Steroids in Duchenne muscular dystrophy--deflazacort trial

Evolving Therapeutic Options for the Treatment of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is the most common childhood form of muscular dystrophy. It is caused by mutations in the DMD gene, leading to reduced or absent expression of the dystrophin protein. Clinically, this results in loss of ambulation, cardiomyopathy, respiratory failure, and eventually death. In the past decades, the use of corticosteroids has slowed down the disease progression. More recently, the development of genetically mediated therapies has emerged as the most promising treatment for DMD. These strategies include exon skipping with antisense oligonucleotides, gene replacement therapy with adeno-associated virus, and gene editing with CRISPR (clustered regularly interspaced short palindromic repeats) technology. In this review, we highlight the most up-to-date therapeutic progresses in the field, with emphasis on past and recent experiences, as well as the latest clinical results of DMD micro-dystrophin gene therapy. Additionally, we discuss the lessons learned along the way and the challenges encountered, all of which have helped advance the field, with the potential to finally alleviate such a devastating disease.

Prognostic indicators of disease progression in Duchenne muscular dystrophy: A literature review and evidence synthesis

BACKGROUND

Duchenne muscular dystrophy (DMD) is a rare, severely debilitating, and fatal neuromuscular disease characterized by progressive muscle degeneration. Like in many orphan diseases, randomized controlled trials are uncommon in DMD, resulting in the need to indirectly compare treatment effects, for example by pooling individual patient-level data from multiple sources. However, to derive reliable estimates, it is necessary to ensure that the samples considered are comparable with respect to factors significantly affecting the clinical progression of the disease. To help inform such analyses, the objective of this study was to review and synthesise published evidence of prognostic indicators of disease progression in DMD. We searched MEDLINE (via Ovid), Embase (via Ovid) and the Cochrane Library (via Wiley) for records published from inception up until April 23 2021, reporting evidence of prognostic indicators of disease progression in DMD. Risk of bias was established with the grading system of the Centre for Evidence-Based Medicine (CEBM).

RESULTS

Our search included 135 studies involving 25,610 patients from 18 countries across six continents (Africa, Asia, Australia, Europe, North America and South America). We identified a total of 23 prognostic indicators of disease progression in DMD, namely age at diagnosis, age at onset of symptoms, ataluren treatment, ATL1102, BMI, cardiac medication, DMD genetic modifiers, DMD mutation type, drisapersen, edasalonexent, eteplirsen, glucocorticoid exposure, height, idebenone, lower limb surgery, orthoses, oxandrolone, spinal surgery, TAS-205, vamorolone, vitlolarsen, ventilation support, and weight. Of these, cardiac medication, DMD genetic modifiers, DMD mutation type, and glucocorticoid exposure were designated core prognostic indicators, each supported by a high level of evidence and significantly affecting a wide range of clinical outcomes.

CONCLUSION

This study provides a current summary of prognostic indicators of disease progression in DMD, which will help inform the design of comparative analyses and future data collection initiatives in this patient population.

Current and Future Therapeutic Strategies for Limb Girdle Muscular Dystrophy Type R1: Clinical and Experimental Approaches

Limb girdle muscular dystrophy type R1 disease is a progressive disease that is caused by mutations in the CAPN3 gene and involves the extremity muscles of the hip and shoulder girdle. The CAPN3 protein has proteolytic and non-proteolytic properties. The functions of the CAPN3 protein that have been determined so far can be listed as remodeling and combining contractile proteins in the sarcomere with the substrates with which it interacts, controlling the Ca²⁺ flow in and out through the sarcoplasmic reticulum, and regulation of membrane repair and muscle regeneration. Even though there are several gene therapies, cellular therapies, and drug therapies, such as glucocorticoid treatment, AAV- mediated therapy, CRISPR-Cas9, induced pluripotent stem cells, MYO-029, and AMBMP, which are either in preclinical or clinical phases, or have been completed, there is no final cure. Inhibitors and small molecules (tauroursodeoxycholic acid, salubrinal, rapamycin, CDN1163, dwarf open reading frame) targeting ER stress factors that are thought to be effective in muscle loss can be considered potential therapy strategies. At present, little can be done to treat the progressive muscle wasting, loss of function, and premature mortality of patients with LGMDR1, and there is a pressing need for more research to develop potential therapies.

Standard of care versus new-wave corticosteroids in the treatment of Duchenne muscular dystrophy: Can we do better?

BACKGROUND

Pharmacological corticosteroid therapy is the standard of care in Duchenne Muscular Dystrophy (DMD) that aims to control symptoms and slow disease progression through potent anti-inflammatory action. However, a major concern is the significant adverse effects associated with long term-use. MAIN: This review discusses the pros and cons of standard of care treatment for DMD and compares it to novel data generated with the new-wave dissociative corticosteroid, vamorolone. The current status of experimental anti-inflammatory pharmaceuticals is also reviewed, with insights regarding alternative drugs that could provide therapeutic advantage.

CONCLUSIONS

Although novel dissociative steroids may be superior substitutes to corticosteroids, other potential therapeutics should be explored. Repurposing or developing novel pharmacological therapies capable of addressing the many pathogenic features of DMD in addition to anti-inflammation could elicit greater therapeutic advantages.

A Review of Deflazacort for Patients With Duchenne Muscular Dystrophy

Objective: The objective of this article is to review the pharmacology, pharmacokinetics, efficacy, safety, dosage and administration, and formulary considerations of deflazacort. Data Sources: A search of MEDLINE and EMBASE (1946 to December 31, 2019) was conducted using the terms deflazacort and Duchenne muscular dystrophy (DMD). Results were limited to clinical trials, humans, and English. Additional sources and data were obtained from the references of included articles and prescribing information. Study Selection and Data Extraction: All articles published after July 2014 related to pharmacology, pharmacokinetics, efficacy, or safety of the therapy in human subjects were included. Data Synthesis: Deflazacort 0.9 mg/kg/d is a once-daily oral corticosteroid and is the first drug of its class to be Food and Drug Administration (FDA) approved for DMD. Studies with deflazacort show improved functional outcomes, delayed onset of cardiomyopathy, reduction in scoliosis surgery, and improved survival, but these improvements are supported by relatively weak evidence. Relevance to Patient Care and Clinical Practice: This review presents data from studies published after the most recent DMD 2016 treatment guidelines and offers prescribing considerations, including pharmacology, pharmacokinetics, adverse effects, formulary considerations, and areas of uncertainty. Conclusions: Deflazacort presents an additional, FDA-approved corticosteroid option for patients that offers improved quality of life for DMD patients. However, there is weak evidence to support these benefits; a full risk-benefit analysis considering adverse events, efficacy, cost, and previous trials of steroid therapy is necessary when selecting therapy. Further research will help clarify deflazacort's optimal dose, duration of treatment, and impact on quality of life.

