Publications by authors named "Basil T Darras"

163 Publications

Nusinersen Treatment in Adults With Spinal Muscular Atrophy.

Neurol Clin Pract 2021 Jun;11(3):e317-e327

Departments of Neurology (TD, CW, SDY, KAH, JS, JWD), Rehabilitation (CEM), and Radiology (MZ, MW), Stanford University School of Medicine, Palo Alto, CA; Departments of Biostatistics and Computational Biology (MPM), and Neurology (MPM and WBM), University of Rochester Medical Center, NY; Department of Neurology (AP,BTD), Boston Children's Hospital, MA; Department of Neurology (DCD), Columbia University, New York; Department of Neurology (AMG EAK, ZZ) Children's Hospital of Philadelphia, PA; and Department of Pediatrics (RSF) Nemours Children's Hospital, Orlando, FL.

Objective: To determine changes in motor and respiratory function after treatment with nusinersen in adults with spinal muscular atrophy (SMA) during the first two years of commercial availability in the USA.

Methods: Data were collected prospectively on adult (age >17 years at treatment initiation) SMA participants in the Pediatric Neuromuscular Clinical Research (PNCR) Network. Baseline assessments of SMA outcomes including the Expanded Hammersmith Functional Rating Scale (HFMSE), Revised Upper Limb Module (RULM), and 6-Minute Walk Test (6MWT) occurred <5 months before treatment, and post-treatment assessments were made up to 24 months after nusinersen initation. Patient-reported experiences, safety laboratory tests and adverse events were monitored. The mean annual rate of change over time was determined for outcome measures using linear mixed effects models.

Results: Forty-two adult SMA participants (mean age: 34 years, range 17-66) receiving nusinersen for a mean of 12.5 months (range 3-24 months) were assessed. Several motor and respiratory measures showed improvement distinct from the progressive decline typically seen in untreated adults. Participants also reported qualitative improvements including muscle strength, stamina, breathing and bulbar related outcomes. All participants tolerated nusinersen with normal surveillance labs and no significant adverse events.

Conclusions: Trends of improvement emerged in functional motor, patient-reported, and respiratory measures, suggesting nusinersen may be efficacious in adults with SMA. Larger well-controlled studies and additional outcome measures are needed to firmly establish the efficacy of nusinersen in adults with SMA.

Classification Of Evidence: This study provides Class IV evidence regarding nusinersen tolerability and efficacy based on reported side effects and pulmonary and physical therapy assessments in an adult SMA cohort.
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http://dx.doi.org/10.1212/CPJ.0000000000001033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8382360PMC
June 2021

Different trajectories in upper limb and gross motor function in spinal muscular atrophy.

Muscle Nerve 2021 Nov 9;64(5):552-559. Epub 2021 Aug 9.

Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital, London, UK.

Introduction: The Hammersmith Functional Motor Scale Expanded (HFMSE) and the Revised Upper Limb Module (RULM) have been widely used in natural history studies and clinical trials. Our aim was to establish how the scales relate to each other at different age points in spinal muscular atrophy (SMA) type 2 and 3, and to describe their coherence over 12 mo.

Methods: The study was performed by cross-sectional and longitudinal reanalysis of previously published natural history data. The longitudinal analysis of the 12-mo changes also included the analysis of concordance between scales with changes grouped as stable (±2 points), improved (>+2) or declined (>-2).

Results: Three hundred sixty-four patients were included in the cross-sectional analysis, showing different trends in score and point of slope change for the two scales. For type 2, the point of slope change was 4.1 y for the HFMSE and 5.8 for the RULM, while for type 3, it was 6 y for the HFMSE and 7.3 for the RULM. One-hundred-twenty-one patients had at least two assessments at 12 mo. Full concordance was found in 57.3% of the assessments, and in 40.4% one scale remained stable and the other changed. Each scale appeared to be more sensitive to specific age or functional subgroups.

Discussion: The two scales, when used in combination, may increase the sensitivity to detect clinically meaningful changes in motor function in patients with SMA types 2 and 3.
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http://dx.doi.org/10.1002/mus.27384DOI Listing
November 2021

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

N Engl J Med 2021 07;385(5):427-435

From the Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston (B.T.D.); the Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan (R.M., G.B.), and the Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa (C.B.) - both in Italy; the Department of Developmental Neurology, Medical University of Gdańsk, Gdańsk, Poland (M.M.-B.); the Paediatric Gait Analysis Service of New South Wales, the Children's Hospital at Westmead and the University of Sydney, Sydney (K.R.); the Department of Pediatrics, Peking University First Hospital, Beijing (H.X.), and Children's Hospital of Fudan University, Shanghai (Y.W.) - both in China; the Department of Neurology, Faculdade de Medicina, Universidade de São Paulo, São Paulo (E.Z.); the Dubowitz Neuromuscular Centre, National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, University College London Great Ormond Street Institute of Child Health, and Great Ormond Street Hospital for Children NHS Foundation Trust, London (G.B.), Roche Products, Welwyn Garden City (M.E.-K.), and the Muscular Dystrophy UK Oxford Neuromuscular Centre, the Department of Paediatrics, University of Oxford, Oxford (L.S.) - all in the United Kingdom; Russian Children Neuromuscular Center, Veltischev Clinical Pediatric Research Institute, Pirogov Russian National Research Medical University, Moscow (D.V.); Pharma Development, Safety (M.G.), Product Development Medical Affairs - Neuroscience and Rare Disease (K.G., P.F.), and Pharma Development Neurology (R.S.S.), F. Hoffmann-La Roche, and Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel (O.K., H.K.) - both in Basel, Switzerland; the Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, the Department of Pediatrics, University Hospital Liege, University of Liege, Liege, Belgium (L.S.); and I-Motion, Institut de Myologie, Assistance Publique Hôpitaux de Paris, Hôpital Armand Trousseau, Paris (L.S.).

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 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.).
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http://dx.doi.org/10.1056/NEJMoa2102047DOI Listing
July 2021

Psychometric properties of the PEDI-CAT for children and youth with spinal muscular atrophy.

