,95% CI: 0.08-0.95, P = 0.042). Moreover, incidence of serious adverse events, and fatal adverse events were both significantly lower than in the placebo group (OR = 0.47, 95%CI: 0.32-0.69, P < 0.01), and (OR = 0.37, 95%CI: 0.23-0.59, P < 0.01), respectively.

Conclusion

Nusinersen direct adverse events are rare, and it can effectively reduces common, serious, and fatal adverse events in children and adolescents with spinal muscular atrophy.

Improvement of muscle strength in specific muscular regions in nusinersen-treated adult patients with 5q-spinal muscular atrophy

Real-world data have shown mild improvement of overall motor function in adult patients treated with nusinersen, the first approved therapy for 5q-spinal muscular atrophy (SMA). However, knowledge about preferably targeted muscle functions is sparse. The aim of this study was to evaluate strength of distinct muscles and body regions in adult SMA patients in the early course of nusinersen therapy. 72 muscles of 15 patients were tested on the Medical Research Council (MRC) 0-10 scale (translated into MRC %) from nusinersen start to 14 months of treatment. The whole body muscular strength improved slightly or remained stable in 80% of SMA patients with a median improvement of + 2%. However, relevant increases of muscle strength of distinct regions were identified in the proximal upper limbs and shoulder girdle (median + 8%) and in muscle groups with a preserved function pre-treatment, even in more advanced diseased SMA patients. MRC grading was additionally performed in seven patients enrolled during ongoing treatment. Here, further improvement of muscle strength until month 18-26 was seen with the highest increases in the proximal upper and lower limbs. Our findings suggest that sole evaluation of the overall muscle strength might underestimate nusinersen therapy benefits.

New therapies for spinal muscular atrophy: where we stand and what is next

The natural history of spinal muscular atrophy has been radically changed by the advent of improved standards of care and the availability of disease-modifying therapies. The aim of this paper is to provide the current therapeutic scenario including new perspectives and to report the challenges related to new phenotypes a few years after the therapies have become available. The paper also includes a review of real-world data that provides information on safety and efficacy in individuals that were not included in clinical trials. Special attention is paid to future perspectives both in terms of new drugs that are currently investigated in clinical trials or providing details on current developments in the use of the available drugs, including combination therapies or new modalities of dose or administration.  Conclusion: Clinical trials and real world data support the efficacy and safety profiles of the available drugs. At the moment there is not enough published evidence about the superiority of one product compared to the others. What is Known: • Safety and efficacy results of clinical trials have led in the last 6 years to the marketing of three drugs for spinal muscular atrophy, with different mechanisms of action. What is New: • Since the drug's approval, real-world data allow us to have data on bigger and heterogeneous groups of patients in contrast with those included in clinical trials. • In addition to the new molecules, combinations of therapies are currently being evaluated.

An observational cohort study on pulmonary function in adult patients with 5q-spinal muscular atrophy under nusinersen therapy

BACKGROUND

Few studies assessed the effect of nusinersen on respiratory function in adult patients with spinal muscular atrophy (SMA). The aim of this single-center study was to analyze pulmonary function and its association with muscle function and quality of life (QoL) in adult patients with 5q-SMA under nusinersen.

METHODS

We recorded forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF) during nusinersen treatment in 38 adult SMA patients. Revised Upper Limb Module (RULM), Hammersmith Functional Motor Scale Expanded (HFMSE), 36-Item Short Form Health Survey (SF-36) questionnaire and Fatigue Severity Scale (FSS) were recorded and correlations between muscle function, QoL, fatigue and respiratory parameters were analyzed.

RESULTS

No differences were detected between mean FVC, FEV1, PEF at different timepoints versus baseline. Ambulatory patients showed significant improvement in mean PEF at month 30, compared to non-ambulatory patients (+ 0.8 ± 0.5 vs. - 0.0 ± 0.5, p < 0.05). Patients with fatigue at baseline showed significant improvement in mean PEF at month 10, compared to patients without fatigue at baseline (+ 0.6 ± 0.9 vs. - 0.4 ± 0.5, p < 0.05). Physical domains of SF-36 positively correlated with the change in FVC and FEV1. FSS negatively correlated with the change in mean PEF.

