The impact of three SMN2 gene copies on clinical characteristics and effect of disease-modifying treatment in patients with spinal muscular atrophy: a systematic literature review.

Objective: To review the clinical characteristics and effect of treatment in patients with spinal muscular atrophy (SMA) and three copies of the SMN2 gene. Methods: We conducted a literature search in October 2022 to identify English-language clinical research on SMA that included SMN2 copy number according to PRISMA guidelines. Results: Our search identified 44 studies examining the impact of three SMN2 copies on clinical characteristics (21 on phenotype, 13 on natural history, and 15 on functional status and other signs/symptoms). In children with type I SMA or presymptomatic infants with an SMN1 deletion, three SMN2 copies was associated with later symptom onset, slower decline in motor function and longer survival compared with two SMN2 copies. In patients with SMA type II or III, three SMN2 copies is associated with earlier symptom onset, loss of ambulation, and ventilator dependence compared with four SMN2 copies. Eleven studies examined treatment effects with nusinersen (nine studies), onasemnogene abeparvovec (one study), and a range of treatments (one study) in patients with three SMN2 copies. In presymptomatic infants, early treatment delayed the onset of symptoms and maintained motor function in those with three SMN2 copies. The impact of copy number on treatment response in symptomatic patients is still unclear. Conclusion: SMN2 copy number is strongly correlated with SMA phenotype in patients with SMN1 deletion, while no correlation was found in patients with an SMN1 mutation. Patients with three SMN2 copies show a highly variable clinical phenotype. Early initiation of treatment is highly effective in presymptomatic patients with three SMN2 copies.

The IAAM LTBP4 Haplotype is Protective Against Dystrophin-Deficient Cardiomyopathy.

Background: Dilated cardiomyopathy (DCM) is a major complication of, and leading cause of mortality in Duchenne muscular dystrophy (DMD). Its severity, age at onset, and rate of progression display wide variability, whose molecular bases have been scarcely elucidated. Potential DCM-modifying factors include glucocorticoid (GC) and cardiological treatments, DMD mutation type and location, and variants in other genes. Methods and Results: We retrospectively collected 3138 echocardiographic measurements of left ventricular ejection fraction (EF), shortening fraction (SF), and end-diastolic volume (EDV) from 819 DMD participants, 541 from an Italian multicentric cohort and 278 from the Cooperative International Neuromuscular Group Duchenne Natural History Study (CINRG-DNHS). Using generalized estimating equation (GEE) models, we estimated the yearly rate of decrease of EF (-0.80%) and SF (-0.41%), while EDV increase was not significantly associated with age. Utilizing a multivariate generalized estimating equation (GEE) model we observed that mutations preserving the expression of the C-terminal Dp71 isoform of dystrophin were correlated with decreased EDV (-11.01 mL/m2, p = 0.03) while for dp116 were correlated with decreased EF (-4.14%, p = <0.001). The rs10880 genotype in the LTBP4 gene, previously shown to prolong ambulation, was also associated with increased EF and decreased EDV (+3.29%, p = 0.002, and -10.62 mL/m2, p = 0.008) with a recessive model. Conclusions: We quantitatively describe the progression of systolic dysfunction progression in DMD, confirm the effect of distal dystrophin isoform expression on the dystrophin-deficient heart, and identify a strong effect of LTBP4 genotype of DCM in DMD.

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

OBJECTIVE: The aim of this study was to assess early language acquisitions in treated individuals with spinal muscular atrophy (SMA) type 1 and in infants identified by newborn screening (NBS). METHODS: Parents of SMA individuals aged between 8 and 36 months were asked to fill in the MacArthur-Bates Communicative Development Inventory (MB-CDI) that assesses comprehension, gesture and expressive skills. A follow-up assessment was performed in 21 of the 36. RESULTS: The MB-CDI was completed by parents of 24 type 1 and 12 infants identified by NBS. Comprehension skills were preserved in 81% of the type 1 SMA and in 87% infants identified by NBS. Gesture abilities were <5th centile in 55% of the type 1 SMA and in none of those identified by NBS. Lexical expressions were <5th centile in more than 80% type 1 SMA and in 50% of infants identified by NBS. At follow-up, despite an increase in lexical expression skills, the scores remained below the fifth centile in 43% type 1 SMA and in 86% of infants identified by NBS. CONCLUSIONS: These results suggest that language and communication development may follow a similar pattern to that observed in motor function with the possibility to develop skills (eg, ability to say clear words) that are not usually present in untreated infants but with a level of performance that does not reach that of their typically developing peers.