J Pediatr Rehabil Med 2021;14(3):451-461

Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.

Purpose: The purpose of this study was to examine the psychometric properties of the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT) in children and youth with Spinal Muscular Atrophy (SMA).

Methods: In this prospective cross-sectional study, caregivers of children and youth with SMA completed the PEDI-CAT Daily Activities and Mobility domains. A subset of caregivers completed a questionnaire about the measure.

Results: Mean ranks of scaled scores for Daily Activities (n = 96) and Mobility (n = 95) domains were significantly different across the three SMA types and across the three motor classifications. Normative scores indicated that 85 participants (89.5%) had limitations in Mobility and 51 in Daily Activities (53.1%). Floor effects were observed in≤10.4% of the sample for Daily Activities and Mobility. On average, caregivers completed the Mobility domain in 5.4 minutes and the Daily Activities domain in 3.3 minutes. Most caregivers reported that they provided meaningful information (92.1%), were willing to use the PEDI-CAT format again (79%), and suggested adding content including power wheelchair mobility items.

Conclusion: Convergent validity was demonstrated for the Daily Activities and Mobility domains. Normative scores detected limitations in Mobility and Daily Activity performance for most participants with SMA. The PEDI-CATwas feasible to administer and caregivers expressed willingness to complete the PEDI-CAT in the future.
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http://dx.doi.org/10.3233/PRM-190664DOI Listing
January 2021

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

Ann Clin Transl Neurol 2021 08 24;8(8):1622-1634. Epub 2021 Jun 24.

Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital, London, United Kingdom.

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

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

Results: Over 75% of the 144 patients had a 12-month follow-up. There was an increase in the mean scores from baseline to 12 months on both HFMSE (1.18 points, p = 0.004) and RULM scores (0.58 points, p = 0.014) but not on the 6MWT (mean difference = 6.65 m, p = 0.33). When the 12-month HFMSE changes in the treated cohort were compared to an external cohort of untreated patients, in all untreated patients older than 7 years, the mean changes were always negative, while always positive in the treated ones. To reduce a selection bias, we also used a multivariable analysis. On the HFMSE scale, age, gender, baseline value, and functional status contributed significantly to the changes, while the number of SMN2 copies did not contribute. The effect of these variables was less obvious on the RULM and 6MWT.

Interpretation: Our results expand the available data on the effect of Nusinersen on type III patients, so far mostly limited to data from adult type III patients.
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http://dx.doi.org/10.1002/acn3.51411DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8351459PMC
August 2021

Age related treatment effect in type II Spinal Muscular Atrophy pediatric patients treated with nusinersen.

Neuromuscul Disord 2021 07 2;31(7):596-602. Epub 2021 Apr 2.

Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy. Electronic address:

Previous natural history studies suggest that type II SMA patients remain stable over one year but show some progression over two years. Since nusinersen approval, there has been increasing attention to identify more specific age-related changes. The aim of the study was to establish 12-month changes in a cohort of pediatric type II SMA treated with nusinersen and to establish possible patterns of treatment effect in relation to different variables such as age, baseline value and SMN2 copy number. The Hammersmith Functional Motor Scale Expanded and the Revised Upper Limb Module were performed at T0 and 12 months after treatment (T12). Data in treated patients were compared to available data in untreated patients collected by the same evaluators.Seventy-seven patients of age between 2.64 and 17.88 years (mean:7.47, SD:3.79) were included. On t-test there was an improvement, with increased mean scores between T0 and T12 on both scales (p < 0.001). Using multivariate linear regression analysis, age and baseline scores were predictive of changes on both scales (p < 0.05) while SMN2 copy number was not. Differences were also found between study cohort and untreated data on both scales (p < 0.001). At 12 months, an increase in scores was observed in all the age subgroups at variance with natural history data. Our real-world data confirm the treatment effect of nusinersen in pediatric type II SMA patients and that the data interpretation should take into account different variables. These data confirm and expand the ones already reported in the Cherish study.
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http://dx.doi.org/10.1016/j.nmd.2021.03.012DOI Listing
July 2021

Massachusetts' Findings from Statewide Newborn Screening for Spinal Muscular Atrophy.

Int J Neonatal Screen 2021 May 23;7(2). Epub 2021 May 23.

New England Newborn Screening Program, University of Massachusetts Medical School, Worcester, MA 01605, USA.

Massachusetts began newborn screening (NBS) for Spinal Muscular Atrophy (SMA) following the availability of new treatment options. The New England Newborn Screening Program developed, validated, and implemented a screening algorithm for the detection of SMA-affected infants who show absent Exon 7 by Real-Time™ quantitative PCR (qPCR). We screened 179,467 neonates and identified 9 SMA-affected infants, all of whom were referred to a specialist by day of life 6 (average and median 4 days of life). Another ten hybrids were observed but never referred. The nine referred infants who were confirmed to have SMA were entered into treatment protocols. Early data show that some SMA-affected children have remained asymptomatic and are meeting developmental milestones and some have mild to moderate delays. The Massachusetts experience demonstrates that SMA NBS is feasible, can be implemented on a population basis, and helps engage infants for early treatment to maximize benefit.
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http://dx.doi.org/10.3390/ijns7020026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8162354PMC
May 2021

Putting the patient first: The validity and value of surface-based electrical impedance myography techniques.

Clin Neurophysiol 2021 07 20;132(7):1752-1753. Epub 2021 Apr 20.

Department of Neurology, Barrow Neurological Institute, Phoenix, AZ, USA.

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http://dx.doi.org/10.1016/j.clinph.2021.03.020DOI Listing
July 2021

Clinical, neuroimaging, and molecular spectrum of TECPR2-associated hereditary sensory and autonomic neuropathy with intellectual disability.

Hum Mutat 2021 06 11;42(6):762-776. Epub 2021 May 11.

Oxford Centre for Genomic Medicine, Oxford, UK.

