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INTRODUCTION: Dystrophinopathy is a rare, severe muscle disorder, and nonsense mutations are found in 13% of cases. Ataluren was developed to enable ribosomal readthrough of premature stop codons in nonsense mutation (nm) genetic disorders. METHODS: Randomized, double-blind, placebo-controlled study; males ≥ 5 years with nm-dystrophinopathy received study drug orally 3 times daily, ataluren 10, 10, 20 mg/kg (N=57); ataluren 20, 20, 40 mg/kg (N=60); or placebo (N=57) for 48 weeks. The primary endpoint was change in 6-Minute Walk Distance (6MWD) at Week 48. RESULTS: Ataluren was generally well tolerated. The primary endpoint favored ataluren 10, 10, 20 mg/kg versus placebo; the week 48 6MWD Δ=31.3 meters, post hoc P=0.056. Secondary endpoints (timed function tests) showed meaningful differences between ataluren 10, 10, 20 mg/kg, and placebo. CONCLUSIONS: As the first investigational new drug targeting the underlying cause of nm-dystrophinopathy, ataluren offers promise as a treatment for this orphan genetic disorder with high unmet medical need.
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Códon sem Sentido/genética , Distrofina/genética , Distrofia Muscular de Duchenne/tratamento farmacológico , Distrofia Muscular de Duchenne/genética , Oxidiazóis/uso terapêutico , Adolescente , Criança , Pré-Escolar , Relação Dose-Resposta a Droga , Método Duplo-Cego , Humanos , Cooperação Internacional , Masculino , Distrofia Muscular de Duchenne/fisiopatologia , Avaliação de Resultados em Cuidados de Saúde , Estudos Prospectivos , Fatores de Tempo , CaminhadaRESUMO
INTRODUCTION: An international clinical trial enrolled 174 ambulatory males ≥5 years old with nonsense mutation Duchenne muscular dystrophy (nmDMD). Pretreatment data provide insight into reliability, concurrent validity, and minimal clinically important differences (MCIDs) of the 6-minute walk test (6MWT) and other endpoints. METHODS: Screening and baseline evaluations included the 6-minute walk distance (6MWD), timed function tests (TFTs), quantitative strength by myometry, the PedsQL, heart rate-determined energy expenditure index, and other exploratory endpoints. RESULTS: The 6MWT proved feasible and reliable in a multicenter context. Concurrent validity with other endpoints was excellent. The MCID for 6MWD was 28.5 and 31.7 meters based on 2 statistical distribution methods. CONCLUSIONS: The ratio of MCID to baseline mean is lower for 6MWD than for other endpoints. The 6MWD is an optimal primary endpoint for Duchenne muscular dystrophy (DMD) clinical trials that are focused therapeutically on preservation of ambulation and slowing of disease progression.
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Teste de Esforço , Distrofia Muscular de Duchenne/fisiopatologia , Avaliação de Resultados em Cuidados de Saúde , Caminhada/fisiologia , Progressão da Doença , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Humanos , Masculino , Distrofia Muscular de Duchenne/diagnóstico , Distrofia Muscular de Duchenne/tratamento farmacológico , Oxidiazóis/uso terapêutico , Reprodutibilidade dos Testes , Fatores de TempoRESUMO
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.
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Teste de Esforço , Distrofia Muscular de Duchenne/fisiopatologia , Avaliação de Resultados em Cuidados de Saúde , Caminhada/fisiologia , Adolescente , Criança , Pré-Escolar , Método Duplo-Cego , Eletromiografia , Glucocorticoides/uso terapêutico , Força da Mão/fisiologia , Humanos , Estudos Longitudinais , Masculino , Distrofia Muscular de Duchenne/tratamento farmacológico , Observação , Oxidiazóis/uso terapêutico , Valor Preditivo dos Testes , Fatores de TempoRESUMO
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.