Gain and loss of upper limb abilities in Duchenne muscular dystrophy patients: A 24-month study.

Duchenne muscular dystrophy (DMD) is a neuromuscular condition characterized by muscle weakness. The Performance of upper limb (PUL) test is designed to evaluate upper limb function in DMD patients across three domains. The aim of this study is to identify frequently lost or gained PUL 2.0 abilities at distinct functional stages in DMD patients. This retrospective study analyzed prospectively collected data on 24-month PUL 2.0 changes related to ambulatory function. Ambulant patients were categorized based on initial 6MWT distance, non-ambulant patients by time since ambulation loss. Each PUL 2.0 item was classified as shift up, no change, or shift down. The study's cohort incuded 274 patients, with 626 paired evaluations at the 24-month mark. Among these, 55.1 % had activity loss, while 29.1 % had gains. Ambulant patients showed the lowest loss rates, mainly in the shoulder domain. The highest loss rate was in the shoulder domain in the transitioning subgroup and in elbow and distal domains in the non-ambulant patients. Younger ambulant patients demonstrated multiple gains, whereas in the other functional subgroups there were fewer gains, mostly tied to singular activities. Our findings highlight divergent upper limb domain progression, partly linked to functional status and baseline function.

Clinical Phenotype of Pediatric and Adult Patients With Spinal Muscular Atrophy With Four SMN2 Copies: Are They Really All Stable?

OBJECTIVE: The aim of this study was to provide an overview of the clinical phenotypes associated with 4 SMN2 copies. METHODS: Clinical phenotypes were analyzed in all the patients with 4 SMN2 copies as part of a nationwide effort including all the Italian pediatric and adult reference centers for spinal muscular atrophy (SMA). RESULTS: The cohort includes 169 patients (102 men and 67 women) with confirmed 4 SMN2 copies (mean age at last follow-up = 36.9 ± 19 years). Six of the 169 patients were presymptomatic, 8 were classified as type II, 145 as type III (38 type IIIA and 107 type IIIB), and 8 as type IV. The remaining 2 patients were asymptomatic adults identified because of a familial case. The cross-sectional functional data showed a reduction of scores with increasing age. Over 35% of the type III and 25% of the type IV lost ambulation (mean age = 26.8 years ± 16.3 SD). The risk of loss of ambulation was significantly associated with SMA type (p < 0.0001), with patients with IIIB and IV less likely to lose ambulation compared to type IIIA. There was an overall gender effect with a smaller number of women and a lower risk for women to lose ambulation. This was significant in the adult (p = 0.009) but not in the pediatric cohort (p = 0.43). INTERPRETATION: Our results expand the existing literature on natural history of 4 SMN2 copies confirming the variability of phenotypes in untreated patients, ranging from type II to type IV and an overall reduction of functional scores with increasing age. ANN NEUROL 2023;94:1126-1135.

Upper Limb Changes in DMD Patients Amenable to Skipping Exons 44, 45, 51 and 53: A 24-Month Study.

INTRODUCTION: The Performance of Upper Limb version 2.0 (PUL 2.0) is increasingly used in Duchenne Muscular Dystrophy (DMD) to study longitudinal functional changes of motor upper limb function in ambulant and non-ambulant patients. The aim of this study was to evaluate changes in upper limb functions in patients carrying mutations amenable to skipping exons 44, 45, 51 and 53. METHODS: All DMD patients were assessed using the PUL 2.0 for at least 2 years, focusing on 24-month paired visits in those with mutations eligible for skipping exons 44, 45, 51 and 53. RESULTS: 285 paired assessments were available. The mean total PUL 2.0 12-month change was -0.67 (2.80), -1.15 (3.98), -1.46 (3.37) and -1.95 (4.04) in patients carrying mutations amenable to skipping exon 44, 45, 51 and 53, respectively. The mean total PUL 2.0 24-month change was -1.47 (3.73), -2.78 (5.86), -2.95 (4.56) and -4.53 (6.13) in patients amenable to skipping exon 44, 45, 51 and 53, respectively. The difference in PUL 2.0 mean changes among the type of exon skip class for the total score was not significant at 12 months but was significant at 24 months for the total score (p < 0.001), the shoulder (p = 0.01) and the elbow domain (p < 0.001), with patients amenable to skipping exon 44 having smaller changes compared to those amenable to skipping exon 53. There was no difference within ambulant or non-ambulant cohorts when subdivided by exon skip class for the total and subdomains score (p > 0.05). CONCLUSIONS: Our results expand the information on upper limb function changes detected by the PUL 2.0 in a relatively large group of DMD patients with distinct exon-skipping classes. This information can be of help when designing clinical trials or in the interpretation of the real world data including non-ambulant patients.