Bi-allelic TECPR2 variants have been associated with a complex syndrome with features of both a neurodevelopmental and neurodegenerative disorder. Here, we provide a comprehensive clinical description and variant interpretation framework for this genetic locus. Through international collaboration, we identified 17 individuals from 15 families with bi-allelic TECPR2-variants. We systemically reviewed clinical and molecular data from this cohort and 11 cases previously reported. Phenotypes were standardized using Human Phenotype Ontology terms. A cross-sectional analysis revealed global developmental delay/intellectual disability, muscular hypotonia, ataxia, hyporeflexia, respiratory infections, and central/nocturnal hypopnea as core manifestations. A review of brain magnetic resonance imaging scans demonstrated a thin corpus callosum in 52%. We evaluated 17 distinct variants. Missense variants in TECPR2 are predominantly located in the N- and C-terminal regions containing β-propeller repeats. Despite constituting nearly half of disease-associated TECPR2 variants, classifying missense variants as (likely) pathogenic according to ACMG criteria remains challenging. We estimate a pathogenic variant carrier frequency of 1/1221 in the general and 1/155 in the Jewish Ashkenazi populations. Based on clinical, neuroimaging, and genetic data, we provide recommendations for variant reporting, clinical assessment, and surveillance/treatment of individuals with TECPR2-associated disorder. This sets the stage for future prospective natural history studies.
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http://dx.doi.org/10.1002/humu.24206DOI Listing
June 2021

Dysphagia Phenotypes in Spinal Muscular Atrophy: The Past, Present, and Promise for the Future.

Am J Speech Lang Pathol 2021 05 6;30(3):1008-1022. Epub 2021 Apr 6.

Department of Neurology, Boston Children's Hospital, MA.

Purpose The aim of this study was to provide clinicians with an overview of literature relating to dysphagia in spinal muscular atrophy (SMA) to guide assessment and treatment. Method In this clinical focus article, we review literature published in Scopus and PubMed between 1990 and 2020 pertaining to dysphagia in SMA across the life span. Original research articles that were published in English were included. Searches were conducted within four themes of inquiry: (a) etiology and phenotypes, (b) respiratory systemic deficits and management, (c) characteristics of natural history dysphagia and its treatment, and (d) dysphagia outcomes with disease-modifying therapies. Articles for the first two themes were selected by content experts who identified the most salient articles that would provide clinicians foundational background knowledge about SMA. Articles for the third theme were identified using search terms, including OR . Search terms for the fourth theme included AND OR . Review of Pertinent Literature Twenty-nine articles were identified. Findings across identified articles support the fact that patients with SMA who do not receive disease-modifying therapy exhibit clinically significant deficits in oropharyngeal swallow function. Few investigations provided systematic information regarding the underlying physiological deficits responsible for this loss in function, the timing of the degradation, or how disease-modifying therapies change these outcomes. Conclusion Future research outlining the physiological and functional oropharyngeal swallowing deficits among patients with SMA who receive disease-modifying therapy is critical in developing standards of dysphagia care to guide clinicians.
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http://dx.doi.org/10.1044/2021_AJSLP-20-00217DOI Listing
May 2021

Onasemnogene abeparvovec gene therapy for symptomatic infantile-onset spinal muscular atrophy in patients with two copies of SMN2 (STR1VE): an open-label, single-arm, multicentre, phase 3 trial.

Lancet Neurol 2021 04 17;20(4):284-293. Epub 2021 Mar 17.

Center for Gene Therapy, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, Ohio State University, Columbus, OH, USA; Department of Neurology, Ohio State University, Columbus, OH, USA.

Background: Spinal muscular atrophy type 1 is a motor neuron disorder resulting in death or the need for permanent ventilation by age 2 years. We aimed to evaluate the safety and efficacy of onasemnogene abeparvovec (previously known as AVXS-101), a gene therapy delivering the survival motor neuron gene (SMN), in symptomatic patients (identified through clinical examination) with infantile-onset spinal muscular atrophy.

Methods: STR1VE was an open-label, single-arm, single-dose, phase 3 trial done at 12 hospitals and universities in the USA. Eligible patients had to be younger than 6 months and have spinal muscular atrophy with biallelic SMN1 mutations (deletion or point mutations) and one or two copies of SMN2. Patients received a one-time intravenous infusion of onasemnogene abeparvovec (1·1 × 10 vector genomes per kg) for 30-60 min. During the outpatient follow-up, patients were assessed once per week, beginning at day 7 post-infusion for 4 weeks and then once per month until the end of the study (age 18 months or early termination). Coprimary efficacy outcomes were independent sitting for 30 s or longer (Bayley-III item 26) at the 18 month of age study visit and survival (absence of death or permanent ventilation) at age 14 months. Safety was assessed through evaluation of adverse events, concomitant medication usage, physical examinations, vital sign assessments, cardiac assessments, and laboratory evaluation. Primary efficacy endpoints for the intention-to-treat population were compared with untreated infants aged 6 months or younger (n=23) with spinal muscular atrophy type 1 (biallelic deletion of SMN1 and two copies of SMN2) from the Pediatric Neuromuscular Clinical Research (PNCR) dataset. This trial is registered with ClinicalTrials.gov, NCT03306277 (completed).

Findings: From Oct 24, 2017, to Nov 12, 2019, 22 patients with spinal muscular atrophy type 1 were eligible and received onasemnogene abeparvovec. 13 (59%, 97·5% CI 36-100) of 22 patients achieved functional independent sitting for 30 s or longer at the 18 month of age study visit (vs 0 of 23 patients in the untreated PNCR cohort; p<0·0001). 20 patients (91%, 79-100]) survived free from permanent ventilation at age 14 months (vs 6 [26%], 8-44; p<0·0001 in the untreated PNCR cohort). All patients who received onasemnogene abeparvovec had at least one adverse event (most common was pyrexia). The most frequently reported serious adverse events were bronchiolitis, pneumonia, respiratory distress, and respiratory syncytial virus bronchiolitis. Three serious adverse events were related or possibly related to the treatment (two patients had elevated hepatic aminotransferases, and one had hydrocephalus).