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Corticosteroides/uso terapêutico , Coleta de Dados , Distrofia Muscular de Duchenne/tratamento farmacológico , Distrofia Muscular de Duchenne/epidemiologia , Médicos/normas , Ensaios Clínicos Fase II como Assunto/métodos , Coleta de Dados/métodos , Europa (Continente)/epidemiologia , Humanos , Guias de Prática Clínica como Assunto/normas , Ensaios Clínicos Controlados Aleatórios como Assunto/métodos , Estados Unidos/epidemiologiaRESUMO
RATIONALE: Nonsense (premature stop codon) mutations in mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis (CF) in approximately 10% of patients. Ataluren (PTC124) is an oral drug that permits ribosomes to readthrough premature stop codons in mRNA to produce functional protein. OBJECTIVES: To evaluate ataluren activity, safety, and pharmacokinetics in children with nonsense mutation CF. METHODS: Patients were assessed in two 28-day cycles, comprising 14 days on and 14 days off ataluren. Patients took ataluren three times per day (morning, midday, and evening) with randomization to the order of receiving a lower dose (4, 4, and 8 mg/kg) and a higher dose (10, 10, and 20 mg/kg) in the two cycles. MEASUREMENTS AND MAIN RESULTS: The study enrolled 30 patients (16 male and 14 female, ages 6 through 18 yr) with a nonsense mutation in at least one allele of the CFTR gene, a classical CF phenotype, and abnormal baseline nasal epithelial chloride transport. Ataluren induced a nasal chloride transport response (at least a -5-mV improvement) or hyperpolarization (value more electrically negative than -5 mV) in 50% and 47% of patients, respectively, with more hyperpolarizations at the higher dose. Improvements were seen in seven of nine nonsense mutation genotypes represented. Ataluren significantly increased the proportion of nasal epithelial cells expressing apical full-length CFTR protein. Adverse events and laboratory abnormalities were infrequent and usually mild. Ataluren pharmacokinetics were similar to those in adults. CONCLUSIONS: In children with nonsense mutation CF, ataluren can induce functional CFTR production and is well tolerated.
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Códon sem Sentido/efeitos dos fármacos , Regulador de Condutância Transmembrana em Fibrose Cística/biossíntese , Fibrose Cística/tratamento farmacológico , Regulação da Expressão Gênica/efeitos dos fármacos , Oxidiazóis/uso terapêutico , Adolescente , Criança , Códon sem Sentido/genética , Códon sem Sentido/fisiologia , Estudos Cross-Over , Fibrose Cística/genética , Fibrose Cística/metabolismo , Fibrose Cística/fisiopatologia , Regulador de Condutância Transmembrana em Fibrose Cística/fisiologia , Relação Dose-Resposta a Droga , Feminino , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/fisiologia , Humanos , Masculino , Mucosa Nasal/metabolismo , Mucosa Nasal/fisiopatologia , Oxidiazóis/administração & dosagem , Oxidiazóis/farmacologiaRESUMO
In this study we used the 6-minute walk distance (6MWD) to characterize ambulation over time in Duchenne/Becker muscular dystrophy (DBMD). The 6MWD was assessed in 18 boys with DBMD and 22 healthy boys, ages 4-12 years, over mean [range] intervals of 58 [39-87] and 69 [52-113] weeks, respectively. Height and weight increased similarly in both groups. At 52 weeks, 6MWD decreased in 12 of 18 (67%) DBMD subjects (overall mean [range]: 357 [125-481] to 300 [0-510] meters; Δ -57 meters, -15.9%), but increased in 14 of 22 (64%) healthy subjects (overall mean [range]: 623 [479-754] to 636 [547-717] meters; Δ +13 meters, +2.1%). Two DBMD subjects lost ambulation. Changes in 6MWD depended on stride length and age; improvements usually occurred by 7-8 years of age; older DBMD subjects worsened, whereas older healthy subjects were stable. The 6MWD changes at 1 year confirm the validity of this endpoint and emphasize that preserving ambulation must remain a major goal of DBMD therapy.
