Prolia and Xgeva just got rivals: FDA clears BILDYOS and BILPREVDA biosimilars for U.S. launch

The U.S. Food and Drug Administration (FDA) has granted approval to Shanghai Henlius Biotech, Inc. (HKG: 2696) and Organon (NYSE: OGN) for two denosumab biosimilars—BILDYOS® (denosumab-nxxp, 60 mg/mL) and BILPREVDA® (denosumab-nxxp, 120 mg/1.7 mL)—marking a key regulatory milestone that expands access to critical bone health treatments across the U.S.

The biosimilars are approved for all indications covered by their reference biologics, Prolia® and Xgeva®, developed by Amgen. These include a broad range of conditions such as postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, bone loss in hormone therapy for breast and prostate cancers, skeletal complications from cancer-related bone metastases, and giant cell tumor of bone. The announcement places Henlius and Organon at the forefront of a growing biosimilars market expected to deliver cost-effective therapeutic alternatives to millions of patients, particularly in women’s health and oncology.

What clinical data and regulatory considerations led to the FDA’s approval of BILDYOS and BILPREVDA?

The FDA’s decision was based on a comprehensive dossier submitted by Henlius, encompassing analytical data, pharmacokinetics, and comparative clinical studies. According to both companies, the evidence demonstrated a high degree of similarity between BILDYOS and Prolia, and between BILPREVDA and Xgeva—without any clinically meaningful differences in safety, purity, or potency.

These data packages adhered to the FDA’s rigorous biosimilar approval pathway, which emphasizes molecular fingerprinting, pharmacodynamic equivalence, and outcome consistency across patient groups. The approval followed international best practices for demonstrating biosimilarity, consistent with precedents set by earlier denosumab biosimilar approvals in the EU and other major markets.

Henlius’ CEO Dr. Jason Zhu said the decision reaffirms the company’s “commitment to scientific excellence and consistent product quality,” noting that this is another U.S. approval for a Henlius-developed and -manufactured biosimilar. The approvals also reflect the companies’ adherence to safety requirements including long-term monitoring plans, post-market pharmacovigilance, and REMS (Risk Evaluation and Mitigation Strategy) participation for BILDYOS.

How could these biosimilars impact access, affordability, and treatment uptake in osteoporosis and cancer care?

Organon has emphasized that BILDYOS and BILPREVDA are designed to improve affordability and access to biologics that treat some of the most prevalent chronic and cancer-related bone conditions. The U.S. faces a significant burden from osteoporosis and skeletal complications of cancer. Osteoporosis alone affects approximately 10 million Americans—80% of whom are women—while another 44 million have low bone mass, placing them at increased fracture risk.

BILDYOS is approved to treat both men and women with osteoporosis at high risk of fracture, as well as those receiving hormonal therapy for cancer. BILPREVDA, meanwhile, is indicated to prevent skeletal-related events in patients with multiple myeloma, bone metastases from solid tumors, or giant cell tumor of bone.

Institutional stakeholders, including payers and hospital systems, are expected to monitor pricing closely as biosimilar competition increases. Analysts suggest that while denosumab biosimilars may not initially undercut prices drastically, they could introduce downward pricing pressure over time—especially as more biosimilar manufacturers enter the space. That, in turn, could improve treatment adherence in underinsured populations and reduce out-of-pocket costs in Medicare Part B settings.

What safety concerns are associated with BILDYOS and BILPREVDA, and how are they being mitigated?

As with all denosumab-based therapies, the newly approved biosimilars carry safety risks that must be managed with clinical oversight. For BILDYOS, serious concerns include severe hypocalcemia, particularly in patients with advanced chronic kidney disease or those with mineral bone disorders. Organon and Henlius noted that treatment initiation should only occur after correcting pre-existing hypocalcemia and under supervision from physicians with expertise in managing CKD-MBD (chronic kidney disease–mineral bone disorder).

In oncology applications, BILPREVDA also comes with warnings about osteonecrosis of the jaw (ONJ), hypersensitivity reactions, and atypical femur fractures, all of which have been observed in patients using the originator biologics. FDA guidance calls for preventive dentistry, calcium and vitamin D supplementation, and regular monitoring of serum calcium and phosphate levels throughout treatment. Both drugs also advise patients to avoid invasive dental procedures during therapy to minimize ONJ risk.

The companies clarified that these risks are not new or unique to their biosimilars, and that the safety profile remains consistent with the reference biologics. Still, these factors may influence how prescribers position BILDYOS and BILPREVDA against other therapies, particularly in older adults or patients with poor renal function.

How does this approval fit into Henlius and Organon’s broader commercial strategy and biosimilars portfolio?

The approval of BILDYOS and BILPREVDA marks another major milestone in the strategic alliance between Shanghai Henlius Biotech and Organon, originally formed through a license and supply agreement signed in 2022. That agreement gave Organon exclusive rights to commercialize several Henlius biosimilars outside of China, including these two denosumab products.

Organon has steadily expanded its U.S. biosimilars presence over the past eight years and now covers five therapeutic areas. The company has publicly tied its biosimilars strategy to broader women’s health goals—underscoring that treatments like BILDYOS support its ambition to address disproportionately female disease burdens like postmenopausal osteoporosis.

In contrast, Henlius has focused heavily on R&D and global regulatory approvals, building a 50-molecule pipeline that includes immuno-oncology therapies such as serplulimab (HANSIZHUANG), rituximab biosimilars (HANLIKANG), and trastuzumab biosimilars (HANQUYOU). With multiple international filings under review and approvals secured in China, the EU, and now the U.S., the Chinese biopharma firm is accelerating its transformation into a global player.

According to Ping Cao, Senior Vice President and Chief Business Development Officer at Henlius, these approvals highlight how collaboration with Organon is helping the company expand patient access while advancing its global market footprint.

What is the investor and institutional response to these biosimilar approvals?

Investor sentiment toward Organon (NYSE: OGN) has been cautiously optimistic amid efforts to rebalance its post-spinoff portfolio. While the biosimilars division remains smaller than its core generics and women’s health businesses, it has drawn attention for its consistent regulatory wins and commercial partnerships.

Institutional analysts have flagged biosimilars as a modest but growing contributor to Organon’s revenue base, particularly in geographies where it has exclusive commercialization rights. The company’s ability to launch BILDYOS and BILPREVDA successfully in the U.S.—while managing supply chain, formulary access, and provider education—will be closely watched in upcoming quarters.

For Henlius (HKG: 2696), the U.S. approval continues to validate its development pipeline and international regulatory strategy. The company’s track record of gaining FDA and EMA approvals for Chinese-developed biosimilars has positioned it as a credible global challenger in the biologics space. Market participants may view this latest milestone as further proof that Henlius is executing well on its innovation-to-commercialization model.

What lies ahead for commercialization, pricing, and competitive positioning?

Organon has not yet disclosed the exact launch timeline or pricing for BILDYOS and BILPREVDA, though industry observers expect them to enter the market in late 2025 or early 2026. The launch timing may coincide with other biosimilar entrants in the denosumab space, increasing the potential for early price competition.

With several denosumab biosimilar candidates already approved or under review—including by Sandoz, Fresenius Kabi, and Samsung Bioepis—the U.S. market may see meaningful shifts in formulary preference and hospital purchasing behavior over the next 12–18 months. Payers are likely to evaluate all options based on interchangeability, pharmacoeconomic data, and manufacturer support programs.

Organon’s success may ultimately hinge on its ability to integrate these biosimilars into existing commercial channels while differentiating on service, supply reliability, and patient support—factors that have become increasingly important in competitive therapeutic areas like osteoporosis and cancer care.