Survival among patients receiving eteplirsen for up to 8 years for the treatment of Duchenne muscular dystrophy and contextualization with natural history controls.

INTRODUCTION/AIMS: Eteplirsen, approved in the US for patients with Duchenne muscular dystrophy (DMD) with exon 51 skip-amenable variants, is associated with attenuated ambulatory/pulmonary decline versus DMD natural history (NH). We report overall survival in a US cohort receiving eteplirsen and contextualize these outcomes versus DMD NH. METHODS: US patients with DMD receiving eteplirsen were followed through a patient support program, with data collected on ages at eteplirsen initiation and death/end of follow-up. Individual DMD NH data were extracted by digitizing Kaplan-Meier (KM) curves from published systematic and targeted literature reviews. Overall survival age was analyzed using KM curves and contextualized with DMD NH survival curves; subanalyses considered age groups and duration of eteplirsen exposure. Overall survival time from treatment initiation was also evaluated. RESULTS: A total of 579 eteplirsen-treated patients were included. During a total follow-up of 2119 person-years, median survival age was 32.8 years. DMD NH survival curves extracted from four publications (follow-up for 1224 DMD NH controls) showed overall pooled median survival age of 27.4 years. Eteplirsen-treated patients had significantly longer survival from treatment initiation versus age-matched controls (age-adjusted hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.44-0.98; p < .05). Longer treatment exposure was associated with improved survival (HR, 0.15; 95% CI, 0.05-0.41; p < .001). Comparisons using different DMD NH cohorts to address common risks of bias yielded consistent findings. DISCUSSION: Data suggest eteplirsen may prolong survival in patients with DMD across a wide age range. As more data become available, the impact of eteplirsen on survival will be further elucidated.

Rate of Change in Cardiac Magnetic Resonance Imaging Measures Is Associated With Death in Duchenne Muscular Dystrophy.

BACKGROUND: Cardiovascular disease is the leading cause of death among patients with Duchenne muscular dystrophy (DMD). Identifying patients at risk of early death could allow for increased monitoring and more intensive therapy. Measures that associate with death could serve as surrogate outcomes in clinical trials. METHODS AND RESULTS: Duchenne muscular dystrophy subjects prospectively enrolled in observational studies were included. Models using generalized least squares were used to assess the difference of cardiac magnetic resonance measurements between deceased and alive subjects. A total of 63 participants underwent multiple cardiac magnetic resonance imaging and were included in the analyses. Twelve subjects (19.1%) died over a median follow-up of 5 years (interquartile range, 3.1-7.0). Rate of decline in left ventricular ejection fraction was faster in deceased than alive subjects (P<0.0001). Rate of increase in indexed left ventricular end-diastolic (P=0.0132) and systolic (P<0.0001) volumes were higher in deceased subjects. Faster worsening in midcircumferential strain was seen in deceased subjects (P=0.049) while no difference in global circumferential strain was seen. The rate of increase in late gadolinium enhancement, base T1, and mid T1 did not differ between groups. CONCLUSIONS: Duchenne muscular dystrophy death is associated with the rate of change in left ventricular ejection fraction, midcircumferential strain, and ventricular volumes. Aggressive medical therapy to decrease the rate of progression may improve the mortality rate in this population. A decrease in the rate of progression may serve as a valid surrogate outcome for therapeutic trials.

Respiratory comorbidities and treatments in Duchenne muscular dystrophy: impact on life expectancy and causes of death.

BACKGROUND: Duchenne muscular dystrophy (DMD) is a neuromuscular disorder with progressive decline of pulmonary function increasing the risk of early mortality. The aim of this study was to explore the respiratory-related comorbidities, and the effect of these comorbidities and treatments on life expectancy and causes of death. METHODS: All male patients living in Sweden with DMD, born and deceased 1970-2019, were included. Data regarding causes of death were collected from the Cause of Death Registry and cross-checked with the medical records along with diagnostics and relevant clinical features. RESULTS: Hundred and twenty nine patients were included with a median lifespan of 24.3 years. Acute respiratory failure accounted for 63.3% of respiratory-related causes of death. 70.1% suffered at least one pneumonia, with first episode at a median age of 17.8 years. Hypoventilation was found in 73.0% with onset at 18.1 years. 60.5% had their first pneumonia before established hypoventilation. Age at onset of hypoventilation showed a strong correlation with age at first pneumonia. First pneumonia and scoliosis non-treated with scoliosis surgery increased the risk of dying of respiratory-related causes. In 10% of the patients, first pneumonia resulted in acute tracheostomy or early death. Patients treated with assisted ventilation had higher life expectancy compared to untreated patients. CONCLUSIONS: Our results highlight the importance of identifying subclinical hypoventilation in a timely manner and the importance of an active treatment regime upon clinical signs of pneumonia.