Interpretation: Results from this multicentre trial build on findings from the phase 1 START study by showing safety and efficacy of commercial grade onasemnogene abeparvovec. Onasemnogene abeparvovec showed statistical superiority and clinically meaningful responses when compared with observations from the PNCR natural history cohort. The favourable benefit-risk profile shown in this study supports the use of onasemnogene abeparvovec for treatment of symptomatic patients with genetic or clinical characteristics predictive of infantile-onset spinal muscular atrophy type 1.

Funding: Novartis Gene Therapies.
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http://dx.doi.org/10.1016/S1474-4422(21)00001-6DOI Listing
April 2021

Risdiplam in Type 1 Spinal Muscular Atrophy.

N Engl J Med 2021 03 24;384(10):915-923. Epub 2021 Feb 24.

From the Dubowitz Neuromuscular Centre, National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, Great Ormond Street Institute of Child Health University College London, and Great Ormond Street Hospital Trust, London (G.B.), Roche Products, Welwyn Garden City (M.E.-K.), and the Muscular Dystrophy UK Oxford Neuromuscular Centre, Department of Paediatrics, University of Oxford, Oxford (L.S.) - all in the United Kingdom; the Developmental Neurology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan (G.B., R.M.), and the Pediatric Neurology Institution, Catholic University and Nemo Pediatrico, Fondazione Policlinico Gemelli IRCCS, Rome (E.M.); the Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston (B.T.D.); the Department of Neurology, Stanford University, Palo Alto, CA (J.W.D.); Centre de Référence des Maladies Neuromusculaires, Queen Fabiola Children's University Hospital, Université Libre de Bruxelles, Brussels (N.D.), the Neuromuscular Reference Center, Universitair Ziekenhuis Gent, Ghent (N.D.), and the Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liege and University of Liege, Liege (L.S.) - all in Belgium; the Division of Pediatric Neurology, University Children's Hospital Basel (A.K.), Pharma Development Safety (M.G.), Product Development Medical Affairs-Neuroscience and Rare Disease (K.G., P.F.), and Pharma Development Neurology (R.S.S.), F. Hoffmann-La Roche, and Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel (O.K., H.K., T.S.), Basel, and Pediatric Neurology, Inselspital, University of Bern, Bern (A.K.) - both in Switzerland; the Discipline of Physiotherapy, Faculty of Medicine and Health, University of Sydney, Sydney (K.R.); and I-Motion, Hôpital Armand Trousseau, Paris (L.S.).

Background: Type 1 spinal muscular atrophy is a rare, progressive neuromuscular disease that is caused by low levels of functional survival of motor neuron (SMN) protein. Risdiplam is an orally administered, small molecule that modifies pre-messenger RNA splicing and increases levels of functional SMN protein.

Methods: We report the results of part 1 of a two-part, phase 2-3, open-label study of risdiplam in infants 1 to 7 months of age who had type 1 spinal muscular atrophy, which is characterized by the infant not attaining the ability to sit without support. Primary outcomes were safety, pharmacokinetics, pharmacodynamics (including the blood SMN protein concentration), and the selection of the risdiplam dose for part 2 of the study. Exploratory outcomes included the ability to sit without support for at least 5 seconds.

Results: A total of 21 infants were enrolled. Four infants were in a low-dose cohort and were treated with a final dose at month 12 of 0.08 mg of risdiplam per kilogram of body weight per day, and 17 were in a high-dose cohort and were treated with a final dose at month 12 of 0.2 mg per kilogram per day. The baseline median SMN protein concentrations in blood were 1.31 ng per milliliter in the low-dose cohort and 2.54 ng per milliliter in the high-dose cohort; at 12 months, the median values increased to 3.05 ng per milliliter and 5.66 ng per milliliter, respectively, which represented a median of 3.0 times and 1.9 times the baseline values in the low-dose and high-dose cohorts, respectively. Serious adverse events included pneumonia, respiratory tract infection, and acute respiratory failure. At the time of this publication, 4 infants had died of respiratory complications. Seven infants in the high-dose cohort and no infants in the low-dose cohort were able to sit without support for at least 5 seconds. The higher dose of risdiplam (0.2 mg per kilogram per day) was selected for part 2 of the study.

Conclusions: In infants with type 1 spinal muscular atrophy, treatment with oral risdiplam led to an increased expression of functional SMN protein in the blood. (Funded by F. Hoffmann-La Roche; ClinicalTrials.gov number, NCT02913482.).
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http://dx.doi.org/10.1056/NEJMoa2009965DOI Listing
March 2021

Reldesemtiv in Patients with Spinal Muscular Atrophy: a Phase 2 Hypothesis-Generating Study.

Neurotherapeutics 2021 04 23;18(2):1127-1136. Epub 2021 Feb 23.

Stanford University, Stanford, CA, USA.

This phase 2, double-blind, placebo-controlled, hypothesis-generating study evaluated the effects of oral reldesemtiv, a fast skeletal muscle troponin activator, in patients with spinal muscular atrophy (SMA). Patients ≥ 12 years of age with type II, III, or IV SMA were randomized into 2 sequential, ascending reldesemtiv dosing cohorts (cohort 1: 150 mg bid or placebo [2:1]; cohort 2: 450 mg bid or placebo [2:1]). The primary objective was to determine potential pharmacodynamic effects of reldesemtiv on 8 outcome measures in SMA, including 6-minute walk distance (6MWD) and maximum expiratory pressure (MEP). Changes from baseline to weeks 4 and 8 were determined. Pharmacokinetics and safety were also evaluated. Patients were randomized to reldesemtiv 150 mg, 450 mg, or placebo (24, 20, and 26, respectively). The change from baseline in 6MWD was greater for reldesemtiv 450 mg than for placebo at weeks 4 and 8 (least squares [LS] mean difference, 35.6 m [p = 0.0037] and 24.9 m [p = 0.058], respectively). Changes from baseline in MEP at week 8 on reldesemtiv 150 and 450 mg were significantly greater than those on placebo (LS mean differences, 11.7 [p = 0.038] and 13.2 cm HO [p = 0.03], respectively). For 6MWD and MEP, significant changes from placebo were seen in the highest reldesemtiv peak plasma concentration quartile (C > 3.29 μg/mL; LS mean differences, 43.3 m [p = 0.010] and 28.8 cm HO [p = 0.0002], respectively). Both dose levels of reldesemtiv were well tolerated. Results suggest reldesemtiv may offer clinical benefit and support evaluation in larger SMA patient populations.
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http://dx.doi.org/10.1007/s13311-020-01004-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8423982PMC
April 2021

Medical management of muscle weakness in Duchenne muscular dystrophy.

