Efficacy and Safety of Vamorolone Over 48 Weeks in Boys With Duchenne Muscular Dystrophy: A Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Vamorolone is a dissociative agonist of the glucocorticoid receptor that has shown similar efficacy and reduced safety concerns in comparison with prednisone in Duchenne muscular dystrophy (DMD). This study was conducted to determine the efficacy and safety of vamorolone over 48 weeks and to study crossover participants (prednisone to vamorolone; placebo to vamorolone).

METHODS

A randomized, double-blind, placebo-controlled and prednisone-controlled clinical trial of 2 doses of vamorolone was conducted in participants with DMD, in the ages from 4 years to younger than 7 years at baseline. The interventions were 2 mg/kg/d of vamorolone and 6 mg/kg/d of vamorolone for 48 weeks (period 1: 24 weeks + period 2: 24 weeks) and 0.75 mg/kg/d of prednisone and placebo for the first 24 weeks (before crossover). Efficacy was evaluated through gross motor outcomes and safety through adverse events, growth velocity, body mass index (BMI), and bone turnover biomarkers. This analysis focused on period 2.

RESULTS

A total of 121 participants with DMD were randomized. Vamorolone at a dose of 6 mg/kg/d showed maintenance of improvement for all motor outcomes to week 48 (e.g., for primary outcome, time to stand from supine [TTSTAND] velocity, week 24 least squares mean [LSM] [SE] 0.052 [0.0130] rises/s vs week 48 LSM [SE] 0.0446 [0.0138]). After 48 weeks, vamorolone at a dose of 2 mg/kg/d showed similar improvements as 6 mg/kg/d for North Star Ambulatory Assessment (NSAA) (vamorolone 6 mg/kg/d-vamorolone 2 mg/kg/d LSM [SE] 0.49 [1.14]; 95% CI -1.80 to 2.78, p = 0.67), but less improvement for other motor outcomes. The placebo to vamorolone 6 mg/kg/d group showed rapid improvements after 20 weeks of treatment approaching benefit seen with 48-week 6 mg/kg/d of vamorolone treatment for TTSTAND, time to run/walk 10 m, and NSAA. There was significant improvement in linear growth after crossover in the prednisone to vamorolone 6 mg/kg/d group, and rapid reversal of prednisone-induced decline in bone turnover biomarkers in both crossover groups. There was an increase in BMI after 24 weeks of treatment that then stabilized for both vamorolone groups.

DISCUSSION

Improvements of motor outcomes seen with 6 mg/kg/d of vamorolone at 24 weeks of treatment were maintained to 48 weeks of treatment. Vamorolone at a dose of 6 mg/kg/d showed better maintenance of effect compared with vamorolone at a dose of 2 mg/kg/d for most (3/5) motor outcomes. Bone morbidities of prednisone (stunting of growth and declines in serum bone biomarkers) were reversed when treatment transitioned to vamorolone.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov Identifier: NCT03439670.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for boys with DMD, the efficacy of vamorolone at a dose of 6 mg/kg/d was maintained over 48 weeks.

Expansion of the phenotypic spectrum associated with pathogenic missense variation in DHX16

Pathogenic heterozygous variants in DHX16 have been recently identified in association with a variety of clinical features, including neuromuscular disease, sensorineural hearing loss, ocular anomalies, and other phenotypes. All DHX16 disease-causing variants previously reported in affected individuals are missense in nature, nearly all of which were found to be de novo. Here we report on a patient with neuromuscular disease, hearing loss, retinal degeneration, and previously unreported phenotypic features including mitochondrial deficiency and primary ovarian insufficiency, in whom a novel de novo likely pathogenic variant in DHX16 NM_003587.4:c.2033A > G (p.Glu678Gly) was identified. Furthermore, we conducted an in-depth literature review of DHX16's role in disease and utilized high-performing in silico prediction algorithms to compare and contrast the predicted effects of all reported disease-associated DHX16 variants on protein structure and function.

The Early Care (0-3 Years) In Duchenne Muscular Dystrophy Meeting Report

Objective

This report summarizes the key discussions from the "Early Care (0-3 years) in Duchenne Muscular Dystrophy" meeting, which aimed to address the challenges and opportunities in the diagnosis and care of Duchenne muscular dystrophy (DMD) and female carriers within the 0-3-year age group.

Methods

The meeting brought together experts and healthcare providers who shared insights, discussed advancements in DMD care, and identified research needs. Presentations covered diagnostic challenges, approved therapies, clinical trials, identification of young female carriers, and the importance of clinical care and support for families.

Results

The meeting highlighted the importance of timely diagnosis and the lack of evidence-based guidelines for the care of children with DMD aged 0-3 years. Diagnostic challenges were discussed, including delays in receiving a DMD diagnosis and disparities based on ethnicity. The potential benefits and process of newborn screening were addressed.Approved therapeutic interventions, such as corticosteroids and exon-skipping drugs, were explored, with studies indicating the potential benefits of early initiation of corticosteroid therapy and the safety of exon-skipping drugs in DMD. Clinical trials involving infants and young boys were discussed, focusing on drugs like ataluren, vamorolone, and gene therapies.The meeting emphasized the importance of clinical care and support for families, including comprehensive information provision, early intervention services, and individualized support. The identification and care of young female carriers were also addressed.

