Health, wellbeing and lived experiences of adults with SMA: a scoping systematic review

SMA Community Priorities for Future Drug Therapies: Cross-Sectional Survey Findings Representing 410 Adults with SMA

INTRODUCTION

Despite advances in the therapeutic landscape for spinal muscular atrophy (SMA), unmet needs for those with this condition persist. This study seeks to characterize unmet needs that adults with SMA hope future therapies will address and explores associations between reported needs and health status and demographic characteristics.

METHODS

Close-ended questions from 2021 to 2023 Cure SMA Community Update Survey data were used to assess the importance of needs related to muscle and motor function, lung function and bulbar function, and general functioning. Data was stratified by SMA type and mobility status, and Fisher's exact tests were used to assess for statistically significant differences based on these characteristics. Variations in reported needs were further explored with regressions controlling for sex, education, maximum mobility, and drug treatment status.

RESULTS

The sample included 410 adults who answered questions on unmet needs. Most had type 2 or type 3 SMA (48% and 45%, respectively). Gaining muscle strength was the most frequently reported unmet need, and followed by improving daily functioning, achieving new motor function, and stabilizing motor function. Stratifications and regressions identified statistically significant differences in treatment needs based on health status and demographic characteristics (p < 0.05). Most notably, people with more severe types of SMA and lower mobility were more likely to report items related to lung function and bulbar function as important.

CONCLUSION

This research highlights treatment priorities for adults with SMA.

Global Economic Burden of Spinal Muscular Atrophy: A Systematic Literature Review

Spinal muscular atrophy (SMA) is a rare inherited neuromuscular disease classified into four main subtypes and characterized by severe muscle weakness and loss of motor function. Its high mortality rates, high treatment costs, and lengthy care requirements place a heavy burden on patients, caregivers, and the healthcare system. This study aims to explore the economic burden of SMA subtypes by analyzing costs, healthcare resource use, and loss of productivity for patients and their caregivers. We conducted a systematic literature review, searching for studies published since 2010 via Medline, Embase, Google Scholar, and gray literature databases. We extracted data concerning costs, healthcare resources, and productivity losses among SMA subtypes. The quality of the included studies was assessed using the Newcastle-Ottawa Scale and the Quality of Health Economic Studies tools. We retrieved 55 studies from 32 countries with economic data variation due to the study design, location, and SMA subtype. The weighted average annual cost for an SMA patient was US$109,906 with the highest costs observed in type 1 patients, who incurred direct medical costs without disease-modifying treatments of US$187,88. The non-medical costs accounted for US$109,379 per patient, along with frequent hospitalizations and high caregiver productivity losses, requiring 2,947 hours of caregiving annually. The direct and indirect costs of SMA are substantial. The necessity for standardized approaches to evaluate and analyze the economic impact across various SMA subtypes is highlighted by the heterogeneity of the data. In order to control the financial burden of SMA, governments and healthcare systems can benefit from these insights to develop policies aimed at improving financial sustainability and patient support.

A contemporary analysis of the Australian clinical and genetic landscape of spinal muscular atrophy: a registry based study

Background

New paradigms of diagnosis and treatment have changed the neurodegenerative trajectory for individuals with spinal muscular atrophy (SMA). Registries are a critical tool to provide real-world data on treatment patterns, their effects and health care provision within this evolving paradigm of care. This study aimed to evaluate the phenotypic and genotypic landscape, treatment patterns and health impact of SMA in Australia through the national registry.

Methods

This cross-sectional study investigated demographic, clinical and genetic information, sequelae of weakness, treatment patterns and patient-reported outcomes amongst individuals with SMA enrolled in the Australian Neuromuscular Disease Registry (ANMDR) from 1st January 2020 to 30th April 2023. Descriptive statistics were used for analysis and Chi-Squared or Fisher's exact tests for associations.

Findings

195 individuals with SMA enrolled into the ANMDR. 5/195 (2.6%) were deceased by censor date. Of (n = 190) individuals living with SMA, 104/190 (54.7%) were children. Minimum Australian prevalence was 0.73/100,000. SMN2 copies were inversely associated with phenotype in those with homozygous SMN1 deletions (p < 0.0001)). Treatment was utilised in 154/190 (81%) of the population, with 65/137 (47.6%) of individuals perceiving improvements with therapeutic intervention on Patient/Parent Global Impression of Improvement scale (p < 0.0001). Engagement with multidisciplinary care practitioners was significantly higher among children with SMA than adults (93% versus 12%, p < 0.0001).

Interpretation

Despite diagnostic and therapeutic advances, mortality and the multi-systemic health impact of SMA continue to be experienced within the Australian population. Healthcare provision must align with patient-centred outcomes, adapting to meeting their changing but ongoing care requirements. The study identified the considerable unmet need for multidisciplinary care, not only for adults with SMA but also for the emerging cohort of treated children, emphasising the imperative for comprehensive healthcare provision to address their evolving needs.

Funding

No funding was received for this study.

The transition from children to young people living with home mechanical ventilation

PURPOSE

This study aimed to examine how young people living with Home Mechanical Ventilation experience the transition from childhood to young adulthood in relation to everyday life, perceived health and transition into adult professional healthcare.

METHODS

Nine young adults (three females and six males aged 18-31) were interviewed, and data was primary analysed using phenomenological hermeneutics. In the actual study, data was reworked using secondary analysis as described by Beck. Two interviewees were ventilated invasively and six non-invasively, and one was treated with continuous positive airway pressure (CPAP).

