OSPOMYV

What it is

OSPOMYV is a biosimilar medicine to Prolia containing denosumab. Each 1 mL single-use pre-filled syringe contains 60 mg denosumab. Denosumab is a human monoclonal IgG2 antibody with high affinity and specificity for RANK ligand (RANKL). OSPOMYV is a sterile, preservative-free, clear, colourless to slightly yellowish or slightly brownish solution for injection at pH approximately 5.2.

Approved indications

— Treatment of osteoporosis in postmenopausal women; OSPOMYV significantly reduces the risk of vertebral, non-vertebral and hip fractures. — Treatment to increase bone mass in men with osteopaenia receiving androgen deprivation therapy for non-metastatic prostate cancer. — Treatment to increase bone mass in men with osteoporosis at increased risk of fracture. — Treatment to increase bone mass in women and men at increased risk of fracture due to long-term systemic glucocorticoid therapy.

Dosing overview

The recommended dose of OSPOMYV is a single subcutaneous injection of 60 mg, once every 6 months. To reduce the risk of hypocalcaemia, patients must be adequately supplemented with calcium and vitamin D; in the major clinical trials of denosumab, daily supplementation with 1,000 mg of calcium and at least 400 IU vitamin D was recommended. No dose adjustment is necessary in elderly patients or in patients with renal impairment.

Key safety warnings

Hypocalcaemia must be corrected prior to initiating therapy with OSPOMYV. In the post-marketing setting, severe symptomatic hypocalcaemia resulting in hospitalisation, life-threatening events and fatal cases has been reported, particularly in patients with severe renal impairment, receiving dialysis or treatment with other calcium lowering drugs. Clinical monitoring of calcium levels is recommended before each dose, and in patients predisposed to hypocalcaemia, clinical monitoring of calcium levels is recommended during treatment, especially in the first two weeks of initiating therapy. Patients receiving OSPOMYV may develop skin infections predominantly cellulitis leading to hospitalisation; patients should be advised to seek prompt medical attention if they develop signs or symptoms of cellulitis. Osteonecrosis of the jaw (ONJ) has been reported in patients treated with denosumab or bisphosphonates. Most cases have been in cancer patients; however some have occurred in patients with osteoporosis. ONJ has been reported rarely in clinical studies in patients receiving denosumab at a dose of 60 mg every 6 months for osteoporosis. It is important to evaluate patients for risk factors for ONJ before starting treatment, and if risk factors are identified, a dental examination with appropriate preventive dentistry is recommended prior to treatment with OSPOMYV. Atypical femoral fractures have been reported in patients receiving denosumab. Atypical femoral fractures may occur with little or no trauma in the subtrochanteric and diaphyseal regions of the femur and may be bilateral. Multiple vertebral fractures (MVF) may occur following discontinuation of treatment with OSPOMYV, particularly in patients with a history of vertebral fracture. New vertebral fractures occurred as early as 7 months after the last dose of denosumab.

Contraindications

Hypocalcaemia is a contraindication. Hypersensitivity to the active substance, to CHO-derived proteins or to any of the excipients is a contraindication. OSPOMYV is contraindicated in pregnancy and in women trying to get pregnant.

PBS listing

OSPOMYV denosumab 60 mg/1 mL solution for injection pre-filled syringe is listed on the ARTG with registration number 445963 under licence category RE, first listed on 9 July 2025. PBS listing details are not available in the provided sources.

Regulatory history

The TGA approved OSPOMYV on 13 June 2025. OSPOMYV was approved by the TGA as a biosimilar medicine to Prolia; the approval was based on demonstrated comparability across quality, nonclinical, and clinical aspects, supporting its use for the specified indications. The TGA's quality evaluation found that OSPOMYV is comparable to the reference product Prolia in terms of structure, function, and degradation profile. A bridging study further confirmed the comparability of the EU reference product to the Australian registered product, demonstrating that the active substance has been successfully developed as a biosimilar.