Denosumab is a RANKL (Receptor Activator of Nuclear factor Kappa-B Ligand) inhibitor that works by suppressing the differentiation and activation of osteoclasts, thereby blocking bone resorption. Unlike existing bisphosphonate-based drugs, it has become a new standard in osteoporosis treatment due to its convenience of subcutaneous injection every six months and its excellent bone mineral density improvement effects. Amgen's original drugs, 'Prolia' and 'Xgeva,' are used for osteoporosis treatment and prevention of skeletal-related events in cancer patients with bone metastasis, respectively. Prolia, in particular, is a blockbuster drug with annual sales exceeding $5 billion, and its market size continues to expand with the aging global population. In the development process of its denosumab biosimilar, Celltrion conducted extensive analytical and clinical studies to demonstrate structural equivalence and functional similarity of the complex monoclonal antibody. The company successfully replicated complex biological functions, such as Fc receptor binding characteristics, complement activation levels, and antibody-dependent cell-mediated cytotoxicity (ADCC), to a level equivalent to the original drug. This U.S. launch is expected to be a significant milestone in expanding Celltrion's global biosimilar portfolio. The company has already achieved successful results in the U.S. market with its trastuzumab biosimilar 'Vegzelma' and has now secured its position in the bone disease treatment market with the denosumab biosimilar. Celltrion is also accelerating the development of innovative new drugs, with plans to invest over 500 billion won in R&D by 2025. The company is focusing on developing high-value biopharmaceuticals, such as immune-oncology drugs and autoimmune disease treatments, to transition from a biosimilar specialist to a global innovative pharmaceutical company.