Two More Pairs of Denosumab Biosimilars Enter US Market

The US biosimilar market recently saw the introduction of 2 pairs of denosumab biosimilars from Fresenius Kabi and Celltrion USA, significantly expanding treatment options for individuals living with bone-related conditions.^1,2

The pairs of denosumab competitors follow the launches of Sandoz’ Wyost and Jubbonti (denosumab-bbdz for both), which launched in March 2025. | Image credit: SoftSheep - stock.adobe.com

Fresenius Kabi announced the commercial availability of Conexxence (denosumab-bnht) and Bomyntra (denosumab-bnht). Conexxence is a biosimilar referencing Prolia (denosumab), and Bomyntra is a biosimilar referencing Xgeva (denosumab). The biosimilars received approval from the FDA for all indications of their respective reference products in March 2024.³

Conexxence is indicated for various adult patient populations at high risk for fractures.¹ This includes individuals with osteoporosis, people undergoing certain cancer treatments that affect bone density, and patients receiving long-term glucocorticoid therapy. It is available in a 60-mg/mL single-use prefilled syringe. Fresenius Kabi noted that Conexxence carries a black box warning and is part of a Risk Evaluation and Mitigation Strategy program designed to inform prescribers and patients about the risk of severe hypocalcemia in individuals with advanced chronic kidney disease, including those on dialysis. The biosimilar is contraindicated in patients with hypocalcemia, during pregnancy, and in cases of known hypersensitivity to denosumab products.

Bomyntra is approved for the prevention of skeletal-related events in patients with multiple myeloma and in individuals with bone metastases from solid tumors. It is also indicated for the treatment of hypercalcemia of malignancy that is refractory to bisphosphonate therapy and for the treatment of adults and skeletally mature adolescents with giant cell tumor of the bone that is unresectable or where surgical resection is likely to result in severe morbidity. Bomyntra is available in a 120-mg/1.7-mL vial and a 120-mg/1.7-mL single-use prefilled syringe. It is contraindicated in patients with hypocalcemia and those with known hypersensitivity to denosumab products.

Sang Jin Pak, PhD, president of Fresenius Kabi Biopharma, expressed the company’s commitment to consistent biosimilar launches, stating, “Access to high-quality biological medicines creates the opportunity to provide more affordable therapies to patients and as our biosimilar portfolio expands, we will be able to provide access for even more patients.” Earlier this year, Fresenius Kabi reached a global settlement with Amgen regarding its denosumab biosimilars.

Just a week after, Celltrion USA announced the commercial availability of its denosumab biosimilars, Stoboclo (denosumab-bmwo) and Osenvelt (denosumab-bmwo). Stoboclo references Prolia (denosumab), while Osenvelt references Xgeva (denosumab).² Stoboclo and Osenvelt were approved by the FDA in March 2025.⁴

Stoboclo is available as a 60-mg/mL injection. It is approved to treat postmenopausal women with osteoporosis at high risk for fracture, to increase bone mass in men with osteoporosis at high risk for fracture, and to treat glucocorticoid-induced osteoporosis in men and women at high risk for fracture. Additionally, it is indicated to increase bone mass in men at high risk for fracture who are receiving androgen deprivation therapy for nonmetastatic prostate cancer and to increase bone mass in women at high risk for fracture receiving adjuvant aromatase inhibitor therapy for breast cancer.

Osenvelt, available as a 120-mg/1.7-mL (70 mg/mL) injection, is indicated to prevent skeletal-related events in patients with multiple myeloma and in individuals with bone metastases from solid tumors. It is also approved to treat adults and skeletally mature adolescents with giant cell tumor of bone that is unresectable or where surgical resection is likely to result in severe morbidity and to treat hypercalcemia of malignancy refractory to bisphosphonate therapy.

Thomas Nusbickel, chief commercial officer at Celltrion USA, highlighted the significance of the launches, stating, "We are proud to introduce our denosumab biosimilars to the U.S. market, offering patients and professionals a valuable alternative treatment option." Celltrion also reached a global settlement with Amgen concerning its denosumab biosimilars. To support patients, Celltrion offers comprehensive patient support programs, including the Celltrion Connect patient support program and the Celltrion Cares co-pay assistance program, with options for uninsured patients to potentially receive treatment at no cost.

Growing Denosumab Competition

The pairs of denosumab competitors follow the launches of Sandoz’ Wyost and Jubbonti (denosumab-bbdz for both), which launched in March 2025, nearly a year after they became the first denosumab biosimilars to be greenlit by the FDA.⁵

Now that Xgeva and Prolia have 3 competitors each, the market is starting to stack up, with Ospomyv and Xbryk (denosumab-dssb for both), which were developed by Samsung Bioepis are waiting in the wings to launch next.⁶

“By providing quality-proven biosimilars, we are helping to address a critical healthcare need and reduce the burden of skeletal fractures that impact patients’ quality of life,” Byoungin Jung, vice president and regulatory affairs team leader at Samsung Bioepis, commented.

References

1. Fresenius expands biosimilars portfolio with the launch of denosumab biosimilars in the U.S. News release. Fresenius Kabi. July 1, 2025. Accessed July 9, 2025. https://www.businesswire.com/news/home/20250701511446/en/Fresenius-Expands-Biosimilars-Portfolio-With-The-Launch-of-Denosumab-Biosimilars-in-the-U.S

2. Celltrion USA announces U.S. launch of denosumab biosimilars, Stoboclo and Osenvelt (denosumab-bmwo). News release. Celltrion USA. July 7, 2025. Accessed July 9, 2025. https://www.prnewswire.com/news-releases/celltrion-usa-announces-us-launch-of-denosumab-biosimilars-stoboclo-and-osenvelt-denosumab-bmwo-302499495.html

3. Santoro C. FDA approves another pair of denosumab biosimilars, Conexxence and Bomyntra. The Center for Biosimilars^®. March 27, 2025. Accessed July 9, 2025. https://www.centerforbiosimilars.com/view/fda-approves-another-pair-of-denosumab-biosimilars-conexxence-and-bomyntra

4. Jeremias S. FDA approves third pair of denosumab biosimilars. The Center for Biosimilars. March 4, 2025. Accessed July 9, 2025. https://www.centerforbiosimilars.com/view/fda-approves-third-pair-of-denosumab-biosimilars

5. Jeremias S. Wyost and Jubbonti launch as first denosumab biosimilars in the US. The Center for Biosimilars. June 2, 2025. Accessed July 9, 2025. https://www.centerforbiosimilars.com/view/wyost-and-jubbonti-launch-as-first-denosumab-biosimilars-in-the-us

6. Jeremias S. FDA, EMA approve second pair of denosumab biosimilars. The Center for Biosimilars. February 17, 2025. Accessed July 9, 2025. https://www.centerforbiosimilars.com/view/fda-ema-approve-second-pair-of-denosumab-biosimilars