CONCLUSION

Mean pulmonary function remained stable during nusinersen treatment over a period of up to 30 months. Improvement in pulmonary function was associated with improvement in motor function, fatigue and QoL, early after nusinersen initiation.

Nusinersen for adults with spinal muscular atrophy

INTRODUCTION

Nusinersen was effective in improving motor function and survival in infantile and childhood-onset spinal muscular atrophy (SMA), and the value of real-world experiences in adult SMA patients increase gradually. Here, we present our clinical experience in adult SMA patients treated with nusinersen according to CHERISH study.

MATERIAL AND METHODS

Thirty-two SMA patients treated with nusinersen were included in the study.

RESULTS

Median age at nusinersen initiation was 33.5 (20.0-60.0) years and 23 of SMA patients were male. Six (18.8%) patients had SMA type 2, and 26 (81.2%) had SMA type 3. Median follow-up period of patients under nusinersen treatment was 17 months (9-21). Twenty-three patients improved by at least 3 Hammersmith Functional Motor Scale Expanded (HFMSE) points after loading doses. There was significant HFMSE score increase in type 3 patients at each time point, whereas type 2 patients seem to benefit from nusinersen loading doses, subsequently stayed stable. Motor improvement was positively correlated with baseline HFMSE scores in patients whose baseline HFMSE scores were ≤47. There was a correlation between the changes in Amyotrophic Lateral Sclerosis Functional Rating Scale Revised (ALSFRS-R) score and HFMSE scores. Ambulatory patients who could not show clinically meaningful increase in HFMSE scores improved at least 30 m by 6-min walk test (6MWT).

CONCLUSION

Overall, 78% of patients have responded to treatment according to HFMSE or 6MWT. ALSFRS-R and 6MWT may be alternative tools to monitor nusinersen effect.

Examining Real-World Adherence to Nusinersen for the Treatment of Spinal Muscular Atrophy Using Two Large US Data Sources

INTRODUCTION

Spinal muscular atrophy (SMA) is a rare neuromuscular disease characterized by progressive muscular atrophy and weakness. Nusinersen was the first treatment approved for SMA. Per the US label, the nusinersen administration schedule consists of three loading doses at 14-day intervals, a fourth loading dose 30 days later, and maintenance doses every 4 months thereafter. Using two large US databases, we evaluated real-world adherence to nusinersen with its unique dosing schedule among generalizable populations of patients with SMA.

METHODS

Patients with SMA treated with nusinersen, likely to have complete information on date of treatment initiation, were identified in the Optum^® de-identified electronic health records (EHR) database (7/2017-9/2019), and in the Merative™ MarketScan^® Research Databases from commercial (1/2017-6/2020) and Medicaid claims (1/2017-12/2019). Baseline demographics, number of nusinersen administrations on time, and distribution of inter-dose intervals were summarized.

RESULTS

Totals of 67 and 291 patients were identified in the EHR and claims databases, respectively. Most nusinersen doses were received on time (93.9% EHR, 80.5% claims). Adherence was higher during the maintenance phase (90.6%) than the loading phase (71.1%) in the claims analysis, in contrast with the EHR analysis (95.5% and 92.6%, respectively), suggesting that not all loading doses of nusinersen may be accurately captured in claims. Inter-dose intervals captured in both databases aligned with the expected dosing schedule.

CONCLUSION

Most nusinersen doses were received on time, consistent with the recommended schedule. Our findings also highlight the importance of careful methodological approaches when using real-world administrative databases for evaluation of nusinersen treatment patterns.

