Clinical trial readiness in non-ambulatory boys and men with duchenne muscular dystrophy: MDA-DMD network follow-up.

INTRODUCTION: Outcomes sensitive to change over time in non-ambulatory boys/men with Duchenne muscular dystrophy (DMD) are not well-established. METHODS: Subjects (n = 91; 16.8 ± 4.5 years old) were assessed at baseline and 6-month intervals for 2 years. We analyzed all subjects using an intent-to-treat model and a subset of stronger subjects with Brooke Scale score ≤4, using repeated measures. RESULTS: Eight patients (12-33 years old) died during the study. Sixty-six completed 12-month follow-up, and 51 completed 24-month follow-up. Those taking corticosteroids performed better at baseline, but rates of decline were similar. Forced vital capacity percent predicted (FVC% predicted) declined significantly only after 2 years. However, Brooke and Egen Klassifikation (EK) Scale scores, elbow flexion, and grip strength declined significantly over both 1 and 2 years. CONCLUSION: Brooke and EK Scale scores, elbow flexion, and grip strength were outcomes most responsive to change. FVC% predicted was responsive to change over 2 years. Corticosteroids benefited non-ambulatory DMD subjects but did not affect decline rates of measures tested here. Muscle Nerve 54: 681-689, 2016.

Outcome reliability in non-ambulatory boys/men with Duchenne muscular dystrophy.

INTRODUCTION: Therapeutic trials in Duchenne muscular dystrophy (DMD) often exclude non-ambulatory individuals. Here we establish optimal and reliable assessments in a multicenter trial. METHODS: Non-ambulatory boys/men with DMD (N = 91; 16.7 ± 4.5 years of age) were assessed by trained clinical evaluators. Feasibility (percentage completing task) and reliability [intraclass correlation coefficients (ICCs) between morning and afternoon tests] were measured. RESULTS: Forced vital capacity (FVC), assessed in all subjects, showed a mean of 47.8 ± 22% predicted (ICC 0.98). Brooke Upper Extremity Functional Rating (Brooke) and Egen Klassifikation (EK) scales in 100% of subjects showed ICCs ranging from 0.93 to 0.99. Manual muscle testing, range of motion, 9-hole peg test, and Jebsen-Taylor Hand Function Test (JHFT) demonstrated varied feasibility (99% to 70%), with ICCs ranging from 0.99 to 0.64. We found beneficial effects of different forms of corticosteroids for the Brooke scale, percent predicted FVC, and hand and finger strength. CONCLUSIONS: Reliable assessment of non-ambulatory boys/men with DMD is possible. Clinical trials will have to consider corticosteroid use.

Motor and cognitive assessment of infants and young boys with Duchenne Muscular Dystrophy: results from the Muscular Dystrophy Association DMD Clinical Research Network.

Therapeutic trials in Duchenne Muscular Dystrophy (DMD) exclude young boys because traditional outcome measures rely on cooperation. The Bayley III Scales of Infant and Toddler Development (Bayley III) have been validated in developing children and those with developmental disorders but have not been studied in DMD. Expanded Hammersmith Functional Motor Scale (HFMSE) and North Star Ambulatory Assessment (NSAA) may also be useful in this young DMD population. Clinical evaluators from the MDA-DMD Clinical Research Network were trained in these assessment tools. Infants and boys with DMD (n = 24; 1.9 ± 0.7 years) were assessed. The mean Bayley III motor composite score was low (82.8 ± 8; p ≤ .0001) (normal = 100 ± 15). Mean gross motor and fine motor function scaled scores were low (both p ≤ .0001). The mean cognitive comprehensive (p=.0002), receptive language (p ≤ .0001), and expressive language (p = .0001) were also low compared to normal children. Age was negatively associated with Bayley III gross motor (r = -0.44; p = .02) but not with fine motor, cognitive, or language scores. HFMSE (n=23) showed a mean score of 31 ± 13. NSAA (n = 18 boys; 2.2 ± 0.4 years) showed a mean score of 12 ± 5. Outcome assessments of young boys with DMD are feasible and in this multicenter study were best demonstrated using the Bayley III.

