Use of corticosteroids in a population-based cohort of boys with duchenne and becker muscular dystrophy

Disease-associated comorbidities, medication records and anthropometric measures in adults with Duchenne muscular dystrophy

We investigated the comorbidities, associated factors, and the relationship between anthropometric measures and respiratory function and functional abilities in adults with Duchenne muscular dystrophy (DMD). This was a single-centre cross-sectional study in genetically diagnosed adults with DMD (>16 years old). Univariate and multivariate analyses identified factors associated with dysphagia, constipation, Body Mass Index (BMI), and weight. Regression analysis explored associations between BMI, weight, and respiratory/motor abilities. We included 112 individuals (23.4 ± 5.2 years old), glucocorticoid-treated 66.1 %. The comorbidities frequency was 61.6 % scoliosis (61.0 % of them had spinal surgery), 36.6 % dysphagia, 36.6 % constipation, and 27.8 % urinary conditions. The use of glucocorticoids delayed the time to spinal surgery. The univariate analysis revealed associations between dysphagia and constipation with age, lack of glucocorticoid treatment, and lower respiratory and motor function. In the multivariate analysis, impaired cough ability remained as the factor consistently linked to both conditions. Constipation associated with lower BMI and weight. BMI and weight positively correlated with respiratory parameters, but they did not associate with functional abilities. Glucocorticoids reduce the frequency of comorbidities in adults with DMD. The ability to cough can help identifying dysphagia and constipation. Lower BMI and weight in individuals with DMD with compromised respiratory function may suggest a higher calories requirement.

Clinical and Genetic Characteristics in Young, Glucocorticoid-Naive Boys With Duchenne Muscular Dystrophy

BACKGROUND AND OBJECTIVES

Duchenne muscular dystrophy (DMD) is a pediatric neuromuscular disorder caused by mutations in the dystrophin gene. Genotype-phenotype associations have been examined in glucocorticoid-treated boys, but there are few data on the young glucocorticoid-naive DMD population. A sample of young glucocorticoid-naive DMD boys is described, and genotype-phenotype associations are investigated.

METHODS

Screening and baseline data were collected for all the participants in the Finding the Optimum Corticosteroid Regime for Duchenne Muscular Dystrophy (FOR-DMD) study, an international, multicenter, randomized, double-blind, clinical trial comparing 3 glucocorticoid regimens in glucocorticoid-naive, genetically confirmed boys with DMD between 4 and <8 years of age.

RESULTS

One hundred ninety-six boys were recruited. The mean ± SD age at randomization was 5.8 ± 1.0 years. The predominant mutation type was out-of-frame deletions (67.4%, 130 of 193), of which 68.5% (89 of 130) were amenable to exon skipping. The most frequent mutations were deletions amenable to exon 51 skipping (13.0%, 25 of 193). Stop codon mutations accounted for 10.4% (20 of 193). The mean age at first parental concerns was 29.8 ± 18.7 months; the mean age at genetic diagnosis was 53.9 ± 21.9 months; and the mean diagnostic delay was 25.9 ± 18.2 months. The mean diagnostic delay for boys diagnosed after an incidental finding of isolated hyperCKemia (n = 19) was 6.4 ± 7.4 months. The mean ages at independent walking and talking in sentences were 17.1 ± 4.2 and 29.0 ± 10.7 months, respectively. Median height percentiles were below the 25th percentile regardless of age group. No genotype-phenotype associations were identified expect for boys with exon 8 skippable deletions, who had better performance on time to walk/run 10 m (p = 0.02) compared to boys with deletions not amenable to skipping.

DISCUSSION

This study describes clinical and genetic characteristics of a sample of young glucocorticoid-naive boys with DMD. A low threshold for creatine kinase testing can lead to an earlier diagnosis. Motor and speech delays were common presenting symptoms. The effects of low pretreatment height on growth and adult height require further study. These findings may promote earlier recognition of DMD and inform study design for future clinical trials. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT01603407.

Effect of Chinese herbal medicines on the overall survival of patients with muscular dystrophies in Taiwan

ETHNOPHARMACOLOGICAL RELEVANCE

Muscular dystrophies are a rare, severe, and genetically inherited group of disorders characterized by progressive loss of muscle fibers, leading to muscle weakness. The current treatment plan for muscular dystrophies includes the use of steroids to slow muscle deterioration by dampening the inflammatory response.

AIM OF THE STUDY

Chinese herbal medicine (CHM) has been offered as an adjunctive therapy in Taiwan's medical healthcare plan, making it possible to track CHM usage in patients with muscular dystrophic disease. Therefore, we explored the long-term effects of CHM use on the overall mortality of patients with muscular dystrophies.

MATERIALS AND METHODS

A total of 581 patients with muscular dystrophies were identified from the database of Registry for Catastrophic Illness Patients in Taiwan. Among them, 80 and 201 patients were CHM users and non-CHM users, respectively. Student's t-test, chi-squared test, Cox proportional hazard model, and Kaplan-Meier curve (log-rank test) were used for evaluation. Association rules and network analyses were performed to explore the combination of CHMs used in muscular dystrophies.

RESULTS

Compared to non-CHM users, there were more female patients, more comorbidities, including chronic pulmonary disease and peptic ulcer disease in the CHM user group. Patients with prednisolone usage exhibited a lower risk of overall mortality than those who did not, after adjusting for age, sex, use of CHM, and comorbidities. CHM users showed a lower risk of overall mortality after adjusting for age, sex, prednisolone use, and comorbidities. The cumulative incidence of the overall survival was significantly higher in CHM users. Association rule and network analysis showed that one main CHM cluster was commonly used to treat patients with muscular dystrophies in Taiwan. The cluster includes Yin-Qiao-San, Ban-Xia-Bai-Zhu-Tian-Ma-Tang, Zhi-Ke (Citrus aurantium L.), Yu-Xing-Cao (Houttuynia cordata Thunb.), Che-Qian-Zi (Plantago asiatica L.), and Da-Huang (Rheum palmatum L.).