Vamorolone targets dual nuclear receptors to treat inflammation and dystrophic cardiomyopathy

Cardiomyopathy is a leading cause of death for Duchenne muscular dystrophy. Here, we find that the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) can share common ligands but play distinct roles in dystrophic heart and skeletal muscle pathophysiology. Comparisons of their ligand structures indicate that the Δ9,11 modification of the first-in-class drug vamorolone enables it to avoid interaction with a conserved receptor residue (N770/N564), which would otherwise activate transcription factor properties of both receptors. Reporter assays show that vamorolone and eplerenone are MR antagonists, whereas prednisolone is an MR agonist. Macrophages, cardiomyocytes, and CRISPR knockout myoblasts show vamorolone is also a dissociative GR ligand that inhibits inflammation with improved safety over prednisone and GR-specific deflazacort. In mice, hyperaldosteronism activates MR-driven hypertension and kidney phenotypes. We find that genetic dystrophin loss provides a second hit for MR-mediated cardiomyopathy in Duchenne muscular dystrophy model mice, as aldosterone worsens fibrosis, mass and dysfunction phenotypes. Vamorolone successfully prevents MR-activated phenotypes, whereas prednisolone activates negative MR and GR effects. In conclusion, vamorolone targets dual nuclear receptors to treat inflammation and cardiomyopathy with improved safety.

Cataract development associated with long-term glucocorticoid therapy in Duchenne muscular dystrophy patients

PURPOSE

To evaluate the development of cataracts or elevated intraocular pressure (IOP) in patients with Duchenne muscular dystrophy (DMD) on long-term glucocorticoid (GC) treatment.

METHODS

The medical records of DMD patients evaluated from 2010 to 2015 at a single center were reviewed retrospectively. The main outcome measures were prevalence of cataracts and elevated IOP, age of first detection of cataract, time from initial steroid use to first detection of cataract, and relative risk of cataract development for deflazacort versus prednisone treatment.

RESULTS

Of 596 DMD patients, 514 underwent GC therapy; all but one was male. The racial distribution was 82.1% white, 1.0% African American, 5.0% Hispanic, 2.9% Asian, and 8.0% more than one race or "other." The prevalence of cataracts was 22.4% in patients on GC therapy. The mean age at which cataract formation was first documented was 12.9 ± 4.1 years (IQR, 9.6-14.6). The mean time from initial steroid use to the first detection of cataract was 6.5 ± 3.6 years (IQR, 4.0-8.6). The odds of cataract development were 2.4-fold higher for patients on deflazacort compared with prednisone (95% CI, 1.3-4.5; P = 0.004). Only 7 patients (1.4%) underwent cataract surgery, at a mean age of 16.9 years (range, 10.7-24.6 years); all were on deflazacort. Among patients with available intraocular pressure measurements, elevated IOP occurred in only 1 patient (1.1%), who was on deflazacort.

CONCLUSIONS

In patients undergoing GC therapy for DMD, the rate of cataract formation was slow and well tolerated, with a higher risk among deflazacort patients. The percentage of patients requiring cataract extraction or with elevated IOP was very small. These findings suggest that a schedule of annual eye examinations is appropriate.

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.

Practice guideline update summary: Corticosteroid treatment of Duchenne muscular dystrophy: Report of the Guideline Development Subcommittee of the American Academy of Neurology

OBJECTIVE

To update the 2005 American Academy of Neurology (AAN) guideline on corticosteroid treatment of Duchenne muscular dystrophy (DMD).

METHODS

We systematically reviewed the literature from January 2004 to July 2014 using the AAN classification scheme for therapeutic articles and predicated recommendations on the strength of the evidence.

RESULTS

Thirty-four studies met inclusion criteria.

RECOMMENDATIONS

In children with DMD, prednisone should be offered for improving strength (Level B) and pulmonary function (Level B). Prednisone may be offered for improving timed motor function (Level C), reducing the need for scoliosis surgery (Level C), and delaying cardiomyopathy onset by 18 years of age (Level C). Deflazacort may be offered for improving strength and timed motor function and delaying age at loss of ambulation by 1.4-2.5 years (Level C). Deflazacort may be offered for improving pulmonary function, reducing the need for scoliosis surgery, delaying cardiomyopathy onset, and increasing survival at 5-15 years of follow-up (Level C for each). Deflazacort and prednisone may be equivalent in improving motor function (Level C). Prednisone may be associated with greater weight gain in the first years of treatment than deflazacort (Level C). Deflazacort may be associated with a greater risk of cataracts than prednisone (Level C). The preferred dosing regimen of prednisone is 0.75 mg/kg/d (Level B). Over 12 months, prednisone 10 mg/kg/weekend is equally effective (Level B), with no long-term data available. Prednisone 0.75 mg/kg/d is associated with significant risk of weight gain, hirsutism, and cushingoid appearance (Level B).

Corticosteroids for the treatment of Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy of childhood. Untreated, this incurable disease, which has an X-linked recessive inheritance, is characterised by muscle wasting and loss of walking ability, leading to complete wheelchair dependence by 13 years of age. Prolongation of walking is a major aim of treatment. Evidence from randomised controlled trials (RCTs) indicates that corticosteroids significantly improve muscle strength and function in boys with DMD in the short term (six months), and strength at two years (two-year data on function are very limited). Corticosteroids, now part of care recommendations for DMD, are largely in routine use, although questions remain over their ability to prolong walking, when to start treatment, longer-term balance of benefits versus harms, and choice of corticosteroid or regimen.We have extended the scope of this updated review to include comparisons of different corticosteroids and dosing regimens.

OBJECTIVES

To assess the effects of corticosteroids on prolongation of walking ability, muscle strength, functional ability, and quality of life in DMD; to address the question of whether benefit is maintained over the longer term (more than two years); to assess adverse events; and to compare efficacy and adverse effects of different corticosteroid preparations and regimens.

SEARCH METHODS

On 16 February 2016 we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, EMBASE, CINAHL Plus, and LILACS. We wrote to authors of published studies and other experts. We checked references in identified trials, handsearched journal abstracts, and searched trials registries.

SELECTION CRITERIA

We considered RCTs or quasi-RCTs of corticosteroids (e.g. prednisone, prednisolone, and deflazacort) given for a minimum of three months to patients with a definite DMD diagnosis. We considered comparisons of different corticosteroids, regimens, and corticosteroids versus placebo.

DATA COLLECTION AND ANALYSIS

The review authors followed standard Cochrane methodology.

MAIN RESULTS

We identified 12 studies (667 participants) and two new ongoing studies for inclusion. Six RCTs were newly included at this update and important non-randomised cohort studies have also been published. Some important studies remain unpublished and not all published studies provide complete outcome data.

PRIMARY OUTCOME MEASURE

one two-year deflazacort RCT (n = 28) used prolongation of ambulation as an outcome measure but data were not adequate for drawing conclusions.

