Amneal Pharmaceuticals and Mabxience have secured FDA approvals for Boncresa (denosumab-mobz), a biosimilar to Prolia, and Oziltus (denosumab-mobz), a biosimilar to Xgeva, covering osteoporosis and oncology-related bone health indications. The partners split roles with Mabxience leading development and manufacturing and Amneal holding exclusive U.S. commercialization rights. With combined U.S. sales for Prolia and Xgeva estimated at approximately $5.3 billion in the last 12 months, denosumab represents one of the most commercially consequential biologic categories to enter the next wave of biosimilar competition.
The strategic question is how fast denosumab biosimilars will convert in two very different markets: buy-and-bill oncology and largely office-administered osteoporosis. Oncology has historically moved faster on biosimilar adoption due to established pathways in Part B, practice economics around ASP+ reimbursement, and group purchasing leverage. Osteoporosis has more diffuse prescriber bases and workflow friction around six-month dosing, monitoring, and patient scheduling, which can slow switching. If Amneal can leverage early contracting, distribution reliability, and medical support to minimize operational drag, Oziltus may see quicker traction than Boncresa, mirroring earlier oncology supportive-care biosimilar dynamics.
This matters now because denosumab sits at the intersection of affordability pressure and population health. For payers, denosumab is a large, chronic spend in older adults where fractures drive downstream costs and oncology practices rely on predictable access for skeletal event prevention. Pricing and contracting choices will determine how rapidly ASPs step down and how broadly systems steer to one or two preferred options. For providers, consistency of supply and clear coding and reimbursement pathways will be decisive, especially as HCPCS codes are assigned and ASP benchmarks mature. For patients, lower net costs could expand access in osteoporosis and metastatic disease if formulary management is pragmatic and infusion centers and specialty distributors avoid stocking complexity.
Safety and labeling will shape Medical Affairs priorities. The class carries a boxed warning for severe hypocalcemia in advanced chronic kidney disease and requires vigilant calcium and vitamin D management, with different dosing cadences across osteoporosis and oncology populations. As multiple biosimilars arrive, Medical Affairs teams will need to standardize guidance on lab monitoring, supplementation, and treatment interruptions to prevent rebound bone turnover, while generating real-world evidence on adherence and outcomes in CKD and high-risk cohorts. Payers will expect robust post-launch data to support policies that favor biosimilars without compromising safety in vulnerable populations.
For competitors, denosumab underscores a broader reshaping of the U.S. biosimilar market. Multi-sourcing across high-value, office-administered biologics is accelerating, and the entry of generics-focused players pairing with global biologics manufacturers signals a more modular model: development and GMP expertise centralized with partners like Mabxience, commercialization localized to companies with channel and contracting reach. As IDNs and GPOs consolidate influence, the winners will be those that marry low net price with assured supply, seamless distribution through specialty channels, and field teams fluent in both buy-and-bill economics and patient management nuances.
The next six to twelve months will reveal whether denosumab follows the rapid oncology biosimilar playbook or a more gradual osteoporosis curve. Watch the first ASP prints, the depth of GPO and Medicare Advantage contracting, and how many systems choose a single preferred biosimilar. If adoption proves swift in oncology and steady in osteoporosis, denosumab could become the template for biosimilar expansion into large, chronic specialty categories—and a bellwether for how aggressively payers will push medical-benefit biosimilar substitution in 2026 and beyond.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
