Registry Study to Observe Long-term Safety of Vamorolone (AGAMREE®) in Patients With Duchenne Muscular Dystrophy-SUMMIT

Standing height in participants 2 years of age and older will be measured using a stadiometer mounted at a right angle between a level floor and against a straight, vertical surface. When transitioning from recumbent length to standing height measurements in participants between 2 to 3 years of age, measure both length and height. If collecting standing height measurements is not feasible, height will be estimated using arm span measurements. To estimate the height, the arm span will be measured from fingertip to fingertip with arms fully extended horizontally. The same standardized technique will be used at all study visits.

Weight will be measured according to the site's standard of care procedures. For ambulatory patients, this typically involves a standing scale; for non-ambulatory patients, a wheelchair or bed scale may be used. Sites should document the method used at each visit.

The North Star Ambulatory Assessment is a clinical assessment scale specifically designed to measure functional ability in ambulant male patients with DMD. The North Star Ambulatory Assessment consists of 17 scored items and 2 timed tests, including the Time to Run/Walk Test and the Time to Stand Test. The Time to Run/Walk Test measures the time (in seconds) that it takes the patient to run or walk 10 meters. The Time to Stand Test measures the time (in seconds) required for the patient to stand in an erect position from supine (floor). Patients should be barefoot and comfortably clothed.

North Star Ambulatory Assessment score range is 0 to 34, with higher scores indicating better ambulatory function.

The Performance of Upper Limb assessment is an observer-rated measure of upper-limb function in individuals with Duchenne muscular dystrophy. It includes an entry item to determine the participant's starting functional level and a series of tasks evaluating shoulder, mid-level (elbow), and distal (wrist/hand) abilities. Total scores reflect the participant's ability to perform defined functional movements, with higher scores indicating better function.

Pubertal development will be assessed by a physician using Tanner Stages assessment. This assessment uses Male External Genitalia Scale.

Stage 1: Testicular volume < 4 ml or long axis < 2.5 cm Stage 2: 4 ml-8 ml (or 2.5 to 3.3 cm long), 1st pubertal sign in males Stage 3: 9 ml-12 ml (or 3.4 to 4.0 cm long) Stage 4: 15-20 ml (or 4.1 to 4.5 cm long) Stage 5: > 20 ml (or > 4.5 cm long) Pubic Hair Scale Stage 1: No hair Stage 2: Downy hair Stage 3: Scant terminal hair Stage 4: Terminal hair that fills the entire triangle overlying the pubic region Stage 5: Terminal hair that extends beyond the inguinal crease onto the thigh Pubertal development assessments will be discontinued when the patient has completed puberty.

Presence of cataract and glaucoma will be assessed by an optometrist or ophthalmologist.

Lateral spine x-ray will be performed to evaluate vertebral fractures and for spine deformities.

Anterior-posterior/Posterior-anterior spine x-ray will be performed to evaluate spine deformities.

Posteroanterior hand x-ray will be performed for the bone age assessment.

Bone mineral content, bone mineral density, bone area, and bone mineral density Z-score will be assesses using dual x-ray absorptiometry (DXA). Summary statistics will be tabulated by anatomical location at each visit.

Fat mass, lean mass, and fat-free mass will be assessed using DXA. Summary statistics will be tabulated by visit.

Body fat percentage, tissue fat percentage, android/gynoid body fat percent ratio, and android/gynoid tissue fat percent ratio will be assessed using DXA. Summary statistics will be tabulated by visit.

If available as per standard of care, findings from echocardiography will be collected. This is not required if not available as part of the standard of care.

Adverse events (AEs) and serious adverse events (SAEs) will be collected after signing the informed consent through the end of study participation. The frequency and percentage of patients experiencing any AE or SAE will be summarized. Adverse events will be assessed and documented by the investigator based on routine clinical evaluations, including vital signs, physical examinations, laboratory assessments, and medical record review. For each adverse event, the Investigator will document relevant clinical details, including timing, severity, outcome, and assessments of the seriousness and causality. Adverse events will be assessed by the current version of the CTCAE at the time the adverse event is identified, and will be summarized by MedDRA system organ class and preferred term using the current version of MedDRA.

Myocardial damage will be assessed through magnetic resonance imaging using late gadolinium enhancement. Late gadolinium enhancement is a technique used in cardiac MRI for cardiac tissue characterization, in particular, the assessment of myocardial scar formation and regional myocardial fibrosis

Presence of cardiomyopathy will be assessed by echocardiography using transmural strain profile (only in a subset of patients taking part in the cardiac sub-study).

Duchenne Muscular Dystrophy Quality of Life questionnaire is a patient-reported outcome measure designed to assess how Duchenne muscular dystrophy affects physical, emotional, and social aspects of daily life.

Duchenne Muscular Dystrophy Quality of Life questionnaire proxy report will be completed by a parent/guardian for patients aged 7 years and older. For patients aged 10 years and older, a self-report will be completed by the patient, and, if feasible, a proxy report will also be completed by the parent or guardian.

Patient Reported Outcome Measure for the Upper Limb is a questionnaire for young males/children with DMD from the age of 7 years. The PROM UL will be completed by parent/legal guardian up to the age of 16 years and by the patient from the age of 17 years. It consists of 32 items covering four domains of activities of daily living: (1) food, (7 items, max score 14); (2) self-care, (8 items, max score 16); (3) household and environment, (6 items, max score 12); (4) leisure and communication, (11 items, max score 22). For each question, the patients and/or their parent/legal guardian are asked to report their perceived difficulty in performing the activity on a 3-level scale: Cannot do (0); Can do with difficulty (1); Can do easily (2). The maximum total score is 64, with higher score indicating better function.