FDA Approves Biosimilars Referencing Denosumab for Osteoporosis-, Cancer-Related Skeletal Events

The FDA granted regulatory approval to Stoboclo (CT-P41, denosumab-bmwo) and Osenvelt (CT-P41, denosumab-bmwo), both biosimilars referencing denosumab (Prolia, Xgeva; Amgen), for all indications of the reference products, including osteoporosis-related fractures and cancer-related skeletal events in patients with a high risk of bone damage.¹

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"Biosimilars have expanded into new therapeutic areas such as immunology, oncology, and ophthalmology as they continue to offer significant cost-saving potential while expanding patient access,” Jean-Yves Reginster, director of the World Health Organization Collaborating Center for Epidemiology of Musculoskeletal Health and Aging, said in a news release. “Having a denosumab product with a clinically proven track record in quality and safety is a valuable addition for my patients."¹

These approvals are based on a litany of clinical evidence, including phase 3 clinical trial results from analyses of postmenopausal women with osteoporosis. The trials were engineered to investigate the efficacy, pharmacodynamics (PD), pharmacokinetics (PK), safety, and immunogenicity of CT-P41 compared with denosumab. Results indicated that CT-P41 led to equivalent efficacy and PD to the reference product, with similar PK and comparable safety and immunogenicity profiles, according to investigators.¹

Stoboclo, a receptor activator of NF-κb ligand (RANKL) inhibitor that references Prolia, has multiple FDA-approved indications through a 60 mg/mL injection. These include for the treatment of postmenopausal women with osteoporosis at high risk of fracture, to increase bone mass in men with osteoporosis at high fracture risk, and to treat glucocorticoid-induced osteoporosis in both men and women at high risk of fracture, according to the news release. Like the reference product, Stoboclo is contraindicated in hypocalcemia, pregnant women, and in patients with a known denosumab hypersensitivity.¹

Osenvelt, a RANKL inhibitor that references Xgeva, also has a variety of approved indications through a 70 mg/mL injection based on robust clinical evidence. These US approvals include preventing skeletal-related events in patients with multiple myeloma and patients with solid tumor-related bone metastases, the treatment of adults and skeletally mature adolescents with unresectable giant cell tumor of the bone, and the treatment of malignant hypercalcemia refractory to therapy. Importantly, for patients taking either biosimilar, they should not be receiving other denosumab products concomitantly.¹

Stoboclo and Osenvelt’s respective approvals follow the FDA clearance of biologics license applications for 2 other denosumab biosimilars: Xbryk (denosumab-dssb 120 mg vial; Samsung Bioepis Co) and Ospomyv (denosumab-dssb 60 mg prefilled syringe; Samsung Bioepis Co). The indications are like those of Stoboclo and Osenvelt and contribute to the ever-growing portfolio of denosumab biosimilars that are poised to offer cost savings and more optimized treatment for patients dealing with bone-related disease complications.²

"The approval of Stoboclo and Osenvelt is another step forward in our efforts to deliver cost-effective and high-quality treatments that address critical unmet needs in osteoporosis-related fracture as well as cancer-related skeletal events," Thomas Nusbickel, chief commercial officer at Celltrion USA, said in the news release. "Patients deserve therapeutic options that have the potential to make real impacts on their care and their lives.”¹

REFERENCES

1. Celltrion. Celltrion receives US FDA approval for STOBOCLO® (denosumab-bmwo) and OSENVELT® (denosumab-bmwo) biosimilars referencing PROLIA® and XGEVA®. News Release. Released March 4, 2025. Accessed March 4, 2025. https://www.celltrion.com/en-us/company/media-center/press-release/3768

2. Halpern L. FDA approves biosimilar denosumab-dssb to treat osteoporosis-, cancer-related bone loss. Pharmacy Times. Published February 17, 2025. Accessed March 4, 2025. https://www.pharmacytimes.com/view/fda-approves-biosimilar-denosumab-dssb-to-treat-osteoporosis--cancer-related-bone-loss