PLoS One 2020 19;15(10):e0240687. Epub 2020 Oct 19.

Departments of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America.

Introduction: Duchenne muscular dystrophy (DMD) is a childhood onset muscular dystrophy leading to shortened life expectancy. There are gaps in published DMD care guidelines regarding recently approved DMD medications and alternative steroid dosing regimens.

Methods: A list of statements about use of currently available therapies for DMD in the United States was developed based on a systematic literature review and expert panel feedback. Panelists' responses were collected using a modified Delphi approach.

Results: Among corticosteroid regimens, either deflazacort or prednisone weekend dosing was preferred when payer requirements do not dictate choice. Most patients with exon 51 skip-amenable mutations should be offered eteplirsen, before or with a corticosteroid.

Discussion: The options available for medical management of the motor symptoms of DMD are expanding rapidly. The choice of medical therapies should balance expected benefit with side effects.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0240687PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7571693PMC
December 2020

Respiratory Trajectories in Type 2 and 3 Spinal Muscular Atrophy in the iSMAC Cohort Study.

Neurology 2021 01 16;96(4):e587-e599. Epub 2020 Oct 16.

From the Dubowitz Neuromuscular Centre (F.T., M.S., M.L.M., F.M.) and Population, Policy and Practice Programme (D.R.), UCL GOS Institute of Child Health, London, UK; DINOGMI, University of Genoa (F.T.), IRCCS Istituto G. Gaslini, Italy; NIHR Great Ormond Street Hospital Biomedical Research Centre (D.R., F.M.), Great Ormond Street Institute of Child Health, University College London, and Great Ormond Street Hospital Trust, UK; Paediatric Neurology (G.C., M.P., E.M.), Catholic University; Centro Clinico Nemo (G.C., M.P., E.M.), Fondazione Policlinico Universitario Agostino Gemelli IRCSS, Rome, Italy; John Walton Muscular Dystrophy Research Centre (R.M.L., C.M.-B.), Newcastle University and Newcastle Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK; Departments of Neurology and Pediatrics (J.M., D.C.D.V.) and Departments of Rehabilitation and Regenerative Medicine (J.M.), Columbia University Irving Medical Center, New York, NY; Paediatric Neurology and Centro Clinico Nemo (V.S., E.A.), Milan; Unit of Neuromuscular and Neurodegenerative Disorders (A.D., E.B.), Post-Graduate Bambino Gesù Children's Research Hospital, IRCCS, Rome; Department of Clinical and Experimental Medicine (S.M.), University of Messina Paediatric Neurology and Nemo Sud Clinical Centre; Center of Translational and Experimental Myology (C.B.), IRCCS Istituto Giannina Gaslini, Genova, Italy; University Hospitals Birmingham NHSFT (D.P.); Leeds Children Hospital (A.-M.C.); Evelina Children's Hospital (V.G.), London; The Robert Jones and Agnes Hunt Orthopaedic Hospital (T.W.), Oswestry; Sheffield Children's Hospital (M.O.), UK; Department of Neurology (B.T.D.), Boston Children's Hospital and Harvard Medical School, MA; Stanford University (J.D.), Medical Centre, Palo Alto, CA; Divisions of Pediatric Neurology (E.A.K.), Pulmonology (O.H.M.) and Physical Therapy (A.M.G.), The Children's Hospital of Philadelphia, and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia; and Divisions of Neurology (R.S.F.) and Pulmonary Medicine (A.A.N.N.), Department of Pediatrics, Nemours Children's Hospital, Orlando, FL.

Objective: To describe the respiratory trajectories and their correlation with motor function in an international pediatric cohort of patients with type 2 and nonambulant type 3 spinal muscular atrophy (SMA).

Methods: This was an 8-year retrospective observational study of patients in the International SMA Consortium (iSMAc) natural history study. We retrieved anthropometrics, forced vital capacity (FVC) absolute, FVC percent predicted (FVC%P), and noninvasive ventilation (NIV) requirement. Hammersmith Functional Motor Scale (HFMS) and revised Performance of Upper Limb (RULM) scores were correlated with respiratory function. We excluded patients in interventional clinical trials and on nusinersen commercial therapy.

Results: There were 437 patients with SMA: 348 with type 2 and 89 with nonambulant type 3. Mean age at first visit was 6.9 (±4.4) and 11.1 (±4) years. In SMA type 2, FVC%P declined by 4.2%/y from 5 to 13 years, followed by a slower decline (1.0%/y). In type 3, FVC%P declined by 6.3%/y between 8 and 13 years, followed by a slower decline (0.9%/y). Thirty-nine percent with SMA type 2% and 9% with type 3 required NIV at a median age 5.0 (1.8-16.6) and 15.1 (13.8-16.3) years. Eighty-four percent with SMA type 2% and 80% with type 3 had scoliosis; 54% and 46% required surgery, which did not significantly affect respiratory decline. FVC%P positively correlated with HFMS and RULM scores in both subtypes.

Conclusions: In SMA type 2 and nonambulant type 3, lung function declines differently, with a common leveling after age 13 years. Lung and motor function correlated in both subtypes. Our data further define the milder SMA phenotypes and provide information to benchmark the long-term efficacy of new treatments for SMA.
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http://dx.doi.org/10.1212/WNL.0000000000011051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7905794PMC
January 2021

Yeo and Darras: Extraneuronal Phenotypes of Spinal Muscular Atrophy.

