Longitudinal effect of eteplirsen versus historical control on ambulation in Duchenne muscular dystrophy

To continue evaluation of the long-term efficacy and safety of eteplirsen, a phosphorodiamidate morpholino oligomer designed to skip DMD exon 51 in patients with Duchenne muscular dystrophy (DMD). Three-year progression of eteplirsen-treated patients was compared to matched historical controls (HC). METHODS: Ambulatory DMD patients who were 657 years old and amenable to exon 51 skipping were randomized to eteplirsen (30/50mg/kg) or placebo for 24 weeks. Thereafter, all received eteplirsen on an open-label basis. The primary functional assessment in this study was the 6-Minute Walk Test (6MWT). Respiratory muscle function was assessed by pulmonary function testing (PFT). Longitudinal natural history data were used for comparative analysis of 6MWT performance at baseline and months 12, 24, and 36. Patients were matched to the eteplirsen group based on age, corticosteroid use, and genotype. RESULTS: At 36 months, eteplirsen-treated patients (n = 12) demonstrated a statistically significant advantage of 151m (p < 0.01) on 6MWT and experienced a lower incidence of loss of ambulation in comparison to matched HC (n = 13) amenable to exon 51 skipping. PFT results remained relatively stable in eteplirsen-treated patients. Eteplirsen was well tolerated. Analysis of HC confirmed the previously observed change in disease trajectory at age 7 years, and more severe progression was observed in patients with mutations amenable to exon skipping than in those not amenable. The subset of patients amenable to exon 51 skipping showed a more severe disease course than those amenable to any exon skipping. INTERPRETATION: Over 3 years of follow-up, eteplirsen-treated patients showed a slower rate of decline in ambulation assessed by 6MWT compared to untreated matched HC. Ann Neurol 2016;79:257-271

Consensus guidelines for improving quality of assessment and training for neuromuscular diseases

Critical components of successful evaluation of clinical outcome assessments (COAs) in multisite clinical trials and clinical practice are standardized training, administration, and documented reliability of scoring. Experiences of evaluators, alongside patient differences from regional standards of care, may contribute to heterogeneity in clinical center\u27s expertise. Achieving low variability and high reliability of COA is fundamental to clinical research and to give confidence in our ability to draw rational, interpretable conclusions from the data collected. The objective of this manuscript is to provide a framework to guide the learning process for COAs for use in clinics and clinical trials to maximize reliability and validity of COAs in neuromuscular disease (NMD). This is a consensus-based guideline with contributions from fourteen leading experts in clinical outcomes and the field of clinical outcome training in NMD. This framework should guide reliable and valid assessments in NMD specialty clinics and clinical trials. This consensus aims to expedite study start up with a progressive training pathway ranging from research naïve to highly experienced clinical evaluators. This document includes recommendations for education guidelines and roles and responsibilities of key stakeholders in COA assessment and implementation to ensure quality and consistency of outcome administration across different settings

Assessing Dysferlinopathy Patients Over Three Years With a New Motor Scale

The Jain COS Consortium.[Objective] Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD.[Methods] We collected a longitudinal series of functional assessments from 187 patients with dysferlinopathy over 3 years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and nonambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories.[Results] The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3 to 8 years post symptom onset at baseline.[Interpretation] The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinical practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short-term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy. ANN NEUROL 2021;89:967–978The estimated US $4 million needed to fund this study was provided by the Jain Foundation. (www.jain-foundation.org) The Jain COS consortium would like to thank the study participants and their families for their invaluable contribution. The John Walton Centre Muscular Dystrophy Research Centre is part of the MRC Centre for Neuromuscular Diseases (Grant number MR/K000608/1).Peer reviewe

Assessing dysferlinopathy patients over three years with a new motor scale

OBJECTIVE: Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD. METHODS: We collected a longitudinal series of functional assessments from 187 dysferlinopathy patients over three years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and non-ambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories. RESULTS: The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3-8 years post symptom onset at baseline. INTERPRETATION: The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinics practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short-term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy

Remote Delivery of Motor Function Assessment and Training for Clinical Trials in Neuromuscular Disease: A Response to the COVID-19 Global Pandemic