CONCLUSIONS

Our data suggest that adjunctive therapy with CHM may help to reduce the overall mortality among patients with muscular dystrophies. The identification of the CHM cluster allows us to narrow down the key active compounds and may enable future therapeutic developments and clinical trial designs to improve overall survival in these patients.

Steroid switching in dystrophinopathy treatment: a US chart review of patient characteristics and clinical outcomes

Aim: To describe reasons for switching from prednisone/prednisolone to deflazacort and associated clinical outcomes among patients with Duchenne and Becker muscular dystrophy (DMD and BMD, respectively) in the USA. Methods: A chart review of patients with DMD (n = 62) or BMD (n = 30) who switched from prednisone to deflazacort (02/2017-12/2018) collected demographic/clinical characteristics, reasons for switching, outcomes and common adverse events. Results: The mean ages at switch were 20.1 (DMD) and 9.2 (BMD) years. The primary physician-reported reasons for switching were 'to slow disease progression' (DMD: 83%, BMD: 79%) and 'tolerability' (67 and 47%). Switching was 'very' or 'somewhat' effective at addressing the primary reasons in 90-95% of patients. Conclusion: Physician-reported outcomes were consistent with deflazacort addressing patients' primary reasons for switching.

Clinical Phenotypes of DMD Exon 51 Skip Equivalent Deletions: A Systematic Review

BACKGROUND

Eteplirsen, the first FDA-approved RNA-modifying therapy for DMD, is applicable to ∼13% of patients with DMD. Because multiple exonic deletions are amenable to exon 51 skipping, the isoforms resulting from the various exon 51-skipped transcripts may vary in stability, function, and phenotype.

OBJECTIVE/METHODS

We conducted a detailed review of dystrophinopathy published literature and unpublished databases to compile phenotypic features of patients with exon 51 "skip-equivalent" deletions.

RESULTS

Theoretically, 48 different in-frame transcripts may result from exon 51 skipping. We found sufficient clinical information on 135 patients carrying mutations that would result in production of 11 (23%) of these transcripts, suggesting the remainder have not been identified in vivo. The majority had mild phenotypes: BMD (n = 81) or isolated dilated cardiomyopathy (n = 3). Particularly interesting are the asymptomatic (n = 10) or isolated hyperCKemia (n = 20) patients with deletions of exons 45- 51, 48- 51, 49- 51 and 50- 51. Finally, 16 (12%) had more severe phenotypes described as intermediate (n = 2) or DMD (n = 14), and 6 reports had no definitive phenotype.

CONCLUSIONS

This review shows that the majority of exon 51 "skip-equivalent" deletions result in milder (BMD) phenotypes and supports that exon 51 skipping therapy could provide clinical benefit, although we acknowledge that other factors, such as age at treatment initiation or ongoing standard of care, may influence the degree of benefit.

Clinical practice with steroid therapy for Duchenne muscular dystrophy: An expert survey in Asia and Oceania

BACKGROUND

Several studies on clinical practice for Duchenne muscular dystrophy (DMD) have been conducted in Western countries. However, there have been only a few similar studies in Asia and Oceania. Here, we investigate the steroid therapy-related clinical practice for DMD among the local experts. In 2015, we conducted a DMD expert survey in Asia and Oceania to acquire information regarding patients with DMD and to assess current clinical practice with the cooperation of Asian and Oceanian Myology Centre, a neuromuscular disease research network.

RESULTS

We obtained survey responses from 87 out of 148 clinicians (62%) from 13 countries and regions. In China, 1385 DMD patients were followed-up by 5 respondent neurologists, and 84% were between 0 and 9 years of age (15% were 10-19 years, 1% > 19 years). While in Japan, 1032 patients were followed-up by 20 clinicians, and the age distribution was similar between the 3 groups (27% were 0-9 years, 35% were 10-19 years, 38% were >19 years). Most respondent clinicians (91%) were aware of DMD standard of care recommendations. Daily prednisolone/prednisone administration was used most frequently at initiation (N = 45, 64%). Inconsistent opinion on steroid therapy after loss of ambulation and medication for bone protection was observed.

CONCLUSIONS

Rare disease research infrastructures have been underdeveloped in many of Asian and Oceanian countries. In this situation, our results show the snapshots of current medical situation and clinical practice in DMD. For further epidemiological studies, expansion of DMD registries is necessary.

A Review of MD STAR net's Research Contributions to Pediatric-Onset Dystrophinopathy in the United States; 2002-2017

Population studies of rare disorders, such as Duchenne and Becker muscular dystrophies (dystrophinopathies), are challenging due to diagnostic delay and heterogeneity in disorder milestones. To address these challenges, the Centers for Disease Control and Prevention established the Muscular Dystrophy Surveillance, Tracking, and Research Network (MD STAR net) in 2002 in the United States. From 2002 to 2012, MD STAR net longitudinally tracked the prevalence, clinical, and health care outcomes of 1054 individuals born from 1982 to 2011 with pediatric-onset dystrophinopathy through medical record abstraction and survey data collection. This article summarizes 31 MD STAR net peer-reviewed publications. MD STAR net provided the first population-based prevalence estimates of childhood-onset dystrophinopathy in the United States. Additional publications provided insights into diagnostic delay, dystrophinopathy-specific growth charts, and health services use. Ongoing population-based surveillance continually improves our understanding of clinical and diagnostic outcomes of rare disorders.

Implementation of Duchenne Muscular Dystrophy Care Considerations

BACKGROUND

Duchenne muscular dystrophy (DMD) is an X-linked disorder characterized by progressive muscle weakness and multisystem involvement. Recent advances in management of individuals with DMD have prolonged survival. Lack of standardized care spurred an international collaboration to develop consensus-based care considerations for diagnosis and management. In this study, we evaluate adherence to considerations at selected sites.

METHODS

We collaborated with the Muscular Dystrophy Surveillance, Tracking, and Research Network. Our sample included males with DMD and Becker muscular dystrophy <21 years as of December 31, 2010, with 1 health care encounter on or after January 1, 2012. We collected data from medical records on encounters occurring January 1, 2012, through December 31, 2014. Adherence was determined when frequency of visits or assessments were at or above recommendations for selected care considerations.

