WHAT IS THYROGEN USED FOR?

Why is Thyrogen prescribed?

Thyrogen allows you to stay on your thyroid hormone replacement medication in preparation for radioactive iodine ablation or diagnostic follow-up testing.1 Injections of Thyrogen raise the levels of TSH in your body, which is important when preparing for these procedures.

Thyrogen is used for two main purposes1:

  • 1. Radioactive iodine ablation: to help patients prepare for treatment with a form of iodine to remove leftover thyroid tissue in patients who have had surgery to take out the entire thyroid gland for patients with well differentiated thyroid cancer who do not have signs of thyroid cancer which has spread to other parts of the body.

    Limitations of Use: In a study of people being prepared for treatment with a form of iodine after thyroid surgery, results were similar between those who received Thyrogen and those who stopped taking their thyroid hormone. Researchers do not know if results would be similar over a longer period of time

  • 2. Diagnostic testing: to help identify thyroid disease by testing the blood for a hormone called thyroglobulin in the follow up of patients with a certain type of thyroid cancer known as well differentiated thyroid cancer. It is used with or without a radiology test using a form of iodine.

    Limitations of Use: The effect of Thyrogen on long term thyroid cancer outcomes has not been determined. When Thyrogen is used to help detect thyroid cancer, there is still a chance all or parts of the cancer could be missed.

Radioactive iodine ablation1

If you have been diagnosed with thyroid cancer your physician will need to consider the most appropriate treatment. For most patients, surgery is performed to remove all or part of the thyroid gland. However, surgery does not usually remove 100% of the thyroid tissue in your neck. Removing all thyroid tissue facilitates diagnostic testing follow-up procedures and could reduce the risk of recurrence of thyroid cancer.

To destroy this remaining tissue, another procedure called radioactive iodine ablation may take place. Ablation plays a major therapeutic and diagnostic role in the management of thyroid cancer patients. In order to prepare you for ablation, your physician must stimulate remaining thyroid tissue to absorb the radioactive iodine that you ingest.

Your physician can stimulate remaining thyroid tissue in two ways:

  • The first method, withholding thyroid hormone medication, was used exclusively until Thyrogen was introduced. As a result of withholding your thyroid hormone medication, your thyroid hormone levels will drop to very low levels making you hypothyroid.
  • The second option involves the use of Thyrogen which can be injected into patients prior to ablation thus avoiding some of the signs and symptoms of hypothyroidism. In essence, Thyrogen allows your physician to start you on thyroid hormone replacement therapy right after your surgery.

Both methods of increasing thyroid stimulating hormone (TSH), withholding thyroid hormone replacement medication or using Thyrogen, have shown comparable success rates in thyroid remnant ablation.

Thyrogen is the only way to raise your TSH without having to stop taking thyroid hormone replacement therapy.

Diagnostic testing (whole body scanning and stimulated thyroglobulin testing)1

Follow up visits with your doctor are essential to determine if any thyroid cancer remains or has returned—and if so, to ensure that you receive additional treatment. To test for a recurrence of thyroid cancer, your doctor will want to perform diagnostic testing, usually once per year.

In order to obtain the most reliable diagnostic test results to detect thyroid cancer recurrence, TSH must be at high levels in the bloodstream. This triggers thyroid cancer cells (if any remain):

  • to better absorb radioiodine, which can be seen on specialized x-rays such as a whole body scan, and
  • to release thyroglobulin (Tg), a protein that can be tested in the blood (stimulated thyroglobulin blood test).

One option to increase your TSH levels is by stopping your thyroid hormone replacement medication (thyroid hormone withdrawal) for about four to six weeks, which will cause hypothyroidism. Symptoms of hypothyroidism can continue for a few weeks after restarting thyroid hormone replacement therapy until the thyroid hormone level is back to normal.

The other option for increasing TSH levels is by using Thyrogen. Thyrogen is the only way to raise your TSH without having to stop taking thyroid hormone replacement therapy.

Resources

Thyroid Cancer Glossary

My Doctor Discussion Guide

My Doctor Discussion Guide

Thyrogen Patient Kit

Thyrogen Patient Kit

More Resources

Thyrogen® (thyrotropin alfa for injection) 0.9 mg/mL after reconstitution

INDICATIONS AND USAGE

Diagnostic: Thyrogen is used to help identify thyroid disease by testing the blood for a hormone called thyroglobulin in the follow up of patients with a certain type of thyroid cancer known as well differentiated thyroid cancer. It is used with or without a radiology test using a form of iodine.

Limitations of Use:

The effect of Thyrogen on long term thyroid cancer outcomes has not been determined.

When Thyrogen is used to help detect thyroid cancer, there is still a chance all or parts of the cancer could be missed.

Ablation: Thyrogen is also used to help patients prepare for treatment with a form of iodine to remove leftover thyroid tissue in patients who have had surgery to take out the entire thyroid gland for patients with well differentiated thyroid cancer who do not have signs of thyroid cancer which has spread to other parts of the body.

Limitations of Use:

In a study of people being prepared for treatment with a form of iodine after thyroid surgery, results were similar between those who received Thyrogen and those who stopped taking their thyroid hormone. Researchers do not know if results would be similar over a longer period of time.

IMPORTANT SAFETY INFORMATION

There have been reports of events that led to death in patients who not had surgery to have their thyroid gland removed, and in patients with thyroid cancer cells that have spread to other parts of the body.

Patients over 65 years old with large amounts of leftover thyroid tissue after surgery, or with a history of heart disease, should discuss with their physicians the risks and benefits of Thyrogen.

Thyrogen can be administered in the hospital for patients at risk for complications from Thyrogen administration.

Since Thyrogen was first approved for use, there have been reports of central nervous system problems such as stroke in young women who have a higher chance of having a stroke, and weakness on one side of the body.

Patients should remain hydrated prior to treatment with Thyrogen.

Leftover thyroid tissue after surgery and cancer cells that have spread to other parts of the body can quickly grow and become painful after Thyrogen administration.

Patients with cancer cells near their windpipe, in their central nervous system, or in their lungs may need treatment with a glucocorticoid (a medication to help prevent an increase in the size of the cancer cells before using Thyrogen.)

ADVERSE REACTIONS

In clinical studies, the most common side effects reported were nausea and headache.

USE IN SPECIFIC PATIENT POPULATIONS

Pregnant patients: Thyrogen should be given to a pregnant woman only if the doctor thinks there is a clear need for it.

Breastfeeding patients: It is not known whether Thyrogen can appear in human milk. Breastfeeding women should discuss the benefits and risks of Thyrogen with their physician.

Children: Safety and effectiveness in young patients (under the age of 18) have not been established.

Elderly: Studies do not show a difference in the safety and effectiveness of Thyrogen between adult patients less than 65 years and those over 65 years of age.

Patients with kidney disease: Thyrogen exits the body much slower in dialysis patients and can lead to longer high TSH levels.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.

References

  1. Thyrogen (thyrotropin alfa for injection) Package Insert. Cambridge, MA. Genzyme Corporation.