SECONDARY OUTCOME MEASURES

meta-analyses showed that corticosteroids (0.75 mg/kg/day prednisone or prednisolone) improved muscle strength and function versus placebo over six months (moderate quality evidence from up to four RCTs). Evidence from single trials showed 0.75 mg/kg/day superior to 0.3 mg/kg/day on most strength and function measures, with little evidence of further benefit at 1.5 mg/kg/day. Improvements were seen in time taken to rise from the floor (Gowers' time), timed walk, four-stair climbing time, ability to lift weights, leg function grade, and forced vital capacity. One new RCT (n = 66), reported better strength, function and quality of life with daily 0.75 mg/kg/day prednisone at 12 months. One RCT (n = 28) showed that deflazacort stabilised muscle strength versus placebo at two years, but timed function test results were too imprecise for conclusions to be drawn.One double-blind RCT (n = 64), largely at low risk of bias, compared daily prednisone (0.75 mg/kg/day) with weekend-only prednisone (5 mg/kg/weekend day), finding no overall difference in muscle strength and function over 12 months (moderate to low quality evidence). Two small RCTs (n = 52) compared daily prednisone 0.75 mg/kg/day with daily deflazacort 0.9 mg/kg/day, but study methods limited our ability to compare muscle strength or function.

ADVERSE EFFECTS

excessive weight gain, behavioural abnormalities, cushingoid appearance, and excessive hair growth were all previously shown to be more common with corticosteroids than placebo; we assessed the quality of evidence (for behavioural changes and weight gain) as moderate. Hair growth and cushingoid features were more frequent at 0.75 mg/kg/day than 0.3 mg/kg/day prednisone. Comparing daily versus weekend-only prednisone, both groups gained weight with no clear difference in body mass index (BMI) or in behavioural changes (low quality evidence for both outcomes, one study); the weekend-only group had a greater linear increase in height. Very low quality evidence suggested less weight gain with deflazacort than with prednisone at 12 months, and no difference in behavioural abnormalities. Data are insufficient to assess the risk of fractures or cataracts for any comparison.Non-randomised studies support RCT evidence in showing improved functional benefit from corticosteroids. These studies suggest sustained benefit for up to 66 months. Adverse effects were common, although generally manageable. According to a large comparative longitudinal study of daily or intermittent (10 days on, 10 days off) corticosteroid for a mean period of four years, a daily regimen prolongs ambulation and improves functional scores over the age of seven, but with a greater frequency of side effects than an intermittent regimen.

AUTHORS' CONCLUSIONS

Moderate quality evidence from RCTs indicates that corticosteroid therapy in DMD improves muscle strength and function in the short term (twelve months), and strength up to two years. On the basis of the evidence available for strength and function outcomes, our confidence in the effect estimate for the efficacy of a 0.75 mg/kg/day dose of prednisone or above is fairly secure. There is no evidence other than from non-randomised trials to establish the effect of corticosteroids on prolongation of walking. In the short term, adverse effects were significantly more common with corticosteroids than placebo, but not clinically severe. A weekend-only prednisone regimen is as effective as daily prednisone in the short term (12 months), according to low to moderate quality evidence from a single trial, with no clear difference in BMI (low quality evidence). Very low quality evidence indicates that deflazacort causes less weight gain than prednisone after a year's treatment. We cannot evaluate long-term benefits and hazards of corticosteroid treatment or intermittent regimens from published RCTs. Non-randomised studies support the conclusions of functional benefits, but also identify clinically significant adverse effects of long-term treatment, and a possible divergence of efficacy in daily and weekend-only regimens in the longer term. These benefits and adverse effects have implications for future research and clinical practice.

Duchenne Muscular Dystrophy: From Diagnosis to Therapy

Duchenne muscular dystrophy (DMD) is an X-linked inherited neuromuscular disorder due to mutations in the dystrophin gene. It is characterized by progressive muscle weakness and wasting due to the absence of dystrophin protein that causes degeneration of skeletal and cardiac muscle. The molecular diagnostic of DMD involves a deletions/duplications analysis performed by quantitative technique such as microarray-based comparative genomic hybridization (array-CGH), Multiple Ligation Probe Assay MLPA. Since traditional methods for detection of point mutations and other sequence variants require high cost and are time consuming, especially for a large gene like dystrophin, the use of next-generation sequencing (NGS) has become a useful tool available for clinical diagnosis. The dystrophin gene is large and finely regulated in terms of tissue expression, and RNA processing and editing includes a variety of fine tuned processes. At present, there are no effective treatments and the steroids are the only fully approved drugs used in DMD therapy able to slow disease progression. In the last years, an increasing variety of strategies have been studied as a possible therapeutic approach aimed to restore dystrophin production and to preserve muscle mass, ameliorating the DMD phenotype. RNA is the most studied target for the development of clinical strategies and Antisense Oligonucleotides (AONs) are the most used molecules for RNA modulation. The identification of delivery system to enhance the efficacy and to reduce the toxicity of AON is the main purpose in this area and nanomaterials are a very promising model as DNA/RNA molecules vectors. Dystrophinopathies therefore represent a pivotal field of investigation, which has opened novel avenues in molecular biology, medical genetics and novel therapeutic options.

Corticosteroid Treatments in Males With Duchenne Muscular Dystrophy: Treatment Duration and Time to Loss of Ambulation

This population-based study examines the association between corticosteroid treatment and time to loss of ambulation, stratifying by treatment duration (short: 0.25-3 years, long: >3 years), among 477 Duchenne muscular dystrophy cases identified by the Muscular Dystrophy Surveillance Tracking and Research Network (MDSTARnet). Those cases who received short-term corticosteroid treatment had a time to loss of ambulation that was 0.8 years shorter (t test) and an annual risk of losing ambulation 77% higher than the untreated (Cox regression). Conversely, cases who received long-term corticosteroid treatment had a time to loss of ambulation that was 2 years longer and an annual risk of losing ambulation 82% lower than the untreated, up to age 11 years; after which the risks were not statistically different. The relationship of corticosteroids and time to loss of ambulation is more complex than depicted by previous studies limited to treatment responders or subjects who lost ambulation during study follow-up.

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.

Current treatment and management of dystrophinopathies

OPINION STATEMENT

• Duchenne muscular dystrophy (DMD), the most common and severe type of dystrophinopathy, is a progressive disease affecting primordially skeletal and cardiac muscle. A coordinated multidisciplinary approach is required to address its multisystemic manifestations and secondary problems.• Treatment with glucocorticosteroids (GCS) is accepted as standard of care in ambulant DMD. Daily and intermittent administrations are both in common use with different efficacy and different side effect profile.• There are no established guidelines for age/stage at initiation and treatment duration of GCS. Common practice is initiation of GCS before the child is starting to decline (between age 3 and 6 years) and continuation of monitored treatment after loss of ambulation, aiming at delaying cardiac and respiratory manifestations and preventing the development of scoliosis.• Prevention, monitoring, and treatment of the side effects of long-term chronic GCS use, such as excessive weight gain, hypertension, osteoporosis, impairment of glucose metabolism, delayed puberty, and cataract, should be integrated in the standards of care.• Noninvasive ventilatory support associated with cough assisting techniques has significantly improved the longevity in DMD.• Pharmacologic treatment for cardiac manifestations includes the standard treatments of dilated cardiomyopathy and arrhythmia such as the use of angiotensin converting enzyme (ACE) inhibitors, beta-blockers and diuretics. The lack of robust controlled data hampers clear recommendations about preventive treatment with ACE inhibitors.• DMD is associated with low bone mineral content, which is aggravated by the use of corticosteroids. The use of biphosphonates can be considered in the treatment of painful vertebral fractures. The use of biphosphonates as a preventive treatment should be investigated in randomized controlled studies.• DMD has evolved from a pediatric disease to an adult condition. This underscores the need to prepare adult neurologists for the optimal surveillance and management of patients with a severe chronic disease that have outgrown the pediatric care and that may develop new disease manifestations with improved longevity.