RESULTS

Our analytic sample included 299 individuals, 7% of whom (20/299) were classified as childhood-onset Becker muscular dystrophy. Adherence for neuromuscular and respiratory clinician visits was 65% for the cohort; neuromuscular assessments and corticosteroid side effect monitoring measures ranged from 16% to 68%. Adherence was 83% for forced vital capacity and ≤58% for other respiratory diagnostics. Cardiologist assessments and echocardiograms were found for at least 84%. Transition planning for education or health care was documented for 31% of eligible males.

CONCLUSIONS

Medical records data were used to identify areas in which practice aligns with the care considerations. However, there remains inconsistency across domains and insufficiency in critical areas. More research is needed to explain this variability and identify reliable methods to measure outcomes.

Development of a New Self-Reporting Instrument Measuring Benefits and Side Effects of Corticosteroids in Duchenne Muscular Dystrophy: Report from a Pilot Study

BACKGROUND

There is no cure for Duchenne Muscular Dystrophy (DMD); treatment is symptomatic and corticosteroids slow the progression. Side effects of corticosteroids - especially the physical effects - have been described, however patients' and caregivers perception on chronic corticosteroid treatment and their side effects is less well known, in particular with regards to cognition, behaviour, and emotional functioning.

OBJECTIVE

The primary aim of this pilot study was to (i) construct a self-report questionnaire to assess the perceived benefits and side effects of corticosteroids for patients with DMD and their parents. Furthermore we aimed to (ii) investigate the psychometric qualities of this questionnaire, (iii) whether there was a difference between parents' and patient's perceptions, and finally (iv) to what extent reported side effects may alter over time.

METHODS

A 23-item questionnaire (SIDECORT: side effect of corticosteroids) was constructed to assess the perception of these benefits and side effects in a systematic manner.

RESULTS

In total, 86 patients (aged 5 - 28 years) and 125 of their parents completed the questionnaire. Internal consistency was good. Using factor analyses on the side effect items as reported by parents, two underlying factors were found, with the first factor describing cognitive, behavioural and emotional functioning, and the second factor describing physical functioning. The potential benefits of corticosteroids were highly rated among both parents and patients, although parents rated the importance of the benefits higher than their sons (p = 0.002). Similarly, parents rated the severity of the side effects generally higher than their sons (p = 0.011), especially with regards to the physical side effects (p = 0.014). Based on the parent's perception, the neurodevelopmental side effects generally appeared to decline the longer corticosteroids were used.

CONCLUSIONS

To our knowledge, this is the first explicit study on perceived cognitive-, behavioural-, and emotional side effects and the allocation of benefits to corticosteroids in DMD. On the basis of our research we suggest a short form questionnaire, which proves to be reliable and valid for research- and clinical practice. This questionnaire could provide useful insights for the care of boys and men with DMD.

Surgical Correction of Scoliosis in Patients With Duchenne Muscular Dystrophy: 30-Year Experience

BACKGROUND

The natural history of scoliosis in Duchenne muscular dystrophy (DMD) is progressive and debilitating if neglected. The purpose of this study was to evaluate outcomes related to spinal deformity surgery in patients with DMD over a 30-year period.

METHODS

This was a single center retrospective study of all operatively treated scoliosis in DMD patients over 30 years. Minimum follow-up was 2 years. Owing to changes in instrumentation over time, patients were divided into 2 groups: Luque or pedicle screws (PS) constructs. Radiographic, perioperative variables, pulmonary function test (preoperatively and postoperatively), and complication data were evaluated.

RESULTS

There were 60 subjects (Luque: 47, PS: 13). The Luque group was on average 13 years old, 53 kg, and had 7 years of follow-up. Coronal Cobb was 31±12 degrees preoperatively, 16±11 degrees at first postoperatively, and 21±15 degrees at final follow-up (P≤0.001). Pelvic obliquity was 7±6 degrees preoperatively, 5±5 degrees at first postoperatively (P=0.43), and 5±4 degrees at final follow-up (P=0.77). The majority of this group was fused to L5 (45%) or the sacrum (49%). The PS group was on average 14 years old, 65 kg, and had 4 years of follow-up. Coronal Cobb was 43±19 degrees preoperatively, 12±9 degrees at first postoperatively (P≤0.001), and 12±8 degrees at final follow-up. Pelvic obliquity was 6±5 degrees preoperatively, 3±3 degrees at first postoperatively (P=0.06), and 2±2 degrees at final follow-up (P=0.053). The majority were fused to the pelvis (92%). Both groups' pulmonary function declined with time. Both groups had high complication rates (Luque 68%; PS group 54%). The Luque group had more implant-related complications (26%); the PS group had a higher rate of early postoperative infections (23%).

CONCLUSIONS

Over a 30-year period of operative treatment of scoliosis in DMD, both PS constructs and Luque instrumentation improved coronal Cobb. The PS group had improved and maintained pelvic obliquity. Both groups had high complication rates.

LEVEL OF EVIDENCE

Level IV-therapeutic.

Brazilian consensus on Duchenne muscular dystrophy. Part 1: diagnosis, steroid therapy and perspectives

ABSTRACT Significant advances in the understanding and management of Duchenne muscular dystrophy (DMD) took place since international guidelines were published in 2010. Our objective was to provide an evidence-based national consensus statement for multidisciplinary care of DMD in Brazil. A combination of the Delphi technique with a systematic review of studies from 2010 to 2016 was employed to classify evidence levels and grade of recommendations. Our recommendations were divided in two parts. We present Part 1 here, where we describe the guideline methodology and overall disease concepts, and also provide recommendations on diagnosis, steroid therapy and new drug treatment perspectives for DMD. The main recommendations: 1) genetic testing in diagnostic suspicious cases should be the first line for diagnostic confirmation; 2) patients diagnosed with DMD should have steroids prescribed; 3) lack of published results for phase 3 clinical trials hinders, for now, the recommendation to use exon skipping or read-through agents.

