FDA Approves Prolia and Xgeva Biosimilars, Stoboclo and Osenvelt

The FDA has approved Celltrion’s Stoboclo (denosumab-bmwo) and Osenvelt (denosumab-bmwo), which are biosimilars for Prolia and Xgeva, respectively, according to a news release. Both are expected to be available in the United States in June 2025.

Stoboclo is a RANK ligand (RANKL) inhibitor approved to increase bone mass in men and women with osteoporosis, in women receiving adjuvant aromatase inhibitor therapy for breast cancer and in men receiving androgen deprivation therapy for nonmetastatic prostate cancer.

Stoboclo will be available as a 60 mg/mL injection in a single-use, prefilled syringe administered every six months as a subcutaneous injection in the upper arm, upper thigh or abdomen. Patients taking Stoboclo should also take 1,000 mg of calcium and at least 400 mg of vitamin D daily, according to the prescribing information.

The most common adverse reactions in postmenopausal women taking Stoboclo were back pain, pain in extremities and hypercholesterolemia. More than 5% of male osteoporosis patients reported back pain, arthritis, and nasopharyngitis. At least 10% of male and female patients taking Stoboclo for bone loss due to hormone ablation reported arthralgia and back pain.

Patients with advanced kidney disease who take Stoboclo are at an increased risk for severe hypocalcemia.

Osenvelt is a receptor activator of NF-κb ligand (RANKL) inhibitor indicated to prevent skeletal-related events, which are complications that can arise when cancer spreads to the bones, potentially leading to fractures or spinal compression. Specifically, Osenvelt is indicated for patients with multiple myeloma, bone metastases from solid tumors, patients with unresectable bone tumors, as well as for treating hypercalcemia of malignancy refractory to bisphosphonate therapy.

Osenvelt is approved as a 120 mg/1.7 mL injection in a single-use, prefilled syringe. Directions for use depend on indication, but all doses must be administered subcutaneously. Indications include patients with hypercalcemia of malignancy, giant cell tumors of bone and patients with multiple myeloma and bone metastasis from solid tumors.

In patients with bone metastasis, the most common adverse reactions reported by at least 25% of patients were fatigue, hypophosphatemia and nausea. In patients with hypercalcemia of malignancy, more than 20% reported nausea, dyspnea and decreased appetite. At least 10% of multiple myeloma patients reported diarrhea, nausea and anemia.

Osenvelt is not recommended for pregnant women due to the risk of fetal harm. Osenvelt also carries a risk of osteonecrosis of the jaw.

"Denosumab is used to improve or protect bone health in patients with osteoporosis or those undergoing various cancer treatments and as a therapy for a lifetime for postmenopausal osteoporosis (PMO) patients," Jean-Yves Reginster, professor of medicine and Protein Research Chair in the College of Science at King Saud University in Riyadh, Saudi Arabia, and director of the WHO Collaborating Centre for Epidemiology of Musculoskeletal Health and Aging in Liège, Belgium, said in the news release. “Having a denosumab product with a clinically proven track record in quality and safety is a valuable addition for my patients."

There are currently three Prolia biosimilars and three Xgeva biosimilars, including yesterday's approval. The three Prolia biosimilars are Ospomyv, Stoboclo and Jubbonti and the three Xgeva biosimilars are Xbryk, Osenvelt and Wyost.

Prolia was the first approved in June 2010 for men and women with osteoporosis. Xgeva was approved in November 2010.