Conclusion

The meeting provided a platform for experts and healthcare providers to discuss and identify key aspects of early care for children with DMD aged 0-3 years. The meeting emphasized the need for early diagnosis, evidence-based guidelines, and comprehensive care and support for affected children and their families. Further research, collaboration, and the development of consensus guidelines are needed to improve early diagnosis, treatment, and outcomes in this population.

Axonal polyneuropathy and ataxia in children: consider Perrault Syndrome, a case report

BACKGROUND

Perrault Syndrome (PRLTS) is a rare, autosomal recessive disorder that presents with bilateral sensorineural hearing loss in all patients and gonadal dysfunction in females. It has been linked to variants in CLPP, ERAL1, HARS2, HSD17B4, LARS2, and TWNK genes. All reported cases due to TWNK variants have included neurologic features, such as ataxia and axonal sensorimotor neuropathy.

CASE PRESENTATION

A 4.5-year-old female presented to neuromuscular clinic due to ataxia. Neurological examination revealed truncal ataxia and steppage gait, reduced deep tendon reflexes, and axonal sensorimotor polyneuropathy. Auditory brainstem response testing revealed an uncommon type of sensorineural hearing loss known as auditory neuropathy/auditory synaptopathy (AN/AS) affecting both ears. Magnetic Resonance Imaging (MRI) revealed subtle cauda equina enhancement. Nerve conduction studies led to a provisional diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP), and intravenous immune globulin (IVIG) was initiated. The patient was unresponsive to treatment, thus whole exome testing (WES) was conducted in tandem with IVIG weaning. WES revealed a compound heterozygous state with two variants in the TWNK gene and a diagnosis of Perrault Syndrome was made.

CONCLUSIONS

Perrault Syndrome should be considered in the differential for children who present with bilateral sensorineural hearing loss, axonal polyneuropathy, and ataxia. Further examination includes testing for ovarian dysgenesis and known PRLTS genetic variants.

AMFR dysfunction causes autosomal recessive spastic paraplegia in human that is amenable to statin treatment in a preclinical model

Hereditary spastic paraplegias (HSP) are rare, inherited neurodegenerative or neurodevelopmental disorders that mainly present with lower limb spasticity and muscle weakness due to motor neuron dysfunction. Whole genome sequencing identified bi-allelic truncating variants in AMFR, encoding a RING-H2 finger E3 ubiquitin ligase anchored at the membrane of the endoplasmic reticulum (ER), in two previously genetically unexplained HSP-affected siblings. Subsequently, international collaboration recognized additional HSP-affected individuals with similar bi-allelic truncating AMFR variants, resulting in a cohort of 20 individuals from 8 unrelated, consanguineous families. Variants segregated with a phenotype of mainly pure but also complex HSP consisting of global developmental delay, mild intellectual disability, motor dysfunction, and progressive spasticity. Patient-derived fibroblasts, neural stem cells (NSCs), and in vivo zebrafish modeling were used to investigate pathomechanisms, including initial preclinical therapy assessment. The absence of AMFR disturbs lipid homeostasis, causing lipid droplet accumulation in NSCs and patient-derived fibroblasts which is rescued upon AMFR re-expression. Electron microscopy indicates ER morphology alterations in the absence of AMFR. Similar findings are seen in amfra-/- zebrafish larvae, in addition to altered touch-evoked escape response and defects in motor neuron branching, phenocopying the HSP observed in patients. Interestingly, administration of FDA-approved statins improves touch-evoked escape response and motor neuron branching defects in amfra-/- zebrafish larvae, suggesting potential therapeutic implications. Our genetic and functional studies identify bi-allelic truncating variants in AMFR as a cause of a novel autosomal recessive HSP by altering lipid metabolism, which may potentially be therapeutically modulated using precision medicine with statins.

A Virtual Reality Exergame: Clinician-Guided Breathing and Relaxation for Children with Muscular Dystrophy

This study introduces a VR-based breathing and relaxation exergame tailored for individuals with Duchenne muscular dystrophy (DMD). DMD is a rare neuromuscular disease that leads to respiratory muscle dysfunction with anxiety being a common comorbidity. Clinical management requires frequent visits to rare disease specialists to manage symptom progression. Limited availability and/or proximity of rare disease experts present challenges to care and can lead to missed care opportunities and reduced quality of life. We propose a breathing and relaxation exergame with remote telehealth applicability that incorporates shared patient-clinician VR interaction, and physiological sensors that provide both real-time feedback to the patient and health analytics for the clinician. The game focuses on two key aspects of DMD clinical care that can be mediated through control of breathing: relaxation/mindfulness training and respiratory muscle exercise. The system was evaluated among 13 individuals, including 4 participants with DMD. Feedback surveys, interviews, and focus group discussions with participants, accompanying family members, and clinicians demonstrated the feasibility of this VR tool for telehealth or as part of a home exercise program.