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.

Idiopathic intracranial hypertension in a child with Duchenne muscular dystrophy

Duchenne muscular dystrophy is an X-linked, recessively inherited disorder characterized by progressive weakness attributable to the absence of dystrophin expression in muscle. In multiple studies, the chronic administration of corticosteroids slowed the loss of ambulation that develops in mid to late childhood. Corticosteroids, however, frequently produce unacceptable side effects, including Cushingoid appearance and weight gain. Deflazacort, an oxazoline analogue of prednisolone, produces equivalent benefits on muscle with fewer reported Cushingoid side effects. We present a 9-year-old boy with Duchenne muscular dystrophy who developed morbid obesity and subsequent idiopathic intracranial hypertension after 2 years of receiving deflazacort. Although deflazacort is typically thought to produce less obesity than prednisone, severe Cushingoid side effects may occur in some individuals. To our knowledge, this description is the first of idiopathic intracranial hypertension complicating chronic corticosteroid treatment of Duchenne muscular dystrophy.

Duchenne muscular dystrophy: Canadian paediatric neuromuscular physicians survey

BACKGROUND

Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in childhood.

METHOD

To assess the current care of paediatric DMD patients in Canada, a questionnaire was mailed to 17 physicians who were members of the Canadian paediatric neuromuscular group. Areas of enquiry included; 1) multidisciplinary team composition; 2) means of DMD diagnosis; 3) corticosteroid use; surveillance and management for: 4) orthopaedic, 5) respiratory and 6) cardiac complications and 7) health maintenance (nutrition & immunizations).

RESULTS

Completed surveys were returned by 14/17 (82%) of physicians. Twelve respondents followed DMD patients. All centres had multidisciplinary teams, including respirology (11/12), child neurology or physiatry (11), physiotherapy (9), occupational therapy (9) and orthopaedic surgery (7). Deflazacort 0.9 mg/kg/d was used at all centres, which was continued after loss of independent ambulation (11), along with routine calcium and vitamin D supplementation (10). Night splints were prescribed at all centres. Routine surveillance studies included pulmonary function testing (11), sleep studies (10), EKG/echocardiogram (10), bone density (DEXA) scans (10), spine radiography (9), and dietician referral (4).

CONCLUSION

Paediatric DMD patients are receiving relatively consistent care in multidisciplinary clinics across Canada, in accordance with recommended guidelines for DMD.

Diagnosis and management of Duchenne muscular dystrophy, part 1: diagnosis, and pharmacological and psychosocial management

Duchenne muscular dystrophy (DMD) is a severe, progressive disease that affects 1 in 3600-6000 live male births. Although guidelines are available for various aspects of DMD, comprehensive clinical care recommendations do not exist. The US Centers for Disease Control and Prevention selected 84 clinicians to develop care recommendations using the RAND Corporation-University of California Los Angeles Appropriateness Method. The DMD Care Considerations Working Group evaluated assessments and interventions used in the management of diagnostics, gastroenterology and nutrition, rehabilitation, and neuromuscular, psychosocial, cardiovascular, respiratory, orthopaedic, and surgical aspects of DMD. These recommendations, presented in two parts, are intended for the wide range of practitioners who care for individuals with DMD. They provide a framework for recognising the multisystem primary manifestations and secondary complications of DMD and for providing coordinated multidisciplinary care. In part 1 of this Review, we describe the methods used to generate the recommendations, and the overall perspective on care, pharmacological treatment, and psychosocial management.

Effect of deflazacort on cardiac and sternocleidomastoid muscles in Duchenne muscular dystrophy: a magnetic resonance imaging study

OBJECTIVE

To evaluate the involvement of cardiac and sternocleidomastoid muscles by magnetic resonance imaging (MRI) measurement of T2 relaxation time and the left ventricular systolic function in patients with Duchenne muscular dystrophy (DMD) on treatment with deflazacort and compare them with DMD patients without treatment.

SUBJECTS

Seventeen patients with DMD (aged 17-22 years) on treatment with deflazacort for at least 7 years and 17 boys with DMD of younger age (12-15 years) without steroid treatment. All patients were free of cardiac or respiratory symptoms and had normal ECG and Holter monitor examination.

METHODS

T2 relaxation time of the myocardium (H), left (SCM-L) and right sternocleidomastoid (SCM-R) muscles and left ventricular systolic function were evaluated by magnetic resonance imaging (MRI) in two groups of DMD patients. Myocardial and sternocleidomastoid muscles T2 relaxation time was calculated using 16 TEs (10-85 msec) and TR at least 2000 ms and T2 maps were created.

RESULTS

DMD on deflazacort had higher T2 relaxation time values of the heart and of both sternocleidomastoid muscles (T2H median (range): 47 (41-48) vs. 33 (31-37)ms, p<0.001, T2 SCM-L median (range): 35 (30-37) vs. 23 (20-26)ms, p<0.001, T2 SCM-R median (range): 35 (32-37) vs. 23 (20-27)ms, p<0.001) and left ventricular systolic function (LVEDV median (range): 95 (75-120) vs. 90 (80-105)ml, p=0.03, LVESV median (range): 45 (38-55) vs. 47 (41-51)ml, p=0.81(NS), LVEF median (range): 53% (51-57) vs. 48% (42-51), p<0.001) compared to DMD without treatment.

CONCLUSIONS

DMD patients on deflazacort are characterized by better preservation of the T2 relaxation time of myocardium and sternocleidomastoid muscles and better LV systolic function. The duration of this beneficial effect needs to be studied prospectively.

Deflazacort use in Duchenne muscular dystrophy: an 8-year follow-up

Data reported here were collected over an 8-year period for 79 Duchenne muscular dystrophy patients, 37 of whom were treated with deflazacort. Mean length of treatment was 66 months. Treated boys stopped walking at 11.5 +/- 1.9 years, compared with 9.6 +/- 1.4 years for untreated boys. Cardiac function was better preserved with the use of deflazacort, as shown by a normal shortening fraction in treated (30.8 +/- 4.5%) vs untreated boys (26.6 +/- 5.7%, P < 0.05), a higher ejection fraction (52.9 +/- 6.3% treated vs 46 +/- 10% untreated), and lower frequency of dilated cardiomyopathy (32% treated vs 58% untreated). Scoliosis was much less severe in treated (14 +/- 2.5 degrees ) than in untreated boys (46 +/- 24 degrees ). No spinal surgery was necessary in treated boys. Limb fractures were similarly frequent in treated (24%) and untreated (26%) boys, but vertebral fractures occurred only in the treated group (7/37) (compared with zero for the untreated group). In both groups, body weight excess tripled between the ages of 8 and 12 years. All untreated patients grew normally (>4 cm/year), as opposed to only 15% of treated boys. Deflazacort improves cardiac function, prolongs walking, and seems to eliminate the need for spinal surgery, although vertebral fractures and stunted growth occur. The overall impact on quality of life appears positive.