Sobrevida de pacientes con distrofia muscular de Duchenne / Survival of patients with Duchenne muscular dystrophy

INTRODUCCIÓN: La distrofia muscular de Duchenne (DMD) conduce a un deterioro progresivo de la función muscular y muerte prematura. Los estudios longitudinales sobre el curso de esta patología en Chile, son nulos. OBJETIVO: Determinar sobrevida entre los años 1993-2013, en 2 periodos (1993 2002 y 2003-2013); y efecto de determinantes sociales en pacientes con DMD ingresados a Institutos Teletón Chile (IT). PACIENTES Y MÉTODO: Estudio pronóstico de seguimiento en serie clínica de 462 pacientes portadores de DMD. La información requerida se obtuvo mediante búsqueda de pacientes con DMD en cubo OLAP (On-Line Analytical Processing). De las fichas clínicas del IT-Stgo, se registraron las variables correspondientes al método diagnóstico, etapa de DMD descrito en función al deterioro muscular y funcionamiento mediante Escala Swinyard; existencia y tipo de exámenes que concluyen el diagnóstico y en los casos que se informó, la existencia de antecedentes familiares. Se realizó análisis de sobrevida de Kaplan Meier, donde la sobrevida global se definió entre el nacimiento y edad de muerte. Los factores determinantes analizados fueron estimados a través del modelo de riesgos proporcionales de Cox-Snell. RESULTADOS: La sobrevida a los 20 años de edad desde el ingreso a los IT, fue de 51,7% (IC95%: 45,1-57,8%); en el período 1993-2002 de 48,5% y entre 2003-2013 de 72,8%. El porcentaje de sobrevida a la misma edad, según nivel socioeconómico alto fue de 82%, medio 67% y bajo 42%, diferencia estadísticamente significativa entre nivel alto y medio, respecto de extrema pobreza. Según zonas del país, la sobrevida fue cercana al 75% a los 17 años de edad. CONCLUSIONES: La información de sobrevida aportada en pacientes con DMD desde la infancia hasta la vida adulta, es valiosa para predecir el curso clínico de la enfermedad con la atención médica actual. Se evidencia mejoría en la probabilidad de sobrevida a los 20 años e inequidad pronunciada según variable socioeconómica.

INTRODUCTION: Duchenne muscular dystrophy (DMD) leads to a progressive deterioration of the mus cle function and premature death. There are no longitudinal studies on the course of this pathology in Chile. OBJECTIVE: To determine survival between the years 1993-2013, divided into two periods (1993-2002 and 2003-2013), and the effect of social determinants in patients with DMD admitted in Teleton Institutes of Chile (TI). PATIENTS AND METHOD: Prospective follow-up study in a clinical series of 462 patients with DMD. The information was obtained by searching for patients with DMD in OLAP cube (Online Analytical Processing). From the clinical records of the TI of Santiago, the variables corresponding to the diagnostic method, stage of DMD described in terms of muscle de terioration and function according to Swinyard classification were recorded; existence and type of tests that conclude the diagnosis and, in the cases reported, the existence of family history. Kaplan Meier survival analysis was applied, where global survival was defined between birth and age of death. The determinant factors analyzed were estimated through the Cox-Snell's proportional risk model. RESULTS: Survival at 20 years of age from TI entry was 51.7% (CI95%: 45.1-57.8), 48.5% in the period 1993-2002 and 72.8% between 2003-2013. The percentage of survival at the same age according to socioeconomic status (SES) was 82% in high SES, 67% in middle SES, and 42% in low SES, with a statistically significant difference between high and middle SES in relation to extreme poverty. Ac cording to country areas, the survival was close to 75 % at 17 years of age. CONCLUSIONS: The survival information from patients with DMD from childhood to adult life is valuable for predicting the clinical course of the disease with the current medical care. There is evidence of improvement in the probability of survival at the age of 20 and marked inequity according to the socioeconomic variable.