Onasemnogene abeparvovec in spinal muscular atrophy: predictors of efficacy and safety in naïve patients with spinal muscular atrophy and following switch from other therapies.

Background: Efficacy and safety of onasemnogene abeparvovec (OA) for Spinal Muscular Atrophy infants under 7 months and <8.5 kg has been reported in clinical trials. This study examines efficacy and safety predictors in a wide age (22 days-72 months) and weight (3.2-17 kg) range, also including patients previously treated with other drugs. Methods: 46 patients were treated for 12 months between January 2020 and March 2022. Safety profile was also available for another 21 patients with at least 6 month follow-up after OA infusion. 19/67 were treatment naïve when treated with OA. Motor function was measured with the CHOP-INTEND. Findings: CHOP-INTEND changes varied among age groups. Baseline score and age at OA treatment best predicted changes. A mixed model post-hoc analysis showed that in patients treated before the age of 24 months the CHOP-INTEND changes were already significant 3 months after OA while in those treated after the age of 24 months the difference was only significant 12 months after OA. Adverse events occurred in 51/67. The risk for elevated transaminases serum levels was higher in older patients. This was also true for weight and for pre-treatment with nusinersen when analysed individually. A binomial negative regression analysis showed that only age at OA treatment had a significant effect on the risk of elevated transaminases. Interpretation: Our paper describes OA 12-month follow-up showing efficacy across various age and weight groups not targeted by clinical trials. The study identifies prognostic factors for safety and efficacy in treatment selection. Funding: None.

Longitudinal Analysis of PUL 2.0 Domains in Ambulant and Non-Ambulant Duchenne Muscular Dystrophy Patients: How do they Change in Relation to Functional Ability?

BACKGROUND: The performance of upper limb 2.0 (PUL) is widely used to assess upper limb function in DMD patients. The aim of the study was to assess 24 month PUL changes in a large cohort of DMD patients and to establish whether domains changes occur more frequently in specific functional subgroups. METHODS: The PUL was performed in 311 patients who had at least one pair of assessments at 24 months, for a total of 808 paired assessments. Ambulant patients were subdivided according to the ability to walk: >350, 250-350, ≤250 meters. Non ambulant patients were subdivided according to the time since they lost ambulation: <1, 1-2, 2-5 or >5 years. RESULTS: At 12 months, the mean PUL 2.0 change on all the paired assessments was -1.30 (-1.51--1.05) for the total score, -0.5 (-0.66--0.39) for the shoulder domain, -0.6 (-0.74--0.5) for the elbow domain and -0.1 (-0.20--0.06) for the distal domain.At 24 months, the mean PUL 2.0 change on all the paired assessments was -2.9 (-3.29--2.60) for the total score, -1.30 (-1.47--1.09) for the shoulder domain, -1.30 (-1.45--1.11) for the elbow domain and -0.4 (-1.48--1.29) for the distal domain.Changes at 12 and 24 months were statistically significant between subgroups with different functional abilities for the total score and each domain (p < 0.001). CONCLUSION: There were different patterns of changes among the functional subgroups in the individual domains. The time of transition, including the year before and after loss of ambulation, show the peak of negative changes in PUL total scores that reflect not only loss of shoulder but also of elbow activities. These results suggest that patterns of changes should be considered at the time of designing clinical trials.

Type I spinal muscular atrophy patients treated with nusinersen: 4-year follow-up of motor, respiratory and bulbar function.