Psychometric evaluation of modified spinal muscular atrophy functional rating scale (SMAFRS) in adult patients using Rasch analysis

INTRODUCTION/AIMS

The Spinal Muscular Atrophy Functional Rating Scale (SMAFRS) was first developed as a secondary functional outcome measure to detect changes over time in patients with spinal muscular atrophy (SMA) in clinical trials. Its modified version evaluates 10 activities of daily living. The aim of the study was to analyze modified SMAFRS data using item response theory psychometric models.

METHODS

A total of 253 responses from 41 adult patients with ambulatory and non-ambulatory SMA types 2, 3, and 4 were analyzed. Rasch analysis was used to explore item-person targeting, fit statistics, category response functioning, dimensionality, and differential item functioning.

RESULTS

Most items had good fitting with the exception of "toileting" and "respiratory." There were no major floor or ceiling effects, and most items covered a good range of disability with only a negligible breech of uni-dimensionality from eating, dressing, and respiratory items. Differential item function highlighted differences in toileting, turning, transferring, walking, and respiratory items between ambulatory and non-ambulatory populations.

DISCUSSION

Despite subtle misfitting of certain items, mainly related to respiratory and bulbar function, overall modified SMAFRS remained a psychometrically stable and unidimensional outcome measure. There were some differences in measuring properties of certain functional items between ambulatory and non-ambulatory items that need to be taken into consideration in clinical trial design. Overall, the modified SMAFRS is a psychometrically reliable tool in assessment of adult patients with SMA.

[Gene Therapies in Motor Neuron Diseases ALS and SMA]

In the past, the diagnosis of motor neuron diseases such as amyotrophic lateral sclerosis (ALS) and 5q-associated spinal muscular atrophy (SMA) meant powerlessness in the face of seemingly untreatable diseases with severe motor-functional limitations and sometimes fatal courses. Recent advances in an understanding of the genetic causalities of these diseases, combined with success in the development of targeted gene therapy strategies, spell hope for effective, innovative therapeutic approaches, pioneering the ability to treat neurodegenerative diseases. While gene therapies have been approved for SMA since a few years, gene therapy research in ALS is still in clinical trials with encouraging results. This article provides an overview of the genetic background of ALS and SMA known to date and gene therapy approaches to them with a focus on therapy candidates that are in clinical trials or have already gained market approval.

Long-term efficacy of nusinersen and its evaluation in adolescent and adult patients with spinal muscular atrophy types 1 and 2

BACKGROUNDS

The efficacy of nusinersen and its evaluation in patients with spinal muscular atrophy (SMA) has been established in clinical trials only for pediatric patients, not for adolescent and adult patients who developed SMA in infancy or early childhood. We report a long-term follow-up in adolescent and adult patients with SMA types 1 and 2.

METHODS

Nusinersen-treated patients with SMA types 1 and 2 between 2017 and 2022 were retrospectively reviewed. We compared baseline motor function tests with those after the final treatment. Physical and occupational therapists performed Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), Hammersmith Functional Motor Scale-Expanded (HFMSE), and Revised Upper Limb Module (RULM). The Landau and Galant reflexes were not performed in CHOP-INTEND. Meaningful improvement was defined as CHOP-INTEND, 4; HFSME, 3; and RULM, 2.

RESULTS

Seven patients with SMA (type 1, 1; type 2, 6) with a median age of 23 (range, 12-40)years were treated with nusinersen for 3.55 (1.78-4.53)years. Improvement was detected in CHOP-INTEND (pre, 5 [0-31]; post, 21 [0-39]; difference, 5 [0-26]; p = 0.100) without significance, although not in HFMSE (pre, 0 [0-3]; post, 0 [0-5]; difference, 0 [0-2]; p = 0.346) and RULM (pre, 1 [0-20]; post, 3 [0-21]; difference, 1 [0-2]; p = 0.089). Owing to prolonged treatment intervals with the COVID-19 pandemic, RULM worsened in two patients.

CONCLUSION

Nusinersen was effective in long-term follow-up. Only CHOP-INTEND showed meaningful improvement. The interval between doses of nusinersen should not be prolonged even with the COVID-19 pandemic.

