Leuprolide

Leuprolide (Lupron Depot) is a type of medicine known as a gonadotropin-releasing hormone (GnRH) agonist, sometimes also called a luteinizing hormone-releasing hormone (LHRH) agonist.

Leuprolide stops the brain from signaling the ovaries to function, which lowers estrogen levels. This is helpful in treating premenopausal women diagnosed with:

• Early-stage hormone receptor-positive breast cancer that has a high risk of recurrence (coming back)
• Metastatic hormone receptor-positive breast cancer

In men with hormone receptor-positive breast cancer, leuprolide suppresses testicle function, which lowers testosterone levels. Because some testosterone gets turned into estrogen, this reduces estrogen levels. As in women, this can slow or stop breast cancer growth.

Who gets leuprolide

Leuprolide is used in premenopausal women to:

• Help lower a high risk of early-stage hormone receptor-positive breast cancer coming back
• Slow or stop the growth of hormone receptor-positive metastatic breast cancer

Leuprolide is given along with another form of hormonal therapy, such as:

• Tamoxifen, a hormonal therapy known as a selective estrogen receptor modulator (SERM)
• Aromatase inhibitors, such as anastrozole (Arimidex), exemestane (Aromasin), or letrozole (Femara). Aromatase inhibitors are usually given to postmenopausal women. Leuprolide causes temporary menopause in premenopausal women, making it possible for them to take these medicines.

Your doctor also may recommend taking a type of targeted therapy called a CDK 4/6 inhibitor along with these treatments. The FDA-approved CDK 4/6 inhibitors are:

• Ribociclib (Kisqali)
• Abemaciclib (Verzenio)
• Palbociclib (Ibrance)

Leuprolide also can be used to protect the ovaries the damaging effects of chemotherapy. Chemotherapy can sometimes lead to early menopause and infertility. Shutting down the ovaries temporarily can lower these risks and protect fertility. Women with either hormone receptor-positive or negative breast cancer can use leuprolide in this way.

In men with metastatic hormone receptor-positive breast cancer, leuprolide is often combined with an aromatase inhibitor or selective estrogen receptor degrader (SERD). A CDK 4/6 inhibitor may be recommended as well.

How is leuprolide given?

Leuprolide is given as an injection once a month or once every 3 months. The injection may be in the thigh, buttock, or shoulder. Your healthcare team may have you come to the office for the injection, or they may teach you how to do it at home.

Side effects and things to remember

Side effects vary from person to person, but common effects can include:

• Pain and/or bruising at the injection site
• Menopausal symptoms, such as hot flashes, night sweats, vaginal dryness and irritation, mood changes, and stopping of menstrual periods
• Insomnia and fatigue
• Loss of sexual interest
• Bone thinning
• Bone pain
• Depression
• Changes in breast size, and/or breast tenderness

In men, side effects can include:

• Hot flashes
• Loss of sexual interest
• Trouble having an erection (erectile dysfunction)
• Enlarged breasts
• Fatigue
• Rare risk of blood clots

Women who are pregnant or plan to become pregnant should not take leuprolide. It can be harmful to an unborn baby.

Rare risks of leuprolide also can include:

• Allergic reactions
• An abnormal heart rhythm called QT prolongation
• Increases in blood sugar levels

You and your healthcare team should discuss whether you have any history of heart problems or diabetes before taking leuprolide.