Faslodex (chemical name: fulvestrant) is an estrogen receptor downregulator (ERD), a type of hormonal therapy. Faslodex blocks the effect of estrogen on breast tissue by sitting in the estrogen receptor in breast cells. Faslodex is a liquid given as an injection into a muscle.
On Aug. 28, 2017, the U. S. Food and Drug Administration (FDA) approved a broader use of Faslodex to treat breast cancer. Faslodex can now be used alone as the first treatment for postmenopausal women diagnosed with hormone-receptor-positive, HER2-negative, advanced-stage breast cancer that hasn’t been treated with hormonal therapy.
Before this, Faslodex was approved to treat postmenopausal women diagnosed with metastatic, hormone-receptor-positive breast cancer that had stopped responding to other hormonal therapy medicines.
The new FDA approval is based on results from the 2016 FALCON trial.
The FALCON trial found that postmenopausal women diagnosed with hormone-receptor-positive, locally advanced or metastatic breast cancer had a lower risk of the cancer growing if they got Faslodex as a first hormonal therapy compared to women who got Arimidex.
Arimidex (chemical name: anastrozole) is an aromatase inhibitor, another type of hormonal therapy. Aromatase inhibitors work by blocking the enzyme aromatase, which turns androgen hormones into small amounts of estrogen in the body. This means that less estrogen is available to stimulate the growth of hormone-receptor-positive breast cancer cells. Aromatase inhibitors can't stop the ovaries from making estrogen, so aromatase inhibitors only work in postmenopausal women.
Metastatic breast cancer is breast cancer that has spread to a part of the body away from the breast, such as the bones or liver. Locally advanced breast cancer is breast cancer that has spread beyond the breast to nearby tissues, such as the skin or the chest wall. Both locally advanced breast cancer and metastatic breast cancer are considered advanced-stage disease.
“[The FALCON] study provides evidence that using fulvestrant as the first option for previously untreated hormone-receptor-positive advanced breast cancer will prolong the time before the disease advances and alternative therapies are required,” said Matthew Ellis, M.D., Ph.D., director of the Lester and Sue Smith Breast Center at the Baylor College of Medicine and one of the researchers who did the FALCON study.
If you’ve been diagnosed with advanced-stage, hormone-receptor-positive breast cancer, you and your doctor will consider a number of treatment options, including hormonal therapy and chemotherapy. If you haven’t been treated with hormonal therapy for advanced-stage disease yet, you might want to talk to your doctor about this new indication for Faslodex and whether Faslodex might be a good first treatment choice for you, depending on your unique situation. Together, you and your doctor will decide on a treatment plan that’s best for you.