THYROGEN

What it is

THYROGEN contains thyrotropin alfa. It is supplied as a sterile, non-pyrogenic, white to off-white, lyophilised powder for injection intended for intramuscular administration after reconstitution with Sterile Water for Injection. Thyrotropin alfa is a recombinant human thyroid stimulating hormone, a heterodimeric glycoprotein produced by recombinant DNA technology that has comparable biochemical properties to those of the human pituitary TSH.

Approved indications

— Use with serum thyroglobulin testing, with or without radioactive iodine imaging, for the detection of thyroid remnants and well-differentiated thyroid cancer in post-thyroidectomy patients maintained on hormone suppression therapy. — Therapeutic use in post-thyroidectomy patients maintained on hormone suppression therapy in the ablation of thyroid remnant tissue in combination with radioactive iodine.

Dosing overview

A two-injection regimen is recommended, consisting of THYROGEN 0.9 mg intramuscularly, followed by a second 0.9 mg intramuscular injection 24 hours later. For radioiodine imaging or treatment, radioiodine administration should be given 24 hours following the final THYROGEN injection. For serum thyroglobulin testing, the serum sample should be obtained 72 hours after the final intramuscular injection of THYROGEN.

Key safety warnings

THYROGEN causes a transient but significant rise in serum thyroid hormone concentration; caution should be exercised in patients with a known history of heart disease and with significant residual thyroid tissue. One case of fatal myocardial infarction has been reported in a patient with residual thyroid tissue and a history of heart disease, with the event considered related to THYROGEN-induced hyperthyroidism. Thyroid cancer patients with metastatic disease in confined spaces such as the brain and spinal cord, orbit, or infiltrating the neck may experience local oedema or focal haemorrhage; pre-treatment with corticosteroids should be considered in these patients prior to THYROGEN administration. Information from post-marketing surveillance suggests that elimination of THYROGEN is significantly slower in dialysis-dependent end-stage renal disease patients, resulting in markedly elevated TSH levels for up to two weeks after treatment, which may lead to increased risk of headache and nausea. The most common adverse reactions reported in clinical trials were nausea (11.9%) and headache (7.3%). THYROGEN administration may cause transient influenza-like symptoms lasting less than 48 hours, which may include fever, chills, myalgia, arthralgia, fatigue and headache.

Contraindications

There are no known contraindications to the use of THYROGEN.

PBS listing

THYROGEN powder for injection 0.9 mg is listed on the PBS as a restricted item with an ex-manufacturer price of A$1425.55.

Regulatory history

THYROGEN was first approved on 14 August 2001 with ARTG registration number 79777.