RESULTS

The results are presented in two main categories. First; moving towards adulthood; and second, To handle changes in health and healthcare contacts. The study highlights the importance of ongoing social relations and being part of a socializing and physically active community. The transfer from paediatric to adult healthcare was solid and worked out well but was a process in which the participants struggled to find their own voice.

CONCLUSIONS

The transition into adulthood is a sensitive and challenging time for young people with HMV, but stable, close relationships and a well-organized transfer can enable this group to feel safe and able to find and use their own voice.

Sensory dysfunction in SMA type 2 and 3 - adaptive mechanism or concomitant target of damage?

BACKGROUND

The motor neuron survival protein performs numerous cellular functions; hence, spinal muscular atrophy (SMA) is considered to be a multi-organ disease with possible sensory system damage. The controversy surrounding the presence of sensory disturbances, prompted us to conduct standard electrophysiological studies and assess the sensory thresholds for different modalities in adults with SMA types 2 and 3. The study group consisted of 44 adult SMA patients (types 2 and 3). All patients underwent neurological examination using the Hammersmith Functional Motor Scale - Expanded (HFMSE). Standard sensory electrophysiological studies in the ulnar nerve and the estimation of vibratory, temperature, and warm- and cold-induced pain thresholds with temperature dispersion assessment were performed using quantitative sensory testing (QST).

RESULTS

The most repeatable result was the high amplitude of the sensory nerve action potentials (SNAP) in SMA patients compared to controls. This was higher in type 2 patients compared to type 3a and 3b patients and patients with low HFSME scores. Patients with SMA, especially type 3b presented a longer sensory latency and slower conduction velocity than did controls. Cold pain threshold was higher and warm dispersion larger in SMA. The vibratory limit was higher in patients with high HFSME scores.

CONCLUSIONS

A high SNAP amplitude suggests sensory fibre hyperactivity, which may be based on overactivation of metabolic pathways as an adaptive mechanism in response to SMN protein deficiency with additionally coexisting small C- and A-delta fibre damage. SMA patients seem to have a concomitant, mild demyelinating process present at the early SMA stage.

Measurement properties of the EQ-5D-Y-3L, PedsQL 4.0, and PROMIS-25 Profile v2.0 in pediatric patients with spinal muscular atrophy

OBJECTIVE

The objective of this study was to examine the psychometric properties of the EQ-5D-Y-3 L, Patient Reported Outcomes Measurement System 25-item version profile v2.0 (PROMIS-25), and Pediatric Quality of Life Inventory™ version 4.0 Generic Core Scale (PedsQL 4.0) in Chinese pediatric patients with spinal muscular atrophy (SMA).

METHODS

The data used in this study were obtained via a web-based cross-sectional survey. Parents of pediatric patients with SMA completed the proxy-reported EQ-5D-Y-3 L, PedsQL 4.0, and PROMIS-25 measures. Information about socioeconomic and health status was also obtained. The ceiling and floor effects, factorial structure, convergent validity, and known-group validity of the three measures were assessed.

RESULTS

Three hundred and sixty-three parents of children aged from 5 to 12 completed the questionnaires. Strong floor effects were observed for the physical function components of the PROMIS-25 (41.3%) and PedsQL 4.0 (67.8%). For EQ-5D-Y-3 L, 84.6% of the respondents reported having "a lot of" problems with the dimensions "walking" and "looking after myself." Minimal ceiling or floor effects were observed for the EQ-5D-Y-3 L index value. The confirmatory factor analysis supported a six-factor structure for the PROMIS-25, but did not support a four-factor structure for the PedsQL 4.0. All hypothesized correlations of the dimensions among the three measures were confirmed, with coefficients ranging from 0.28 to 0.68. Analysis of variance showed that EQ-5D-Y-3 L demonstrated better known-group validity than the other two measures in 14 out of 16 comparisons.

CONCLUSIONS

The EQ-5D-Y-3 L showed better discriminant power than the other two measures. The physical health dimensions of all three measures showed the significant floor effects. These findings provide valuable insights into the effectiveness of these measures at capturing and quantifying the impact of SMA on patients' health-related quality of life.

Nusinersen Treatment for Spinal Muscular Atrophy: Retrospective Multicenter Study of Pediatric and Adult Patients in Kuwait

Spinal muscular atrophy is a neuromuscular genetic condition associated with progressive muscle weakness and atrophy. Nusinersen is an antisense oligonucleotide therapy approved for the treatment of 5q spinal muscular atrophy in pediatric and adult patients. The objective of this clinical case series is to describe the efficacy and safety of nusinersen in treating spinal muscular atrophy in 20 pediatric and 18 adult patients across six treatment centers in Kuwait. Functional motor assessments (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders, Hammersmith Functional Motor Scale Expanded, and Revised Upper Limb Module) were used to assess changes in motor function following nusinersen treatment. The safety assessment involved clinical monitoring of adverse events. The results demonstrate clinically meaningful or considerable improvement in motor performance for nearly all patients, lasting over 4 years in some cases. A total of 70% of patients in the pediatric cohort and 72% of patients in the adult cohort achieved a clinically meaningful improvement in motor function following nusinersen treatment. Additionally, nusinersen was well-tolerated in both cohorts. These findings add to the growing body of evidence relating to the clinical efficacy and safety of nusinersen.

