FDA insists on GnRH agonists risk warning

The US Food and Drug Administration (FDA) has issued a notification to manufacturers of gonadotropin-releasing hormone (GnRH) agonists, a class of drugs used in the treatment of men with prostate cancer, informing them that they must add new safety information to the Warnings and Precautions section of drug labels.

The warning relates to the increased risk of diabetes and some cardiovascular diseases (heart attack, sudden cardiac death and stroke) in men receiving GnRH agonists for the treatment of prostate cancer.

The notification from the FDA follows an ongoing safety review issued by the authority in May 2010, which was based on the review of several published studies. 

GnRH agonists work by suppressing the production of testosterone, which is a key hormone involved in the growth of prostate cancer. This type of treatment is called androgen deprivation therapy (ADT) and has been shown to shrink or slow the growth of prostate cancer.

In the US, GnRH agonists are approved for the treatment of symptoms (palliative treatment) of advanced prostate cancer. They are sold as Lupron (manufactured by Abbott), Zoladex (AstraZeneca), Trelstar (Watson), Viadur (Alza), and Eligard (sanofi-aventis) as well as under several generic labels.

Prostate cancer is the second most common type of cancer among men in the US, after skin cancer, and usually occurs in older men. According to the Centers for Disease Control, National Center for Health Statistics and the National Cancer Institute an estimated 217,730 new cases of prostate cancer will be diagnosed in 2010. Of these, around 32,050 men will die from the disease.