Clinical Experience With Efgartigimod in Generalized Myasthenia Gravis: Results From a Case Series of US-Based Patients Participating in an Expanded Access Program

Objective

To describe the efgartigimod treatment regimens and response among 6 US-based patients with generalized myasthenia gravis (gMG) enrolled in an Expanded Access Program (EAP).

Background

For some patients with gMG, available therapies do not provide sufficient symptom relief and can cause serious side effects. Efgartigimod, a human IgG1 antibody Fc-fragment (natural ligand of the neonatal crystalline fragment receptor [FcRn]), has increased affinity to FcRn vs endogenous IgG. Efgartigimod reduces IgG recycling and increases IgG degradation. Efgartigimod received FDA approval in 2021 for the treatment of gMG in adults who are anti-acetylcholine receptor (AChR) antibody positive.

Design/Methods

In the efgartigimod EAP (NCT04777734), gMG patients had access to open-label efgartigimod. Eligible patients (=18 y) met clinical criteria of the Myasthenia Gravis Foundation of America classifications II–IV and had a Myasthenia Gravis Activities of Daily Living (MG-ADL) score =5 points (>50% attributed to non-ocular symptoms). During the first two, fixed-treatment cycles, patients received 4 weekly infusions of efgartigimod 10 mg/kg. During the 4-week inter-treatment period, patients received their ongoing treatments and no efgartigimod infusions. Baseline demographic characteristics and safety data were collected. Treating physicians had the option to assess and track clinical function and burden of disease among treated patients.

Results

As of the cutoff date (Dec 17, 2021), 8 patients have been enrolled in the US; follow-up data are available for 6 (3 males and 3 females; median age 59 y). 83% (5/6) of patients received at least 2 treatment cycles and 4–5 infusions per cycle. Symptom improvements were noted. Four patients reported 6 AEs: fatigue (resolved), tachycardia and headache (both resolved), dyspnea and diplopia (both not resolved), and back spasms (status unknown).

Conclusions

We report on 6 patients with gMG who received efgartigimod as part of an EAP. Detailed patient narratives will be presented.

An expanded access program of risdiplam for patients with Type 1 or 2 spinal muscular atrophy

Objective

The US risdiplam expanded access program (EAP; NCT04256265) was opened to provide individuals with Type 1 or 2 spinal muscular atrophy (SMA) who had no satisfactory treatment options access to risdiplam prior to commercial availability. The program was designed to collect safety data during risdiplam treatment.

Methods

Patients were enrolled from 23 non‐preselected sites across 17 states and treated with risdiplam orally once daily. Eligible patients had a 5q autosomal recessive Type 1 or 2 SMA diagnosis, were aged ≥2 months at enrollment, and were ineligible for available and approved SMA treatments or could not continue treatment due to a medical condition, lack/loss of efficacy, or the COVID‐19 pandemic.

Results

Overall, 155 patients with Type 1 (n = 73; 47.1%) or 2 SMA (n = 82; 52.9%) were enrolled and 149 patients (96.1%) completed the EAP (defined as obtaining access to commercial risdiplam, if desired). The median treatment duration was 4.8 months (range, 0.3–9.2 months). The median patient age was 11 years (range, 0–50 years), and most patients (n = 121; 78%) were previously treated with a disease‐modifying therapy. The most frequently reported adverse events were diarrhea (n = 10; 6.5%), pyrexia (n = 7; 4.5%), and upper respiratory tract infection (n = 5; 3.2%). The most frequently reported serious adverse event was pneumonia (n = 3; 1.9%). No deaths were reported.

Interpretation

In the EAP, the safety profile of risdiplam was similar to what was reported in pivotal risdiplam clinical trials. These safety data provide further support for the use of risdiplam in the treatment of adult and pediatric patients with SMA.

The CINRG Becker Natural History Study: Baseline characteristics

We performed an observational, natural history study of males with in-frame dystrophin gene deletions causing Becker muscular dystrophy (BMD). A prospective natural history study collected longitudinal medical, strength, and timed function assessments. Eighty-three participants with genetically confirmed BMD were enrolled (age range 5.6-75.4 years). Lower extremity function and the percentage of participants who retained ambulation declined across the age span. The largest single group of participants had in-frame deletions that corresponded to an out-of-frame deletion treated with an exon 45 skip to restore the reading frame. This group of 54 participants showed similarities in baseline motor functional assessments when compared to the group of all others in the study. A prospective natural history cohort with in-frame dystrophin gene deletions offers the potential to contribute to clinical trial readiness for BMD and to analyze therapeutic benefit of exon skipping for Duchenne muscular dystrophy.