Newborn screening for Duchenne muscular dystrophy in China: follow-up diagnosis and subsequent treatment

BACKGROUND

Newborn screening for Duchenne muscular dystrophy (DMD) is currently being initiated in Zhejiang Province, China and is under consideration in other countries, including the United States. As China begins to implement DMD newborn screening (DMD-NBS), there is ongoing discussion regarding the steps forward for follow up care of positively identified patients as well as false positive and false negative results.

DATA SOURCES

Relevant papers related to DMD-NBS, and NBS in China were reviewed in PubMed.

RESULTS

The current state of DMD-NBS is discussed, along with the steps needed to effectively screen infants for this disease in China, recommendations for establishment of follow up care in patients with positive and negative screens, and measurement of patient outcomes.

CONCLUSIONS

Zhejiang Province, China is ready to implement DMD-NBS. Future challenges that exist for this program, and other countries, include the ability to track patients, assist with access to care, and ensure adequate follow-up care according to evidence-based guidelines. In addition, China's large rural population, lack of specialty providers, and difficulty in educating patients regarding the benefits of treatment create challenges that will need to be addressed.

Clinical and mutational characteristics of Duchenne muscular dystrophy patients based on a comprehensive database in South China

The development of clinical trials for Duchenne muscular dystrophy (DMD) in China faces many challenges due to limited information about epidemiological data, natural history and clinical management. To provide these detailed data, we developed a comprehensive database based on registered DMD patients from South China and analysed their clinical and mutational characteristics. The database included DMD registrants confirmed by clinical presentation, family history, genetic detection, prognostic outcome, and/or muscle biopsy. Clinical data were collected by a registry form. Mutations of dystrophin were detected by multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. Currently, 132 DMD patients from 128 families in South China have been registered, and 91.7% of them were below 10 years old. In mutational detection, large deletions were the most frequent type (57.8%), followed by small deletion/insertion mutations (14.1%), nonsense mutations (13.3%), large duplications (10.9%), and splice site mutations (3.1%). Clinical analysis revealed that most patients reported initial symptoms between 1 and 3 years of age, but the diagnostic age was more frequently between 6 and 8 years. 81.4% of patients were ambulatory. Baseline cardiac assessments at diagnosis were conducted in 39.4% and 29.5% of patients by echocardiograms and electrocardiograms, respectively. Only 22.7% of registrants performed baseline respiratory assessments. A small numbers of patients (20.5%) were treated with glucocorticoids. 13.3% of patients were eligible for stop codon read-through therapy, and 48.4% of patients would potentially benefit from exon skipping. The top five exon skips applicable to the largest group of registrants were skipping of exons 51 (14.8% of total mutations), 53 (12.5%), 45 (7.0%), 55 (4.7%), and 44 (3.9%). In conclusion, our database provided information on the natural history, diagnosis and management status of DMD in South China, as well as potential molecular therapies suitable for these patients. This comprehensive database will promote future experimental therapies in China.

Interventions to prevent and treat corticosteroid-induced osteoporosis and prevent osteoporotic fractures in Duchenne muscular dystrophy

BACKGROUND

Corticosteroid treatment is considered the 'gold standard' for Duchenne muscular dystrophy (DMD); however, it is also known to induce osteoporosis and thus increase the risk of vertebral fragility fractures. Good practice in the care of those with DMD requires prevention of these adverse effects. Treatments to increase bone mineral density include bisphosphonates and vitamin D and calcium supplements, and in adolescents with pubertal delay, testosterone. Bone health management is an important part of lifelong care for patients with DMD.

OBJECTIVES

To assess the effects of interventions to prevent or treat osteoporosis in children and adults with DMD taking long-term corticosteroids; to assess the effects of these interventions on the frequency of vertebral fragility fractures and long-bone fractures, and on quality of life; and to assess adverse events.

SEARCH METHODS

On 12 September 2016, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL Plus to identify potentially eligible trials. We also searched the Web of Science ISI Proceedings (2001 to September 2016) and three clinical trials registries to identify unpublished studies and ongoing trials. We contacted correspondence authors of the included studies in the review to obtain information on unpublished studies or work in progress.

SELECTION CRITERIA

We considered for inclusion in the review randomised controlled trials (RCTs) and quasi-RCTs involving any bone health intervention for corticosteroid-induced osteoporosis and fragility fractures in children, adolescents, and adults with a confirmed diagnosis of DMD. The interventions might have included oral and intravenous bisphosphonates, vitamin D supplements, calcium supplements, dietary calcium, testosterone, and weight-bearing activity.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed reports and selected potential studies for inclusion, following standard Cochrane methodology. We contacted study authors to obtain further information for clarification on published work, unpublished studies, and work in progress.

MAIN RESULTS

We identified 18 potential studies, of which two, currently reported only as abstracts, met the inclusion criteria for this review. Too little information was available for us to present full results or adequately assess risk of bias. The participants were children aged five to 15 years with DMD, ambulant and non-ambulant. The interventions were risedronate versus no treatment in one trial (13 participants) and whole-body vibration versus a placebo device in the second (21 participants). Both studies reported improved bone mineral density with the active treatments, with no improvement in the control groups, but the abstracts did not compare treatment and control conditions. All children tolerated whole-body vibration treatment. No study provided information on adverse events. Two studies are ongoing: one investigating whole-body vibration, the other investigating zoledronic acid.

AUTHORS' CONCLUSIONS

We know of no high-quality evidence from RCTs to guide use of treatments to prevent or treat corticosteroid-induced osteoporosis and reduce the risk of fragility fractures in children and adults with DMD; only limited results from two trials reported in abstracts were available. We await formal trial reports. Findings from two ongoing relevant studies and two trials, for which only abstracts are available, will be important in future updates of this review.

Efficacy and safety of deflazacort vs prednisone and placebo for Duchenne muscular dystrophy

Objective:

To assess safety and efficacy of deflazacort (DFZ) and prednisone (PRED) vs placebo in Duchenne muscular dystrophy (DMD).