Glucocorticoid corticosteroids for Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy (DMD) is the most common muscular dystrophy of childhood. This incurable disease is characterised by muscle wasting and loss of walking ability leading to complete wheelchair dependence by 13 years of age. Prolongation of walking is one of the major aims of treatment.

OBJECTIVES

The aim of this review was to assess whether glucocorticoid corticosteroids stabilize or improve muscle strength and walking in boys with DMD.

SEARCH STRATEGY

This is an update of the Cochrane systematic review first published in 2004 (Manzur 2004). We searched the Cochrane Neuromuscular Disease Group Trials Register (August 2006) using the term 'Duchenne muscular dystrophy'. We also searched MEDLINE (January 1966 to July 2007), EMBASE (January 1980 to August 2006), CINAHL and LILACS (January 1982 to August 2006). We wrote to authors of published studies and other experts in this disease to help identify other trials, checked the references in the identified trials and hand searched the abstracts of relevant journals.

SELECTION CRITERIA

Types of studies: randomised or quasi-randomised trials.

TYPES OF PARTICIPANTS

all patients with a definite diagnosis of Duchenne muscular dystrophy. Types of interventions: glucocorticoids such as prednisone, prednisolone, deflazacort or others, with a minimum treatment period of three months.

PRIMARY OUTCOME MEASURE

prolongation of walking (independent walking without long leg calipers).

SECONDARY OUTCOME MEASURES

strength outcome measures, manual muscle strength testing using Medical Research Council strength scores, functional outcome measures and adverse events.

DATA COLLECTION AND ANALYSIS

We identified six randomised controlled trials that met the inclusion criteria for our review, and one of these (Beenakker 2005) is a new addition to this update, as it was published subsequent to our first review (Manzur 2004). Two review authors independently selected the trials for the review and assessed methodological quality. Data extraction and inputting were double-checked.

PRIMARY OUTCOME MEASURE

data from one small study used prolongation of walking as an outcome measure and did not show significant benefit.

SECONDARY OUTCOME MEASURES

The meta-analysis of the results from four randomised controlled trials with altogether 249 participants showed that glucocorticoid corticosteroids improved muscle strength and function over six months. Improvements were seen in time taken to rise from the floor (Gowers' time), nine metres walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity. One randomised controlled trial with altogether 28 participants showed that glucocorticoid corticosteroids stabilize muscle strength and function for up to two years. The most effective prednisolone regime appears to be 0.75 mg/kg/day, given in a daily dose regime. Not enough data were available to compare efficacy of prednisone with deflazacort. Adverse effects: Excessive weight gain, behavioural abnormalities, cushingoid appearance and excessive hair growth were all more common with glucocorticoid corticosteroids than placebo. Long-term adverse effects of glucocorticoid therapy could not be evaluated because of the short-term duration of the randomised studies.Non-randomised studies: A number of non-randomised studies with important efficacy and adverse effects data are tabulated and discussed.

AUTHORS' CONCLUSIONS

There is evidence from randomised controlled studies that glucocorticoid corticosteroid therapy in Duchenne muscular dystrophy improves muscle strength and function in the short-term (six months to two years). The most effective prednisolone regime appears to be 0.75 mg/kg/day, given daily. In the short term, adverse effects were significantly more common but not clinically severe. Long-term benefits and hazards of glucocorticoid treatment cannot be evaluated from the currently published randomised studies. Non-randomised studies support the conclusions of functional benefits but also identify clinically significant adverse effects of long-term treatment. These benefits and adverse effects have implications for future research studies and clinical practice.

The effects of glucocorticoid therapy on the inflammatory and dendritic cells in muscular dystrophies

Various clinical trials have documented the therapeutic benefit of glucocorticoids (GCs) in enhancing muscle strength and slowing disease progression of Duchenne and Becker muscular dystrophies (DMD/BMD). We hypothesized that GCs may have relevance to the differential anti-inflammatory effect on mononuclear inflammatory cells (MICs) and Dendritic cells (DCs) infiltrating the dystrophic muscles. In this prospective study, two muscle biopsies were obtained (before and after 6-month prednisone therapy) from 30 patients with dystrophies (DMD = 18; BMD = 6; and limb girdle muscular dystrophies (LGMD) = 6). MICs and DCs infiltrating the muscles were examined using mouse monoclonal antibodies and immunoperoxidase staining methods. Muscle strength was evaluated monthly by manual testing, motor ability and timed tests. Prednisone therapy was associated with: (i) functional improvement of overall motor disability, in upper limbs of DMD (P < 0.001) and BMD (P < 0.01) and lower limbs of DMD (P < 0.001) and BMD (P < 0.05); (ii) histological improvement such as fibre size variation (DMD, P < 0.01; BMD, P < 0.05), internalization of nuclei (DMD, P < 0.05), degeneration and necrosis (DMD and BMD, P < 0.01), regeneration (DMD, P < 0.001; BMD, P < 0.01) and endomysial connective tissue proliferation (DMD, P < 0.01; BMD, P < 0.05) and (iii) reduction of total MICs (P < 0.01) and DCs (P < 0.01). There was a positive correlation between the degree of improvement in overall motor disability and reduction of DCs numbers (In upper limbs; r = 0.638, P < 0.01 for DMD and r = 0.725, P < 0.01 for BMD, in Lower limbs; r = 0.547, P < 0.05 for DMD and r = 0.576, P < 0.05 for BMD). Such improvements and changes of MICs/DCs were absent in LGMD. In DMD/BMD, prednisone therapeutic effect was associated with reduced MICs and DCs numbers. Whether this therapeutic effect reflects targeting of the deleterious immune response produced by these cells mandates further investigations.

The role of corticosteroids in muscular dystrophy: A critical appraisal

Over the years various steroid trials have been conducted in Duchenne muscular dystrophy (DMD). In children who are still able to walk as well as in those who are wheelchair-bound, corticosteroids have been found to stabilize muscle strength for a period of time. Controlled clinical observations have shown that some boys remain ambulatory for years longer than reported in natural history data. The two main steroids used are prednisone/prednisolone and deflazacort. They are probably equally effective in stabilizing muscle strength but may have different side-effect profiles; for instance, deflazacort causes less weight gain. The exact mechanism by which steroids slow the dystrophic process is under investigation. DMD children treated long term also seem to develop other complications of the condition less frequently. For instance, they develop respiratory insufficiency later and have fewer cardiac symptoms. The therapeutic value of corticosteroids is limited, but these drugs represent the best treatment option currently available.

Therapeutics in duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a fatal disorder affecting approximately 1 in 3,500 live born males, characterized by progressive muscle weakness. Several different strategies are being investigated in developing a cure for this disorder. Until a cure is found, therapeutic and supportive care is essential in preventing complications and improving the afflicted child's quality of life. Currently, corticosteroids are the only class of drug that has been extensively studied in this condition, with controversy existing over the use of these drugs, especially in light of the multiple side effects that may occur. The use of nutritional supplements has expanded in recent years as researchers improve our abilities to use gene and stem cell therapies, which will hopefully lead to a cure soon. This article discusses the importance of therapeutic interventions in children with DMD, the current debate over the use of corticosteroids to treat this disease, the growing use of natural supplements as a new means of treating these boys and provides an update on the current state of gene and stem cell therapies.

Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy

Duchenne muscular dystrophy is the most common and severe form of the childhood muscular dystrophies. The disease is typically diagnosed between 3 and 7 years of age and follows a predictable clinical course marked by progressive skeletal muscle weakness with loss of ambulation by 12 years of age. Death occurs in early adulthood secondary to respiratory or cardiac failure. Becker muscular dystrophy is less common and has a milder clinical course but also results in respiratory and cardiac failure. The natural history of the cardiomyopathy in these diseases has not been well established. As a result, patients traditionally present for cardiac evaluation only after clinical symptoms become evident. The purpose of this policy statement is to provide recommendations for optimal cardiovascular evaluation to health care specialists caring for individuals in whom the diagnosis of Duchenne or Becker muscular dystrophy has been confirmed.

Steroid therapy and cardiac function in Duchenne muscular dystrophy

Duchenne muscular dystrophy leads to progressive deterioration in skeletal and cardiac muscle function. Steroids prolong ambulation and improve respiratory muscle strength. The authors hypothesized that steroid treatment would stabilize cardiac muscle function. Echocardiograms performed from 1997 to 2004 for 111 subjects 21 years of age or younger with Duchenne muscular dystrophy were restrospectively reviewed. The medical record was reviewed for steroid treatment. Untreated and steroids-treated subjects did not differ in age, height, weight, body mass index, systolic and diastolic blood pressure, or left ventricular mass. The shortening fraction was lower in the untreated group. Of those treated, 29 received prednisone and 19 received deflazacort. There was no difference in the shortening fraction between the two treated subgroups. Treated subjects not receiving steroids still had a normal shortening fraction, which was no different from the shortening fraction of those still receiving treatment. As compared with the treated subjects, the untreated subjects 10 years of age or younger were 4.4 times more likely to have a shortening fraction less than< 28% (p = 0.03), and the untreated subjects older than 10 years were 15.2 times more likely to have a shortening fraction less than< 28% (p < 0.01). This retrospective study suggests that the progressive decline in cardiac function of patients with Duchenne muscular dystrophy can be altered by steroid treatment. The effect appears to be sustained beyond the duration of treatment and independent of steroid type.

Molecular, cellular, and pharmacological therapies for Duchenne/Becker muscular dystrophies

Although the molecular defect causing Duchenne/Becker muscular dystrophy (DMD/BMD) was identified nearly 20 years ago, the development of effective therapeutic strategies has nonetheless remained a daunting challenge. Over the years, a variety of different approaches have been explored in an effort to compensate for the lack of the DMD gene product called dystrophin. This review not only presents some of the most promising molecular, cellular, and pharmacological strategies but also highlights some issues that need to be addressed before considering their implementation. Specifically, we describe current strategies being developed to exogenously deliver healthy copies of the dystrophin gene to dystrophic muscles. We present the findings of several studies that have focused on repairing the mutant dystrophin gene using various approaches. We include a discussion of cell-based therapies that capitalize on the use of myoblast or stem cell transfer. Finally, we summarize the results of several studies that may eventually lead to the development of appropriate drug-based therapies. In this context, we review our current knowledge of the mechanisms regulating expression of utrophin, the autosomal homologue of dystrophin. Given the complexity associated with the dystrophic phenotype, it appears likely that a combinatorial approach involving different therapeutic strategies will be necessary for the appropriate management and eventual treatment of this devastating neuromuscular disease.

Alendronate in the treatment of low bone mass in steroid-treated boys with Duchenne’s muscular dystrophy

OBJECTIVE

To examine alendronates side-effect profile and effect on bone mineral density (BMD) in deflazacort-treated boys with Duchennes muscular dystrophy (DMD) and low BMD.

DESIGN

Before-after trial.

SETTING

Neuromuscular clinic at a children's hospital in Canada between 1999 and 2000.

PARTICIPANTS

All consenting boys with DMD who had z scores less than -1.00 (spine and/or total body) and in whom BMD testing was feasible.

INTERVENTION

Boys received .08 mg.kg(-1) .d(-1) of alendronate orally, with 750 mg of daily calcium and 1000 IU of vitamin D. BMD, height, weight, physical activity, Tanner stage, and adverse effects were followed for 2 years.

MAIN OUTCOME MEASURES

BMD z scores at the lumbar spine (L1-4) and total body.

RESULTS

Of the 42 eligible boys assessed, 23 had low BMD; for 16 of the 23, future BMD testing was feasible. Mean age was 10.8 years (range, 6.9-15.6 y). Mean baseline z scores at the total body and spine were -0.80 and -1.94, respectively. At 2 years, mean z scores were unchanged. Furthermore, alendronate response varied by baseline age. In multivariable analysis, improvement in total body and spine z scores was associated with younger age at baseline ( P =.01 for both).

CONCLUSIONS

In deflazacort-treated boys, alendronate had a positive effect on BMD z scores; the effect was greatest when given early in the course of disease.

Evolving therapeutic strategies for Duchenne muscular dystrophy: targeting downstream events

Duchenne muscular dystrophy (DMD) is a progressive, lethal, muscle wasting disease that affects 1 of 3500 boys born worldwide. The disease results from mutation of the dystrophin gene that encodes a cytoskeletal protein associated with the muscle cell membrane. Although gene therapy will likely provide the cure for DMD, it remains on the distant horizon, emphasizing the need for more rapid development of palliative treatments that build on improved understanding of the complex pathology of dystrophin deficiency. In this review, we have focused on therapeutic strategies that target downstream events in the pathologic progression of DMD. Much of this work has been developed initially using the dystrophin-deficient mdx mouse to explore basic features of the pathophysiology of dystrophin deficiency and to test potential therapeutic interventions to slow, reverse, or compensate for functional losses that occur in muscular dystrophy. In some cases, the initial findings in the mdx model have led to clinical treatments for DMD boys that have produced improvements in muscle function and quality of life. Many of these investigations have concerned interventions that can affect protein balance in muscle, by inhibiting specific proteases implicated in the DMD pathology, or by providing anabolic factors or depleting catabolic factors that can contribute to muscle wasting. Other investigations have exploited the use of anti-inflammatory agents that can reduce the contribution of leukocytes to promoting secondary damage to dystrophic muscle. A third general strategy is designed to increase the regenerative capacity of dystrophic muscle and thereby help retain functional muscle mass. Each of these general approaches to slowing the pathology of dystrophin deficiency has yielded encouragement and suggests that targeting downstream events in dystrophinopathy can yield worthwhile, functional improvements in DMD.