Spinal muscular atrophy care in the COVID-19 pandemic era

The coronavirus disease 2019 (COVID‐19) pandemic has resulted in reorganization of healthcare settings affecting the delivery of clinical care to patients with spinal muscular atrophy (SMA). There is a concern that patients with SMA may be at increased risk of manifesting severe symptoms of COVID‐19. Currently approved therapies for SMA improve survival and motor function; however, their delivery requires an increased exposure to the health system and a dedicated healthcare team. In this study, we discuss consensus recommendations pertaining to care of SMA patients during the pandemic. We highlight that SMA treatments should not be perceived as elective. Decisions regarding the delay of treatments should be made with consideration of the potential risks of COVID‐19 exposure and the risk of that delay. We emphasize the importance of collaborative treatment decisions between the patient, family, and healthcare provider, considering any geographic‐ or institution‐specific policies and precautions for COVID‐19.

Transforaminal Intrathecal Access for Injection of Nusinersen in Adult and Pediatric Patients with Spinal Muscular Atrophy

The main purpose of this article is to assess the safety and efficacy of transforaminal lumbar puncture for the injection of nusinersen (Spinraza) in patients with extensive spinal fusion and/or scoliosis.

A retrospective chart reviews of all spinal muscular atrophy patients (adults and children) were conducted. Demographic data, procedure details, follow-ups, and related complications were recorded.

We performed 85 transforaminal injections in nine pediatric patients (5 male and 4 female) aged between 8 and 17 years (mean = 11 years) and seven adult patients (5 females and 2 males) aged between 24 and 41 years (mean= 30 years). Fluoroscopy guidance was used in 87% of our patients. No major complication was reported.

Fluoroscopy-guided transforaminal nusinersen injection is a safe and successful alternative approach in adult and pediatric patients with severe spinal scoliosis, interlaminar osseous fusion, and spinal fusion hardware.

Pediatric Cancer Patients' Treatment Journey: Child, Adolescent, and Young Adult Cancer Narratives

PURPOSE

The National Cancer Institute has acknowledged that for children, adolescents and young adults (AYAs), cancer is a leading cause of disability and death. This population has unique needs and until we fully understand those needs, we will not be able to provide optimal care. The purpose of this study was to understand the self-reported experience of cancer according to children and AYAs.

DESIGN AND METHODS

A qualitative descriptive design was used. After obtaining IRB approval, participants were interviewed in Spanish or English. Thirty interviews were conducted with children and AYAs ages 10-22. Questions were asked about the patient's treatment journey and the impact on their lifestyle. The interviews were recorded directly in digital audio files, then transcribed using Verbal Ink®. Themes were derived after the data were organized using Dedoose® and then coded.

RESULTS

Children and AYAs described the cancer experience as difficult due to activity challenges and disconnection from school. Patients noted that their physical inactivity led to deconditioning. Children and AYAs reported storytelling as a way to cope with newfound disabilities. Patients reported that their illness allowed them to build closer relationships to family. Feelings on other issues arose, such as communication challenges experienced with transition from adult to pediatric hospitals. The value of altruism emerged as a way to provide purpose in their journey.

CONCLUSIONS

Children and AYAs have particular concerns that the healthcare community needs to address. These qualitative findings have specific recommendations for practice.

Treatment Algorithm for Infants Diagnosed with Spinal Muscular Atrophy through Newborn Screening

Background:

Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by the degeneration of alpha motor neurons in the spinal cord, leading to muscular atrophy. SMA is caused by deletions or mutations in the survival motor neuron 1 gene (SMN1). In humans, a nearly identical copy gene, SMN2, is present. Because SMN2 has been shown to decrease disease severity in a dose-dependent manner, SMN2 copy number is predictive of disease severity.

Objective:

To develop a treatment algorithm for SMA-positive infants identified through newborn screening based upon SMN2 copy number.

Methods:

A working group comprised of 15 SMA experts participated in a modified Delphi process, moderated by a neutral third-party expert, to develop treatment guidelines.

Results:

The overarching recommendation is that all infants with two or three copies of SMN2 should receive immediate treatment (n = 13). For those infants in which immediate treatment is not recommended, guidelines were developed that outline the timing and appropriate screens and tests to be used to determine the timing of treatment initiation.

Conclusions:

The identification SMA affected infants via newborn screening presents an unprecedented opportunity for achievement of maximal therapeutic benefit through the administration of treatment pre-symptomatically. The recommendations provided here are intended to help formulate treatment guidelines for infants who test positive during the newborn screening process.

Phase IIa trial in Duchenne muscular dystrophy shows vamorolone is a first-in-class dissociative steroidal anti-inflammatory drug