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Marcha/fisiologia , Distrofia Muscular de Duchenne/fisiopatologia , Caminhada/fisiologia , Estatura , Peso Corporal , Criança , Pré-Escolar , Progressão da Doença , Seguimentos , Humanos , MasculinoRESUMO
Walking abnormalities are prominent in Duchenne muscular dystrophy (DMD). We modified the 6-minute walk test (6MWT) for use as an outcome measure in patients with DMD and evaluated its performance in 21 ambulatory boys with DMD and 34 healthy boys, ages 4 to 12 years. Boys with DMD were tested twice, approximately 1 week apart; controls were tested once. The groups had similar age, height, and weight. All tests were completed. Boys who fell recovered rapidly from falls without injury. Mean +/- SD [range] 6-minute walk distance (6MWD) was lower in boys with DMD than in controls (366 +/- 83 [125-481] m vs. 621 +/- 68 [479-754] m; P < 0.0001; unpaired t-test). Test-retest correlation for boys with DMD was high (r = 0.91). Stride length (R(2) = 0.89; P < 0.0001) was the major determinant of 6MWD for both boys with DMD and controls. A modified 6MWT is feasible and safe, documents disease-related limitations on ambulation, is reproducible, and offers a new outcome measure for DMD natural history and therapeutic trials.
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Teste de Esforço/métodos , Distrofia Muscular de Duchenne/diagnóstico , Distrofia Muscular de Duchenne/fisiopatologia , Caminhada/fisiologia , Criança , Pré-Escolar , Teste de Esforço/normas , Humanos , Masculino , Avaliação de Resultados em Cuidados de Saúde , Reprodutibilidade dos Testes , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Chronic wounds are a fundamental issue for patients with epidermolysis bullosa (EB). Herein, we assess the natural history of wound closure in patients with EB who were randomly assigned to the vehicle-control arm of the multicenter, randomized, double-blind, phase 3 ESSENCE (NCT02384460) trial. METHODS: ESSENCE was designed to assess the efficacy and safety of a topical cream formulation of 6% allantoin (SD-101 6%) vs vehicle (SD-101 0%) in patients ≥1 month old who had a diagnosis of EB (simplex, recessive dystrophic, or intermediate junctional) and a target wound 10-50 cm2 present for ≥21 days. Time to complete target wound closure and the proportion of patients with target wound closure over time were analyzed overall and by parameters including patient age and baseline body surface area index (BSAi) of total wound burden (< 5% and ≥ 5%). Changes in BSAi of lesional skin, pain, and itching were also assessed. RESULTS: The vehicle-control arm included 87 patients. Mean (standard deviation [SD]) time to target wound closure within 3 months was 53.6 (28.6) days, with a range of 14 to 142 days. The proportion of patients with target wound closure increased over time from 7.1% at day 14 to 53.6% at month 3. Mean (SD) changes from baseline in BSAi of total wound burden and BSAi of lesional skin at month 3 were -2.3% (6.3) and -5.0% (13.5) of total body coverage, respectively. Reductions in pain and itching were observed at day 7 and maintained for 3 months. Faster healing times and a greater proportion of patients with wound closure were observed in patients aged 1 month to < 2 years; those with wounds < 30 days old, and in those with BSAi of total body wound burden < 5%. CONCLUSIONS: Treatment response observed in the vehicle-control arm of the ESSENCE study was unexpectedly high and may have been due to unforeseen benefits of vehicle or enhanced wound care provided by the clinical trial staff. These observations will help inform the study design of future trials in patients with EB. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02384460 ; Date of registration: February 13, 2015; First participant enrollment: March 11, 2015.
