FDA Approves 2 More Denosumab Biosimilars

In prior columns, we reported on how the use of biosimilar treatments may improve patient access by increasing the number of medication options that have the potential to lower costs. Biosimilars are highly similar to existing biologic medications approved by the U.S. Food & Drug Administration (FDA) and have no clinically meaningful differences from their FDA-approved reference products.¹

Biosimilars that are considered interchangeable with their reference products have met other legal requirements, and the dispensing pharmacy can substitute the treatment for the reference product without consulting the prescriber.² This practice is subject to pharmacy laws, which vary by state, and is similar to how generic drugs are substituted for brand-named drugs by pharmacies. An example of these products include denosumab-bbdz (Jubbonti) and denosumab-bbdz (Wyost), which are both biosimilar to denosumab and were FDA approved as interchangeable with denosumab.³

New FDA Approvals

In September, the FDA approved denosumab-nxxp (Bildyos) and denosumab-nxxp (Bilprevda), which are both biosimilar to denosumab (Prolia and Xgeva), for all indications of the reference product. Denosumab-nxxp is available as an 60 mg/mL injection, and denosumab-nxxp is available as a 120 mg/1.7 mL injection.⁴

Denosumab binds to receptor activator of nuclear factor kappa beta ligand (RANKL), blocking its ability to bind to its receptor protein, RANK. The inhibition of the RANKL/RANK interaction helps prevent bone cells (i.e., osteoclasts) from breaking down bone in the body. 

Both biosimilar treatments are FDA approved for all indications of denosumab, including:

1. The treatment of postmenopausal women with osteoporosis at high risk of fracture;
2. To increase bone mass in men with osteoporosis at high risk of fracture;
3. The treatment of men and women with glucocorticoid-induced osteoporosis who are at high risk of fracture;
4. To increase bone mass in men at high risk for fracture who are receiving androgen deprivation therapy for nonmetastatic prostate cancer; and
5. To increase bone mass in women at high risk for fracture who are receiving adjuvant aromatase inhibitor therapy for breast cancer.

Currently, it does not appear that these newly FDA-approved biosimilar products have been granted interchangeability status.

Michele B. Kaufman, PharmD, BCGP, is a freelance medical writer based in New York City and a pharmacist at New York Presbyterian Lower Manhattan Hospital.

References

1. FDA approves first interchangeable biosimilars to Prolia and Xgeva to treat certain types of osteoporosis and prevent bone events in cancer [news release]. U.S. Food & Drug Administration. 2024 Mar 5.
2. 9 things to know about biosimilar products. U.S. Food & Drug Administration. 2024 Jun 20.
3. Purple book database of licensed biological products. U.S. Food & Drug Administration. 2025 Aug 27.
4. U.S. Food & Drug Administration approves Henlius and Organon’s Bildyos (denosumab-nxxp) and Bilprevda (denosumab-nxxp), biosimilars to Prolia (denosumab) and Xgeva (denosumab), respectively [news release]. Organon. 2025 Sep 2.