FDA issues advisory on prostate cancer drugs

FDA Conducting Safety Review of Commonly Used Prostate Cancer DrugsPreliminary review suggests an increase in the risk of diabetes and certain cardiovascular diseases in men treated with GnRH agonists

Gonadotropin-Releasing Hormone (GnRH) agonists, a class of medications primarily used to treat men with prostate cancer, have been associated with a small increased risk for diabetes, heart attack, stroke, and sudden death in men treated with one of the medications, according to a preliminary and ongoing analysis of several studies by the U.S. Food and Drug Administration.

Based on initial findings, FDA advises:

• Health care professionals should be aware of these potential risks and carefully weigh the benefits and risks of GnRH agonists when determining a treatment for patients with prostate cancer.
• Patients receiving a GnRH agonist should be monitored for the development of diabetes and cardiovascular disease.
• Cardiovascular risk factors such as smoking and increases in blood pressure, cholesterol, blood sugar and weight should be managed according to current clinical practice.
• Patients should not stop treatment with a GnRH agonist unless instructed to do so by a health care professional.

At this time, FDA has not made any conclusions about whether GnRH agonists cause an increase in the risk of diabetes and heart disease in patients receiving one of these medications to treat prostate cancer.

"While our review of these prostate cancer treatments is ongoing and there are some limitations to the data, FDA believes it is important to tell patients and health care professionals that there may be an increased risk of serious side effects," said Robert Justice, M.D., director of the Division of Drug Oncology Products in FDA's Center for Drug Evaluation and Research.

Medications in the GnRH class are marketed under the brand names Eligard, Lupron, Synarel, Trelstar, Vantas, Viadur, and Zoladex. There are also several generic products available.

The prostate gland is part of the male reproductive system. Prostate cancer is the second most common type of cancer among men in the United States, behind skin cancer, and usually occurs in older men. This year an estimated 203,415 new cases of prostate cancer will be diagnosed and about 28,372 men will die from the disease, according to the Centers for Disease Control and Prevention.

GnRH agonists are drugs that suppress the production of testosterone, a hormone that is involved in the growth of prostate cancer. This type of treatment is called androgen deprivation therapy, or ADT. Suppressing testosterone has been shown to shrink or slow the growth of prostate cancer.

Some GnRH agonists are also used in women to help manage the pain caused by endometriosis, to improve anemia associated with uterine fibroids prior to hysterectomy and in some cases for palliative treatment of advanced breast cancer. Use of these products should not exceed one year for women except in treating breast cancer. There are no known comparable studies that have evaluated the risk of diabetes and heart disease in women taking GnRH agonists.

Some GnRH agonists are also used in children to treat central precocious puberty. There are no known studies that have evaluated the risk of diabetes and heart disease in children taking GnRH agonists.

Eligard is marketed by Bridgewater, N.J.-based Sanofi-Aventis.
Lupron is marketed by Abbott Park, Ill.-based Abbott Laboratories.
Synarel is marketed by New York City-based Pfizer.
Trelstar is marketed by Corona, Calif.-based Watson Pharmaceuticals.
Vantas is marketed by Chadds Ford, Pa.-based Endo Pharmaceuticals.
Viadur is marketed by Wayne, N.J.-based Bayer Pharmaceuticals.
Zoladex is marketed by Wilmington, Del.-based AstraZeneca.

 For more information:

• Drug Safety Communication: Ongoing Safety Review of GnRH Agonists and Possible Increased Risk of Diabetes and Certain Cardiovascular Diseases
• FDA Office of Oncology Drug Products