Glucocorticoid treatment alleviates dystrophic myofiber pathology by activation of the calcineurin/NF-AT pathway

Duchenne muscular dystrophy (DMD) is a progressive and ultimately fatal skeletal muscle disease. Currently, the most effective therapy is the administration of a subclass of glucocorticoids, most notably deflazacort. Although deflazacort treatment can attenuate DMD progression, extend ambulation, and maintain muscle strength, the mechanism of its action remains unknown. Prior observations have shown that activation of a JNK1-mediated signal transduction cascade contributes to the progression of the DMD phenotype, in part by phosphorylation and inhibition of a calcineurin sensitive NF-ATc1 transcription factor. Here, we observed that deflazacort treatment restored myocyte viability in muscle cells with constitutive activation of JNK1 and in dystrophic mdx mice. However, deflazacort treatment did not alter JNK1 activity itself, but rather led to an increase in the activity of the calcineurin phosphatase and an up-regulation of NF-ATc1-dependent gene expression. The prophylactic effect of deflazacort treatment was associated with increased expression of NF-ATc1 target genes such as the dystrophin homologue utrophin. Moreover, the muscle sparing effects of deflazacort were completely abolished when used in conjunction with the calcineurin inhibitor cyclosporine. Collectively, these results show that deflazacort attenuates loss of dystrophic myofiber integrity by up-regulating the activity of the phosphatase calcineurin, which in turn negates JNK1 inhibition of NF-ATc1-mediated phosphorylation and nuclear exclusion of NF-ATc1.

Prednisolone therapy in Duchenne muscular dystrophy prolongs ambulation and prevents scoliosis

Steroids may have a beneficial effect on the course of Duchenne muscular dystrophy (DMD). However, results vary in different studies. This study consisted of 66 DMD boys who were in the therapy group and 22 DMD boys in the control group. The mean ages were 6.8 +/- 2.1 years (range 2.5-12.5) and 7.0 +/- 1.3 years (range 5.0-9.0), respectively. We assessed muscle strength, 10-m walking, ankle contracture, and loss of independent walking ability age and onset of scoliosis. Treatment regimen was oral prednisolone 0.75 mg/kg on alternate days, plus vitamin D 600-1200 units/day and a calcium-enriched diet. After a follow-up period of 2.75 +/- 1.1 years (range 1.5-5) and when compared with controls, there was a statistically significant change in muscle strength between the two groups after 12 months (P < 0.05). Although 10-m walking time decreased in therapy group (P < 0.05), there was not significance between the groups in the end. Boys in the control group developed significantly less ankle contractures (P < 0.05). None of the therapy group had scoliosis during the follow-up period (mean age 10.8 +/- 1.2 years), whereas seven boys of the control group had scoliosis at a mean age of 11.7 +/- 2 years. Loss of walking ability age was statistically different between groups (P < 0.05). Our results indicate that, alternate-day prednisolone regimen may prolong ambulation and scoliosis can be delayed or prevented.

Steroid treatment and the development of scoliosis in males with duchenne muscular dystrophy

BACKGROUND

Scoliosis due to progressive muscle weakness occurs in almost all males with Duchenne muscular dystrophy, and it progresses relentlessly. Previous studies have shown that corticosteroid treatment slows the decline in muscle strength and stabilizes muscle strength in patients with this disease. We hypothesized that steroids may also attenuate the development of scoliosis. The purpose of this study was to compare the prevalence of scoliosis in male patients with Duchenne muscular dystrophy who received steroids with a control group of such patients who did not.

METHODS

A group of seven to ten-year-old boys with Duchenne muscular dystrophy who were able to walk were enrolled in a nonrandomized comparative study to determine the effect of deflazacort (a derivative of prednisone) on muscle strength and pulmonary function. Thirty patients were treated with deflazacort (treatment group), and twenty-four were not (control group). The patients were matched for age and pulmonary function at baseline. To assess the development of scoliosis, the patients in each group were followed for at least five years. Survival curves were plotted to determine the chance of scoliosis of >/==" BORDER="0">20 degrees developing. The difference between the groups with respect to the chance of scoliosis developing was determined with Kaplan-Meier analysis.

RESULTS

A curve of >/==" BORDER="0">20 degrees developed during the follow-up period in sixteen (67%) of the twenty-four patients in the control group but in only five (17%) of the thirty patients in the treatment group. Fifteen of the twenty-four patients in the control group underwent spine surgery, at a mean age of thirteen years, whereas only five of the thirty patients in the treatment group underwent spine surgery, at a mean age of fifteen years. Kaplan-Meier analysis demonstrated a significant difference between the two groups with regard to development of scoliosis of >/==" BORDER="0">20 degrees (p < 0.001). Cataracts developed in ten patients in the treatment group, and stress fractures developed in three patients in the treatment group. Patients in the treatment group weighed a mean of 3.7 kg more than did those in the control group.

CONCLUSIONS

Steroid treatment slows the progression of scoliosis in males with Duchenne muscular dystrophy; however, longer-term evaluation will be necessary to determine if the treatment prevents the development of scoliosis or just delays its onset. At the very least, steroid treatment delays the need for spinal surgery.

LEVEL OF EVIDENCE

Therapeutic study, Level II-1 (prospective cohort study). See Instructions to Authors for a complete description of levels of evidence.

Glucocorticoid corticosteroids for Duchenne muscular dystrophy

BACKGROUND

Duchenne muscular dystrophy is the most common muscular dystrophy of childhood. This incurable disease is characterised by muscle wasting and loss of walking ability leading to complete wheelchair dependence by 13 years of age. Prolongation of walking is one of the major aims of treatment.

OBJECTIVES

The aim of this review was to assess whether glucocorticoid corticosteroids stabilize or improve muscle strength and walking in boys with DMD.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group specialised register (October 2003) using the term 'Duchenne muscular dystrophy'. We also searched MEDLINE (January 1966 to October 2003), EMBASE (January 1980 to October 2003), CINAHL and LILACS (January 1982 to October 2003). We wrote to authors of published studies and other experts in this disease to help identify other trials, checked the references in the identified trials and handsearched the abstracts of relevant journals.

SELECTION CRITERIA

Types of studies: randomised or quasi-randomised trials.

TYPES OF PARTICIPANTS

all patients with a definite diagnosis of Duchenne muscular dystrophy. Types of interventions: glucocorticoids such as prednisone, prednisolone, deflazacort or others, with a minimum treatment period of three months.

PRIMARY OUTCOME MEASURE

prolongation of walking (independent walking without long leg calipers).

SECONDARY OUTCOME MEASURES

strength outcome measures, manual muscle strength testing using Medical Research Council strength scores, functional outcome measures and adverse events.

DATA COLLECTION AND ANALYSIS

We identified five randomised controlled trials that met the inclusion criteria for our review. Two reviewers independently selected the trials for the review and assessed methodological quality. Data extraction and inputting were double-checked.

PRIMARY OUTCOME MEASURE

data from one small study used prolongation of walking as an outcome measure and did not show significant benefit.