Ann Neurol 2021 01 29;89(1):24-26. Epub 2020 Oct 29.

Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.

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http://dx.doi.org/10.1002/ana.25930DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7756714PMC
January 2021

Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia.

Brain 2020 10;143(10):2929-2944

Division of Neurology, Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA.

Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 ± 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 ± 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 ± 5.1 years, SD) and later tetraplegia (mean age: 16.1 ± 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 ± 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 ± 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.
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http://dx.doi.org/10.1093/brain/awz307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7780481PMC
October 2020

Clinical Variability in Spinal Muscular Atrophy Type III.

Ann Neurol 2020 12 2;88(6):1109-1117. Epub 2020 Oct 2.

Department of Child Neurology, University Hospitals Leuven, Leuven, Belgium.

Objective: We report natural history data in a large cohort of 199 patients with spinal muscular atrophy (SMA) type III assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE). The aim of the study was to establish the annual rate and possible patterns of progression according to a number of variables, such as age of onset, age at assessment, SMN2 copy number, and functional status.

Methods: HFMSE longitudinal changes were assessed using piecewise linear mixed-effects models. The dependency in the data due to repeated measures was accounted for by a random intercept per individual and an unstructured covariance R matrix was used as correlation structure. An additional descriptive analysis was performed for 123 patients, for a total of 375 12-month assessments.

Results: A break point at age 7 years was set for the whole cohort and for SMA IIIA and IIIB. Age, SMA type, and ambulatory status were significantly associated with changes in mean HFMSE score, whereas gender and SMN2 copy number were not. The increase in response before the break point of age 7 years is significant only for SMA IIIA (β = 1.79, p < 0.0001). After the break point, the change in the rate of HFMSE score significantly decrease for both SMA IIIA (β = -1.15, p < 0.0001) and IIIB (β = -0.69, p = 0.002).

Interpretation: Our findings contribute to the understanding of the natural history of SMA type III and will be helpful in the interpretation of the real-world data of patients treated with commercially available drugs. ANN NEUROL 2020;88:1109-1117.
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http://dx.doi.org/10.1002/ana.25900DOI Listing
December 2020

Gain and loss of abilities in type II SMA: A 12-month natural history study.

Neuromuscul Disord 2020 09 13;30(9):765-771. Epub 2020 Jul 13.

Pediatric Neurology, Università Cattolica del Sacro Cuore, Rome, Italy; Centro Clinico Nemo, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy. Electronic address:

The advent of clinical trials in spinal muscular atrophy (SMA) has highlighted the need to define patterns of progression using functional scales. It has recently been suggested that the analysis of abilities gained or lost applied to functional scales better reflects meaningful changes. We defined as "gain" a positive change between scores from 0 to either 1 or 2 and as "loss" a negative change from either 2 or 1 to 0. The aim of this study was to describe, over 12 months, which abilities on the Hammersmith Functional Motor Scale Expanded (HFMSE) were more frequently lost or gained in patients with SMA II. The cohort included 614 12-month assessments from 243 patients (age range: 30 months - 63 years; mean 9.94, SD ±7.91). The peak of abilities gained occurred before the age of 5 years while the highest number of lost abilities was found in the group 5-13 years. A correlation between the HFMSE baseline score and the ordinal number of the items was found for both lost (p<0.001) or gained (p<0.001) activities. No correlation was found with SMN2 copy number. These findings will have implications for clinical trial design and for the interpretation of real-world data using new therapeutic approaches.
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http://dx.doi.org/10.1016/j.nmd.2020.07.004DOI Listing
September 2020

Meta-analyses of ataluren randomized controlled trials in nonsense mutation Duchenne muscular dystrophy.

J Comp Eff Res 2020 10 27;9(14):973-984. Epub 2020 Aug 27.

PTC Therapeutics Inc., South Plainfield, NJ 07080, USA.

Assess the totality of efficacy evidence for ataluren in patients with nonsense mutation Duchenne muscular dystrophy (nmDMD). Data from the two completed randomized controlled trials (ClinicalTrials.gov: NCT00592553; NCT01826487) of ataluren in nmDMD were combined to examine the intent-to-treat (ITT) populations and two patient subgroups (baseline 6-min walk distance [6MWD] ≥300-<400 or <400 m). Meta-analyses examined 6MWD change from baseline to week 48. Statistically significant differences in 6MWD change with ataluren versus placebo were observed across all three meta-analyses. Least-squares mean difference (95% CI): ITT (n = 342), +17.2 (0.2-34.1) m, p = 0.0473; ≥300-<400 m (n = 143), +43.9 (18.2-69.6) m, p = 0.0008; <400 m (n = 216), +27.7 (6.4-49.0) m, p = 0.0109. These meta-analyses support previous evidence for ataluren in slowing disease progression versus placebo in patients with nmDMD over 48 weeks. Treatment benefit was most evident in patients with a baseline 6MWD ≥300-<400 m (the ambulatory transition phase), thereby informing future trial design.
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http://dx.doi.org/10.2217/cer-2020-0095DOI Listing
October 2020

Overturning the Paradigm of Spinal Muscular Atrophy as Just a Motor Neuron Disease.

Pediatr Neurol 2020 08 22;109:12-19. Epub 2020 Jan 22.