Current treatments of spinal muscular atrophy in adults

Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disorder related to motor neuron degeneration. SMA patients present generally severe muscular weakness and atrophy, which can reduce life expectancy and lead to severe functional disability. In recent years, the management of this condition has been revolutionized by the development of innovative therapies that target alternative splicing of pre-messenger SMN2 RNA by antisense oligonucleotides or small molecules and by the approval of the first vector-based SMN1 gene therapy. The high significance of the trials in children led to fast-tracking of these therapies to all SMA patients despite the absence of data in adults. Real-life data are progressively providing a better understanding of the expected benefits and tolerability. They also highlight the difficulties of evaluating these patients and the need to take into account the patients' reported expectations and outcome. A review of the main data in adult patients is presented. The mechanisms of action of these innovative therapies are discussed as well as the limits of evaluations of these therapies in adults with longstanding severe amyotrophy.

[Oral disease-modifying therapy for adult patients with spinal muscular atrophy type 2]

Disease modifying therapy for adult patients with SMA still raises certain questions regarding its effectiveness, given the long-term chronic process with often significant neurological deficits at the time of initiation of therapy. This paper presents three clinical cases of adult sitter patients with SMA type 2, who began risdiplam therapy 16.5-41 years after the disease onset. All patients have been receiving therapy since 2020, at the time of observation for 2.5-3 years. All patients showed subjective and objective (using specialized scales) improvement during long-term therapy with risdiplam. In addition to an increase in muscle strength, mainly in the proximal and distal parts of the arms, several non-motor effects were also noted (including improved swallowing and breathing), which cannot be recorded using scales. No adverse events were recorded during therapy.

The Japan Registry for Adult Subjects of Spinal Muscular Atrophy (jREACT-SMA): Protocol for a Longitudinal Observational Study

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive genetic neuromuscular disorder with progressive muscle weakness and atrophy, mainly caused by lower motor neuron degeneration resulting from decreased levels of the survival motor neuron protein. Recently, 3 disease-modifying therapies for SMA (nusinersen, onasemnogene abeparvovec, and risdiplam) were approved in Japan that are expected to improve the prognosis of patients with SMA. Long-term clinical follow-up of adult patients treated with disease-modifying therapies and the natural history of SMA are essential to assess the real-world effectiveness of available treatments. Until recently, nusinersen was the only treatment option for patients with SMA in Japan; however, because Japanese approval of nusinersen was based on global clinical trials in infants and children aged 0-15 years with SMA, the effectiveness of nusinersen in adult patients has not been fully assessed in Japan. In addition, longitudinal clinical data of adult patients have not been systematically collected in Japan.

OBJECTIVE

This longitudinal observational study of adult patients with SMA who have been diagnosed with 5q-SMA in Japan aims to gain a better understanding of the natural history of SMA, as well as the long-term effectiveness of disease-modifying therapies. Here, we describe the protocol for the study.

METHODS

The Japan Registry for Adult Subjects of Spinal Muscular Atrophy (jREACT-SMA) study is a longitudinal (prospective and retrospective) observational study with a 60-month prospective follow-up being conducted at 19 investigational sites using the newly established jREACT-SMA registry. Patients aged ≥18 years with genetically confirmed 5q-SMA were planned to be enrolled in the registry from December 2020 to May 2022. The planned enrollment was 100 patients. The protocol was approved on September 28, 2020 (approval 2020-0289) by the ethical review committee of Nagoya University. Registration, demographics, genetic diagnosis, motor functions, patient-reported outcomes/quality-of-life outcomes, and other clinical data have been or will be collected.

RESULTS

As of May 2022, 113 patients had been enrolled, and the completion of patient registration has been extended from May 2022 to December 2022. Data at registration and during the follow-up period were and will be prospectively collected at least once a year until November 2025 (maximum 60 months). Data analyses will be conducted when all data have been collected. Results are expected to be available in 2026 and the study is expected to be completed by March 2027.

