Findings
Traditional DMD endpoints focus on ambulation, excluding non-ambulatory patients and limiting trial inclusivity.
Accelerometer technology offers objective, real-world data collection, reducing the burden on patients and caregivers while enabling longitudinal assessment.
“Total arm movement” as a concept of interest captures meaningful functional activities across ambulatory and non-ambulatory populations.
Challenges include ensuring compliance with device use, minimizing variability from external factors (e.g., seasons, school schedules), and correlating data with meaningful treatment effects.
Continuous collaboration and data sharing among stakeholders, including regulators and technology manufacturers, is essential for endpoint development.

Recommendations
Define meaningful activities of daily living (ADLs) for DMD patients and correlate them with accelerometer-derived metrics, such as total arm movement.
Validate accelerometer data through natural history studies, cross-sectional analyses, and correlation with existing DMD-specific measures (e.g., DMD Upper Limb PROM).
Optimize measurement schedules to balance patient compliance with longitudinal data collection needs, focusing on real-world settings.
Collaborate with regulators to align endpoints with evidentiary requirements for clinical trials, ensuring their relevance and applicability.
Develop frameworks for continuous data sharing and standardization to streamline endpoint validation and regulatory acceptance.

Regulatory Considerations
Validate the endpoint to reflect meaningful treatment effects and ensure alignment with regulatory standards for phase III trials.
Address variability in data collection due to environmental or behavioral factors to enhance reliability and applicability.
Develop methodologies to correlate accelerometer-derived metrics with clinically meaningful outcomes and validated DMD measures.
Engage regulators early to obtain feedback and ensure endpoints meet the criteria for use in pivotal trials.
Explore the potential for composite endpoints combining accelerometer data with PROs to provide a comprehensive view of patient outcomes.