Fatigue in Spinal Muscular Atrophy: a fundamental open issue

Hereditary proximal 5q Spinal Muscular Atrophy (SMA) is a severe neuromuscular disorder with onset mainly in infancy or childhood. The underlying pathogenic mechanism is the loss of alpha motor neurons in the anterior horns of spine, due to deficiency of the survival motor neuron (SMN) protein as a consequence of the deletion of the SMN1 gene. Clinically, SMA is characterized by progressive loss of muscle strength and motor function ranging from the extremely severe, the neonatal onset type 1, to the mild type 4 arising in the adult life. All the clinical variants share the same molecular defect, the difference being driven mainly by the copy number of SMN2 gene, a centromeric gene nearly identical to SMN1 with a unique C to T transition in Exon 7 that results in exclusion of Exon 7 during post-transcriptional processing. In all the types of SMA the clinical picture is characterized by hypotonia, weakness and areflexia. Clinical severity can vary a lot between the four main recognized types of SMA. As for the most of patients affected by different neuromuscular disorders, also in SMA fatigability is a major complaint as it is frequently reported in common daily activities and negatively impacts on the overall quality of life. The increasing awareness of fatigability as an important dimension of impairment in Neuromuscular Disorders and particularly in SMA, is making it both a relevant subject of study and identifies it as a fundamental therapeutic target. In this review, we aimed to overview the current literature articles concerning this problem, in order to highlight what is known and what deserves further research.

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.

Self-Reported Health-Related Quality of Life of Children with Spinal Muscular Atrophy: Preliminary Insights from a Nationwide Patient Registry in Germany

BACKGROUND

Spinal muscular atrophy (SMA) is a rare, severely debilitating neuromuscular disease characterized by a wide spectrum of progressive muscular atrophy and weakness.

OBJECTIVES

The objective of this pilot study was to estimate self-assessed health-related quality of life (HRQoL) of children with SMA.

METHODS

Children with SMA were recruited via the German national TREAT-NMD SMA patient registry and asked to self-complete the following rating-scales: KIDSCREEN-27, KINDL, the PedsQL 3.0 Neuromuscular Module (PedsQL 3.0 NMM), EQ-5D-5L, and the Health Utilities Index (HUI). Estimates were stratified by current best motor function of the lower limb and trunk (i.e., non-sitter, sitter, and walker) and SMA type (i.e., type I, II, and III).

RESULTS

In total, 17 children with SMA (mean age: 9.88 years, SD: 4.33 years, range: 5-16 years; 59% female) participated in the study. Across examined strata, the mean KIDSCREEN-27 total score was estimated at between 48.24 and 83.81; the mean KINDL total score at between 60.42 and 76.73; the mean PedsQL 3.0 NMM total score at between 58.00 and 83.83; the mean EQ-5D-5L utility at between 0.31 and 0.99; and the mean HUI-derived utility at between -0.02 and 0.96.

CONCLUSIONS

The results from this pilot study show that German children with SMA, despite significant physical disability, have surprisingly good HRQoL as assessed using KIDSCREEN-27. Yet, many reside in health states associated with low utility. The disease burden was generally higher among non-sitters compared with walkers, and SMA type I compared with type III, but more research is needed to further delineate this variability. Our preliminary findings contribute to the understanding of HRQoL in pediatric patients with SMA and should be helpful to inform the design of future studies of this patient population.

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

Objectives

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

Methods

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

Results

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

Interpretation

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

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.

Spinal muscular atrophy and anorexia nervosa: a case report

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive condition affecting lower motor neurons causing progressive muscle atrophy. Anorexia nervosa (AN) is a psychiatric disorder characterised by intense fear of weight gain, restriction of energy intake, and preoccupation with body weight and shape. Low weight, gastrointestinal dysmotility, and respiratory infections are common in SMA but may mask AN. No paediatric cases of AN in SMA have been reported to date.

CASE PRESENTATION

A 14-year-old female with SMA2 presented with 12 months of declining body weight to a nadir of 24.8 kg (BMI 11). This was initially attributed to medical complications including pneumonia and gastroenteritis, and chronic gut dysmotility associated with SMA. Despite almost 2 years of dietetic input and nutritional supplementation due to the weight plateauing from age 11, no significant restoration or gain was achieved. The Eating Disorder Examination-Questionnaire (EDE-Q) indicated a possible eating disorder and psychiatric evaluation confirmed AN. Initial management prioritised close medical monitoring and outpatient weight restoration on an oral meal plan. Skin fold anthropometric measurement was conducted to determine a minimum healthy weight. Individual psychological therapy and family sessions were undertaken. The patient developed major depression and a brief relapse with weight loss to 28 kg. Since then, the patient has maintained a weight of around 35 kg with stable mood.

CONCLUSIONS

Low body weight, feeding issues, gastrointestinal dysmotility, and respiratory infections are common in SMA and diagnostic overshadowing can lead to delayed recognition of anorexia nervosa. Change to growth trajectory and prolonged weight loss should prompt consideration of comorbid psychiatric issues. Screening measures such as the EDE-Q and DASS may be helpful in this population. Close liaison between the neurogenetics and psychiatry teams is helpful. Skin fold anthropometry can assist in identifying a minimum healthy weight range.

Validation of a Set of Instruments to Assess Patient- and Caregiver-Oriented Measurements in Spinal Muscular Atrophy: Results of the SMA-TOOL Study

INTRODUCTION

Outcome measures traditionally used in spinal muscular atrophy (SMA) clinical trials are inadequate to assess the full range of disease severity. The aim of this study was to assess the psychometric properties of a set of existing questionnaires and new items, gathering information on the impact of SMA from the patient and caregiver perspectives.

METHODS

This was a multicenter, prospective, noninterventional study including patients with a confirmed diagnosis of 5q-autosomal-recessive SMA aged 8 years and above, or their parents (if aged between 2 and 8 years). The set of outcome measurements included the SMA Independence Scale (SMAIS) patient and caregiver versions, the Neuro-QoL Fatigue Computer Adaptive Test (CAT), the Neuro-QoL Pain Short Form-Pediatric Pain, the PROMIS adult Pain Interference CAT, and new items developed by Fundación Atrofia Muscular España: perceived fatigability, breathing and voice, sleep and rest, and vulnerability. Reliability, construct validity, discriminant validity, and sensitivity to change (4 months from baseline) were measured.

