The U.S. Food and Drug Administration has granted final approval to Hikma Pharmaceuticals' biosimilar version of denosumab, therapeutically equivalent to Amgen's Prolia, according to regulatory records published Tuesday — a development that positions the London-headquartered generic manufacturer to enter one of the most lucrative osteoporosis drug markets in the United States.

Denosumab, sold by Amgen under the brand names Prolia and Xgeva, generated combined US revenues exceeding $3.2 billion in 2025. Prolia is indicated for postmenopausal women with osteoporosis at high risk of fracture, while Xgeva is used in oncology settings to prevent skeletal-related events in patients with bone metastases. Hikma's approval covers the osteoporosis indication, targeting the Prolia segment directly.

The approval follows a period of intense regulatory activity in the biosimilar denosumab space. Amgen's own biosimilar arm and several Indian and European manufacturers have been advancing denosumab candidates through FDA review. Hikma's clearance makes it among the earlier entrants in a field that analysts at GlobalData expect to erode Amgen's branded revenue by 15 to 20 percent within 18 months of competitive launch.

Hikma, which operates significant manufacturing capacity in the United States through its facilities in Columbus, Ohio and Cherry Hill, New Jersey, is expected to initiate commercial supply discussions with major pharmacy benefit managers and hospital group purchasing organisations in the coming weeks. The company declined to confirm launch timing ahead of pricing negotiations, a standard practice in the biosimilar sector.

The approval is likely to accelerate pressure on Amgen, which has faced mounting competition across its legacy biologics portfolio. Industry observers noted that Tuesday's development reinforces a broader trend of biosimilar market maturation in the US, where payers and insurers have increasingly mandated step-therapy protocols requiring patients to try lower-cost alternatives before accessing branded biologics.