Thyrogen

Common name: Thyrotropin alfa/Thyrotropin-alpha freeze-dried powder

Trade name: Thyrogen/Shi banjin

Full names: Thyrogen, thyrotropin alfa, thyrotropin alpha recombinant lyophilized powder injection, thyrotropin alpha, suitable for relegation

Indications:

Thyrogen can be used for serum thyroglobulin (Tg) testing with or without radioactive iodine imaging to detect thyroid remnant and well-differentiated thyroid cancer in patients after thyroidectomy maintained with hormone suppressive therapy (THST).

Low-risk patients with poorly differentiated thyroid cancer whose THST serum Tg levels are undetectable and whose rh (recombinant human) TSH-stimulated Tg levels do not increase can be followed up by analyzing the rhTSH-stimulated Tg levels.

Thyroid hormone is indicated for pre-treatment stimulation, combined with 30 mCi (1.1GBq) to 100 mCi (3.7GBq) of radioactive iodine, to ablate residual thyroid cancer in well-differentiated thyroid tissue and without evidence of distant metastatic thyroid cancer in patients who have undergone near-total or total thyroidectomy.

Dosage:

The recommended dosage regimen is two doses of 0.9 mg thyrotropin alfa administered by intramuscular injection over 24 hours only.

Due to the lack of data on the use of thyroxine in children, thyroxine should be given to children only in exceptional circumstances.

No dose adjustment is required for the elderly.

Patients with Renal/Hepatic Impairment: Information from postmarketing surveillance and published information indicates that in patients with dialysis-dependent end-stage renal disease (ESRD), the rate of elimination of thyroid hormone is significantly reduced, resulting in persistently elevated thyroid-stimulating hormone (TSH) levels for several days after treatment. This may lead to an increased risk of headaches and nausea. There are currently no studies on the use of thyroid hormone replacement dosing regimens in patients with ESRD to guide dose reduction in this population. In patients with severe renal insufficiency, the nuclear medicine physician should carefully select the activity of the radioactive iodine. No special considerations are required for the use of thymosin hormones in patients with hepatic impairment.

Dosage method:

After reconstitution with water for injection, administer 1.0 ml solution (0.9 mg thyrotropin α) into the buttocks by intramuscular injection. Instructions for reconstituting the medication before administration.

For radioactive iodine imaging or ablation, radioactive iodine should be given 24 hours after the last injection of thyroxine. Diagnostic scintigraphy should be performed 48 to 72 hours after radioactive iodine administration, whereas post-ablation scintigraphy may be delayed for a few additional days to allow background activity to decrease.

For diagnostic follow-up serum thyroglobulin (Tg) testing, serum samples should be obtained 72 hours after the final injection of thyroxine. The use of Tg-tested thyroxine in the follow-up of patients with well-differentiated thyroid cancer after thyroidectomy should comply with official guidelines.

Specifications:

0.9mg bottle

Adverse reactions:

The most common adverse reactions reported in clinical trials are nausea and headache.

Contraindications:

Hypersensitivity to bovine or human thyroid stimulating hormone or any of the excipients listed.

Pregnant.

Precautions:

THYROGEN has the risk of inducing hyperthyroidism. Inpatient treatment and post-administration observation of THYROGEN should be considered for at-risk patients.

Stroke in female patients and other neurologic events in patients with central nervous system metastases.

Distant metastatic thyroid cancer enlarges suddenly, rapidly, and painfully.

Storage:

Reconstituted solutions can be stored in a light-protected refrigerator (2°C-8°C) for up to 24 hours while avoiding microbial contamination.

Store in refrigerator (2°C-8°C).

Place vials in outer carton to protect from light.

Mechanism of action:

Thyrotropin α (recombinant human thyroid-stimulating hormone) is a heterodimeric glycoprotein produced by recombinant DNA technology. It consists of two non-covalently linked subunits. This cDNA encodes a 92-amino acid residue alpha subunit containing two N-linked glycosylation sites and a 118-residue beta subunit containing one N-linked glycosylation site. It has biochemical properties comparable to natural human thyroid stimulating hormone (TSH). Binding of thyrotropin alpha to TSH receptors on thyroid epithelial cells stimulates iodine uptake and organization, as well as the synthesis and release of thyroglobulin, triiodothyladenine (T3), and thyroxine (T4).

In patients with well-differentiated thyroid cancer, a nearly total thyroidectomy, or total thyroidectomy, will be performed. For optimal diagnosis of thyroid remnant or cancer by radioiodine scintigraphy or thyroglobulin testing, as well as radioiodine therapy of thyroid remnant, high serum TSH concentrations are required to stimulate radioactive iodine uptake and/or thyroglobulin release. The standard approach to raising TSH levels is to withdraw the patient from thyroid hormone suppressive therapy (THST), which often causes the patient to experience signs and symptoms of hypothyroidism. By using thyroxine, the TSH stimulation necessary for radioactive iodine uptake and thyroglobulin release is achieved while the patient maintains euthyroid function in THST, thereby avoiding hypothyroidism-related morbidity.

Safety and efficacy:

The U.S. Food and Drug Administration (FDA) approved Thyrogen as an adjuvant for thyroid cancer screening methods as early as the end of 1998. The drug can not only increase the sensitivity of thyroglobulin (Tg), but also avoid symptoms of hypothyroidism (such as fatigue, depression, weight gain) during whole-body scans. Since then, the FDA approved the supplementary indication of Thyrogen® (thyrotropin alfa for injection) on December 17, 2007, which is to be used in combination with radioactive iodine to ablate or destroy the remaining thyroid tissue in patients who have removed cancerous thyroid.