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Epidermólise Bolhosa , Método Duplo-Cego , Epidermólise Bolhosa/tratamento farmacológico , Humanos , Recém-Nascido , CicatrizaçãoRESUMO
BACKGROUND: Little information is available regarding the burden of living with and managing epidermolysis bullosa, including the distinct challenges faced by patients with different disease types/subtypes. METHODS: A 90-question/item survey was developed to collect demographics, diagnostic data, management practices, and burden of illness information for patients with epidermolysis bullosa living in the United States. Recruitment was conducted via email and social media in partnership with epidermolysis bullosa patient advocacy organizations in the United States, and the survey was conducted via telephone interview by a third-party health research firm. Respondents aged ≥ 18 years with a confirmed diagnosis of epidermolysis bullosa or caring for a patient with a confirmed diagnosis of epidermolysis bullosa were eligible to participate in the survey. RESULTS: In total, 156 responses were received from patients (n = 63) and caregivers (n = 93) representing the epidermolysis bullosa types of simplex, junctional, and dystrophic (subtypes: dominant and recessive). A large proportion of patients (21%) and caregivers (32%) reported that the condition was severe or very severe, and 19% of patients and 26% of caregivers reported a visit to an emergency department in the 12 months prior to the survey. Among the types/subtypes represented, recessive dystrophic epidermolysis bullosa results in the greatest wound burden, with approximately 60% of patients and caregivers reporting wounds covering > 30% of total body area. Wound care is time consuming and commonly requires significant caregiver assistance. Therapeutic options are urgently needed and reducing the number and severity of wounds was generally ranked as the most important treatment factor. CONCLUSIONS: Survey responses demonstrate that epidermolysis bullosa places a considerable burden on patients, their caregivers, and their families. The limitations caused by epidermolysis bullosa mean that both patients and caregivers must make difficult choices and compromises regarding education, career, and home life. Finally, survey results indicate that epidermolysis bullosa negatively impacts quality of life and causes financial burden to patients and their families.
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Epidermólise Bolhosa/epidemiologia , Adolescente , Adulto , Idoso , Cuidadores/estatística & dados numéricos , Efeitos Psicossociais da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Qualidade de Vida , Inquéritos e Questionários , Estados Unidos/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Epidermolysis bullosa (EB) is a rare genetic disorder that manifests as blistering and/or skin erosion. There is no approved treatment for EB; current standard of care consists of wound and pain management. SD-101 6% is a topical cream containing 6% allantoin that was developed for treating skin lesions in patients with EB. The aim of this phase 3, multicenter, randomized, double-blind, vehicle-controlled study was to assess the efficacy and safety of SD-101 6% cream versus vehicle (0% allantoin) on lesions in patients with EB. METHODS: Eligible patients were ≥1 month old, had a diagnosis of EB (simplex, recessive dystrophic, or intermediate junctional) and a target wound 10-50 cm2 in size that was present for ≥21 days. Patients were randomly assigned to SD-101 6% cream or vehicle, which was applied topically once a day to the entire body for 3 months. Primary efficacy endpoints were time to complete target wound closure within 3 months and the proportion of patients who experienced complete target wound closure within 3 months. Post hoc subgroup analyses were conducted by patient age and in those with body surface area index of total body wound burden ≥5% at baseline. RESULTS: In total, 169 patients were enrolled and randomly assigned to SD-101 6% (n = 82) or vehicle (n = 87). Baseline demographics and disease characteristics were similar between treatment groups. There were no statistically significant differences between treatment groups in time to target wound closure (hazard ratio, 1.004; 95% confidence interval [CI] 0.651, 1.549; P = 0.985) or proportion of patients with complete target wound closure within 3 months (odds ratio [95% CI], 0.733 [0.365, 1.474]; nominal P = 0.390). A positive trend toward faster wound closure with SD-101 6% versus vehicle was observed in patients aged 2 to <12 years and those with total body wound burden ≥5% at baseline. SD-101 6% cream was well tolerated. CONCLUSIONS: SD-101 6% cream for treatment of EB-associated lesions was not more effective than vehicle in shortening the time to complete target wound closure or achieving complete target wound closure within 3 months. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02384460; Date of trial registration, February 13, 2015; First participant enrolled, March 11, 2015.