We report a first-in-patient study of vamorolone, a first-in-class dissociative steroidal anti-inflammatory drug, in Duchenne muscular dystrophy. This 2-week, open-label Phase IIa multiple ascending dose study (0.25, 0.75, 2.0, and 6.0 mg/kg/day) enrolled 48 boys with Duchenne muscular dystrophy (4 to <7 years), with outcomes including clinical safety, pharmacokinetics and pharmacodynamic biomarkers. The study design included pharmacodynamic biomarkers in three contexts of use: 1. Secondary outcomes for pharmacodynamic safety (insulin resistance, adrenal suppression, bone turnover); 2. Exploratory outcomes for drug mechanism of action; 3. Exploratory outcomes for expanded pharmacodynamic safety. Vamorolone was safe and well-tolerated through the highest dose tested (6.0 mg/kg/day) and pharmacokinetics of vamorolone were similar to prednisolone. Using pharmacodynamic biomarkers, the study demonstrated improved safety of vamorolone versus glucocorticoids as shown by reduction of insulin resistance, beneficial changes in bone turnover (loss of increased bone resorption and decreased bone formation only at the highest dose level), and a reduction in adrenal suppression. Exploratory biomarkers of pharmacodynamic efficacy showed an anti-inflammatory mechanism of action and a beneficial effect on plasma membrane stability, as demonstrated by a dose-responsive decrease in serum creatine kinase activity. With an array of pre-selected biomarkers in multiple contexts of use, we demonstrate the development of the first dissociative steroid that preserves anti-inflammatory efficacy and decreases steroid-associated safety concerns. Ongoing extension studies offer the potential to bridge exploratory efficacy biomarkers to clinical outcomes.

Recruitment & retention program for the NeuroNEXT SMA Biomarker Study: Super Babies for SMA!

Background/Aims

Recruitment and retention of research participants are challenging and critical components of successful clinical trials and natural history studies. Infants with spinal muscular atrophy (SMA) have been a particularly challenging population to study due to their fragile and complex medical issues, poor prognosis and, until 2016, a lack of effective therapies. Recruitment of healthy infants into clinical trials and natural history studies is also challenging and sometimes assumed to not be feasible.

Methods

In 2011, our group initiated a two-year, longitudinal natural history study of infants with SMA and healthy infant controls to provide data to assist in the analysis and interpretation of planned clinical trials in infants with SMA. The recruitment goal was to enroll 27 infants less than 6 months of age with SMA and 27 age-matched healthy infants within the two-year enrollment period. A detailed recruitment and retention plan was developed for this purpose. In addition, a survey was administered to participant families to understand the determinants of participation in the study.

Results

All healthy infants were recruited within the study's first year and 26 SMA infants were recruited within the two-year recruitment period. Thirty-eight participant families responded to the recruitment determinants survey. Nearly half of respondents (18/38, 48%) reported that they first heard of the study from their physician or neurologist. The most common reason to decide to enroll their infant (22/38, 58%) and to remain in the study (28/38, 74%) was their understanding of the importance of the study. Thematic recruitment tools such as a study brochure, video on social media, and presentations at advocacy meetings were reported to positively influence the decision to enroll.

Conclusions

A proactive, thematic and inclusive recruitment and retention plan that effectively communicates the rationale of a clinical study and partners with patients, advocacy groups and the local communities can effectively recruit participants in vulnerable populations. Recommendations for the proactive integration of recruitment and retention plans into clinical trial protocol development are provided.

Natural history of infantile-onset spinal muscular atrophy

OBJECTIVE

Infantile-onset spinal muscular atrophy (SMA) is the most common genetic cause of infant mortality, typically resulting in death preceding age 2. Clinical trials in this population require an understanding of disease progression and identification of meaningful biomarkers to hasten therapeutic development and predict outcomes.

METHODS

A longitudinal, multicenter, prospective natural history study enrolled 26 SMA infants and 27 control infants aged <6 months. Recruitment occurred at 14 centers over 21 months within the NINDS-sponsored NeuroNEXT (National Network for Excellence in Neuroscience Clinical Trials) Network. Infant motor function scales (Test of Infant Motor Performance Screening Items [TIMPSI], The Children's Hospital of Philadelphia Infant Test for Neuromuscular Disorders, and Alberta Infant Motor Score) and putative physiological and molecular biomarkers were assessed preceding age 6 months and at 6, 9, 12, 18, and 24 months with progression, correlations between motor function and biomarkers, and hazard ratios analyzed.

RESULTS

Motor function scores (MFS) and compound muscle action potential (CMAP) decreased rapidly in SMA infants, whereas MFS in all healthy infants rapidly increased. Correlations were identified between TIMPSI and CMAP in SMA infants. TIMPSI at first study visit was associated with risk of combined endpoint of death or permanent invasive ventilation in SMA infants. Post-hoc analysis of survival to combined endpoint in SMA infants with 2 copies of SMN2 indicated a median age of 8 months at death (95% confidence interval, 6, 17).

INTERPRETATION

These data of SMA and control outcome measures delineates meaningful change in clinical trials in infantile-onset SMA. The power and utility of NeuroNEXT to provide "real-world," prospective natural history data sets to accelerate public and private drug development programs for rare disease is demonstrated. Ann Neurol 2017;82:883-891.

International consensus guidance for management of myasthenia gravis: Executive summary

Objective:

To develop formal consensus-based guidance for the management of myasthenia gravis (MG).

