FDA Clears 2 New Denosumab Biosimilars in Osteoporosis and Cancer-Related Bone Events

The FDA has approved Bosaya and Aukelso (denosumab-kyqq) as biosimilars for Prolia and Xgeva, respectively, for the treatment of cancer- and treatment-related bone loss.¹

Bosaya 60 mg/mL subcutaneous injection is approved for the treatment of patients at high risk of fracture receiving androgen deprivation therapy for nonmetastatic prostate cancer and adjuvant aromatase inhibitor therapy for breast cancer. It is also approved for the treatment of patients with osteoporosis at high risk for fracture.

Aukelso 70 mg/mL subcutaneous injection is approved for the prevention of skeletal-related events in patients with multiple myeloma and in patients with bone metastases from solid tumors. It is also approved for the treatment of adult or skeletally mature adolescent patients with unresectable giant cell tumor of bone or to treat hypercalcemia of malignancy refractory to bisphosphonate therapy.

“The FDA’s approval of Bosaya and Aukelso is a significant milestone in our mission to expand access to critical biologic therapies. With Bosaya, we are proud to offer a more affordable treatment option for patients with osteoporosis, and with Aukelso, we are further expanding our oncology care portfolio. This achievement … reinforces our commitment to delivering high-quality biosimilars that support sustainable healthcare systems and improve patient outcomes,” said Shreehas Tambe, CEO and managing director of Biocon Biologics, in a press release.

Data show that both denosumab biosimilars demonstrated comparable quality, safety, and efficacy to their reference products. Bosaya maintains the same risk evaluation and mitigation strategy (REMS) plan as Prolia. There is a risk of severe hypocalcemia associated with Bosaya in patients with advanced chronic kidney disease.

Regarding safety, the most common (≥10%) adverse events (AEs) associated with Bosaya in patients who have bone loss due to hormone ablation for cancer were arthralgia and back pain.

In patients treated with Aukelso for bone metastasis from solid tumors, the most common (≥25%) AEs were fatigue/asthenia, hypophosphatemia, and nausea. In patients with multiple myeloma, the most common (≥10%) AEs were diarrhea, nausea, anemia, back pain, thrombocytopenia, peripheral edema, hypocalcemia, upper respiratory tract infection, rash, and headache. In patients with giant cell tumor of bone, the most common (≥10%) AEs were arthralgia, headache, nausea, back pain, fatigue, and extremity pain.

Earlier this month, the FDA approved Bildyos and Bilprevda (denosumab-nxxp), 2 additional denosumab biosimilars for Prolia and Xgeva, respectively.² In March 2025, the FDA approved the biosimilars Stoboclo and Osenvelt (deniosumab-bmwo).³

“Denosumab is used to improve or protect bone health in patients with osteoporosis or those undergoing various cancer treatments and as a lifetime therapy for patients with postmenopausal osteoporosis,” said Jean-Yves Reginster, MD, PhD, in a press release.³ Reginster is professor of medicine and protein research chair of the Biochemistry Department, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia and director of WHO Collaborating Centre for Epidemiology of Musculoskeletal Health and Aging in Liège, Belgium.

“Biosimilars have expanded into new therapeutic areas such as immunology, oncology, and ophthalmology as they continue to offer significant cost-saving potential and expanding patient access. Having a denosumab product with a clinically proven track record in quality and safety is a valuable addition for my patients,” Reginster added.

REFERENCES:

1. Biocon Biologics Receives U.S. Food and Drug Administration Approval for Bosaya™ and Aukelso™, Denosumab Biosimilars. News release. Biocon Biologics. September 17, 2025. Accessed September 17, 2025. https://tinyurl.com/4r59a2n8

2. US Food and Drug Administration (FDA) Approves Henlius and Organon’s BILDYOS® (denosumab-nxxp) and BILPREVDA® (denosumab-nxxp), Biosimilars to PROLIA (denosumab) and XGEVA (denosumab), Respectively. Henlius Biotech. September 2, 2025. Accessed September 17, 2025. https://tinyurl.com/y9sh9jaz

3. Celltrion receives U.S. FDA approval for STOBOCLO® (denosumab-bmwo) and OSENVELT® (denosumab-bmwo) biosimilars referencing PROLIA® and XGEVA®. Prnewswire.com. March 3, 2025. Accessed September 17, 2025. https://tinyurl.com/yv8hp2s6