RESULTS

A total of 113 patients were included (59.3% 2-17 years old, 59.3% male, and 50.4% with SMA type II). Patients required moderate assistance [mean patient and caregiver SMAIS (SD) scores were 31.1 (12.8) and 7.6 (11.1), respectively]. Perceived fatigability was the most impacted domain, followed by vulnerability. Cronbach's alpha coefficient for perceived fatigability, breathing and voice, and vulnerability total scores were 0.92, 0.88, and 0.85, respectively. The exploratory factor analysis identified the main factors considered in the design, except in the sleep and rest domain. All questionnaires were able to discriminate between the Clinical Global Impression-Severity scores and SMA types. Sensitivity to change was only found for the SMAIS caregiver version and vulnerability items.

CONCLUSIONS

This set of outcome measures showed adequate reliability, construct validity, and discriminant validity and may constitute a valuable option to measure symptom severity in patients with SMA.

Health-Related Quality of Life in Spinal Muscular Atrophy Patients and Their Caregivers-A Prospective, Cross-Sectional, Multi-Center Analysis

Spinal muscular atrophy (SMA) is a disabling disease that affects not only the patient’s health-related quality of life (HRQoL), but also causes a high caregiver burden (CGB). The aim of this study was to evaluate HRQoL, CGB, and their predictors in SMA. In two prospective, cross-sectional, and multi-center studies, SMA patients (n = 39) and SMA patient/caregiver couples (n = 49) filled in the EuroQoL Five Dimension Five Level Scale (EQ-5D-5L) and the Short Form Health Survey 36 (SF-36). Caregivers (CGs) additionally answered the Zarit Burden Interview (ZBI) and the Hospital Anxiety and Depression Scale (HADS). Patients were clustered into two groups with either low or high HRQoL (EQ-5D-5L index value <0.259 or >0.679). The latter group was mostly composed of ambulatory type III patients with higher motor/functional scores. More severely affected patients reported low physical functioning but good mental health and vitality. The CGB (mean ZBI = 22/88) correlated negatively with patients’ motor/functional scores and age. Higher CGB was associated with a lower HRQoL, higher depression and anxiety, and more health impairments of the CGs. We conclude that patient and CG well-being levels interact closely, which highlights the need to consider the health of both parties while evaluating novel treatments.

[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.

Behavioral problems in infants and young children with spinal muscular atrophy and their siblings: A cross-sectional study

INTRODUCTION

Older children and adults with spinal muscular atrophy (SMA) have been shown to have more anxiety, depression, and other behavioral problems in a few studies. But no similar studies have been performed in infants and young children with SMA.

METHOD

Behavioral co-morbidities of young children with SMA were compared with healthy and children with chronic non-neurological illness control group. Infant Behavior Questionnaire-Revised (IBQ-R) and parent-report version of chid behavior checklist (CBCL) were used for infants and preschool-age children respectively.

RESULTS

A total of 35 SMA children (age at symptom onset-5.9 ± 2.8 months, at enrolment-21.4 ± 7.1 months, 65% boys, 11, 19 and 5 were SMA 1, 2 and 3 respectively) and 24 siblings (38.6 ± 11.2 months, 71% boys) were enrolled. We also enrolled 15 children with nephrotic syndrome as age and gender matched control to SMA children in age-group 2-5 years (27.7 ± 9.1 months, 67% boys). In infants with SMA, the scale scores of IBQ-R were significantly higher for distress to limitation, fear, sadness, and falling reactivity/rate of recovery from distress (p = 0.005; 0.03; 0.001, and 0.04) and lower for soothability as compared to healthy control group (p = 0.04). Similarly, for the three dimensions of temperament computed from these 13 domains, the mean scale score for surgency/extraversion was lower and negative affectivity was higher (p = 0.04 and 0.03), in infants with SMA as compared to healthy controls. For preschool age group, the internalizing problem scores (p = 0.009 and 0.03) and stress problem scores (p = 0.002 and 0.04) were higher in the SMA group, as compared to both the healthy control group and diseased control group. While assessing the syndrome scale scores, the score was higher for emotionally reactive (p = 0.0002 and 0.01) and anxious domains (p < 0.0001 and p = 0.0002) compared to both healthy and diseased control groups.

CONCLUSION

Infants and young children with SMA suffer from increased internalizing problems like anxiety, depression and probably their healthy siblings are also at increased levels of stress, depicted by increased somatic complaints.

Advances and limitations for the treatment of spinal muscular atrophy

Spinal muscular atrophy (5q-SMA; SMA), a genetic neuromuscular condition affecting spinal motor neurons, is caused by defects in both copies of the SMN1 gene that produces survival motor neuron (SMN) protein. The highly homologous SMN2 gene primarily expresses a rapidly degraded isoform of SMN protein that causes anterior horn cell degeneration, progressive motor neuron loss, skeletal muscle atrophy and weakness. Severe cases result in limited mobility and ventilatory insufficiency. Untreated SMA is the leading genetic cause of death in young children. Recently, three therapeutics that increase SMN protein levels in patients with SMA have provided incremental improvements in motor function and developmental milestones and prevented the worsening of SMA symptoms. While the therapeutic approaches with Spinraza^®, Zolgensma^®, and Evrysdi^® have a clinically significant impact, they are not curative. For many patients, there remains a significant disease burden. A potential combination therapy under development for SMA targets myostatin, a negative regulator of muscle mass and strength. Myostatin inhibition in animal models increases muscle mass and function. Apitegromab is an investigational, fully human, monoclonal antibody that specifically binds to proforms of myostatin, promyostatin and latent myostatin, thereby inhibiting myostatin activation. A recently completed phase 2 trial demonstrated the potential clinical benefit of apitegromab by improving or stabilizing motor function in patients with Type 2 and Type 3 SMA and providing positive proof-of-concept for myostatin inhibition as a target for managing SMA. The primary goal of this manuscript is to orient physicians to the evolving landscape of SMA treatment.    