BACKGROUND: We report the 4-year follow-up in type I patients treated with nusinersen and the changes in motor, respiratory and bulbar function in relation to subtype, age and SMN2 copy number. METHODS: The study included SMA 1 patients with at least one assessment after 12, 24 and 48 months from the first dose of nusinersen. The assessments used were Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) and the Hammersmith Infant Neurological Examination (HINE-II). RESULTS: Forty-eight patients, with ages ranging from 7 days to 12 years (mean 3.3 years, SD 3.6 years) were included in the study. The CHOP INTEND and HINE-II scores significantly increased between baseline and 48 months (p < 0.001). When age at starting treatment subgroups (<210 days, <2 years, 2-4 years, 5-11 years, ≥12 years) were considered, the CHOP INTEND increased significantly in patients younger than 4 years at treatment, while the HINE-2 increased significantly in patients younger than 2 years at treatment. In a mixed-model analysis, age, nutritional and respiratory status were predictive of changes on both scales while SMN2 copy number and decimal classification were not. CONCLUSIONS: Our results confirm the safety profile previously reported and support the durability of the efficacy of nusinersen at 4 years with an overall stability or mild improvement and no evidence of deterioration over a long period of time.

Prevalence of Spinal Muscular Atrophy in the Era of Disease-Modifying Therapies: An Italian Nationwide Survey.

OBJECTIVE: Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in the SMN1 gene. The aim of this study was to assess the prevalence of SMA and treatment prescription in Italy. METHODS: An online survey was distributed to 36 centers identified by the Italian government as referral centers for SMA. Data on the number of patients with SMA subdivided according to age, type, SMN2 copy number, and treatment were collected. RESULTS: One thousand two hundred fifty-five patients with SMA are currently followed in the Italian centers with an estimated prevalence of 2.12/100,000. Of the 1,255, 284 were type I, 470 type II, 467 type III, and 15 type IV with estimated prevalence of 0.48, 0.79, 0.79 and 0.02/100,000, respectively. Three patients with SMA 0 and 16 presymptomatic patients were also included. Approximately 85% were receiving one of the available treatments. The percentage of treated patients decreased with decreasing severity (SMA I: 95.77%, SMA II: 85.11%, SMA III: 79.01%). DISCUSSION: The results provide for the first time an estimate of the prevalence of SMA at the national level and the current distribution of patients treated with the available therapeutical options. These data provide a baseline to assess future changes in relation to the evolving therapeutical scenario.

Risdiplam in types 2 and 3 spinal muscular atrophy: A randomised, placebo-controlled, dose-finding trial followed by 24 months of treatment.

BACKGROUND AND PURPOSE: Spinal muscular atrophy (SMA) is caused by reduced levels of survival of motor neuron (SMN) protein due to deletions and/or mutations in the SMN1 gene. Risdiplam is an orally administered molecule that modifies SMN2 pre-mRNA splicing to increase functional SMN protein. METHODS: SUNFISH Part 1 was a dose-finding study conducted in 51 individuals with types 2 and 3 SMA aged 2-25 years. A dose-escalation method was used to identify the appropriate dose for the subsequent pivotal Part 2. Individuals were randomized (2:1) to risdiplam or placebo at escalating dose levels for a minimum 12-week, double-blind, placebo-controlled period, followed by treatment for 24 months. The dose selection for Part 2 was based on safety, tolerability, pharmacokinetic, and pharmacodynamic data. Exploratory efficacy was also measured. RESULTS: There was no difference in safety findings for all assessed dose levels. A dose-dependent increase in blood SMN protein was observed; a median twofold increase was obtained within 4 weeks of treatment initiation at the highest dose level. The increase in SMN protein was sustained over 24 months of treatment. Exploratory efficacy showed improvement or stabilization in motor function. The pivotal dose selected for Part 2 was 5 mg for patients with a body weight ≥20 kg or 0.25 mg/kg for patients with a body weight <20 kg. CONCLUSIONS: SUNFISH Part 1 demonstrated a twofold increase in SMN protein after treatment with risdiplam. The observed safety profile supported the initiation of the pivotal Part 2 study. The long-term efficacy and safety of risdiplam are being assessed with ongoing treatment.

