A type of drug given to men with prostate cancer, called GnRH (gonadotropin-releasing hormone) agonists have been linked to a higher risk of developing diabetes, stroke or heart disease, and thus must have new warnings on their labels, said the US Food and Drug Administration (FDA). An ongoing analysis which started in May this year found that men on GnRH agonists had a slightly elevated risk of having a heart attack, becoming diabetic, suffering from a stroke, or sudden death.

The FDA announced today that such medications will include updated information on these risks in the Warning and Precautions section in their labeling.

According to the CDC (Centers for Disease Control and Prevention), prostate cancer is the second most common male cancer in the USA, after skin cancer – those who develop this type of cancer usually do so during old age.

Approximately 217,730 males will have been diagnosed with prostate cancer by the end of this year in the USA, and about 32,050 people will die.

GnRH agonists cause the inhibition of lutenizing hormone production, which in turn brings down the production of testosterone – prostate cancer cells depend on testosterone for their growth.

Androgen deprivation therapy – androgen is a male sex hormone that promotes male sex development and characteristics, the major androgen is testosterone. Androgen deprivation therapy is treatment which suppresses the production of androgen (testosterone). Prescribing a GnRH agonist is an example of androgen deprivation therapy, also known as ADT.

Examples of GnRH agonists available today in the USA are:

  • Eligard
  • Lupron
  • Synarel
  • Trelstar
  • Vantas
  • Viadur
  • Zoladex
  • ..and several generic products

GnRH agonists are approved and used in the USA for palliative treatment in patients with advanced prostate cancer. The benefits of this type of medication for non-metastatic prostate cancer (early stage cancer that has not spread) have not been established, according to the FDA.

In a communiqué, the FDA writes:

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.

The FDA advises doctors to monitor blood glucose and/or glycosylated hemoglobin (HbA1c) of patients receiving GnRH agonist therapy. Elevated blood glucose levels may be an indication of diabetes development or a complication for patients who already have diabetes. These patients should also be monitored for signs and symptoms linked to cardiovascular disease.

Before being given GnRH agonists, patients should tell their doctors if they have heart disease, prior stroke or heart attack, or hypertension (high blood pressure). Smokers should also tell their doctors that they smoke, even if they have none of the above-mentioned risk factors.

Source: FDA

Written by Christian Nordqvist