• Diagnosis of OI Type I, III, or IV as confirmed by identification of pathogenic or likely pathogenic genetic variants in COL1A1 or COL1A2. If a variant of uncertain significance is identified, then clinical presence of the expected phenotype can be used to confirm the diagnosis

• ≥ 1 fracture in the past 12 months, ≥ 2 fractures in the past 24 months or ≥ 1 tibia, femur or humerus fracture in the past 24 months

• Serum 25-hydroxyvitamin D ≥ 20 ng/mL at the Screening Visit. If 25-hydroxyvitamin D levels are below 20 ng/mL, 25-hydroxyvitamin D testing can repeated after a minimum of 14 days of vitamin D supplementation as directed by the treating physician

• Willing to not receive bisphosphonate therapy during the study

• From the period following informed consent to 60 days after the last dose of the study drug, females of childbearing potential and fertile males must consent to use highly effective contraception. If female, agree not to become pregnant. If male, agree not to father a child or donate sperm

• Willing and able to provide informed consent for subjects greater than or equal to 18 years of age, or provide assent (if possible) and have a legally authorized representative provide informed consent, after the nature of the study has been explained and prior to any research-related procedures

• Willing to provide access to medical records for the collection of radiographic data, fracture data, growth data, and disease history

• Must, in the opinion of the Investigator, be willing and able to complete all aspects of the study, adhere to the study visit schedule, and comply with the assessments