SECONDARY OUTCOME MEASURES

The meta-analysis of the results from three randomised controlled trials showed that glucocorticoid corticosteroids improved muscle strength and function over six months. Improvements were seen in time taken to rise from the floor (Gowers' time), nine metres walking time, four-stair climbing time, ability to lift weights, leg function grade and forced vital capacity. One randomised controlled trial showed that glucocorticoid corticosteroids stabilize muscle strength and function for up to two years. The most effective prednisolone regime appears to be 0.75 mg/kg/day. Not enough data were available to compare efficacy of prednisone with deflazacort.Adverse effects: Excessive weight gain, behavioural abnormalities, cushingoid appearance and excessive hair growth were all more common with glucocorticoid corticosteroids than placebo. Long-term adverse effects of glucocorticoid therapy could not be evaluated because of the short-term duration of the randomised studies.Non-randomised studies: a number of non-randomised studies with important efficacy and adverse effects data are tabulated and discussed.

REVIEWERS' CONCLUSIONS

There is evidence from randomised controlled studies that glucocorticoid corticosteroid therapy in Duchenne muscular dystrophy improves muscle strength and function in the short-term (six months to two years). The most effective prednisolone regime appears to be 0.75 mg/kg/day. In the short term, adverse effects were significantly more common but not clinically severe. Long-term benefits and hazards of glucocorticoid treatment cannot be evaluated from the currently published randomised studies. Non-randomised studies support the conclusions of functional benefits but also indicate clinically significant adverse effects of long-term treatment. These benefits and adverse effects have implications for future research studies and clinical practice.

Deflazacort for the treatment of Duchenne Dystrophy: a systematic review

BACKGROUND

To complete a systematic review and meta-analysis based on the clinical question: Is Deflazacort (DFZ), a prednisolone derivative, an effective therapy for improving strength, with acceptable side effects, in children with Duchenne Dystrophy (DD)?

METHODS

MEDLINE, EMBASE, Current Contents, Dissertation Abstracts, Health Star, PsychINFO and Cochrane, were searched using the following inclusion criteria: 1) A randomized controlled trial comparing DFZ with placebo or another therapy; 2) Male participants age 2-18 years with DD; 3) Outcomes of (a) any form of strength or functional testing, or (b) any form of side effect.

RESULTS

Fifteen studies of potential relevance were identified, with five meeting the inclusion criteria. These five studies included 291 children and were published in English language journals between 1994 and 2000. Two studies compared DFZ versus placebo, two studies compared DFZ with prednisone and one study had both placebo and prednisone comparisions. Two large trials were identified that have not been published in article format. Due to the heterogeneity in outcome measures and the inconsistent reporting of summary statistics a meta-analytic approach could not be taken.

CONCLUSIONS

Examining individual studies it appears that DFZ improves strength and functional outcomes compared to placebo, but it remains unclear if it has a benefit over prednisone on similar outcomes. Two trials found that DFZ causes less weight gain than prednisone.

Early prednisone treatment in Duchenne muscular dystrophy

The purpose of this long-term, open parallel-group, double-consent study of alternate-day, low-dose prednisone in 2-4-year-old patients with Duchenne muscular dystrophy (DMD) was to determine whether prednisone produces a beneficial effect when given earlier than usual. Muscle function was evaluated by timed tests, and muscle strength with a hand-held myometer. After 55 months of treatment, the five patients (mean age 8.3 years) in the prednisone group were still able to get up from the floor, whereas two of the three in the control group had lost this ability. Side effects included a decline in growth rate in the prednisone-treated patients and excessive weight gain in one control and three treated patients. Because steroids are effective in prolonging function, but not in recovering lost function, we propose that treatment be started with low-dose prednisone in DMD patients as soon as the diagnosis is definite.

An effective, low-dosage, intermittent schedule of prednisolone in the long-term treatment of early cases of Duchenne dystrophy

The aim of this study was to evaluate the long-term effects in young children with Duchenne dystrophy of an intermittent low dosage regime of prednisolone (0.75 mg/kg per day for 10 days per month, or 10 days on and 10 days off). Six children under 5 years with Duchenne dystrophy have been commenced on this schedule, four of whom have been followed for at least 30 months and are reported here. All four presented with classical Duchenne dystrophy, and had an out-of-frame deletion in the Duchenne gene and absence of dystrophin in their muscle. All four showed a rapid and dramatic response in muscle function and strength. In three of the four there was an almost complete remission of all clinical signs of dystrophy. Their functional scores remained well above the average scores recorded in untreated Duchenne boys at the same age. There was no increase in weight, stunting of growth, decreased bone density or any other significant side effects related to the prednisolone. Our current experience suggests that this intermittent, low-dosage prednisolone regime is well tolerated and can be safely given long-term in young children with Duchenne dystrophy. The striking response also suggests that there may be an optimal window for treatment of Duchenne dystrophy in the early stages of the disease.

Considerations to the policy of future clinical therapeutic trials in DMD

In spite of rapidly increasing insight into the molecular basis of neuromuscular diseases, treatment still relies on convention and clinical studies. Experience with a multicentre double blind treatment study in Duchenne muscular dystrophy and with consecutive steroid treatment documentation for up to 8 years enables us to identify a series of crucial points on which to focus while planning such clinical trials. The most important seem to be: a carefully structured, detailed study, clear-cut aims and objectives, expertise of investigators, sufficient training of examiners, and careful monitoring. If patients with neuromuscular diseases are treated outside structured studies, their course should be monitored comparably. Examples of the impact of such documentation are available from the ongoing German multicentre trial on the treatment of Duchenne muscular dystrophy.

Duchenne muscular dystrophy: current knowledge, treatment, and future prospects

The cloning of the dystrophin gene has led to major advances in the understanding of the molecular genetic basis of Duchenne, Becker, and other muscular dystrophies associated with mutations in genes encoding members of the dystrophin-associated glycoprotein complex. The recent introduction of pharmaceutical agents such as prednisone has shown great promise in delaying the progression of Duchenne muscular dystrophy but there remains a need to develop more long-term therapeutic interventions. Knowledge of the nature of the dystrophin gene and the glycoprotein complex has led many researchers to think that somatic gene replacement represents the most promising approach to treatment. The potential use of this strategy has been shown in the mdx mouse model of Duchenne muscular dystrophy, where germ line gene transfer of either a full-length or a smaller Becker-type dystrophin minigene prevents necrosis and restores normal muscle function.

Corticosteroids in Duchenne muscular dystrophy: a reappraisal

Duchenne muscular dystrophy is the most common and most severe form of childhood muscular dystrophies, resulting in early loss of ambulation between the ages of 7 and 13 years and death in the teens and twenties. Despite the phenomenal advances made in the understanding of the molecular genetics of the disease, no definitive cure has been found. Of all of the therapeutic drugs studied in Duchenne muscular dystrophy, only prednisone seems to have the potential for providing interim functional improvement for boys with Duchenne muscular dystrophy while they wait for a cure with gene or cell therapy. There is still no consensus regarding recommending corticosteroids as standard therapy for boys. This is an evidence-based review of all of the studies of corticosteroids (prednisone, deflazacort, and oxandrolone) in Duchenne muscular dystrophy. From this review, it is clear that until a definitive treatment for Duchenne muscular dystrophy is available, the use of deflazacort and prednisone with judicious dietary control and close clinical monitoring for side effects seems the best intervention for interim preservation of function in such a common devastating disorder of young growing boys.