Safety and efficacy of risdiplam in patients with type 1 spinal muscular atrophy (FIREFISH part 2): secondary analyses from an open-label trial.

BACKGROUND: Risdiplam is an orally administered therapy that modifies pre-mRNA splicing of the survival of motor neuron 2 (SMN2) gene and is approved for the treatment of spinal muscular atrophy. The FIREFISH study is investigating the safety and efficacy of risdiplam in treated infants with type 1 spinal muscular atrophy versus historical controls. The primary endpoint of part 2 of the FIREFISH study showed that infants with type 1 spinal muscular atrophy attained the ability to sit without support for at least 5 s after 12 months of treatment. Here, we report on the safety and efficacy of risdiplam in FIREFISH part 2 over 24 months of treatment. METHODS: FIREFISH is an ongoing, multicentre, open-label, two-part study. In FIREFISH part 2, eligible infants (aged 1-7 months at enrolment, with a genetically confirmed diagnosis of spinal muscular atrophy, and two SMN2 gene copies) were enrolled in 14 hospitals in ten countries across Europe, North America, South America, and Asia. Risdiplam was orally administered once daily at 0·2 mg/kg for infants between 5 months and 2 years of age; once an infant reached 2 years of age, the dose was increased to 0·25 mg/kg. Infants younger than 5 months started at 0·04 mg/kg (infants between 1 month and 3 months old) or 0·08 mg/kg (infants between 3 months and 5 months old), and this starting dose was adjusted to 0·2 mg/kg once pharmacokinetic data were available for each infant. The primary and secondary endpoints included in the statistical hierarchy and assessed at month 12 have been reported previously. Here we present the remainder of the secondary efficacy endpoints that were included in the statistical hierarchy at month 24: the ability to sit without support for at least 30 s, to stand alone, and to walk alone, as assessed by the Bayley Scales of Infant and Toddler Development, third edition gross motor subscale. These three endpoints were compared with a performance criterion of 5% that was defined based on the natural history of type 1 spinal muscular atrophy; the results were considered statistically significant if the lower limit of the two-sided 90% CI was above the 5% threshold. FIREFISH is registered with ClinicalTrials.gov, NCT02913482. Recruitment is closed; the 36-month extension period of the study is ongoing. FINDINGS: Between March 13 and Nov 19, 2018, 41 infants were enrolled in FIREFISH part 2. After 24 months of treatment, 38 infants were ongoing in the study and 18 infants (44% [90% CI 31-58]) were able to sit without support for at least 30 s (p<0·0001 compared with the performance criterion derived from the natural history of untreated infants with type 1 spinal muscular atrophy). No infants could stand alone (0 [90% CI 0-7]) or walk alone (0 [0-7]) after 24 months of treatment. The most frequently reported adverse event was upper respiratory tract infection, in 22 infants (54%); the most common serious adverse events were pneumonia in 16 infants (39%) and respiratory distress in three infants (7%). INTERPRETATION: Treatment with risdiplam over 24 months resulted in continual improvements in motor function and achievement of developmental motor milestones. The FIREFISH open-label extension phase will provide additional evidence regarding long-term safety and efficacy of risdiplam. FUNDING: F Hoffmann-La Roche.

Identification of a cytokine profile in serum and cerebrospinal fluid of pediatric and adult spinal muscular atrophy patients and its modulation upon nusinersen treatment.

