Setrusumab vs Bisphosphonates in Pediatric Subjects With Osteogenesis Imperfecta

Inclusion Criteria: * Male or female 2 to \< 7 years of age at time of informed consent * Clinical diagnosis of OI Types I, III, or IV confirmed by identification of genetic mutation in COL1A1 or COL1A2 * History of ≥ 1 fracture in the past 12 months, ≥ 2 fractures in the past 24 months, or ≥ 1 femur, tibia, or humerus fracture in the past 24 months * Any prior exposure to, or currently receiving, IV-bisphosphonate therapy for treatment of OI * Serum 25-hydroxyvitamin D level ≥ 20 ng/mL at the Screening visit. If 25-hydroxyvitamin D levels are below 20 ng/mL, the subject may be rescreened after a minimum of 14 days of vitamin D supplementation as directed by the Investigator Exclusion Criteria: * Contraindication for the use of IV bisphosphonates based on clinical judgment of the Investigator * History of skeletal malignancies or bone metastases at any time * History of neural foraminal stenosis (except if due to scoliosis) * Clinical manifestations of Chiari malformation or basilar invagination. Presence of any other neurologic disease that has been clinically unstable within past 2 years requires review by the Medical Monitor. * History of or current uncontrolled concomitant diseases that may impact bone metabolism, such as hypo/hyperparathyroidism, abnormal thyroid function, nephrotic syndrome, or Stage IV/V renal disease * Any skeletal condition (other than OI) leading to bone deformity and/or increased risk of fractures, such as rickets, osteopetrosis, idiopathic juve…