Methods:

In October 2013, the Myasthenia Gravis Foundation of America appointed a Task Force to develop treatment guidance for MG, and a panel of 15 international experts was convened. The RAND/UCLA appropriateness methodology was used to develop consensus guidance statements. Definitions were developed for goals of treatment, minimal manifestations, remission, ocular MG, impending crisis, crisis, and refractory MG. An in-person panel meeting then determined 7 treatment topics to be addressed. Initial guidance statements were developed from literature summaries. Three rounds of anonymous e-mail votes were used to attain consensus on guidance statements modified on the basis of panel input.

Results:

Guidance statements were developed for symptomatic and immunosuppressive treatments, IV immunoglobulin and plasma exchange, management of impending and manifest myasthenic crisis, thymectomy, juvenile MG, MG associated with antibodies to muscle-specific tyrosine kinase, and MG in pregnancy.

Conclusion:

This is an international formal consensus of MG experts intended to be a guide for clinicians caring for patients with MG worldwide.

Baseline results of the NeuroNEXT spinal muscular atrophy infant biomarker study

OBJECTIVE

This study prospectively assessed putative promising biomarkers for use in assessing infants with spinal muscular atrophy (SMA).

METHODS

This prospective, multi-center natural history study targeted the enrollment of SMA infants and healthy control infants less than 6 months of age. Recruitment occurred at 14 centers within the NINDS National Network for Excellence in Neuroscience Clinical Trials (NeuroNEXT) Network. Infant motor function scales and putative electrophysiological, protein and molecular biomarkers were assessed at baseline and subsequent visits.

RESULTS

Enrollment began November, 2012 and ended September, 2014 with 26 SMA infants and 27 healthy infants enrolled. Baseline demographic characteristics of the SMA and control infant cohorts aligned well. Motor function as assessed by the Test for Infant Motor Performance Items (TIMPSI) and the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) revealed significant differences between the SMA and control infants at baseline. Ulnar compound muscle action potential amplitude (CMAP) in SMA infants (1.4 ± 2.2 mV) was significantly reduced compared to controls (5.5 ± 2.0 mV). Electrical impedance myography (EIM) high-frequency reactance slope (Ohms/MHz) was significantly higher in SMA infants than controls SMA infants had lower survival motor neuron (SMN) mRNA levels in blood than controls, and several serum protein analytes were altered between cohorts.

INTERPRETATION

By the time infants were recruited and presented for the baseline visit, SMA infants had reduced motor function compared to controls. Ulnar CMAP, EIM, blood SMN mRNA levels, and serum protein analytes were able to distinguish between cohorts at the enrollment visit.

Cerebellar mutism in acute disseminating encephalomyelitis

BACKGROUND

Cerebellar mutism in children occurs after posterior fossa tumor resection and can have lasting effects on cognition, language, and behavior. Cerebellar mutism in acute disseminated encephalomyelitis is rare.

PATIENT

A 7-year-old boy with a 3-day history of fever, vomiting, and diarrhea presented with altered mental status and expressive aphasia. Magnetic resonance imaging showed new diffusion restriction in the bilateral dentate nuclei and right cerebellum. With treatment, he began to verbalize again but had long-term cognitive and language difficulties.

CONCLUSION

Acute disseminated encephalomyelitis is commonly a benign process, but its effect on the cerebellum can be long-lasting.

Quantitative MRI analysis in children with multiple sclerosis: a multicenter feasibility pilot study

BACKGROUND

Pediatric multiple sclerosis (MS) is a rare disorder with significant consequences. Quantitative MRI measurements may provide significant insights, however multicenter collaborative studies are needed given the small numbers of subjects. The goal of this study is to demonstrate feasibility and evaluate lesion volume (LV) characteristics in a multicenter cohort of children with MS.

METHODS

A common MRI-scanning guideline was implemented at six member sites of the U.S. Network of Pediatric MS Centers of Excellence. We included in this study the first ten scans performed at each site on patients meeting the following inclusion criteria: pediatric RRMS within 3 years of disease onset, examination within 1 month of MRI and no steroids 1 month prior to MRI. We quantified T2 number, T2-LV and individual lesion size in a total of 53 MRIs passing quality control procedures and assessed gadolinium-enhancing lesion number and LV in 55 scans. We studied MRI measures according to demographic features including age, race, ethnicity and disability scores, controlling for disease duration and treatment duration using negative binomial regression and linear regression.

RESULTS

The mean number of T2 lesions was 24.30 ± 19.68 (range:1-113) and mean gadolinium-enhancing lesion count was 1.85 ± 5.84, (range:0-32). Individual lesion size ranged from 14.31 to 55750.60 mm3. Non-white subjects had higher T2-LV (unadjusted pT2-LV = 0.028; adjusted pT2-LV = 0.044), and maximal individual T2-LV (unadjusted pMax = 0.007; adjusted pMax = 0.011) than white patients. We also found a trend toward larger mean lesion size in males than females (p = 0.07).

CONCLUSION

Assessment of MRI lesion LV characteristics is feasible in a multicenter cohort of children with MS.