Developing normalized strength scores for neuromuscular research.

INTRODUCTION: The Accurate Test of Limb Isometric Strength (ATLIS) device can reliably measure the strength of 12 muscle groups using a fixed load cell. The purpose of this study was to analyze ATLIS data from healthy adults to calculate an individual's predicted strength scores. METHODS: ATLIS data were collected from 432 healthy adults. Linear regression models were developed to predict each muscle group's strength. The R-squared statistic assessed variability accounted for by the models. RESULTS: Simple main effects models stratified by gender were used to establish regression equations for each muscle using factors of age, weight, and height. CONCLUSIONS: Normalizing raw strength scores controls for biometric factors, thus enabling meaningful comparisons between subjects and allowing each muscle to contribute equally to a summary score. Normalized scores are easily interpreted for broad clinical uses, and derived summary scores establish individuals' disease progression rates using a common scale, allowing for more efficient clinical trials.

Familial ALS with extreme phenotypic variability due to the I113T SOD1 mutation.

We describe a large family with amyotrophic lateral sclerosis (ALS) caused by an I113T mutation in superoxide dismuatse type 1 (SOD1). The proband developed symptoms typical for ALS at age 39 years and is still walking five years later. Marked phenotypic variability is manifested by her mother with onset of gait difficulty and decision-making problems at age 67 years and a five-year course marked by progressive mild upper motor neuron weakness, frontotemporal dementia and chorea. An aunt's initial symptoms included foot numbness and an uncle with the mutation is asymptomatic. Penetrance is only 50% at age 60 years and 88% at age 80 years with an 86-year-old woman harboring the mutation and having a normal neurologic examination. This family highlights the extreme variability in age of onset, clinical manifestations, disease progression and penetrance due to the I113T SOD1 mutation.

High dose weekly oral prednisone improves strength in boys with Duchenne muscular dystrophy.

Daily prednisone improves strength in boys with Duchenne muscular dystrophy, but side effects are almost universal. We used a different dosing regimen of prednisone to determine if benefit to boys with Duchenne muscular dystrophy might be maintained with fewer side effects. Twice weekly oral prednisone was given each Friday and Saturday (5mg/kg/dose). This total dose is twice as high as the daily low dosage prednisone regimen (0.75 mg/kg/day). Twenty boys (8.0+/-1.2 years) were treated. Historical control groups included 18 untreated boys (6.1+/-1.6 years) and four boys (7.3+/-0.6 years) treated with daily prednisone. Strength (using a hand-held manometer and grip meter) and timed functional testing were measured. There was an improvement in upper extremity strength for 95% of boys (n=20) at 6 months using quantitative strength testing. Improvement in lower extremity strength occurred in all boys with antigravity quadriceps strength (17/17). The improvement (P=0.001 for proximal upper extremities; P=0.002 for grip; and P<0.0001 for proximal lower extremities) was significant compared to untreated boys. Sixteen boys were treated continuously for more than 12 months (22+/-1.5 months). Of these, 15 remained significantly stronger than prior to treatment and 8/16 showed additional gains in strength after six months of treatment. Six boys were on the weekly prednisolone 2 years or longer without interruption. All six had upper and lower extremity strength at follow-up that was as good or better than at baseline. Functional testing improved in boys less than 8 years without contractures. Three boys without antigravity quadriceps strength at the start of treatment lost the ability to walk unassisted within 6 months. Eight other boys lost the ability to ambulate unassisted between 12 and 24 months of treatment. In each, progressive contractures developed. Linear growth was maintained in all boys on weekly treatment. Obesity rates did not differ from untreated boys. Twice weekly prednisone improved strength over 6-12 months in the majority of boys, but did not slow contracture development. Sustained benefit beyond 12 months is possible with fewer side effects compared to daily prednisone.