Nusinersen in adult patients with 5q spinal muscular atrophy: A multicenter observational cohorts' study

BACKGROUND AND PURPOSE

The aim was to assess the safety and efficacy of nusinersen in adult 5q spinal muscular atrophy (SMA) patients.

METHODS

Patients older than 15 years and followed for at least 6 months with one motor scale (Hammersmith Functional Motor Scale Expanded, HFMSE; Revised Upper Limb Module, RULM) in five referral centers were included. The clinical and patients' global impression of change (CGI-C and PGI-C) were recorded in treated patients at the last visit. Functional scales (Egen Klassification, EK2; Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, ALSFRS-R) and the percentage predicted forced vital capacity were collected when available.

RESULTS

Seventy-nine SMA patients (39 treated with nusinersen) were included. Compared with untreated patients, treated patients showed a significant improvement of 2 points (±0.46) in RULM (p &lt; 0.001) after 6 months. After a mean follow-up of 16 months, nusinersen treatment was associated with a significant improvement in HFMSE (odds ratio [OR] 1.15, p = 0.006), the 6-min walk test (OR = 1.07, p &lt; 0.001) and the EK2 (OR = 0.81, p = 0.001). Compared with untreated patients, more treated patients experienced clinically meaningful improvements in all scales, but these differences were statistically significant only for RULM (p = 0.033), ALSFRS-R (p = 0.005) and EK2 (p &lt; 0.001). According to the CGI-C and PGI-C, 64.1% and 61.5% of treated patients improved with treatment. Being a non-sitter was associated with less response to treatment, whilst a longer time of treatment was associated with better response. Most treated patients (77%) presented at least one adverse event, mostly mild.

CONCLUSIONS

Nusinersen treatment is associated with some improvements in adult SMA patients. Most severely affected patients with complex spines are probably those with the most unfavorable risk-benefit ratio.

Spinal muscular atrophy carrier frequency in Saudi Arabia

BACKGROUND

Spinal Muscular Dystrophy (SMA) is one of the leading causes of death in infants and young children from heritable diseases. Although no large-scale popultion-based studies have been done in Saudi Arabia, it is reported that the incidence of SMA is higher in the Saudi population partly because of the high degree of consanguineous marriages.

METHODS

The final analysis included 4198 normal volunteers aged between 18 and 25 years old, 54.7% males, and 45.3% females. Whole blood was spotted directly from finger pricks onto IsoCode StixTM and genomic DNA was isolated using one triangle from the machine. To discern the SMN1 copy number independently from SMN2, Multiplex PCR with Dral restriction fragment analysis was completed. We used the carrier frequency and population-level data to estimate the prevalence of SMA in the population using the life-table method.

RESULTS

This data analysis showed the presence of one copy of the SMN1 gene in 108 samples and two copies in 4090 samples, which resulted from a carrier frequency of 2.6%. The carrier frequency was twofold in females reaching 3.7% compared to 1.6% in males. 27% of participants were children of first-cousin marriages. We estimated the birth incidence of SMA to be 32 per 100,000 birth and the total number of people living with SMA in the Kingdom of Saudi Arabia to be 2265 of which 188 are type I, 1213 are type II, and 8,64 are type III.

CONCLUSION

The SMA carrier rate of 2.6% in Saudi control subjects is slightly higher than the reported global frequency of 1.25 to 2% with links to the high degree of consanguinity.

Medical student acceptance on gene therapy to increase children's well-being with genetic diseases: a study in Indonesia

Aim: Gene therapy is expected to improve patients' quality of life. Medical students need to be aware about this technology as its application is becoming wider. Materials & methods: A web-based survey was conducted to measure the acceptance of Indonesian medical students regarding gene therapy. Results: Data from 621 valid responses showed that Indonesian medical students have little knowledge of this technology, with 34.4% of them ever heard of gene therapy. However, most of them support the approved gene therapy for health-related matters, but not on the non-health related matters. Their acceptance was determined by the sex, domicile and studentship status. Conclusion: Increasing medical students' knowledge of gene therapy is important to minimize the future conflict of gene therapy application.

Systematic Literature Review to Assess the Cost and Resource Use Associated with Spinal Muscular Atrophy Management

BACKGROUND

Spinal muscular atrophy (SMA) is a severe neuromuscular disease that is inherited in an autosomal recessive manner with an estimated incidence of 1 in 10,000 live births. The traditional classification of SMA includes five types (Types 0-4 SMA) based on patient age at disease onset and the highest motor milestone achieved. Spinal muscular atrophy leads to progressive muscle denervation, skeletal muscle atrophy and loss of motor function and ambulation, though phenotypes vary along a disease continuum. Regardless of disease severity, or access to treatment, a multidisciplinary approach to care is required to ease the burden of disease. To date, limited global data exist regarding the cost and resource use associated with SMA management.

OBJECTIVE

We planned to perform a systematic literature review to identify studies on cost and healthcare resource use associated with SMA.