Background and objectives: Multisystem involvement in spinal muscular atrophy (SMA) is gaining prominence since different therapeutic options are emerging, making the way for new SMA phenotypes and consequent challenges in clinical care. Defective immune organs have been found in preclinical models of SMA, suggesting an involvement of the immune system in the disease. However, the immune state in SMA patients has not been investigated so far. Here, we aimed to evaluate the innate and adaptive immunity pattern in SMA type 1 to type 3 patients, before and after nusinersen treatment. Methods: Twenty one pediatric SMA type 1, 2, and 3 patients and 12 adult SMA type 2 and 3 patients were included in this single-center retrospective study. A Bio-Plex Pro-Human Cytokine 13-plex Immunoassay was used to measure cytokines in serum and cerebrospinal fluid (CSF) of the study cohort before and after 6 months of therapy with nusinersen. Results: We detected a significant increase in IL-1ß, IL-4, IL-6, IL-10, IFN-γ, IL-17A, IL-22, IL-23, IL-31, and IL-33, in serum of pediatric and adult SMA patients at baseline, compared to pediatric reference ranges and to adult healthy controls. Pediatric patients showed also a significant increase in TNF-α and IL-17F levels at baseline. IL-4, IFN-γ, Il-22, IL-23, and IL-33 decreased in serum of pediatric SMA patients after 6 months of therapy when compared to baseline. A significant decrease in IL-4, IL-6, INF-γ, and IL-17A was detected in serum of adult SMA patients after treatment. CSF of both pediatric and adult SMA patients displayed detectable levels of all cytokines with no significant differences after 6 months of treatment with nusinersen. Notably, a higher baseline expression of IL-23 in serum correlated with a worse motor function outcome after treatment in pediatric patients. Moreover, after 6 months of treatment, patients presenting a higher IL-10 concentration in serum showed a better Hammersmith Functional Motor Scale Expanded (HFMSE) score. Discussion: Pediatric and adult SMA patients show an inflammatory signature in serum that is reduced upon SMN2 modulating treatment, and the presence of inflammatory mediators in CSF. Our findings enhance SMA knowledge with potential clinical and therapeutic implications.

Age, corticosteroid treatment and site of mutations affect motor functional changes in young boys with Duchenne Muscular Dystrophy.

The aim of this study was to establish the possible effect of age, corticosteroid treatment and brain dystrophin involvement on motor function in young boys affected by Duchenne Muscular Dystrophy who were assessed using the North Star Ambulatory Assessment between the age of 4 and 7 years. The study includes 951 North Star assessments from 226 patients. Patients were subdivided according to age, to the site of mutation and therefore to the involvement of different brain dystrophin isoforms and to corticosteroids duration. There was a difference in the maximum North Star score achieved among patients with different brain dystrophin isoforms (p = 0.007). Patients with the involvement of Dp427, Dp140 and Dp71, had lower maximum NSAA scores when compared to those with involvement of Dp427 and Dp140 or of Dp427 only. The difference in the age when the maximum score was achieved in the different subgroups did not reach statistical significance. Using a linear regression model on all assessments we found that each of the three variables, age, site of mutation and corticosteroid treatment had an influence on the NSAA values and their progression over time. A second analysis, looking at 12-month changes showed that within this time interval the magnitude of changes was related to corticosteroid treatment but not to site of mutation. Our findings suggest that each of the considered variables appear to play a role in the progression of North Star scores in patients between the age of 4 and 7 years and that these should be carefully considered in the trial design of boys in this age range.

Natural history of Type 1 spinal muscular atrophy: a retrospective, global, multicenter study.

BACKGROUND: ANCHOVY was a global, multicenter, chart-review study that aimed to describe the natural history of Type 1 spinal muscular atrophy (SMA) from a broad geographical area and provide further contextualization of results from the FIREFISH (NCT02913482) interventional study of risdiplam treatment in Type 1 SMA. METHODS: Data were extracted from medical records of patients with first symptoms attributable to Type 1 SMA between 28 days and 3 months of age, genetic confirmation of SMA, and confirmed survival of motor neuron 2 copy number of two or unknown. The study period started on 1 January 2008 for all sites; study end dates were site-specific due to local treatment availabilities. Primary endpoints were time to death and/or permanent ventilation and proportion of patients achieving motor milestones. Secondary endpoints included time to initiation of respiratory and feeding support. RESULTS: Data for 60 patients from nine countries across Asia, Europe and North and South America were analyzed. The median age (interquartile range [IQR]) for reaching death or permanent ventilation was ~ 7.3 (5.9-10.5) months. The median age (IQR) at permanent ventilation was ~ 12.7 (6.9-16.4) months and at death was ~ 41.2 (7.3-not applicable) months. No patients were able to sit without support or achieved any level of crawling, standing or walking. INTERPRETATION: Findings from ANCHOVY were consistent with published natural history data on Type 1 SMA demonstrating the disease's devastating course, which markedly differed from risdiplam-treated infants (FIREFISH Part 2). The results provide meaningful additions to the literature, including a broader geographical representation.