Spasmodic muscle cramps and weakness as presenting symptoms in Wilson disease

Wilson disease (WD) is an autosomal-recessive disorder of hepatic copper metabolism that has tremendous variability in its presentation. Phenotypic diversity of the disease can lead to delayed diagnosis. We describe a case of WD in a 10-year-old boy presenting with 3 months of increasingly intense, spasmodic lower extremity muscle cramps. Physical examination revealed tenderness on calf palpation and dark flat lesions over his ankles, knees, and elbows. Initial testing revealed creatine kinase of 302 IU/L (normal 24-248 IU/L), hemoglobin of 8.9 g/dL (11.5-15.5 g/dL), aspartate aminotransferase of 114 IU/L (16-52 IU/L), alanine aminotransferase of 54 IU/L (2-30 IU/L), and myoglobinuria. Extensive evaluation of his myopathy, including MRI and muscle biopsy, was negative. Additional laboratory tests revealed a prothrombin time of 21.3 seconds (11.8-15.5 seconds), total bilirubin of 1.4 mg/dL (<1 mg/dL), direct bilirubin of 0.5 mg/dL (<0.3 mg/dL), albumin of 2.1 g/dL (3.1-4.6 g/dL), a reticulocyte percentage of 4.5% (0.5%-2.5%), a negative Coombs direct antibody test, ceruloplasmin of 3 mg/dL (21-51 mg/dL), and 24-h urine copper of 393 μg/24 h (15-60 μg/24 h). Liver biopsy showed patchy advanced fibrosis, mild inflammation, positive staining for copper, and a tissue copper concentration of 768 µg/g (10-35 μg/g). Brain MRI revealed symmetric intrinsic T1 shortening within bilateral basal ganglia. Trientene therapy was initiated for WD. Symptoms and laboratory abnormalities resolved and remain normal at 21 months' follow-up. Musculoskeletal involvement in WD is uncommon and typically defined as bone demineralization, arthropathy, or hypokalemic muscle weakness. In patients with unexplained musculoskeletal symptoms and hepatic abnormalities, a diagnosis of WD should be considered and appropriate evaluation initiated.

The DcpS inhibitor RG3039 improves survival, function and motor unit pathologies in two SMA mouse models

Spinal muscular atrophy (SMA) is caused by insufficient levels of the survival motor neuron (SMN) protein due to the functional loss of the SMN1 gene and the inability of its paralog, SMN2, to fully compensate due to reduced exon 7 splicing efficiency. Since SMA patients have at least one copy of SMN2, drug discovery campaigns have sought to identify SMN2 inducers. C5-substituted quinazolines increase SMN2 promoter activity in cell-based assays and a derivative, RG3039, has progressed to clinical testing. It is orally bioavailable, brain-penetrant and has been shown to be an inhibitor of the mRNA decapping enzyme, DcpS. Our pharmacological characterization of RG3039, reported here, demonstrates that RG3039 can extend survival and improve function in two SMA mouse models of varying disease severity (Taiwanese 5058 Hemi and 2B/- SMA mice), and positively impacts neuromuscular pathologies. In 2B/- SMA mice, RG3039 provided a >600% survival benefit (median 18 days to >112 days) when dosing began at P4, highlighting the importance of early intervention. We determined the minimum effective dose and the associated pharmacokinetic (PK) and exposure relationship of RG3039 and DcpS inhibition ex vivo. These data support the long PK half-life with extended pharmacodynamic outcome of RG3039 in 2B/- SMA mice. In motor neurons, RG3039 significantly increased both the average number of cells with gems and average number of gems per cell, which is used as an indirect measure of SMN levels. These studies contribute to dose selection and exposure estimates for the first studies with RG3039 in human subjects.

Antibody response to common viruses and human leukocyte antigen-DRB1 in pediatric multiple sclerosis

BACKGROUND

As remote infections with common herpes viruses are associated with modulation of the risk of multiple sclerosis (MS), we hypothesized that antibody concentrations against these viruses may further modify risk. As many common viruses are first encountered during childhood, pediatric MS offer a unique opportunity to investigate more closely their influence on susceptibility. Our aim was to determine if MS patients who were positive for these viruses had higher levels of antibodies to these viruses. We also assessed whether human leukocyte antigen (HLA)-DRB1*1501 genotype influenced viral antibody levels.

METHODS

Antibody response levels toward Epstein Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus (HSV)-1, and HLA-DRB1*1501 status were determined in pediatric MS patients (n=189) and controls (n=38). Multivariate analyses were used, adjusted for age, gender, race, ethnicity and use of disease-modifying therapies.

RESULTS

The antibody concentrations against EBV (Epstein-Barr nuclear antigen 1 (EBNA-1), viral capsid antigen (VCA) and early antigen (EA)), CMV and HSV-1 were similar between pediatric MS patients and controls positive for seroconversion against the virus of interest. EBNA-1 humoral responses were higher in HLA-DRB1 positive individuals (p=0.005) whereas other viral humoral responses were similar in HLA-DRB1 positive and negative individuals.