METHODS

A comprehensive search was conducted in 2019 using several electronic databases in addition to supplementary sources and updated in 2021 in order to capture recently published studies. Electronic searches performed in Embase, MEDLINE, Evidence-Based Medicine Reviews and EconLit via the Ovid platform were supplemented by searches of the grey literature (reference lists, conference proceedings, global Health Technology Assessment body websites and other relevant sources). Study eligibility criteria were based on the population, interventions, comparators and outcomes (PICO) framework. Quality assessment of full-text publications was evaluated with reference to a published checklist. To accommodate heterogeneity across studies including countries, currencies, populations, time units and methods of reporting used, costs were reported in Euros in 2019.

RESULTS

A total of 51 publications, comprising 49 unique studies of patients with SMA that met all eligibility criteria were included in the final selection. The publications comprised data from 14 countries and seven additional studies that reported multi-national data. Because of the heterogeneity between the different types of SMA, data were frequently reported separately for individuals with Type 1 or early-onset SMA and for Types 2, 3, and 4 SMA or later-onset SMA. Generally, direct medical costs and resource use were reported to be highest for patients with Type 1 SMA, decreasing incrementally for patients with Type 2 and Type 3 disease. Where cost categories were similar, direct costs were much lower in Europe than in the USA. Indirect costs were primarily associated with informal care, which was a substantial burden on patients and families in terms of both cost and time. Cost drivers were generally found to be dependent on SMA type.

CONCLUSIONS

Long-term robust studies are required to fully elucidate the economic burden of SMA. Considering that motor function can vary broadly, especially in Type 2 SMA, it would be beneficial to understand how costs and resource use are affected by different degrees of ambulation. Reporting data in terms of achieved motor function could also mitigate the challenges of comparing global data studies of small populations. Global, regional, and/or local data collection platforms and disease registry networks could play an important role in helping to address current data gaps.

Systematic Literature Review to Assess Economic Evaluations in Spinal Muscular Atrophy (SMA)

BACKGROUND

Spinal muscular atrophy (SMA) is a rare, progressive neuromuscular disease that affects individuals with a broad age range. SMA is typically characterised by symmetrical muscle weakness but is also associated with cardiac defects, life-limiting impairments in respiratory function and bulbar function defects that affect swallowing and speech. Despite the advent of three innovative disease-modifying therapies (DMTs) for SMA, the cost of DMTs in addition to the costs of standard of care can be a barrier to treatment access for patients. Health Technology Assessment (HTA) decision makers evaluate the cost effectiveness of a new treatment before making a reimbursement decision.

OBJECTIVE

The primary objective was to conduct a systematic literature review (SLR) to identify the modelling approaches used in economic evaluations that assess current approved treatments in SMA, with a secondary objective to widen the scope and identify economic evaluations assessing other (non-SMA) neuromuscular disorders.

METHODS

An SLR was performed to identify available economic evaluations associated with any type of SMA (Type 1, 2, 3 and/or 4). Economic evaluations associated with other (non-SMA) neuromuscular disorders were identified but not further analysed. Electronic searches were conducted in Embase, MEDLINE, Evidence-Based Medicine Reviews and EconLit via the Ovid platform in August 2019, and were supplemented by searches of the grey literature (reference lists, conference proceedings, global HTA body websites and other relevant sources). Eligibility criteria were based on the population, interventions, comparators and outcomes (PICO) framework. Quality assessment of full publications was conducted with reference to a published checklist.

RESULTS

Nine publications covering eight unique studies met all eligibility criteria for inclusion in the SLR, including four conference abstracts, two peer-reviewed original research articles and three HTA submissions (conducted in Canada, the US and the UK). Evaluations considered patients with early infantile-onset (most likely to develop Type 1 or Type 2 SMA), later-onset SMA and both infantile- and later-onset SMA. Data for the identified economic models were collected from literature reviews and relatively short-term clinical trials. Several intent-to-treat clinical trial populations were used in the studies, which resulted in variation in cycle length and different outcome measures to determine clinical efficacy. The results of the quality assessment on the five full-text, peer-reviewed publications found that they generally provided clear descriptions of objectives, modelling methods and results. However, key decisions, such as choice of economic evaluation, model type and choice of variables for sensitivity analysis, were often not adequately justified.

CONCLUSIONS

This SLR highlights the need for economic evaluations in SMA to better align in modelling approaches with respect to (i) consistency in model structure and use of motor function milestones as health states; (ii) consensus on measuring quality of life to estimate utilities; (iii) consistency in data collection by registries; and (iv) consensus on SMA-type classification and endpoints that determine intervention efficacy. Future economic evaluations should also incorporate the review group critiques of previous HTA submissions relating to data inputs and approaches to modelling and should include patient data reflective of the SMA population being modelled. Economic evaluations would also be improved with inclusion of long-term efficacy and safety data from clinical trials and valid patient and caregiver utility data.

Preferences and Utilities for Treatment Attributes in Type 2 and Non-ambulatory Type 3 Spinal Muscular Atrophy in the United Kingdom

BACKGROUND

Spinal muscular atrophy (SMA) is a rare neuromuscular disease that affects motor neurons, resulting in progressive skeletal muscle weakness and atrophy.

OBJECTIVE

The aim was to understand the value patients with SMA and caregivers place on treatment attributes and to estimate health utilities for SMA treatment outcomes from a general public sample.

METHODS

Two discrete choice experiments were designed to elicit treatment preferences and health utilities, respectively. Patients with Type 2 and non-ambulatory Type 3 SMA, caregivers of patients with SMA and a general public sample in the UK completed the surveys. Patients and caregiver participants were recruited through patient associations. General public participants were recruited via a survey recruitment panel. Attributes included motor function, breathing function, treatment administration, treatment reactions, eyesight monitoring, contraception (patients only) and overall survival (general public only). Clustered conditional logit models were used to estimate treatment preferences, and marginal rates of substitution were used to estimate disutilities.

