JUBBONTI

What it is

JUBBONTI is a biosimilar medicine to Prolia containing denosumab. Each 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). JUBBONTI 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, in which JUBBONTI 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 JUBBONTI 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, daily supplementation with 1,000 mg of calcium and at least 400 IU vitamin D was recommended.

Key safety warnings

Hypocalcaemia must be corrected prior to initiating therapy with JUBBONTI. 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; while most cases occurred in the first few weeks of initiating therapy, it has also occurred later. Clinical monitoring of calcium levels is recommended before each dose and during treatment in patients predisposed to hypocalcaemia, especially in the first two weeks of initiating therapy. Patients receiving JUBBONTI may develop skin infections predominantly cellulitis leading to hospitalisation, and 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, and 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; if risk factors are identified, a dental examination with appropriate preventive dentistry is recommended prior to treatment with JUBBONTI. Atypical femoral fractures have been reported in patients receiving denosumab and 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 JUBBONTI, particularly in patients with a history of vertebral fracture; new vertebral fractures occurred as early as 7 months after the last dose of denosumab. Patients being treated with JUBBONTI should be advised not to interrupt therapy without prior consultation with their treating physician; if JUBBONTI treatment is discontinued, consideration should be given to transitioning to an alternative antiresorptive therapy.

Contraindications

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

PBS listing

JUBBONTI 60 mg in 1 mL pre-filled syringe is listed on the PBS with streamlined restriction and an ex-manufacturer price of A$159.38.

Regulatory history

JUBBONTI denosumab 60 mg/1 mL solution for injection pre-filled syringe was first listed on the ARTG on 23 August 2024. The Australian Public Assessment Report (AusPAR) was issued on 7 August 2024. In November 2024, the PBAC recommended listing of JUBBONTI as a new biosimilar under the same conditions as the reference biologic Prolia on a cost-minimisation basis.