New warn labels for GnRH agonists as prostate cancer treatment

A class of prostate cancer drugs known as gonadotropin-releasing hormone(GnRH) agonists have been linked to a higher risk of developing heart disease,diabetes and stroke in men treated with  these therapies, according to the US Food and Drug Administration (FDA). The agency thus requests manufacturers to add new warnings to labeling to alert patients and doctors the potential risks.

The FDA announced in May that a preliminary and ongoing analysis found that patients receiving GnRH agonists were at a small elevated risk of having a heart attack, becoming diabetic, suffering from a stroke, or sudden death  .

The agency advises doctors to monitor glycosylated hemoglobin (HbA1c) and blood glucose levels of patients receiving GnRH agonist therapy. These increased marks may be indications of diabetes development or a complication for patients who already have diabetes.
GnRH agonists act through inhibition of lutenizing hormone production, then lead to suppressed production of testosterone, a male hormone involved in the growth of prostate cancer. Suppressing testosterone, a type of treatment called androgen deprivation therapy, has been shown to shrink or slow the growth of prostate cancer.

Current marketed GnRH agnoists include the brand names drugs: Eligard, Lupron, Synarel, Trelstar, Vantas, Viadur, and Zoladex, and there are also several generic products available.

Prostate cancer is the second most common type of cancer among men in the United States, behind skin cancer, and the second leading cause of cancer death in U.S. men after lung cancer. It usually occurs in  men over fifty. This year an estimated 217,730 new cases of prostate cancer will be diagnosed and about 32,050 men will die from the disease, according to the Centers for Disease Control National Center for Health Statistics and the National Cancer Institute.

The US FDA said :

Although the risk for diabetes and cardiovascular diseases appears to be low in men receiving GnRH agonists for prostate cancer, it is important for healthcare professionals to evaluate patients for risk factors for these diseases. Healthcare professionals should always carefully weigh the benefits and risks of using GnRH agonists before determining appropriate treatment for prostate cancer.