Department of Neurology, Neuromuscular Center and SMA Program, Boston Children's Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts. Electronic address:

Spinal muscular atrophy is typically characterized as a motor neuron disease. Untreated patients with the most severe form, spinal muscular atrophy type 1, die early with infantile-onset progressive skeletal, bulbar, and respiratory muscle weakness. Such patients are now living longer due to new disease-modifying treatments such as gene replacement therapy (onasemnogene abeparvovec), recently approved by the US Food and Drug Administration, and nusinersen, a central nervous system-directed treatment which was approved by the US Food and Drug Administration three years ago. This has created an area of pressing clinical need: if spinal muscular atrophy is a multisystem disease, dysfunction of peripheral tissues and organs may become significant comorbidities as these patients survive into childhood and adulthood. In this review, we have compiled autopsy data, case reports, and cohort studies of peripheral tissue involvement in patients and animal models with spinal muscular atrophy. We have also evaluated preclinical studies addressing the question of whether peripheral expression of survival motor neuron is necessary and/or sufficient for motor neuron function and survival. Indeed, spinal muscular atrophy patient data suggest that spinal muscular atrophy is a multisystem disease with dysfunction in skeletal muscle, heart, kidney, liver, pancreas, spleen, bone, connective tissues, and immune systems. The peripheral requirement of SMN in each organ and how these contribute to motor neuron function and survival remains to be answered. A systemic (peripheral and central nervous system) approach to therapy during early development is most likely to effectively maximize positive clinical outcome.
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http://dx.doi.org/10.1016/j.pediatrneurol.2020.01.003DOI Listing
August 2020

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

Orphanet J Rare Dis 2020 04 5;15(1):84. Epub 2020 Apr 5.

Nemours Children's Hospital, University of Central Florida College of Medicine, Orlando, USA.

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

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

Conclusion: A detailed understanding of the existing data is important, as it will be difficult to acquire new systematic longitudinal history data because of the availability of disease modifying therapies. The cumulative findings in this review help to better understand the variability of natural history data in untreated patients and will be of use for comparison to the real world patients treated with the recently approved therapies that have shown encouraging results in clinical trials.
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http://dx.doi.org/10.1186/s13023-020-01356-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7132885PMC
April 2020

Seven-Year Experience From the National Institute of Neurological Disorders and Stroke-Supported Network for Excellence in Neuroscience Clinical Trials.

JAMA Neurol 2020 06;77(6):755-763

Columbia University Irving Medical Center, New York, New York.

Importance: One major advantage of developing large, federally funded networks for clinical research in neurology is the ability to have a trial-ready network that can efficiently conduct scientifically rigorous projects to improve the health of people with neurologic disorders.

Observations: National Institute of Neurological Disorders and Stroke Network for Excellence in Neuroscience Clinical Trials (NeuroNEXT) was established in 2011 and renewed in 2018 with the goal of being an efficient network to test between 5 and 7 promising new agents in phase II clinical trials. A clinical coordinating center, data coordinating center, and 25 sites were competitively chosen. Common infrastructure was developed to accelerate timelines for clinical trials, including central institutional review board (a first for the National Institute of Neurological Disorders and Stroke), master clinical trial agreements, the use of common data elements, and experienced research sites and coordination centers. During the first 7 years, the network exceeded the goal of conducting 5 to 7 studies, with 9 funded. High interest was evident by receipt of 148 initial applications for potential studies in various neurologic disorders. Across the first 8 studies (the ninth study was funded at end of initial funding period), the central institutional review board approved the initial protocol in a mean (SD) of 59 (21) days, and additional sites were added a mean (SD) of 22 (18) days after submission. The median time from central institutional review board approval to first site activation was 47.5 days (mean, 102.1; range, 1-282) and from first site activation to first participant consent was 27 days (mean, 37.5; range, 0-96). The median time for database readiness was 3.5 months (mean, 4.0; range, 0-8) from funding receipt. In the 4 completed studies, enrollment met or exceeded expectations with 96% overall data accuracy across all sites. Nine peer-reviewed manuscripts were published, and 22 oral presentations or posters and 9 invited presentations were given at regional, national, and international meetings.

Conclusions And Relevance: NeuroNEXT initiated 8 studies, successfully enrolled participants at or ahead of schedule, collected high-quality data, published primary results in high-impact journals, and provided mentorship, expert statistical, and trial management support to several new investigators. Partnerships were successfully created between government, academia, industry, foundations, and patient advocacy groups. Clinical trial consortia can efficiently and successfully address a range of important neurologic research and therapeutic questions.
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http://dx.doi.org/10.1001/jamaneurol.2020.0367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7483960PMC
June 2020

Scoliosis Surgery Significantly Impacts Motor Abilities in Higher-functioning Individuals with Spinal Muscular Atrophy1.

J Neuromuscul Dis 2020 ;7(2):183-192

Department of Neurology, Columbia University Irving Medical Center, New York, NY, USA.

Background: Weakness affects motor performance and causes skeletal deformities in spinal muscular atrophy (SMA). Scoliosis surgery decision-making is based on curve progression, pulmonary function, and skeletal maturity. Benefits include quality of life, sitting balance, and endurance. Post-operative functional decline has not been formally assessed.

Objective: To assess the impact of scoliosis surgery on motor function in SMA types 2 and 3.

Methods: Prospective data were acquired during a multicenter natural history study. Seventeen participants (12 type 2, 5 type 3 with 4 of the 5 having lost the ability to ambulate) had motor function assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE) performed pre-operatively and at least 3 months post-operatively. Independent t-tests determined group differences based on post-operative HFMSE changes, age, and baseline HFMSE scores.

Results: Three participants had minimal HFMSE changes (±2 points) representing stability (mean change = -0.7). Fourteen participants lost >3 points, representing a clinically meaningful progressive change (mean change = -12.1, SD = 8.9). No participant improved >2 points. There were no age differences between stable and progressive groups (p = 0.278), but there were significant differences between baseline HFMSE (p = 0.006) and change scores (p = 0.001). Post-operative changes were permanent over time.

Conclusions: Scoliosis surgery has an immediate impact on function. Baseline HFMSE scores anticipate post-operative loss as higher motor function scores were associated with worse decline. Instrumentation that includes fixation to the pelvis reduces flexibility, limiting the ability for compensatory maneuvers. These observations provide information to alert clinicians regarding surgical risk and to counsel families.
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http://dx.doi.org/10.3233/JND-190462DOI Listing
November 2020

Response to "The Spectrum of Neuromuscular Disorders Admitted to a Pediatric Intensive Care Unit Is Broader Than Anticipated".

J Child Neurol 2020 03 3;35(4):302-303. Epub 2020 Jan 3.

