Trial of Pamrevlumab (FG-3019), in Non-Ambulatory Subjects With Duchenne Muscular Dystrophy (DMD)

Each subject will receive pamrevlumab (35 mg/kg) every two weeks by intravenous infusion for
up to 156 weeks. After at least 10 to 12 subjects complete one year of treatment interim
analysis may increase total subjects enrolled to approximately 32. All subjects will be
closely monitored for safety. Efficacy assessments will be performed routinely over the
course of the study.

Inclusion Criteria:

- At least 12 years of age

- Written consent/assent by patient and/or legal guardian as per regional and/or IRB
requirements

- Non-ambulatory

- Brooke Score for Arms and Shoulders ≤5

- Diagnosis of DMD by medical history and confirmed Duchenne mutation in available
genetic testing using a validated genetic test

- Able to perform spirometry

- Able to undergo cardiac and extremity (upper arm) MRI

- Percent predicted FVC between 40 and 90, inclusive

- At least one historical FVC% predicted value within 18 months of baseline

- Left ventricular ejection fraction ≥ 45% as determined by cardiac MRI at screening or
within 3 months prior to day 0

- Subjects currently receiving heart failure cardiac medications (e.g. angiotensin
converting enzyme inhibitors, angiotensin-receptor blockers, and beta-blockers) must
achieve a stable regimen for at least 3 months prior to screening

- On a stable dose of corticosteroids for a minimum of 6 months prior to screening with
no substantial change in dosage for a minimum of 3 months (except for adjustments for
changes in body weight) prior to screening and no foreseen change in corticosteroid
use during the course of study participation

- Received pneumococcal vaccine and is receiving annual influenza vaccinations

- Adequate renal function: cystatin C ≤1.4 mg/L

- Adequate hematological function

1. Platelets >100,000/mcL

2. Hemoglobin >12 g/dL

3. Absolute neutrophil count >1500/μL

- Adequate hepatic function

1. No history or evidence of liver disease

2. Gamma glutamyl transferase (GGT) ≤3 x upper limit of normal (ULN)

3. Total bilirubin ≤1.5xULN

- If sexually active, will use medically accepted contraceptives during participation in
the study and for 3 months after the last dose of study drug

Exclusion Criteria:

- Requires ≥16 hours continuous ventilation

- Prior or ongoing medical condition that, in the investigator's opinion, could
adversely affect the safety of the subject, makes it unlikely that the course of 156
weeks of treatment and follow-up would be completed, or could impair the assessment of
study results

- Anticipated spine surgery within 156 weeks

- Severe uncontrolled heart disease

1. Need for intravenous diuretics or inotropic support within 3 months prior to
screening

2. Hospitalization for a heart failure exacerbation or arrhythmia in last 3 months

- Arrhythmia requiring anti-arrhythmic therapy

- Hospitalization due to respiratory failure in the last 6 weeks

- Poorly controlled asthma or underlying lung disease such as bronchopulmonary dysplasia

- Known or suspected active hepatitis B or C or history of HIV

- BMI ≥40 kg/m^2 or weight >117 kg

- Exposure to another investigational drug within 28 days prior to start of study
treatment

- Exposure to another investigational drug or another approved product for DMD (e.g.
eteplirsen) within 28 days prior to start of study treatment (or 5 half-lives of the
product whichever is longer) prior to first screening visit with the exception of
deflazacort. Use of deflazacort if regarded by the principal investigator as standard
of care is allowed.