RESULTS

Adult patients (n = 84) were twice as likely to choose a treatment with improved (vs. stable) motor and breathing function and four to five times less likely to choose a treatment with deteriorated (vs. stable) motor and breathing function as a treatment outcome. Caregivers (n = 83) were three to nine times more likely to choose improved and two to four times less likely to choose deteriorated (vs. stable) motor and breathing function. Both patients and caregivers preferred oral over intrathecal treatment. Treatment reactions, eyesight monitoring or contraception had no significant effect on patient choices. Conversely, caregivers preferred avoidance of treatment reactions. General public data (n = 506) yielded disutilities for unable to sit (- 0.408), need for > 16 h daily mechanical breathing support (- 0.304) and intrathecal therapy (- 0.071).

CONCLUSIONS

Study results show the importance of motor and breathing function to patients and caregivers, and an oral treatment preference. Disutilities (decrements to utility) were substantial for SMA disease outcomes and care aspects.

Assessment of Health-Related Quality of Life in Adult Spinal Muscular Atrophy Under Nusinersen Treatment—A Pilot Study

5q-Spinal muscular atrophy (SMA) is a severely disabling inherited neuromuscular disease that progressively reduces the motor abilities of affected individuals. The approval of the antisense oligonucleotide nusinersen, which has been shown to improve motor function in adult SMA patients, changed the treatment landscape. However, little is known about its impact on patients' quality of life (QoL), and there is still a need for adequate patient-reported outcome measures. In this study, we used the short form of the Neuro-QoL (Quality of Life in Neurological Disorders) for upper/lower extremity function to prospectively assess the health-related QoL of 17 adult SMA patients prior to initiation of nusinersen treatment and 2, 6, 10, and 14 months afterwards. At baseline, Neuro-QoL scores strongly correlated with motor function scores (Hammersmith Functional Motor Scale Expanded, HFMSE; Revised Upper Limb Module, RULM), but QoL did not increase significantly during the 14-month treatment period despite significant motor improvement as measured by HFMSE. Our results underline the need for novel, disease-specific assessments of QoL in SMA.

A Patient-Centered Evaluation of Meaningful Change on the 32-Item Motor Function Measure in Spinal Muscular Atrophy Using Qualitative and Quantitative Data

The 32-item Motor Function Measure (MFM32) is an assessment of motor function used to evaluate fine and gross motor ability in patients with neuromuscular disorders, including spinal muscular atrophy (SMA). Reliability and validity of the MFM32 have been documented in individuals with SMA. Through semi-structured qualitative interviews (N = 40) and an online survey in eight countries (N = 217) with individuals with Types 2 and 3 SMA aged 2–59 years old and caregivers, the meaning of changes on a patient-friendly version of the MFM32 was explored. In an independent analysis of clinical trial data, anchor- and distribution-based analyses were conducted in a sample of individuals with Type 2 and non-ambulant Type 3 SMA to estimate patient-centered quantitative MFM32 meaningful change thresholds. The results from this study demonstrate that, based on patient and caregiver insights, maintaining functional ability as assessed by a patient-friendly version of the MFM32 is an important outcome. Quantitative analyses using multiple anchors (median age range of 5–8 years old across anchor groups) indicated that an ~3-point improvement in MFM32 total score represents meaningful change at the individual patient level. Overall, the qualitative and quantitative findings from this study support the importance of examining a range of meaningful change thresholds on the MFM32 including ≥0 points change reflecting stabilization or improvement and ≥3 points change reflecting a higher threshold of improvement. Future research is needed to explore quantitative differences in meaningful change on the MFM32 based on age and functional subgroups.

Ethical Perspectives on Treatment Options with Spinal Muscular Atrophy Patients

Since 2016, 3 innovative therapies for spinal muscular atrophy (SMA) have changed the face of the disease. Although these therapies often result in remarkable improvements in infants and children, benefits in adults are modest and treatment is not curative. Concerns have been raised about the enormous costs of these medications, the ultimate burden to taxpayers, and the costs to society of withholding treatments and sacrificing or disadvantaging some individuals. Physicians are best positioned to serve our patients by carefully considering the costs, benefits, implications for quality of life (QOL), and the interplay of these factors within the framework of core ethical principles that guide clinical care. ANN NEUROL 2022;91:305–316

Anxiety and depression in school-age patients with spinal muscular atrophy: a cross-sectional study

BACKGROUND

Spinal muscular atrophy (SMA) is a rare neurogenetic disease which involves multisystem dysfunctions such as respiratory, digestive, and motor disorders. Anxiety, depression and other psychological disorders often accompany severe chronic physical diseases. The aim of this study was to investigate the prevalence of anxiety and depression along with their influencing factors among school-age patients with SMA.

METHODS

We conducted a cross-sectional study on school-age SMA patients in China. Patients aged 8-18 years with a genetic diagnosis of 5qSMA were invited to answer a questionnaire composed of sociodemographic and clinical questions, then to complete the Screen for Child Anxiety-Related Emotional Disorders and Depression Self-Rating Scale for depression and anxiety level evaluation. At the end of the questionnaire, further questions assessed the subjective anxiety and subjective depression of patients' caregivers and their expectations for their child's future.