Clinical outcome assessments of function or strength, assessed by physical therapists, are commonly used as primary endpoints in clinical trials, natural history studies and within clinics for individuals with neuromuscular disorders. These evaluations not only inform the efficacy of investigational agents in clinical trials, but also importantly track disease trajectory to prospectively advise need for equipment, home and work modifications, and other assistive devices. The COVID-19 pandemic had a global impact on the safety and feasibility of in-person visits and assessments, necessitating rapid development of mitigation strategies to ensure ongoing collection of key clinical trial endpoints and access to expert clinical care despite travel restrictions. Physical therapists who are expert in neuromuscular disorders working across clinics, countries, and clinical trials developed initial guidelines and methods for the suitability and feasibility of performing remote evaluations. A number of Sponsors introduced amendments to their study protocols to enable remote evaluations, supported by live video streaming of the assessment to their local clinical evaluators. Similarly, application of these techniques to clinical telemedicine enabled objective evaluations for use in payer discussions, equipment procurement, and general access to expert physical therapy services. Here we report on our methodology for adapting current practices to remote testing and considerations for remote evaluations

Long-Term Pulmonary Function in Duchenne Muscular Dystrophy: Comparison of Eteplirsen-Treated Patients to Natural History

Background: Duchenne muscular dystrophy (DMD) is a rare, degenerative, X-linked genetic disease that results in progressive muscle loss and premature death, most commonly from respiratory or cardiac failure. DMD is primarily caused by whole exon deletions, resulting in a shift of the dystrophin mRNA reading frame that prevents production of functional dystrophin protein. Eteplirsen, a phosphorodiamidate morpholino oligomer (PMO), is designed to skip exon 51, restore the reading frame, and induce production of internally shortened dystrophin in patients with mutations amenable to such treatment. Objective: Describe lung function assessed throughout eteplirsen studies 201/202. Methods: Studies 201/202 included 12 patients treated with eteplirsen over 5 years. Pulmonary function tests included forced vital capacity (FVC), maximum expiratory pressure (MEP), and maximum inspiratory pressure (MIP). With no long-term placebo control, FVC results were compared with data from the United Dystrophinopathy Project (UDP). MIP and MEP were compared to published natural history. Results: Age-adjusted mixed-model repeated-measures analysis showed decreases of 2.3% and 2.6% annually for FVC% p and MEP% p, and an annual increase of 0.6% for MIP% p for the eteplirsen-treated cohort. Data from the UDP demonstrated a 4.1% decline in FVC% p. The published natural history reports annual declines of at least 2.7% and 3.8% for MEP% p and MIP% p, respectively, in patients with DMD. Conclusions: With eteplirsen treatment, deterioration of respiratory muscle function based on FVC% p was half of that seen in the UDP; MEP% p and MIP% p compared favorably with natural history

First Regulatory Qualification of a Novel Digital Endpoint in Duchenne Muscular Dystrophy: A Multi-Stakeholder Perspective on the Impact for Patients and for Drug Development in Neuromuscular Diseases.

BACKGROUND: Functional outcome measures used to assess efficacy in clinical trials of investigational treatments for rare neuromuscular diseases like Duchenne muscular dystrophy (DMD) are performance-based tasks completed by the patient during hospital visits. These are prone to bias and may not reflect motor abilities in real-world settings. Digital tools, such as wearable devices and other remote sensors, provide the opportunity for continuous, objective, and sensitive measurements of functional ability during daily life. Maintaining ambulation is of key importance to individuals with DMD. Stride velocity 95th centile (SV95C) is the first wearable acquired digital endpoint to receive qualification from the European Medicines Agency (EMA) to quantify the ambulation ability of ambulant DMD patients aged ≥5 years in drug therapeutic studies; it is also currently under review for the US Food and Drug Administration (FDA) qualification. SUMMARY: Focusing on SV95C as a key example, we describe perspectives of multiple stakeholders on the promise of novel digital endpoints in neuromuscular disease drug development

Assessing Dysferlinopathy Patients Over Three Years With a New Motor Scale

Objective Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD. Methods We collected a longitudinal series of functional assessments from 187 patients with dysferlinopathy over 3 years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and nonambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories. Results The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3 to 8 years post symptom onset at baseline. Interpretation The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinical practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short-term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy. ANN NEUROL 2021;89:967–97