Department of Neurology, Boston Children's Hospital, Boston, MA, USA.

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http://dx.doi.org/10.1177/0883073819894820DOI Listing
March 2020

The Value of Imaging and Composition-Based Biomarkers in Duchenne Muscular Dystrophy Clinical Trials.

Neurotherapeutics 2020 01;17(1):142-152

Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.

As the drug development pipeline for Duchenne muscular dystrophy (DMD) rapidly advances, clinical trial outcomes need to be optimized. Effective assessment of disease burden, natural history progression, and response to therapy in clinical trials for Duchenne muscular dystrophy are critical factors for clinical trial success. By choosing optimal biomarkers to better assess therapeutic efficacy, study costs and sample size requirements can be reduced. Currently, functional measures continue to serve as the primary outcome for the majority of DMD clinical trials. Quantitative measures of muscle health, including magnetic resonance imaging and spectroscopy, electrical impedance myography, and ultrasound, sensitively identify diseased muscle, disease progression, and response to a therapeutic intervention. Furthermore, such non-invasive techniques have the potential to identify disease pathology prior to onset of clinical symptoms. Despite robust supportive evidence, non-invasive quantitative techniques are still not frequently utilized in clinical trials for Duchenne muscular dystrophy. Non-invasive quantitative techniques have demonstrated the ability to quantify disease progression and potential response to therapeutic intervention, and should be used as a supplement to current standard functional measures. Such methods have the potential to significantly accelerate the development and approval of therapies for DMD.
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http://dx.doi.org/10.1007/s13311-019-00825-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7007477PMC
January 2020

Electrical impedance myography for reducing sample size in Duchenne muscular dystrophy trials.

Ann Clin Transl Neurol 2020 01 25;7(1):4-14. Epub 2019 Dec 25.

Department of Neurology, Washington University in St. Louis, St. Louis, Missouri.

Objective: To evaluate the sensitivity of electrical impedance myography (EIM) to disease progression in both ambulatory and non-ambulatory boys with DMD.

Methods And Participants: A non-blinded, longitudinal cohort study of 29 ambulatory and 15 non-ambulatory boys with DMD and age-similar healthy boys. Subjects were followed for up to 1 year and assessed using the Myolex mView EIM system as part of a multicenter study.

Results: In the ambulatory group, EIM 100 kHz resistance values showed significant change compared to the healthy boys. For example, in lower extremity muscles, the average change in EIM 100 kHz resistance values over 12 months led to an estimated effect size of 1.58. Based on these results, 26 DMD patients/arm would be needed for a 12-month clinical trial assuming a 50% treatment effect. In non-ambulatory boys, EIM changes were greater in upper limb muscles. For example, biceps at 100kHz resistance gave an estimated effect size of 1.92 at 12 months. Based on these results, 18 non-ambulatory DMD patients/arm would be needed for a 12-month clinical trial assuming a 50% treatment effect. Longitudinal changes in the 100 kHz resistance values for the ambulatory boys correlated with the longitudinal changes in the timed supine-to-stand test. EIM was well-tolerated throughout the study.

Interpretation: This study supports that EIM 100 kHz resistance is sensitive to DMD progression in both ambulatory and non-ambulatory boys. Given the technology's ease of use and broad age range of utility it should be employed as an exploratory endpoint in future clinical therapeutic trials in DMD.

Trial Registration: Clincialtrials.gov registration #NCT02340923.
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http://dx.doi.org/10.1002/acn3.50958DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6952321PMC
January 2020

A novel homozygous splice-site mutation in the SPTBN4 gene causes axonal neuropathy without intellectual disability.

Eur J Med Genet 2020 Apr 16;63(4):103826. Epub 2019 Dec 16.

Institute of Human Genetics, Medical Faculty, RWTH Aachen University, Aachen, Germany.

Mutations in spectrin beta non-erythrocytic 4 (SPTBN4) have been linked to congenital hypotonia, intellectual disability and motor neuropathy. Here we report on two siblings with a homozygous splice-site mutation in the SPTBN4 gene, lacking previously reported features of the disorder such as seizures, feeding difficulties, respiratory difficulties or profound intellectual disability. Our findings indicate that muscular hypotonia, myopathic facies with ptosis and axonal neuropathy can be the core clinical features in the SPTBN4 disorder and suggest that SPTBN4 mutation analysis should be considered in infants with marked axonal neuropathy.
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http://dx.doi.org/10.1016/j.ejmg.2019.103826DOI Listing
April 2020

Deflazacort vs prednisone treatment for Duchenne muscular dystrophy: A meta-analysis of disease progression rates in recent multicenter clinical trials.

Muscle Nerve 2020 01 7;61(1):26-35. Epub 2019 Nov 7.

Analysis Group, Inc, Boston, Massachusetts.

Introduction: In this study we characterized disease progression over 48 weeks among boys receiving deflazacort vs prednisone/prednisolone placebo arm treatment in two recent Duchenne muscular dystrophy (DMD) clinical trials.

Methods: Ambulatory boys with DMD receiving placebo in the phase 3 ataluren (N = 115) and tadalafil (N = 116) trials were included. The trials required at least 6 months of prior corticosteroid use and stable baseline dosing. Associations between corticosteroid use and 48-week changes in ambulatory function were estimated using mixed models. Adjusted differences between corticosteroid groups were pooled in a meta-analysis.

Results: In the meta-analysis, deflazacort-treated patients vs prednisone/prednisolone-treated patients experienced, on average, lower declines of 28.3 meters on 6-minute walk distance (95% confidence interval [CI], 5.7, 50.9; 2.9 seconds on rise from supine [95% CI, 0.9, 4.9 seconds]; 2.3 seconds on 4-stair climb [95% CI, 0.5, 4.1 seconds]; and 2.9 [95% CI, 0.1, 5.8] points on the North Star Ambulatory Assessment linearized score).

Discussion: Deflazacort-treated patients experienced significantly lower functional decline over 48 weeks.
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http://dx.doi.org/10.1002/mus.26736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6973289PMC
January 2020
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