June 21, 2001

SOURCE: Genzyme General

CAMBRIDGE, Mass.-- Genzyme General presented interim results from an ongoing post-marketing study that adds new evidence that Thyrogen® (thyrotropin alfa injection) can help doctors identify those at risk of a recurrence of thyroid cancer. The data, which included a more broad patient population than previous studies, were presented at The Endocrine Society's 83rd annual meeting in Denver.

Thyrogen was approved by the FDA in late-1998 as an adjunct to two common thyroid cancer screening tools, serum thyroglobulin (Tg) testing and whole body scanning. It increases the sensitivity of the Tg test while also allowing patients to avoid the side effects of hypothyroidism, such as fatigue, depression and weight gain, associated with whole body scanning.

The preliminary results presented today suggest that Thyrogen can be a useful tool in screening patients who have been treated for thyroid cancer but are in the early stages of disease follow-up, when the risk of recurrence is highest. The study involved 342 patients at 58 centers in the United States who have had their thyroid gland removed in the past 10 years after being diagnosed with cancer, and who are treated with thyroid hormone therapy.

Patients underwent thyroglobulin (Tg) screening both before and after being administered Thyrogen. After Thyrogen was administered, 18 percent of patients had a rise of at least 2 ng/ml above their baseline Tg level, an endpoint chosen because it is considered to be clinically meaningful. Using Thyrogen to accurately identify those with an elevated Tg level, which is an indicator of residual or cancerous thyroid tissue, gives physicians a powerful tool for making decisions about follow-up care.

``This study and previous studies demonstrate that Thyrogen can help improve the sensitivity of thyroglobulin testing at all ends of the spectrum, including high-risk patients and those with otherwise undetectable levels of thyroglobulin,'' said the study's principal investigator, Dr. Leonard Wartofsky of Washington Hospital Center in Washington, D.C. ``This should provide patients and their physicians with a better understanding of who is at risk for recurrence and may need increased follow-up care.''

Patients who have had their thyroid gland removed must take thyroid hormone supplements to maintain their metabolism. Prior to the introduction of Thyrogen in 1998, these patients had to withdraw from hormone supplements for up to six weeks when they underwent diagnostic testing, in order to heighten the sensitivity of the test. This hiatus causes a patient to experience the symptoms of hypothyroidism, which include fatigue, weight gain, constipation, mental dullness, lethargy, depression and other adverse reactions. Thyrogen, which is a recombinant form of thyroid stimulating hormone, allows patients to avoid withdrawing from hormone therapy while undergoing diagnostic testing.

Serum thyroglobulin testing and radioiodine imaging are the two diagnostic procedures most commonly used with patients being examined for remnant thyroid tissue, thyroid cancer recurrence or metastases. In the U.S., physicians order more than 150,000 thyroglobulin tests and 30,000 radioiodine imaging whole body scans each year for thyroid cancer patients.

Genzyme General develops and markets therapeutic products and diagnostic products and services. Genzyme General has four therapeutic products on the market and a strong pipeline of products in development focused on the treatment of genetic disorders and other chronic debilitating diseases with well-defined patient populations. Genzyme General is a division of the biotechnology company Genzyme Corporation.