Methods:

This phase III, double-blind, randomized, placebo-controlled, multicenter study evaluated muscle strength among 196 boys aged 5–15 years with DMD during a 52-week period. In phase 1, participants were randomly assigned to receive treatment with DFZ 0.9 mg/kg/d, DFZ 1.2 mg/kg/d, PRED 0.75 mg/kg/d, or placebo for 12 weeks. In phase 2, placebo participants were randomly assigned to 1 of the 3 active treatment groups. Participants originally assigned to an active treatment continued that treatment for an additional 40 weeks. The primary efficacy endpoint was average change in muscle strength from baseline to week 12 compared with placebo. The study was completed in 1995.

Results:

All treatment groups (DFZ 0.9 mg/kg/d, DFZ 1.2 mg/kg/d, and PRED 0.75 mg/kg/d) demonstrated significant improvement in muscle strength compared with placebo at 12 weeks. Participants taking PRED had significantly more weight gain than placebo or both doses of DFZ at 12 weeks; at 52 weeks, participants taking PRED had significantly more weight gain than both DFZ doses. The most frequent adverse events in all 3 active treatment arms were Cushingoid appearance, erythema, hirsutism, increased weight, headache, and nasopharyngitis.

Conclusions:

After 12 weeks of treatment, PRED and both doses of DFZ improved muscle strength compared with placebo. Deflazacort was associated with less weight gain than PRED.

Classification of evidence:

This study provides Class I evidence that for boys with DMD, daily use of either DFZ and PRED is effective in preserving muscle strength over a 12-week period.

Trends in steroid therapy for Duchenne muscular dystrophy in Japan

Introduction: We conducted a study to reveal trends in steroid prescription for Duchenne muscular dystrophy (DMD) patients in Japan. Methods: We asked patients (ages 5–20 years) identified in the patient registry and their clinicians about steroid therapy experiences. Regimen, dose, and starting age were compared among 3 subgroups according to prednisolone initiation year (2000–2004, 2005–2009, and 2010–2013). Results: Among 157 prednisolone users, 4 different regimens were used. Dose frequencies were: every other day (98 patients), daily (44 patients), 10 days on 20 days off (14 patients), and weekly (1 patient). Median starting age was 6 years, and median dose was 0.42 mg/kg/day. There was an increase in daily regimen use from 2005–2009 (n = 9, 16%) to 2010–2013 (n = 33, 36%). Conclusions: This study revealed a transition over time in steroid use from expert opinion to evidence‐based recommendation. Clinical research should be encouraged to optimize medication worldwide. Muscle Nerve54: 673–680, 2016

Corticosteroid Treatment and Growth Patterns in Ambulatory Males with Duchenne Muscular Dystrophy

OBJECTIVES

To evaluate growth patterns of ambulatory males with Duchenne muscular dystrophy (DMD) treated with corticosteroids compared with ambulatory, steroid-naïve males with DMD and age-matched unaffected general-population males and to test associations between growth and steroid treatment patterns among treated males.

STUDY DESIGN

Using data from the Muscular Dystrophy Surveillance, Tracking, and Research Network, we identified a total of 1768 height, 2246 weight, and 1755 body mass index (BMI) measurements between age 2 and 12 years for 324 ambulatory males who were treated with corticosteroids for at least 6 months. Growth curve comparisons and linear mixed-effects modeling, adjusted for race/ethnicity and birth year, were used to evaluate growth and steroid treatment patterns (age at initiation, dosing interval, duration, cumulative dose).

RESULTS

Growth curves for ambulatory males treated with corticosteroids showed significantly shorter stature, heavier weight, and greater BMI compared with ambulatory, steroid-naïve males with DMD and general-population US males. Adjusted linear mixed-effects models for ambulatory males treated with corticosteroids showed that earlier initiation, daily dosing, longer duration, and greater dosages predicted shorter stature with prednisone. Longer duration and greater dosages predicted shorter stature for deflazacort. Daily prednisone dosing predicted lighter weight, but longer duration, and greater dosages predicted heavier weight. Early initiation, less than daily dosing, longer duration, and greater doses predicted greater BMIs. Deflazacort predicted shorter stature, but lighter weight, compared with prednisone.

CONCLUSION

Prolonged steroid use is significantly associated with short stature and heavier weight. Growth alterations associated with steroid treatment should be considered when making treatment decisions for males with DMD.

Health services received by individuals with duchenne/becker muscular dystrophy

INTRODUCTION

Anecdotal reports from families and care providers suggest a wide variation in services received by individuals with Duchenne/Becker muscular dystrophy (DBMD).

METHODS

We documented the type and frequency of health services received by individuals with DBMD using the Muscular Dystrophy Surveillance Tracking and Research Network (MD STARnet) interview data released in June 2012. Interviews with eligible caregivers from 5 sites (Arizona, Colorado, Georgia, Iowa, and western New York) were conducted from April 2007 to March 2012.

RESULTS

Two hundred ninety-six caregivers (66% of those contactable) participated in the interview. There were significant differences among sites in the specialists seen and services received. Concurrence with cardiac recommendations was higher than that with respiratory recommendations.

CONCLUSIONS

The results of this survey support and quantify the anecdotal reports from families and care providers regarding the disparities in services received by individuals with DBMD. It remains to be determined whether these differences affect outcomes.

A comprehensive database of Duchenne and Becker muscular dystrophy patients (0-18 years old) in East China

Background

Currently, there is no cure for Duchenne and Becker muscular dystrophies (DMD/BMD). However, clinical trials with new therapeutic strategies are being conducted or considered. A comprehensive database is critical for patient recruitment and efficacy evaluation. China has the largest population, yet, no comprehensive database for DMD/BMD is available. Our study registered the data of the DMD/BMD patients in East China.

Methods

A modified registry form of Remudy (http://www.remudy.jp/) was applied to Chinese DMD/BMD patients through the outpatient clinic at Children’s Hospital of Fudan University, Shanghai during the period of August 2011 to December 2013. The data included geographic distribution of patients, age at diagnosis, clinical manifestation, genetic analysis and treatment status.

