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How FASLODEX works

Hormone receptor-positive breast cancer is a type of breast cancer in which cells need the hormone estrogen to grow. In this type of cancer, estrogen is delivered into the breast cancer cells by message-carrying proteins called estrogen receptors.

Given by intramuscular (IM) injection once a month, FASLODEX works by binding to estrogen receptors, which blocks estrogen from binding. FASLODEX causes the estrogen receptor to change shape and not work as well. In addition, FASLODEX causes a decrease (downregulation) in the number of estrogen receptors. This may interfere with cancer cell activity, which, in part, may slow the growth of the breast cancer.

In clinical trials, FASLODEX was found to be effective when tamoxifen no longer worked.

See how FASLODEX works:

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To find out if your tumor may respond to FASLODEX, your doctor can do a test to determine if your tumor is hormone receptor positive. Breast cancer tumors are hormone receptor positive in more than 60% of postmenopausal women.

What is hormone receptor status?

Hormone receptors are message-carrying proteins that bind estrogen or progesterone (female hormones) and take them to the nucleus of the cell. In some breast cancers, these hormones signal the tumor cells to divide and grow. Tumors with estrogen receptors or progesterone receptors present in their cells are said to be hormone receptor positive. Tumors that are hormone receptor positive are more likely to respond to hormonal treatment like FASLODEX.

Ask your doctor about your hormone receptor status, and whether FASLODEX may be right for you.