CONCLUSION

Among those positive for EBNA-1, MS patients did not have higher levels of antibody response to EBNA-1: however, titers for EBNA-1 were higher in those who were HLA-DRB1 positive. This suggests that genotype might influence the humoral response to EBV. Whether other genotypes influence antibody response to other viruses remains to be determined.

Pentoxifylline as a rescue treatment for DMD: a randomized double-blind clinical trial

OBJECTIVE

To determine whether pentoxifylline (PTX) slows the decline of muscle strength and function in ambulatory boys with Duchenne muscular dystrophy (DMD).

METHODS

This was a multicenter, randomized, double-blinded, controlled trial comparing 12 months of daily treatment with PTX or placebo in corticosteroid-treated boys with DMD using a slow-release PTX formulation (~20 mg/kg/day). The primary outcome was the change in mean total quantitative muscle testing (QMT) score. Secondary outcomes included changes in QMT subscales, manual muscle strength, pulmonary function, and timed function tests. Outcomes were compared using Student t tests and a linear mixed-effects model. Adverse events (AEs) were compared using the Fisher exact test.

RESULTS

A total of 64 boys with DMD with a mean age of 9.9 ± 2.9 years were randomly assigned to PTX or placebo in 11 participating Cooperative International Neuromuscular Research Group centers. There was no significant difference between PTX and the placebo group in total QMT scores (p = 0.14) or in most of the secondary outcomes after a 12-month treatment. The use of PTX was associated with mild to moderate gastrointestinal or hematologic AEs.

CONCLUSION

The addition of PTX to corticosteroid-treated boys with DMD at a moderate to late ambulatory stage of disease did not improve or halt the deterioration of muscle strength and function over a 12-month study period.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that treatment with PTX does not prevent deterioration in muscle function or strength in corticosteroid-treated boys with DMD.

Common viruses associated with lower pediatric multiple sclerosis risk

BACKGROUND

Because common viruses are encountered during childhood, pediatric multiple sclerosis (MS) offers a unique opportunity to investigate the influence of these viruses on disease susceptibility and the interactions between seroprevalence and select HLA genotypes. We studied seroprevalence for Epstein-Barr virus (EBV), cytomegalovirus (CMV), and herpes simplex virus (HSV) type 1 and HLA-DRB1*1501/1503 status as predictors of pediatric MS.

METHODS

This was a retrospective analysis of prospectively collected demographic, clinical, and biologic data in subjects up to 18 years of age with early MS, control subjects seen at the same regional referral pediatric MS clinics, and additional healthy pediatric control subjects.

RESULTS

Patients with early pediatric MS (n=189) and pediatric control subjects (n=66) were tested. Epstein-Barr nuclear antigen-1 seropositivity was associated with an increased odds of MS (odds ratio [OR] 3.78, 95% confidence interval [CI] 1.52-9.38, p=0.004) in analyses adjusted for age, sex, race, ethnicity, and HLA-DRB1*1501/1503 status. In multivariate analyses including EBV status, a remote infection with CMV (OR 0.27, 95% CI 0.11-0.67, p=0.004) was associated with a lower risk of developing MS. Although a remote infection with HSV-1 was not associated with an increased odds of MS, a strong interaction was found between HSV-1 status and HLA-DRB1 in predicting MS (p<0.001). HSV-1 was associated with an increased risk of MS in those without a DRB1*15 allele (OR 4.11, 95% CI 1.17-14.37, p=0.03), whereas the effect was reversed in those who were DRB1*15-positive (OR 0.07, 95% CI 0.02-0.32, p=0.001).

CONCLUSIONS

These findings suggest that some infections with common viruses may in fact lower MS susceptibility. If this is confirmed, the pathways for risk modification remain to be elucidated.

Pediatric multiple sclerosis

In the past 5 years, there has been an exponential growth in the knowledge about multiple sclerosis (MS) in children and adolescents. Recent publications have shed light on its diagnosis, pathogenesis, clinical course, and treatment. However, there remain several key areas that require further exploration. This article summarizes the current state of knowledge on pediatric MS and discusses future avenues of investigation.

Liquid formulation of pentoxifylline is a poorly tolerated treatment for duchenne dystrophy

INTRODUCTION

In this study we performed an open-label, pilot study of an orally administered liquid formulation of immediate-release pentoxifylline (PTX) on patients with Duchenne muscular dystrophy (DMD). Treatment efficacy, safety, and tolerability were assessed.

METHODS

The tolerability and safety of PTX and measures of muscle strength and function were evaluated during 12 months of treatment.

RESULTS

Seventeen boys with DMD, between 4 and 8 years of age, were enrolled at one of five Cooperative International Neuromuscular Research Group (CINRG) centers. Only 9 were able to complete the 12-month PTX treatment phase; the primary reason for discontinuation was adverse events. Intolerable gastrointestinal side effects were experienced by 65% of participants. Two participants had severe leukopenia that resolved with medication withdrawal.

CONCLUSIONS

Open-label treatment with a liquid formulation of immediate-release PTX resulted in a high incidence of adverse events in boys with DMD. Poor tolerability of this PTX formulation precluded adequate assessment of efficacy.