FDA Approves Two More Denosumab Biosimilars, Conexxence and Bomyntra

Fresenius announced today that the FDA has approved the biologics licensing applications (BLA) for denosumab biosimilars Conexxence (denosumab-bnht) and Bomyntra (denosumab-bnht), according to a news release. Prolia, the reference product for Conexxence, and Xgeva, the reference product for Bomyntra, were both developed by Amgen. As a result of a global settlement between Fresenius and Amgen, both biosimilars are expected to launch in the United States in mid 2025 and in the second half of 2025 in Europe.

Bomyntra and Conexxence are the fourth pair of denosumab biosimilars. Other Prolia biosimilars include Jubbonti, Ospomyv and Stoboclo. Additional Xgeva biosimilars include Wyost, Xbryk and Osenvelt.

Although the active drug ingredient in Conexxence and and Bomyntra is deosumab, they have different indications.

Conexxence is approved for patients at high risk for fractures, including osteoporosis patients and patients undergoing cancer treatments that affect bone density. It comes as a 60 mg/mL single-dose prefilled injection to be administered every six months via subcutaneous injection. Adverse reactions varied by indication.

More than 5% of postmenopausal osteoporosis patients and male osteoporosis patients reported back pain. More than 3% of glucocorticoid-induced osteoporosis patients reported back pain, and at least 10% of patients with bone loss due to hormone ablation for cancer had back pain and arthralgia, according to the prescribing information.

Due to the risk of severe hypocalcemia in patients with advanced chronic kidney disease, Conexxence is a black box warning product in the United States, which includes a Risk Evaluation and Mitigation Strategy (REMS) program.

Bomyntra is approved to prevent skeletal related events in adult patients’ multiple myeloma and bone metastasis from solid tumors. It can also be used in patients with hypercalcemia from cancer treatments, unresponsive to bisphosphonate therapy. It comes in a prefilled, single-dose syringe of 120 mg/1.7 mL and should be administered subcutaneously.

Patients taking Bomyntra for multiple myeloma and bone metastasis from solid tumors should take 120 mg once every four weeks.

Patients taking Bomyntra for giant cell tumor of bone and hypercalcemia of malignancy should take 120 mg once every four weeks with an additional 120 mg dose on days 8 and 15 of the first month of therapy, according to the prescribing information.

The most common adverse reactions were fatigue, hypophosphatemia, and nausea, occurring in at least 25% of patients.

Both patients taking Bomyntra and Conexxence should take a vitamin D supplement because of the effect they can have on calcium levels. Conexxence patients are advised to take 400 IU of vitamin D daily plus 1000 mg of calcium daily, whereas Bomyntra patients should take vitamin D as necessary.

Denosumab is a monoclonal antibody that slows bone resorption, which is the process by which bone tissue is broken down and released into the bloodstream. When this happens excessively, it can lead to complications such as osteoporosis and bone fractures. Osteoporosis is a natural part of aging for many women who have gone through menopause, but certain cancer treatments can also weaken bone structure.