CONCLUSIONS

This jREACT-SMA study will provide longitudinal prospective follow-up data in adult patients with SMA in Japan, including data on the natural history of the disease and data on the long-term effectiveness of disease-modifying therapies.

TRIAL REGISTRATION

University Hospital Medical Information Network Center Clinical Trials Registry UMIN000042015; https://rctportal.niph.go.jp/en/detail?trial_id=UMIN000042015.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/38878.

Randomized double-blind placebo-controlled crossover trial with pyridostigmine in spinal muscular atrophy types 2-4

Hereditary proximal spinal muscular atrophy causes weakness and increased fatigability of repetitive motor functions. The neuromuscular junction is anatomically and functionally abnormal in patients with spinal muscular atrophy. Pharmacological improvement of neuromuscular transmission may therefore represent a promising additional treatment strategy. We conducted a Phase II, monocentre, placebo-controlled, double-blind, cross-over trial with the acetylcholinesterase inhibitor pyridostigmine in treatment-naïve patients with spinal muscular atrophy types 2-4. We investigated the safety and efficacy of pyridostigmine on fatigability and motor function. Each participant received pyridostigmine and a placebo for 8 weeks, in random order. Primary outcomes were the repeated nine-hole peg test for fatigability and motor function measure. Secondary outcomes were patient-reported effects, endurance shuttle test combined scores and adverse events. We included 35 patients. For the repeated nine-hole peg test, the mean difference was 0.17 s/trial (95% confidence interval: -1.17-1.49; P = 0.8), favouring placebo, and for the motor function measure, 0.74% (95% confidence interval: 0.00-1.49; P = 0.05), favouring pyridostigmine. Around 74% of patients reported medium-to-large beneficial effects of pyridostigmine on fatigability, compared with 29.7% in the placebo arm. This was paralleled by a reduced dropout risk of 70% on the endurance shuttle test combined scores (hazard ratio: 0.30; 95% confidence interval: 0.15-0.58) under pyridostigmine. Adverse events, mostly mild and self-limiting, occurred more frequently under pyridostigmine. No serious adverse events related to the study medication were observed. Patients with spinal muscular atrophy tolerated pyridostigmine well. There were no significant differences in primary outcomes, but the self-reported reduction of fatigability and improved endurance shuttle test combined score performance suggest that pyridostigmine may be useful as an additional therapy to survival motor neuron-augmenting drugs. Trial registration number: EudraCT: 2011-004369-34, NCT02941328.

Validation of motor and functional scales for the evaluation of adult patients with 5q spinal muscular atrophy

BACKGROUND AND PURPOSE

Mos scales currently used to evaluate spinal muscular atrophy (SMA) patients have only been validated in children. The aim of this study was to assess the construct validity and responsiveness of several outcome measures in adult SMA patients.

METHODS

Patients older than 15 years and followed up in five referral centres for at least 6 months, between October 2015 and August 2020, with a motor function scale score (Hammersmith Functional Motor Scale Expanded [HFMSE], Revised Upper Limb module [RULM]) were included. Bedside functional scales (Egen Klassification [EK2], Revised Amyotrophic Lateral Sclerosis Functional Rating Scale [ALSFRS-R]) were also collected when available. Spearman's rho correlations (rs) and Bangdiwala's concordance test (B) were used to evaluate the scales' construct validity. Monthly slopes of change were used to calculate their responsiveness of the scales.

RESULTS

The study included 79 SMA patients, followed up for a mean of 16 months. All scales showed strong correlations with each other (rs &gt; 0.70). A floor effect in motor function scales was found in the weakest patients (HFMSE &lt; 5 and RULM &lt; 10), and a ceiling effect was found in stronger patients (HFMSE &gt; 60 and RULM &gt; 35). The ALSFRS-R (B = 0.72) showed a strong ability to discriminate between walkers, sitters and non-sitters, and the HFMSE (B = 0.86) between walkers and sitters. The responsiveness was low overall, although in treated patients a moderate responsiveness was found for the ALSFRS-R and HFMSE in walkers (0.69 and 0.61, respectively) and for EK2 in sitters (0.65) and non-sitters (0.60).

