 Safety will be regularly assessed throughout the study via the collection of adverse events AEs, laboratory tests, electrocardiograms ECGs, echocardiograms ECHOs, vital signs, and physical examinations. Exploratory efficacy assessments, including PFTs, upper extremity testing, and other measurements of functional status, will occur at functional assessment visits every 12 weeks over the first year of treatment and approximately every 24 weeks over the second year of treatment. 