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Epidermólise Bolhosa , Dermatopatias , Alantoína , Método Duplo-Cego , Humanos , Lactente , Modelos de Riscos Proporcionais , Resultado do TratamentoRESUMO
BACKGROUND: Approximately 13% of boys with Duchenne muscular dystrophy (DMD) have a nonsense mutation in the dystrophin gene, resulting in a premature stop codon in the corresponding mRNA and failure to generate a functional protein. Ataluren (PTC124) enables ribosomal readthrough of premature stop codons, leading to production of full-length, functional proteins. METHODS: This Phase 2a open-label, sequential dose-ranging trial recruited 38 boys with nonsense mutation DMD. The first cohort (nâ=â6) received ataluren three times per day at morning, midday, and evening doses of 4, 4, and 8 mg/kg; the second cohort (nâ=â20) was dosed at 10, 10, 20 mg/kg; and the third cohort (nâ=â12) was dosed at 20, 20, 40 mg/kg. Treatment duration was 28 days. Change in full-length dystrophin expression, as assessed by immunostaining in pre- and post-treatment muscle biopsy specimens, was the primary endpoint. FINDINGS: Twenty three of 38 (61%) subjects demonstrated increases in post-treatment dystrophin expression in a quantitative analysis assessing the ratio of dystrophin/spectrin. A qualitative analysis also showed positive changes in dystrophin expression. Expression was not associated with nonsense mutation type or exon location. Ataluren trough plasma concentrations active in the mdx mouse model were consistently achieved at the mid- and high- dose levels in participants. Ataluren was generally well tolerated. INTERPRETATION: Ataluren showed activity and safety in this short-term study, supporting evaluation of ataluren 10, 10, 20 mg/kg and 20, 20, 40 mg/kg in a Phase 2b, double-blind, long-term study in nonsense mutation DMD. TRIAL REGISTRATION: ClinicalTrials.gov NCT00264888.
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Distrofina/metabolismo , Distrofia Muscular de Duchenne/tratamento farmacológico , Distrofia Muscular de Duchenne/metabolismo , Oxidiazóis/uso terapêutico , Criança , Códon sem Sentido/genética , Humanos , MasculinoRESUMO
We recently described a modified version of the 6-minute walk test (6MWT) for Duchenne muscular dystrophy (DMD) based partly on the American Thoracic Society (ATS) guidelines. This measure has shown reliability, validity and utility as a primary outcome measure in DMD clinical trials. Because loss of muscle function in DMD occurs against the background of normal childhood growth and development, younger children with DMD can show increase in distance walked during 6MWT over ~1 year despite progressive muscular impairment. In this study, we compare 6-minute walk distance (6MWD) data from DMD boys (n=17) and typically developing control subjects (n=22) to existing normative data from age- and sex-matched children and adolescents. An age- and height-based equation fitted to normative data by Geiger and colleagues was used to convert 6MWD to a percent-predicted (%-predicted) value in boys with DMD. Analysis of %-predicted 6MWD data represents a method to account for normal growth and development, and shows that gains in function at early ages represents stable rather than improving abilities in boys with DMD. Boys with DMD from 4-7 years of age maintain a stable 6MWD approximately 80% of that of typically developing peers, with the deficit progressing at a variable rate thereafter.
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BACKGROUND: Although cough is a commonly reported symptom, objective quantitation of cough during normal activity has not been performed in patients with CF. METHODS: An ambulatory device was used to characterize cough over 24 hours. Pulmonary function and subject-reported coughing were also assessed. RESULTS: Patients included 19 clinically stable adults with CF (males:females=10:9; median age [range]=26 [19-57] years; median %-predicted FEV(1) [range]=65 [44-106]%). Median [range] cough rate was 27 [13-66] coughs/hour, with values while awake of 41 [20-102] and while asleep of 2 [0.1-7] (p<0.0001, Wilcoxon signed-rank test). Subjective reporting was consistent with objective data for wake-sleep differences, but correlated poorly with objective waking cough rate. CONCLUSIONS: Outpatient cough quantitation in patients with CF is feasible, indicates frequent coughing even during clinical stability, and may be useful in therapeutic trials in CF.