Results

194 DMD and 35 BMD patients were registered. Most patients lived in East China, namely Jiangsu province, Anhui province, Zhejiang province, Jiangxi province, Shanghai, Fujian province and Shandong province. All individuals aged less than 18 years (age limit to a children’s hospital). Diagnosis was made for a majority of patients during the age of 3–4 (16.6%) and 7–8 (14.8%) years old. Exon deletion was the most frequent genetic mutations (65.5% and 74.3%) followed by point mutations (14.4% and 11.4%), duplications (9.8% and 8.6%) and small insertion/deletion (9.3% and 2.9%) for DMD and BMD, respectively. 82.5% of DMD registrants were ambulatory, and all the BMD registrants were able to walk. 26.3% of DMD registrants have been treated with steroids. Cardiac functions were examined for 46.4% DMD boys and 45.7% BMD boys and respiratory functions were examined for 18.6% DMD boys and 14.3% BMD boys. Four boys with abnormal cardiac function were prescribed for treatment with cardiac medicine. 33.2% of DMD patients are eligible for exon skipping therapy, and among them 9.2% and 4.3% patients are eligible for skipping exon 51 and 53, respectively.

Conclusions

The database is the first linking accurate genetic diagnosis with clinical manifestation and treatment status of dystrophinopathy patients in East China. It provides comprehensive information essential for further patient management, especially for promotion of international cooperation in developing experimental therapies such as exon skipping and read-through of nonsense mutations targeting a subgroup of DMD patient population.

Cardiopulmonary Exercise Testing in Children and Adolescents With Dystrophinopathies: A Pilot Study

PURPOSE

To determine exercise response during cardiopulmonary exercise testing in children and adolescents with dystrophinopathies.

METHODS

Exercise response on the cardiopulmonary exercise test (CPET) was compared with a standard care test protocol.

RESULTS

Nine boys (aged 10.8 ± 4.7 years) with Becker muscular dystrophy (n = 6) and Duchenne muscular dystrophy (n = 3) were included. The feasibility of the CPET was similar to a standard care test protocol, and no serious adverse events occurred. In 67% of the subjects with normal or only mildly impaired functional capacity, the CPET could be used to detect moderate to severe cardiopulmonary exercise limitations.

CONCLUSIONS

The CPET seems to be a promising outcome measure for cardiopulmonary exercise limitations in youth with mild functional limitations. Further research with larger samples is warranted to confirm current findings and investigate the additional value of the CPET to longitudinal follow-up of cardiomyopathy and the development of safe exercise programs for youth with dystrophinopathies.

Optimizing Bone Health in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder characterized by progressive muscle weakness, with eventual loss of ambulation and premature death. The approved therapy with corticosteroids improves muscle strength, prolongs ambulation, and maintains pulmonary function. However, the osteoporotic impact of chronic corticosteroid use further impairs the underlying reduced bone mass seen in DMD, leading to increased fragility fractures of long bones and vertebrae. These serious sequelae adversely affect quality of life and can impact survival. The current clinical issues relating to bone health and bone health screening methods in DMD are presented in this review. Diagnostic studies, including biochemical markers of bone turnover and bone mineral density by dual energy X-ray absorptiometry (DXA), as well as spinal imaging using densitometric lateral spinal imaging, and treatment to optimize bone health in patients with DMD are discussed. Treatment with bisphosphonates offers a method to increase bone mass in these children; oral and intravenous bisphosphonates have been used successfully although treatment is typically reserved for children with fractures and/or bone pain with low bone mass by DXA.

Trends with corticosteroid use in males with Duchenne muscular dystrophy born 1982-2001

This study examines trends in corticosteroid use for males with Duchenne muscular dystrophy by birth year, race/ethnicity, and knowledge of Duchenne muscular dystrophy family history. Firstborn males (n = 521) selected from a population-based surveillance system of Duchenne muscular dystrophy were analyzed using Kaplan Meier and regression methods. Comparing males born 1982 to 1986 with males born 1997 to 2001, steroid use increased from 54% to 72% and mean age at steroid initiation decreased from 8.2 to 7.1 years. Hispanics and non-Hispanic Black males used steroids less frequently and delayed initiation compared to white males. Compared to males without a Duchenne muscular dystrophy family history, males with known family history were half as likely to use steroids. Duration of steroid use increased over time and age at initiation decreased. Racial/ethnic disparities exist for steroid use and should be addressed to improve outcome and quality of life for boys with Duchenne muscular dystrophy.

Online self-report data for duchenne muscular dystrophy confirms natural history and can be used to assess for therapeutic benefits

To assess the utility of online patient self-report outcomes in a rare disease, we attempted to observe the effects of corticosteroids in delaying age at fulltime wheelchair use in Duchenne muscular dystrophy (DMD) using data from 1,057 males from DuchenneConnect, an online registry. Data collected were compared to prior natural history data in regard to age at diagnosis, mutation spectrum, and age at loss of ambulation. Because registrants reported differences in steroid and other medication usage, as well as age and ambulation status, we could explore these data for correlations with age at loss of ambulation. Using multivariate analysis, current steroid usage was the most significant and largest independent predictor of improved wheelchair-free survival. Thus, these online self-report data were sufficient to retrospectively observe that current steroid use by patients with DMD is associated with a delay in loss of ambulation. Comparing commonly used steroid drugs, deflazacort prolonged ambulation longer than prednisone (median 14 years and 13 years, respectively). Further, use of Vitamin D and Coenzyme Q10, insurance status, and age at diagnosis after 4 years were also significant, but smaller, independent predictors of longer wheelchair-free survival. Nine other common supplements were also individually tested but had lower study power. This study demonstrates the utility of DuchenneConnect data to observe therapeutic differences, and highlights needs for improvement in quality and quantity of patient-report data, which may allow exploration of drug/therapeutic practice combinations impractical to study in clinical trial settings. Further, with the low barrier to participation, we anticipate substantial growth in the dataset in the coming years.