RESULTS

Complete data were available for 155 patients. The sample included 45.8% boys and 54.2% girls; 65.2% were type II, 27.1% were type III, and the remainder were type I SMA. Rates of anxiety and depression in these school-age SMA patients were 40.0% and 25.2%, respectively. Gender, age, and disease type were not associated with anxiety or depression, but respiratory system dysfunction, digestive system dysfunction, skeletal deformity, rehabilitation exercise, academic delay, specialized support from school, household income level, caregivers' subjective anxiety, and caregivers' expectations were significantly related to both anxiety and depression.

CONCLUSIONS

There was a high prevalence of anxiety and depression in school-age SMA patients in China. Professional psychological care maybe included in the standard of care. These results also call for possible targets for intervention such as reducing complications, improving drug accessibility, retaining normal schooling, strengthening school support, and enhancing the ability of the caregivers of SMA patients to assist in the diagnosis and treatment of the disease, so improving the mental health of SMA patients.

"I have SMA, SMA doesn't have me": a qualitative snapshot into the challenges, successes, and quality of life of adolescents and young adults with SMA

BACKGROUND

With the approval of three treatments for spinal muscular atrophy (SMA) and several promising therapies on the horizon, the SMA adolescent and young adult populations are expected to evolve in the coming years. It is imperative to understand this cohort as it exists today to provide optimal care and resources, as well as to assess possible treatment effects over time. In 2018, Cure SMA launched two initiatives geared towards understanding adolescents and young adults with SMA, ages 12-25. First, Cure SMA launched a Quality of Life (QoL) survey to capture quantitative and qualitative information on this specific age demographic. Concurrently, Cure SMA invited SMA-affected individuals, ages 12-25, to create a three-minute video on their everyday experiences living with SMA. An inductive thematic analysis of the free-text survey questions along with the video contest findings are reported here.

RESULTS

Eighty-five individuals-6 type Is, 58 type IIs, and 21 type IIIs-completed the Quality of Life free-response, while six individuals participated in the SMA awareness video contest. In both settings, individuals detailed a variety of challenges, including but not limited to forming or maintaining close relationships, experiencing feelings of isolation, challenges with accessibility, independence, and dealing with the stigma of being perceived as mentally disabled. Individuals also discussed their successes, including but not limited to higher education enrollment and attendance, development of quality friendships, and perseverance through obstacles. Additionally, notably in the survey, 39% of respondents requested the creation of an SMA peer support group in efforts to connect with each other as well as collectively navigate the aforementioned challenges they face.

CONCLUSION

Together, these findings provide a rare glimpse into the unique mindsets, challenges and motivations of SMA adolescents and young adults, via patient-reported measures instead of caregiver proxy. The adolescent and young adult age demographics assessed represent a critical transition period in life and in SMA care. No one understands the needs of an adolescent or young adult with SMA better than the individuals themselves, and it is critical to encapsulate their insights to affect change.

In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy

Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.

Design of a Non-Interventional Study to Validate a Set of Patient- and Caregiver-Oriented Measurements to Assess Health Outcomes in Spinal Muscular Atrophy (SMA-TOOL Study)

Introduction

There is a need to optimize the current clinical outcome measures in spinal muscular atrophy (SMA) incorporating patients’ and caregivers’ perspectives. The aim of this study is to evaluate the psychometric properties (validity, reliability and sensitivity to change) of a set of existing questionnaires and newly created items grouped in a “toolbox” to assess the impact of SMA on the physical, psychological and activities of daily living domains of the patient’s life.

Methods

This non-interventional, prospective study will be conducted at 12 neuromuscular clinics specialized in the management of patients with SMA in Spain. An expert panel of pediatric and adult neurologists, rehabilitation physicians, and a patient representative participated in the study design and selected key disease dimensions to explore and their respective measurements: mobility-independence, fatigue and endurance, pain, fatigability, breathing and voice, sleep and rest, and vulnerability. Patients aged 2 years or older with a confirmed diagnosis of 5q-autosomal recessive SMA (genetic confirmation of homozygous deletion or heterozygosity predictive of loss of function of the SMN1 gene) will be recruited.

Planned Outcomes

The development of robust outcome measures in collaboration with the patient community is essential to determine what is meaningful to patients and their caregivers. This study will provide us with a comprehensive set of tools to better capture the course of the disease and the response to treatments.

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

OBJECTIVE

To retrospectively investigate safety and efficacy of nusinersen in a large cohort of adult Italian patients with spinal muscular atrophy (SMA).

METHODS

Inclusion criteria were: (1) clinical and molecular diagnosis of SMA2 or SMA3; (2) nusinersen treatment started in adult age (>18 years); (3) clinical data available at least at baseline (T0-beginning of treatment) and 6 months (T6).

RESULTS

We included 116 patients (13 SMA2 and 103 SMA3) with median age at first administration of 34 years (range 18-72). The Hammersmith Functional Rating Scale Expanded (HFMSE) in patients with SMA3 increased significantly from baseline to T6 (median change +1 point, p<0.0001), T10 (+2, p<0.0001) and T14 (+3, p<0.0001). HFMSE changes were independently significant in SMA3 sitter and walker subgroups. The Revised Upper Limb Module (RULM) in SMA3 significantly improved between T0 and T14 (median +0.5, p=0.012), with most of the benefit observed in sitters (+2, p=0.018). Conversely, patients with SMA2 had no significant changes of median HFMSE and RULM between T0 and the following time points, although a trend for improvement of RULM was observed in those with some residual baseline function. The rate of patients showing clinically meaningful improvements (as defined during clinical trials) increased from 53% to 69% from T6 to T14.

CONCLUSIONS

Our data provide further evidence of nusinersen safety and efficacy in adult SMA2 and SMA3, with the latter appearing to be cumulative over time. In patients with extremely advanced disease, effects on residual motor function are less clear.