FDA Approves Denosumab Biosimilars Stoboclo and Osenvelt

The FDA approved Stoboclo and Osenvelt, denosumab biosimilars that could offer more affordable treatment options for osteoporosis and bone loss in various patient populations. | Image Credit: wladimir1804 - stock.adobe.com

Stoboclo and Osenvelt (both denosumab-bmwo), biosimilars to Prolia and Xgeva (denosumab), respectively, were approved by the FDA for osteoporosis treatment and forms of bone loss.¹

About a year ago, Sandoz received FDA approval for Wyost and Jubbonti (denosumab-bddz) as the first biosimilars to reference denosumab.² They were both approved with interchangeability designations but for slightly different indications.

This latest approval comes after the FDA and European Medicines Agency approved Samsung Bioepis’ denosumab biosimilars, Ospomyv and Xbryk, last month and also granted them interchangeability designation.³ Celltrion’s denosumab biosimilars may further expand patient access to biosimilar treatments in this therapeutic space.

Evidence from a phase 3 clinical trial (NCT04757376) in postmenopausal women with osteoporosis supported the approval.⁴ The trial evaluated the efficacy, pharmacodynamics (PD), pharmacokinetics (PK), safety, and immunogenicity of denosumab-bmwo, when it was known as CT-P41, compared with the reference drug. The study met the primary end point based on equivalence and the PD demonstrated between CT-P41 and reference denosumab. Researchers found comparable efficacy, PD, PK, and safety results among all groups up to week 78, including those who transitioned to CT-P41 from the reference drug.

“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, said in a statement.¹

Stoboclo is a receptor activator of the NF-κb ligand inhibitor referencing Prolia. The FDA approved the drug for a 60 mg/mL injection. Stoboclo is approved for patients who are postmenopausal women with osteoporosis at high risk for fracture.

Doctors can prescribe Stoboclo to increase bone mass in men who are at high risk for fracture receiving androgen deprivation therapy for nonmetastic prostate cancer and to increase bone mass in men with osteoporosis at high-risk fracture. Stoboclo is also indicated for patients with glucocorticoid-induced osteoporosis at high risk for fracture and increased bone mass at high risk for fracture receiving an adjuvant aromatase inhibitor therapy for breast cancer.

“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, MD, PhD, director of the Department of Public Health, Epidemiology and Health Economics at the University of Liège and director of the World Health Organization Collaborating Centre for Public Health Aspects of Musculoskeletal Health and Aging, said in a statement.

Osenvelt is a receptor activator of NF-κb ligand inhibitor referencing Xgeva. The FDA approved the drug as a 120 mg/1.7 mL injection that is indicated to prevent skeletal-related events in patients with multiple myeloma and in patients with metastases from solid tumors. Doctors can also prescribe Osenvelt to treat patients with skeletally mature adolescents with giant cell tumors of bone that are unresectable or where surgical resection is likely to result in severe morbidity or to treat hypercalcemia of malignancy refractory to biophosphate therapy.

Back pain, pain in extremities, hypercholesterolemia, musculoskeletal pain, and cystitis occurred in (> 5%) patients with postmenopausal osteoporosis taking Stoboclo. Previous clinical trials have reported pancreatitis and back pain.In male patients with osteoporosis, arthralgia and nasopharyngitis have occurred. Back pain, hypertension, bronchitis, and headache were reported by (> 3%) patients with glucocorticoid-induced osteoporosis. Arthralgia and back pain were experienced by patients (≥ 10%) who had bone loss due to hormone ablation for cancer. Patients in clinical trials reported pain in extremities and musculoskeletal pain.

Fatigue/asthenia, hypophosphatemia, and nausea occurred in (≥ 25%) patients with bone metastasis from solid tumors taking Osenvelt. In patients with multiple myeloma, Osenvelt was associated with diarrhea, nausea, anemia, back pain, thrombocytopenia, peripheral edema, hypocalcemia, upper respiratory tract infection, rash, and headache. Nausea, dyspnea, decreased appetite, headache, peripheral edema, vomiting, anemia, constipation, and diarrhea were observed in (>20%) patients with hypercalcemia of malignancy treated with Osenvelt.

“Patients deserve therapeutic options that have the potential to make real impacts on their care and lives,” Nusbickel said.

References

1. Celltrion receives US FDA approval for Stoboclo (denosumab-bmwo) and Osenvelt (denosumab-bmwo) biosimilars referencing Prolia and Xgeva. News release. Prnewswire; March 3, 2025. Accessed March 4, 2025. https://www.prnewswire.com/news-releases/celltrion-receives-us-fda-approval-for-stoboclo-denosumab-bmwo-and-osenvelt-denosumab-bmwo-biosimilars-referencing-prolia-and-xgeva-302390957.html
2. Joszt L. FDA approves first 2 denosumab biosimilars. AJMC^®. March 5, 2024. Accessed March 4, 2025. https://www.ajmc.com/view/fda-approves-first-2-denosumab-biosimilars
3. Santoro C. Denosumab biosimilars approved with interchangeability to address osteoporosis, fracture risk. AJMC. February 18, 2025. Accessed March 4, 2025. https://www.ajmc.com/view/denosumab-biosimilars-approved-with-interchangeability-to-address-osteoporosis-fracture-risk
4. Reginster JY, Czerwinski E, Wilk K, et al. Efficacy and safety of candidate biosimilar CT-P41 versus reference denosumab: a double-blind, randomized, active-controlled, phase 3 trial in postmenopausal women with osteoporosis. Osteoporos Int. 2024;35(11):1919-1930. doi:10.1007/s00198-024-07161-x