Leuprolide for Prostate Cancer Treatment

Leuprolide (also known as Lupron) is one of the gonadotropin-releasing hormone (GnRH) agonists used to treat advanced prostate cancer. It binds to the GnRH receptors, as a mimic of GnRH (naturally produced by the hypothalamus), to eventually block the release of sex hormones, such as testosterone, leading to a state of pharmacological castration.

Since their discovery in the 1980s, GnRH agonists have been used for decades in prostate cancer treatment. Even if castration-resistant prostate cancer develops, this androgen deprivation therapy should still be used. Another commonly used GnRH agonist for prostate cancer is goserelin.

As a GnRH agonist, leuprolide delivers a continuous flow of drug molecules that bind to and activate the GnRH receptors in the hypophysis (also known as the pituitary gland, found at the base of the brain), overstimulating and eventually desensitizing them. This process leads to suppression of gonadotropins production in testicles, completely eliminating testosterone. However, this initial overstimulation results in a temporary testosterone surge.

The standard way of leuprolide administration is injection of a drug depot, which is formulated in a way to provide a slow, constant release of the drug to target the tumor cells over a longer period of time. This reduces the number of doses you would need to take, making treatment more convenient for you.

Due to the temporary testosterone surge that commonly accompanies leuprolide treatment:

• Early on in your treatment, you may face symptoms such as bone pain or difficulty urinating. While not commonly seen, if you face blockage of your urine from moving in your body, compression of the spinal cord or other new and worsening symptoms, you should inform your doctor.
• Your doctor may wait a few weeks to observe your response to the drug before deciding if you need a different treatment. They may add on an anti-androgen (e.g. bicalutamide) to counteract these new symptoms.
• If you wish to avoid the side effects associated with the testosterone surge, you may wish to consider GnRH antagonists such as degarelix and relugolix, which work faster and avoid the testosterone surge completely.

You should also note that:

• Your blood sugar levels may need to be monitored on a regular basis due to an increased risk of diabetes while taking leuprolide.
• If you experience any symptoms commonly seen with heart attacks or stroke, you should immediately report this to your doctor, due to an increased risk of heart issues while taking leuprolide. Some may include chest pains that feel like pressure, squeezing or tightness, shortness of breath or discomfort in the upper body (e.g. the shoulders, arms, back or neck).
• You may face a chance of impotence or infertility.

Below are some common side effects reported after taking leuprolide. You may not experience all of these side effects, but there is a risk that you may encounter a few of these at the same time.

Those commonly reported in over 1 in 10 people include:

• Hot flashes
• Fatigue
• Joint pain
• Injection site pain