Thyrogen review-An effective tool for Thyroid cancer

 

Thyrogen is a prescription drug and belongs to the recombinant class of human thyroid stimulating hormone. Thyrotropin alpha is the generic name for this medication, which works by binding to specific TSH receptor sites that are found on normal as well as cancerous thyroid cells in the body. Owing to its mode of action, there are specific indications for its use, which will be discussed in this review.

According to National Cancer Institute, there were an estimated 726,646 people with thyroid cancer in the US alone, in 2014. The number of new cases discovered was 14.2 per 100,000 men and women per year.

According to American Cancer Society, figures for 2017 regarding thyroid cancer are

  • About 56,870 new cases of thyroid cancer (42,470 in women, and 14,400 in men)
  • About 2,010 deaths from thyroid cancer (1,090 women and 920 men)

The thyroid cancer can be diagnosed relatively at an early age as compared to other cancers and their prevalence is higher in women than in men. The incidence of thyroid cancer is rising, particularly in the US, owing to the advancement in thyroid ultrasound techniques, which can detect even the smallest sized thyroid cancer. Thyrogen is important role both in the diagnosis stage and treatment of thyroid cancer particularly with radioactive iodine scans. The details will be revealed in the following analysis.

What is Thyrogen?

Thyrogen is a protein that is structurally identical to human thyroid stimulating hormone (TSH). It is a recombinant protein, according to Britannica.com;

A recombinant technology is the one when DNA from two different species are joined together and inserted into a host organism in such a way that new genetic combination can arise”. Proteins that are expressions of such a recombinant technology are called ‘recombinant proteins’ and Thyrogen is an example of one such protein.

 

Indications for the use of Thyrogen

As mentioned earlier, Thyrogen is a prescription medicine that is administered by a health professional, very occasionally; it can be used at home by the patient himself. The indications for its use are

  1. Diagnostic
  2. Therapeutic

The diagnostic indications for Thyrogen are

  • In cases of well-differentiated thyroid cancer, with or without radioactive iodine
  • In follow up cases of certain thyroid cancers to account for any recurrence

 

The prognostic or therapeutic indications are

  • Thyrogen is used prior to administrating radioactive iodine in cases of iodine ablation
  • Thyrogen helps maintain thyroid hormone replacement therapy while undergoing surgery for the removal of remnants of thyroid cancer

The diagnostic indication of Thyrogen for follow up cases of thyroid cancer was approved by FDA in 1998 and its therapeutic indication for iodine ablation was approved quite recently, in 2007. For such purpose, Thyrogen can be used for serum thyroglobulin testing in patients with well-differentiated thyroid cancer who have already gone thyroidectomy. Such a thyroidectomy is followed by Remnant Thyroid Ablation, in which residual thyroid tissue is destroyed (both cancerous and normal), thus preventing a recurrence of any cancer and facilitation of long-term surveillance. This procedure requires a high level of radioactive iodine uptake that can be achieved with the help of Thyrogen.

For diagnostic function, Thyrogen binds to TSH receptors on normal thyroid cells or cancerous thyroid tissues in the body and this specific action helps locate remaining thyroid cancerous cells after cancer surgery.

How to administer Thyrogen

Thyrogen is administered via intramuscular injection (preferably in the buttocks), by a professionally trained nurse or a physician. IT IS NEVER ADMINISTERED INTRAVENOUSLY.

The administration regime is same for both modes of indications; diagnostic and therapeutic.

First injection        Day 1

Second Injection    Day 2 (well after 24-hour period)

The recommended dose of Thyrogen is about 0.9mg.

Contraindications to the use of Thyrogen

The only contraindication to the use of Thyrogen is an allergy to any of its component.

It is also not approved for patients, in whom there is evidence of distant metastases, i: e. the cancer cells have spread to other parts of the body.

Precautionary conditions for the use of Thyrogen

Some medical and non-medical conditions interact with Thyrogen administration, therefore, a complete detail must be provided to the physician in charge.

  • Planning a pregnancy, already pregnant or breastfeeding mothers
  • A complete detail about any other prescriptive medicines, over-the-counter or herbal supplements
  • Allergies towards products with bovine components
  • Any heart condition, blood pressure or previous history of strokes
  • Any other prevailing thyroid condition
  • Any disturbance with kidney function should be reported
  • Any history of surgery of any kind and specifically any thyroid surgery

Side effects of Thyrogen

The most common documented side effect of Thyrogen is

  • Headache
  • Nausea

Some rare side effects are

  • A warm feeling
  • Itching
  • Redness of upper extremities
  • Redness of skin, overall
  • Loss of vision

Some of the rare side effects are also observed in patients already received previous treatment with Thyrogen

  • Skin rash
  • Faintness and dizziness
  • Redness, itching, and swelling at injection site
  • Tightened chest and wheezing

Some of the symptoms requiring urgent concern and emergency intervention are

  • Paralysis and weakness of one side of body
  • Inability to move any of the limbs

Safety of use in certain conditions

The safety margin for Thyrogen use in some specific conditions is not devoid of risks

  • Children

The well-being of children under the age of 18 years with Thyrogen is not established.

  • Elderly

Likewise, the elderly, at the other extreme of the cohort, are also exposed to side effects and potential risks of Thyrogen treatment.

  • Nursing mothers

There is no established evidence that Thyrogen is not excreted in breast milk, therefore, nursing mothers should consult their physicians before any treatment with Thyrogen.

  • Pregnant women

Animal studies have demonstrated adverse effects on the fetus with Thyrogen dose; therefore, Thyrogen is a category C drug when it comes to pregnancy. There are no controlled studies conducted in humans but when potential benefits outweigh the risks, your physician is the only one with authority to prescribe it.

  • Patients with kidney ailments

Thyrogen should be used with extreme caution or not at all in patients with a low kidney output or on dialysis. In such patients, the renal function is stressed enough to put the TSH on a high level, resulting in hormonal havoc.

Evidence regarding the effectiveness of Thyrogen

The fact that Thyrogen “helps maintain the quality of life for patients undergoing Remnant Ablation or Diagnostic follow up” is backed by clinical trials, the details of which are provided at the official page of Thyrogen. The clinical studies made use of SF-36 Health Survey to judge the mental and physical states of patients regarding eight different areas.

Final words on Thyrogen   

Thyrogen is a safe prescription, both as a diagnostic and therapeutic tool. It can be administered at home but better safe than sorry, the administration at a clinic is more appropriate. The safety margin of Thyrogen is enhanced if the regime is adopted after a thorough history sharing with the physician on patient’s part.

The success rate of Remnant Thyroid Ablation with the help of Thyrogen is backed by two clinical trials (the details are on the official web page) where they were calculated as 92% and 87%. The importance of Thyrogen assisted follow up of cases of thyroid cancer cannot be emphasized enough because these cancers are diagnosed in early stages but recur at an interval of about 10 years or more.

Last but not the least Thyrogen is available via

  • Direct purchase from Sanofi Genzyme (the manufacturer)
  • A wholesale deal
  • Purchase via a specialty pharmacy

Financial assistance is also available, the details of which can be found at the official web page.

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