CONCLUSIONS

This study shows the validity and limitations of the scales most frequently used to assess adult SMA patients. Overall, bedside functional scales showed some advantages over motor scales, although all showed limited responsiveness.

Adults with spinal muscular atrophy: a large-scale natural history study shows gender effect on disease

BACKGROUND

Natural history of spinal muscular atrophy (SMA) in adult age has not been fully elucidated yet, including factors predicting disease progression and response to treatments. Aim of this retrospective, cross-sectional study, is to investigate motor function across different ages, disease patterns and gender in adult SMA untreated patients.

METHODS

Inclusion criteria were as follows: (1) clinical and molecular diagnosis of SMA2, SMA3 or SMA4 and (2) clinical assessments performed in adult age (>18 years).

RESULTS

We included 64 (38.8%) females and 101 (61.2%) males (p=0.0025), among which 21 (12.7%) SMA2, 141 (85.5%) SMA3 and 3 (1.8%) SMA4. Ratio of sitters/walkers within the SMA3 subgroup was significantly (p=0.016) higher in males (46/38) than in females (19/38). Median age at onset was significantly (p=0.0071) earlier in females (3 years; range 0-16) than in males (4 years; range 0.3-28), especially in patients carrying 4 SMN2 copies. Median Hammersmith Functional Rating Scale Expanded scores were significantly (p=0.0040) lower in males (16, range 0-64) than in females (40, range 0-62); median revised upper limb module scores were not significantly (p=0.059) different between males (24, 0-38) and females (33, range 0-38), although a trend towards worse performance in males was observed. In SMA3 patients carrying three or four SMN2 copies, an effect of female sex in prolonging ambulation was statistically significant (p=0.034).

CONCLUSIONS

Our data showed a relevant gender effect on SMA motor function with higher disease severity in males especially in the young adult age and in SMA3 patients.

Long term follow-up of scoliosis progression in type II SMA patients

The aim of this study is to retrospectively assess onset and progression of scoliosis in type II SMA patients not treated with the approved disease modifying treatments. Scoliosis was evaluated by measuring the scoliosis angle on X-ray obtained in the anteroposterior view in sitting position (Cobb's angle method). Eighty-four patients had at least one assessment of scoliosis angle (287 assessments). There was a positive correlation between age and scoliosis angles (p<0.001) with a progressive increase of scoliosis with age. When subdividing the population by HFMSE score (<10; 11-22;> 22), there was a progressive increase in scoliosis angles with decreasing HFMSE scores. The difference between HFMSE categories was significant (p<0.001). Fifty-four patients had at least two assessments at 6-month distance and were retained for the longitudinal analysis. Using a mixed model, age, functional status and scoliosis angle at baseline were predictive on scoliosis progression. The mean annual rate of increase of scoliosis angle was 5.63 (95%CI: 4.74-6.52). Our results confirm the progression of scoliosis in untreated type II SMA providing details of the progression in relation to different variables. With different therapeutical options being available in many countries, our findings will provide reference data for establishing possible differences in the trajectories of progression with treated type II individuals.

Spinal muscular atrophy: state of the art and new therapeutic strategies

Spinal muscular atrophy (SMA) is a severe disorder of motor neurons and the most frequent cause of genetic mortality, due to respiratory complications. We are facing an exciting era with three available therapeutic options in a disease considered incurable for more than a century. However, the availability of effective approaches has raised up ethical, medical, and financial issues that are routinely faced by the SMA community. Each therapeutic strategy has its weaknesses and strengths and clinicians need to know them to optimize clinical care. In this review, the state of the art and the results and challenges of the new SMA therapeutic strategies are highlighted.