Genetic modifiers of upper limb function in Duchenne muscular dystrophy.

Genetic modifiers of Duchenne muscular dystrophy (DMD) are variants located in genes different from the disease-causing gene DMD, but associated with differences in disease onset, progression, or response to treatment. Modifiers described so far have been tested mainly for associations with ambulatory function, while their effect on upper limb function, which is especially relevant for quality of life and independence in non-ambulatory patients, is unknown. We tested genotypes at several known modifier loci (SPP1, LTBP4, CD40, ACTN3) for association with Performance Upper Limb version 1.2 score in an Italian multicenter cohort, and with Brooke scale score in the Cooperative International Neuromuscular Group Duchenne Natural History Study (CINRG-DNHS), using generalized estimating equation (GEE) models of longitudinally collected data, with age and glucocorticoid treatment as covariates. CD40 rs1883832, previously linked to earlier loss of ambulation, emerged as a modifier of upper limb function, negatively affecting shoulder and distal domains of PUL (p = 0.023 and 0.018, respectively) in the Italian cohort, as well as of Brooke score (p = 0.018) in the CINRG-DNHS. These findings will be useful for the design and interpretation of clinical trials in DMD, especially for non-ambulatory populations.

Onasemnogene abeparvovec gene therapy for symptomatic infantile-onset spinal muscular atrophy type 1 (STR1VE-EU): an open-label, single-arm, multicentre, phase 3 trial.

BACKGROUND: Spinal muscular atrophy is a rare, autosomal recessive, neuromuscular disease caused by biallelic loss of the survival motor neuron 1 (SMN1) gene, resulting in motor neuron dysfunction. In this STR1VE-EU study, we aimed to evaluate the safety and efficacy of onasemnogene abeparvovec gene replacement therapy in infants with spinal muscular atrophy type 1, using broader eligibility criteria than those used in STR1VE-US. METHODS: STR1VE-EU was a multicentre, single-arm, single-dose, open-label phase 3 trial done at nine sites (hospitals and universities) in Italy (n=4), the UK (n=2), Belgium (n=2), and France (n=1). We enrolled patients younger than 6 months (180 days) with spinal muscular atrophy type 1 and the common biallelic pathogenic SMN1 exon 7-8 deletion or point mutations, and one or two copies of SMN2. Patients received a one-time intravenous infusion of onasemnogene abeparvovec (1·1 × 1014 vector genomes [vg]/kg). The outpatient follow-up consisted of assessments once per week starting at day 7 post-infusion for 4 weeks and then once per month until the end of the study (at age 18 months or early termination). The primary outcome was independent sitting for at least 10 s, as defined by the WHO Multicentre Growth Reference Study, at any visit up to the 18 months of age study visit, measured in the intention-to-treat population. Efficacy was compared with the Pediatric Neuromuscular Clinical Research (PNCR) natural history cohort. This trial is registered with ClinicalTrials.gov, NCT03461289 (completed). FINDINGS: From Aug 16, 2018, to Sept 11, 2020, 41 patients with spinal muscular atrophy were assessed for eligibility. The median age at onasemnogene abeparvovec dosing was 4·1 months (IQR 3·0-5·2). 32 (97%) of 33 patients completed the study and were included in the ITT population (one patient was excluded despite completing the study because of dosing at 181 days). 14 (44%, 97·5% CI 26-100) of 32 patients achieved the primary endpoint of functional independent sitting for at least 10 s at any visit up to the 18 months of age study visit (vs 0 of 23 untreated patients in the PNCR cohort; p<0·0001). 31 (97%, 95% CI 91-100) of 32 patients in the ITT population survived free from permanent ventilatory support at 14 months compared with six (26%, 8-44) of 23 patients in the PNCR natural history cohort (p<0·0001). 32 (97%) of 33 patients had at least one adverse event and six (18%) had adverse events that were considered serious and related to onasemnogene abeparvovec. The most common adverse events were pyrexia (22 [67%] of 33), upper respiratory infection (11 [33%]), and increased alanine aminotransferase (nine [27%]). One death, unrelated to the study drug, occurred from hypoxic-ischaemic brain damage because of a respiratory tract infection during the study. INTERPRETATION: STR1VE-EU showed efficacy of onasemnogene abeparvovec in infants with symptomatic spinal muscular atrophy type 1. No new safety signals were identified, but further studies are needed to show long-term safety. The benefit-risk profile of onasemnogene abeparvovec seems favourable for this patient population, including those with severe disease at baseline. FUNDING: Novartis Gene Therapies.

