Summary of Published Clinical Experience using Thyrogen-Stimulated Tg testing

The development of Thyrogen^® has provided physicians with an effective tool to manage patients with thyroid cancer who are at risk for residual or recurrent disease. TSH stimulation either with Thyrogen or endogenous TSH is important in the follow-up evaluation of patients with thyroid cancer. TSH stimulation with Thyrogen provides a sensitive way to identify patients with metastatic disease and increases the sensitivity of detecting elevated thyroglobulin in patients who may have residual or recurrent disease. Thyrogen allows patients to undergo TSH stimulation without suffering the effects of hypothyroidism, which can be debilitating for some patients. For more information, please see the important safety information below.

Identifying patients with metastatic disease using Thyrogen-stimulated testing

The primary concern of physicians in the follow-up of their thyroid cancer patients is detecting metastatic disease. Seven recent clinical studies (see Table 1) have evaluated the sensitivity of Thyrogen-stimulated Tg testing with or without whole body scanning to identify patients with residual or recurrent metastatic disease. In five of the studies, Thyrogen-stimulated Tg testing with or without DxWBS identified all patients with metastatic disease. Across all seven studies, which included 303 patients with metastatic disease, Thyrogen-stimulated Tg testing alone identified between 85%-100% of patients who were confirmed to have metastases. The combination of Thyrogen-stimulated Tg testing and whole body scan detected between 93% and 100% of patients with metastatic disease.

Table 1.–Thyrogen-Stimulated Testing to Detect Metastatic Disease in 303 patients

⁺⁺ Thyrogen stimulated Tg > 1 ng/mL used in this study.

For more information, please see the important safety information below.

Using Thyrogen-stimulated Tg testing in long-term follow-up to identify patients who may be at risk for residual or recurrent cancer

Most physicians employ periodic thyroglobulin (Tg) testing and other tests during long-term follow-up to identify patients who may have residual or recurrent cancer. A number of recent studies have shown that stimulation with TSH (either endogenous TSH or Thyrogen) will increase the number of patients identified with elevated Tg levels who may have residual or recurrent disease. In seven recently published clinical studies involving 779 patients (see Table 2), 10% to 43% of patients with low or undetectable baseline Tg levels demonstrated elevated Tg levels of >/= 2 ng/ml following Thyrogen stimulation, and between 17% to 50% of those patients were confirmed to have metastatic disease. This finding suggests that early detection using TSH-stimulated Tg testing may help in the management of patients with metastatic disease.

Table 2. Results of Thyrogen-Stimulated Tg Testing in 901 Patients With Low or Undetectable Unstimulated Tg

*Tg level < 2 ng/mL
^** Yield of rhTSH Tg testing = # of patients with confirmed metastatic disease (by WBS, FNA or pathology cytology or other CT) among patients with stimulated Tg > 2 ng/mL
^*** Results of an analysis of the low risk subset of patients in this study.
^**** Thyrogen-stimulated Tg > 1 ng/mL used in this study

For more information, please see the important safety information below.

Benefits of using Thyrogen

Thyrogen-stimulated testing provides a safe and effective method to elevate TSH levels that allows patients to undergo periodic follow up evaluation while avoiding the often debilitating side effects of hypothyroidism. In one clinical study, Thyrogen administration was not associated with the signs and symptoms of hypothyroidism that can occur during thyroid hormone withdrawal, as measured using the Billewicz scale. In contrast, statistically significant worsening in all signs and symptoms of hypothyroidism was observed during thyroid hormone withdrawal. For more information, please see the important safety information below.

In addition, Thyrogen usage allows for more convenient testing for thyroid cancer. Follow-up testing using Thyrogen can be performed in a 5-day period versus the 5- to 6-week protocol required if patients must be withdrawn from their thyroid hormone. Rescheduling of Tg tests and whole body scans, which may be required for patients whose TSH is not yet appropriately elevated following thyroid hormone withdrawal, can be avoided by using Thyrogen. For more information, please see the important safety information below.

References