A Dose REgimen-Finding Study of AGA2115 in Chinese Patients With Osteogenesis ImpeRfecta (EIR)

This study is to evaluate the safety and efficacy of AGA2115 at three different dose regimens in Chinese adults and adolescents with Type I, III, or IV Osteogenesis imperfecta (OI).

Inclusion Criteria: * Adults (18-75 years) or adolescents (12-17 years) with a confirmed diagnosis of Osteogenesis Imperfecta (OI) Type I, III, or IV with genetic confirmation of pathogenic variants in COL1A1 or COL1A2 genes * BMD T-score of ≤-1.0 at the lumbar spine, total hip, or femoral neck (adults) or BMD Z-score of ≤-1.0 at the lumbar spine, total hip, or femoral neck (adolescents) * Capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol Exclusion Criteria: * Vitamin D deficiency * Concomitant uncontrolled diseases or conditions that could affect bone metabolism such as hypo-/hyperparathyroidism, hypo-/hyperthyroidism, abnormal thyroid function or thyroid disease, or other endocrine disorders. * Current hyper- or hypocalcemia. * History of rickets, osteomalacia, or other significant skeletal disorders (excluding OI) leading to long-bone deformities and/or increased risk of fractures. * Use of bisphosphonates within the past 6 months. * Use of teriparatide, abaloparatide, strontium ranelate, or hormone replacement therapy within the past 12 months. * Use of denosumab (or denosumab biosimilars) within the past 2 years. * Use of anti-sclerostin antibody medications (romosozumab, setrusumab, blosozumab) at any time. * History of myocardial infarction or stroke (or other cardiovascular associated event deemed significant) within the past 12 months. * Malignancy within the last 5 years. * Pregnant or breastfeeding women, or women planning to become pregnant during the study or within 4 months after the last dose of IP.