Risdiplam-Treated Infants with Type 1 Spinal Muscular Atrophy versus Historical Controls.

BACKGROUND: Type 1 spinal muscular atrophy (SMA) is a progressive neuromuscular disease characterized by an onset at 6 months of age or younger, an inability to sit without support, and deficient levels of survival of motor neuron (SMN) protein. Risdiplam is an orally administered small molecule that modifies SMN2 pre-messenger RNA splicing and increases levels of functional SMN protein in blood. METHODS: We conducted an open-label study of risdiplam in infants with type 1 SMA who were 1 to 7 months of age at enrollment. Part 1 of the study (published previously) determined the dose to be used in part 2 (reported here), which assessed the efficacy and safety of daily risdiplam as compared with no treatment in historical controls. The primary end point was the ability to sit without support for at least 5 seconds after 12 months of treatment. Key secondary end points were a score of 40 or higher on the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND; range, 0 to 64, with higher scores indicating better motor function), an increase of at least 4 points from baseline in the CHOP-INTEND score, a motor-milestone response as measured by Section 2 of the Hammersmith Infant Neurological Examination (HINE-2), and survival without permanent ventilation. For the secondary end points, comparisons were made with the upper boundary of 90% confidence intervals for natural-history data from 40 infants with type 1 SMA. RESULTS: A total of 41 infants were enrolled. After 12 months of treatment, 12 infants (29%) were able to sit without support for at least 5 seconds, a milestone not attained in this disorder. The percentages of infants in whom the key secondary end points were met as compared with the upper boundary of confidence intervals from historical controls were 56% as compared with 17% for a CHOP-INTEND score of 40 or higher, 90% as compared with 17% for an increase of at least 4 points from baseline in the CHOP-INTEND score, 78% as compared with 12% for a HINE-2 motor-milestone response, and 85% as compared with 42% for survival without permanent ventilation (P<0.001 for all comparisons). The most common serious adverse events were pneumonia, bronchiolitis, hypotonia, and respiratory failure. CONCLUSIONS: In this study involving infants with type 1 SMA, risdiplam resulted in higher percentages of infants who met motor milestones and who showed improvements in motor function than the percentages observed in historical cohorts. Longer and larger trials are required to determine the long-term safety and efficacy of risdiplam in infants with type 1 SMA. (Funded by F. Hoffmann-La Roche; FIREFISH ClinicalTrials.gov number, NCT02913482.).

Dysregulation of Muscle-Specific MicroRNAs as Common Pathogenic Feature Associated with Muscle Atrophy in ALS, SMA and SBMA: Evidence from Animal Models and Human Patients.

Motor neuron diseases (MNDs) are neurodegenerative disorders characterized by upper and/or lower MN loss. MNDs include amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), and spinal and bulbar muscular atrophy (SBMA). Despite variability in onset, progression, and genetics, they share a common skeletal muscle involvement, suggesting that it could be a primary site for MND pathogenesis. Due to the key role of muscle-specific microRNAs (myomiRs) in skeletal muscle development, by real-time PCR we investigated the expression of miR-206, miR-133a, miR-133b, and miR-1, and their target genes, in G93A-SOD1 ALS, Δ7SMA, and KI-SBMA mouse muscle during disease progression. Further, we analyzed their expression in serum of SOD1-mutated ALS, SMA, and SBMA patients, to demonstrate myomiR role as noninvasive biomarkers. Our data showed a dysregulation of myomiRs and their targets, in ALS, SMA, and SBMA mice, revealing a common pathogenic feature associated with muscle impairment. A similar myomiR signature was observed in patients' sera. In particular, an up-regulation of miR-206 was identified in both mouse muscle and serum of human patients. Our overall findings highlight the role of myomiRs as promising biomarkers in ALS, SMA, and SBMA. Further investigations are needed to explore the potential of myomiRs as therapeutic targets for MND treatment.