Patterns of decline in upper limb function of boys and men with DMD: an international survey

With increasing life expectancy, upper extremity (UE) function becomes more and more important in boys with Duchenne muscular dystrophy (DMD). Knowledge of UE function in these children is, however, limited. The aim of this study was to gain insight into the changing patterns of UE function during the course of DMD. A Web-based questionnaire on UE function, covering all domains of the International Classification of Functioning Disability and Health, was distributed worldwide. Primary domains of the questionnaire were: participant characteristics, UE pain and stiffness, UE activities, and social participation. Data were described per disease stage and analyzed using descriptive analysis. A total of 213 boys/men with DMD (1-35 years) were included in this study. UE pain, stiffness, and activity limitations increased with disease stage. UE activity limitations already occurred in the early ambulatory stage. Compared to the healthy population, social participation was restricted in DMD patients and about 70% of the respondents experienced UE limitations when performing social activities. Despite the existence of UE impairments, only 9% of the respondents used supportive aids. Functional capacities and activities of the UE are limited already in the early ambulatory stage of patients with DMD affecting their social participation. Therefore, clinicians should pay attention to UE limitations before DMD patients lose their capacity to walk. Effective and adequate aids as well as attention for pain and stiffness in the therapeutic management could help to reduce UE activity limitations and related restrictions in social participation.

Administration of glucocorticoids in boys with Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is the most common neuromuscular disease affecting boys. Advances in their care can delay the progression of DMD-related disability and prolong survival. The administration of glucocorticoids is among these advances. Glucocorticoid therapy, however, is associated with a myriad of potential adverse effects, and treating physicians as well as patients and their family members must understand the benefit/risk ratio of glucocorticoid therapy. Although current best evidence supports the use of glucocorticoids in patients with DMD, many are not offered the option. Considerable variability in practice also exists regarding when and how these drugs should be administered.

The cooperative international neuromuscular research group Duchenne natural history study--a longitudinal investigation in the era of glucocorticoid therapy: design of protocol and the methods used

Contemporary natural history data in Duchenne muscular dystrophy (DMD) is needed to assess care recommendations and aid in planning future trials.

METHODS

The Cooperative International Neuromuscular Research Group (CINRG) DMD Natural History Study (DMD-NHS) enrolled 340 individuals, aged 2-28 years, with DMD in a longitudinal, observational study at 20 centers. Assessments obtained every 3 months for 1 year, at 18 months, and annually thereafter included: clinical history; anthropometrics; goniometry; manual muscle testing; quantitative muscle strength; timed function tests; pulmonary function; and patient-reported outcomes/health-related quality-of-life instruments.

RESULTS

Glucocorticoid (GC) use at baseline was 62% present, 14% past, and 24% GC-naive. In those ≥6 years of age, 16% lost ambulation over the first 12 months (mean age 10.8 years).

CONCLUSIONS

Detailed information on the study methodology of the CINRG DMD-NHS lays the groundwork for future analyses of prospective longitudinal natural history data. These data will assist investigators in designing clinical trials of novel therapeutics.

Corticosteroids in Duchenne muscular dystrophy: major variations in practice

INTRODUCTION

In 2004, a Cochrane Review and AAN practice parameter concluded that prednisone 0.75 mg/kg/day is of short-term efficacy in Duchenne muscular dystrophy (DMD). Subsequent efforts to standardize care for DMD indicated wide variation in corticosteroid use.

METHODS

We surveyed physicians who follow patients with DMD, including: (1) clinics in the TREAT-NMD (Translational Research in Europe-Assessment and Treatment of Neuromuscular Diseases) network (predominantly Europe) and (2) U.S. MDA clinic directors. We also documented the co-administered corticosteroids in a trial of a putative treatment (ataluren) for DMD.

RESULTS

Of 105 Treat-NMD clinicians, corticosteroids were not used in 10 clinics, and 29 different regimens were used--the most frequent 0.75 mg/kg/day prednisone (61 centers); 10 days on/10 days off (36 centers); 0.9 mg/kg/day deflazacort (32 centers); and 5 mg/kg/day on weekends (10 centers). Similar diversity was identified in MDA clinics and in the ataluren trial.

CONCLUSIONS

Variability in corticosteroid use suggests uncertainty about risks/benefits of corticosteroid regimens for DMD.

The 6-minute walk test and other endpoints in Duchenne muscular dystrophy: longitudinal natural history observations over 48 weeks from a multicenter study

Introduction: Duchenne muscular dystrophy (DMD) subjects ≥5 years with nonsense mutations were followed for 48 weeks in a multicenter, randomized, double-blind, placebo-controlled trial of ataluren. Placebo arm data (N = 57) provided insight into the natural history of the 6-minute walk test (6MWT) and other endpoints. Methods: Evaluations performed every 6 weeks included the 6-minute walk distance (6MWD), timed function tests (TFTs), and quantitative strength using hand-held myometry. Results: Baseline age (≥7 years), 6MWD, and selected TFT performance are strong predictors of decline in ambulation (Δ6MWD) and time to 10% worsening in 6MWD. A baseline 6MWD of <350 meters was associated with greater functional decline, and loss of ambulation was only seen in those with baseline 6MWD <325 meters. Only 1 of 42 (2.3%) subjects able to stand from supine lost ambulation. Conclusion: Findings confirm the clinical meaningfulness of the 6MWD as the most accepted primary clinical endpoint in ambulatory DMD trials.

Novel approaches to corticosteroid treatment in Duchenne muscular dystrophy

Although prednisone has never been formally approved for use in Duchenne muscular dystrophy (DMD) by regulatory agencies, its efficacy has been confirmed in trials dating from the 1980s. There is a strong need for optimization of both specific type of glucocorticoid (eg, prednisone, vs deflazacort or others) and the dosing regimen. Ideally an optimized regimen would maximize efficacy while minimizing side-effect profiles. A new trial, FOR-DMD, aims to address this gap in knowledge. In parallel, there has been progress in the area of "dissociative steroids," drugs that are able to better separate efficacy and side effects, providing a broader therapeutic window.

Can outcomes in Duchenne muscular dystrophy be improved by public reporting of data?

OBJECTIVE

To review current approaches for obtaining patient data in Duchenne muscular dystrophy (DMD) and consider how monitoring and comparing outcome measures across DMD clinics could facilitate standardized and improved patient care.

METHODS

We reviewed annual standardized data from cystic fibrosis (CF) clinics and DMD care guidelines and consensus statements; compared current approaches to obtain DMD patient data and outcome measures; and considered the best method for implementing public reporting of outcomes, to drive improvements in health care delivery.

RESULTS

Current methods to monitor DMD patient information (MD STARnet, DuchenneConnect, and TREAT-NMD) do not yet provide patients with comparative outcome data. The CF patient registry allows for reporting of standard outcomes across clinics and is associated with improved CF outcomes. A similar patient registry is under development for the Muscular Dystrophy Association (MDA) clinic network. Suggested metrics for quality care include molecular diagnosis, ambulatory status and age at loss of ambulation, age requiring ventilator support, and survival.

CONCLUSIONS

CF longevity has increased by almost 33% from 1986 to 2010, in part due to a CF patient registry that has been stratified by individual care centers since 1999, and publically available since 2006. Implementation of outcome reporting for MDA clinics might promote a similar benefit to patients with DMD.

Pharmacological therapies for muscular dystrophies

PURPOSE OF REVIEW

The study reviews recent advances in pharmacological management of muscular dystrophies. Similarities and differences among the pathophysiology of different forms of muscular dystrophy lead to a broad array of approaches to provide new treatments.

RECENT FINDINGS

In this review, we include only those muscular dystrophies for which advances have been published in the past year. This represents the 'advancing edge' of a large body of research over more than 20 years. This runs the gamut of new discoveries in symptomatic management to mutation-specific strategies that attempt to correct the root cause of the disorder.

SUMMARY

The field of pharmacological therapies for the muscular dystrophies continues to steadily advance. It is encouraging that research into new therapies is increasingly exploring pharmacological strategies with the potential to ameliorate disease pathology to a clinically significant degree.

Muscle sparing in muscle RING finger 1 null mice: response to synthetic glucocorticoids

Skeletal muscle atrophy occurs under a variety of conditions and can result from alterations in both protein synthesis and protein degradation. The muscle-specific E3 ubiquitin ligases, MuRF1 and MAFbx, are excellent markers of muscle atrophy and increase under divergent atrophy-inducing conditions such as denervation and glucocorticoid treatment. While deletion of MuRF1 or MAFbx has been reported to spare muscle mass following 14 days of denervation, their role in other atrophy-inducing conditions is unclear. The goal of this study was to determine whether deletion of MuRF1 or MAFbx attenuates muscle atrophy after 2 weeks of treatment with the synthetic glucocorticoid dexamethasone (DEX). The response of the triceps surae (TS) and tibialis anterior (TA) muscles to 14 days of DEX treatment (3 mg kg(-1) day(-1)) was examined in 4 month-old male and female wild type (WT) and MuRF1 or MAFbx knock out (KO) mice. Following 14 days of DEX treatment, muscle wet weight was significantly decreased in the TS and TA of WT mice. Comparison of WT and KO mice following DEX treatment revealed significant sparing of mass in both sexes of the MuRF1 KO mice, but no muscle sparing in MAFbx KO mice. Further analysis of the MuRF1 KO mice showed significant sparing of fibre cross-sectional area and tension output in the gastrocnemius (GA) after DEX treatment. Muscle sparing in the MuRF1 KO mice was related to maintenance of protein synthesis, with no observed increases in protein degradation in either WT or MuRF1 KO mice. These results demonstrate that MuRF1 and MAFbx do not function similarly under all atrophy models, and that the primary role of MuRF1 may extend beyond controlling protein degradation via the ubiquitin proteasome system.

Expression of glucocorticoid receptors in the regenerating human skeletal muscle

Many stress conditions are accompanied by skeletal muscle dysfunction and regeneration, which is essentially a recapitulation of the embryonic development. However, regeneration usually occurs under conditions of hypothalamus-pituitary-adrenal gland axis activation and therefore increased glucocorticoid (GC) levels. Glucocorticoid receptor (GR), the main determinant of cellular responsiveness to GCs, exists in two isoforms (GRalpha and GRbeta) in humans. While the role of GRalpha is well characterized, GRbeta remains an elusive player in GC signalling. To elucidate basic characteristics of GC signalling in the regenerating human skeletal muscle we assessed GRalpha and GRbeta expression pattern in cultured human myoblasts and myotubes and their response to 24-hour dexamethasone (DEX) treatment. There was no difference in GRalpha mRNA and protein expression or DEX-mediated GRalpha down-regulation in myoblasts and myotubes. GRbeta mRNA level was very low in myoblasts and remained unaffected by differentiation and/or DEX. GRbeta protein could not be detected. These results indicate that response to GCs is established very early during human skeletal muscle regeneration and that it remains practically unchanged before innervation is established. Very low GRbeta mRNA expression and inability to detect GRbeta protein suggests that GRbeta is not a major player in the early stages of human skeletal muscle regeneration.

Novel compounds for the treatment of Duchenne muscular dystrophy: emerging therapeutic agents

The identification of dystrophin and the causative role of mutations in this gene in Duchenne and Becker muscular dystrophies (D/BMD) was expected to lead to timely development of effective therapies. Despite over 20 years of research, corticosteroids remain the only available pharmacological treatment for DMD, although significant benefits and extended life have resulted from advances in the clinical care and management of DMD individuals. Effective treatment of DMD will require dystrophin restitution in skeletal, cardiac, and smooth muscles and nonmuscle tissues; however, modulation of muscle loss and regeneration has the potential to play an important role in altering the natural history of DMD, particularly in combination with other treatments. Emerging biological, molecular, and small molecule therapeutics are showing promise in ameliorating this devastating disease, and it is anticipated that regulatory environments will need to display some flexibility in order to accommodate the new treatment paradigms.