Targeted therapies are treatments that target specific characteristics of cancer cells, such as a protein that allows the cancer cells to grow in a rapid or abnormal way. Targeted therapies are generally less likely than chemotherapy to harm normal, healthy cells. Some targeted therapies are antibodies that work like the antibodies made naturally by our immune systems.
There are currently seven targeted therapies doctors use to treat metastatic breast cancer:
Afinitor (chemical name: everolimus) works against locally advanced-stage or metastatic, hormone-receptor-positive, HER2-negative breast cancer in postmenopausal women previously treated with Femara by interfering with the mTOR kinase (a protein in the body that if acting abnormally, can help certain breast cancers grow). Afinitor is a pill given in combination with Aromasin (chemical name: exemestane). Treatment with Afinitor can be continued indefinitely in order to keep the cancer under control. Your doctor would only recommend you stop taking Afinitor if the cancer stopped responding to it or if you experienced any severe side effects.
Avastin (chemical name: bevacizumab) is given intravenously in combination with Taxol (chemical name: paclitaxel), a type of chemotherapy, to treat people diagnosed with metastatic, HER2-negative breast cancer who haven't yet received chemotherapy for metastatic breast cancer. Avastin works against HER2-negative breast cancer by blocking the growth of new blood vessels that cancer cells depend on to grow and function. More research is needed to determine whether you can stop taking Avastin if the cancer stops progressing.
On Nov. 18, 2011, the U.S. Food and Drug Administration (FDA) announced that it had removed the breast cancer indication from Avastin because the drug has not been shown to be safe and effective for that use. Avastin has not been removed from the market, though, and doctors can choose to use Avastin to treat metastatic breast cancer whether or not that particular use is officially approved by the FDA.
Enhertu (chemical name: fam-trastuzumab-deruxtecan-nxki) is approved to treat HER2-positive breast cancer that can’t be removed with surgery and metastatic HER2-positive breast cancer that has been treated with two or more anti-HER2 therapies. Enhertu is a combination of an anti-HER2 medicine that has the same basic structure as Herceptin, the chemotherapy medicine topoisomerase I inhibitor, and deruxtecan, a compound that links the other two together. Enhertu was designed to deliver topoisomerase I inhibitor to cancer cells in a targeted way by attaching the topoisomerase I inhibitor to the anti-HER2 medicine, which then carries the chemotherapy to the HER2-positive cancer cells. You continue treatment with Enhertu unless the cancer grows or you have severe side effects.
Herceptin (chemical name: trastuzumab) works against locally advanced-stage or metastatic, HER2-positive breast cancers by blocking the ability of the cancer cells to receive chemical signals that tell the cells to grow. Herceptin is given intravenously.
Herceptin has not been used long enough yet to know if people diagnosed with HER2-positive, metastatic breast cancer can stop taking it if they appear to be free of breast cancer for a certain period of time. So if you've been diagnosed with metastatic disease and start taking Herceptin, you continue to take it, unless your doctor recommends you stop taking the medication because it's no longer working or you are unable to tolerate the side effects. The following chemotherapy medications can be given together with or before Herceptin:
- Perjeta (chemical name: pertuzumab)
- Taxotere (chemical name: docetaxel)
- Taxol (chemical name: paclitaxel)
- carboplatin (brand name: Paraplatin)
- Navelbine (chemical name: vinorelbine)
- Xeloda (chemical name: capecitabine)
- Cytoxan (chemical name: cyclophosphamide)
- 5-fluorouracil (5-FU)
Adriamycin (chemical name: doxorubicin) and Ellence (chemical name: epirubicin) are given before or after, but not together with, Herceptin.
Ibrance (chemical name: palbociclib) works against locally advanced-stage or metastatic, estrogen-receptor-positive, HER2-negative breast cancer in postmenopausal women who have never taken hormonal therapy. Ibrance works by inhibiting kinase, a type of protein that helps control cell division. Ibrance, a pill, is used in combination with Femara (chemical name: letrozole). You continue to take Ibrance unless it's no longer working or you’re experiencing side effects that are too severe.
Kadcyla (chemical name: T-DM1 or ado-trastuzumab emtansine) is used to treat HER2-positive, locally advanced-stage or metastatic breast cancer that’s previously been treated with Herceptin and a taxane chemotherapy. Kadcyla is a combination of Herceptin and the chemotherapy medicine emtansine and is given intravenously. Kadcyla blocks HER2-positive breast cancer cells from having the ability to receive signals telling the cells to grow. The emtansine is attached to the Herceptin, so Herceptin carries the emtansine to the HER2-positive cells in a targeted way. Kadcyla is taken indefinitely to keep the cancer under control. The only reason to stop taking Kadcyla is if the cancer progresses or side effects are severe.
Kisqali (chemical name: ribociclib, formerly called LEE011) can work in combination with an aromatase inhibitor in premenopausal, perimenopausal, and postmenopausal women diagnosed with metastatic, hormone-receptor-positive, HER2-negative breast cancer that hasn’t been treated with hormonal therapy yet or in combination with Faslodex (chemical name: fulvestrant) in postmenopausal women diagnosed with metastatic, hormone-receptor-positive, HER2-negative breast cancer that hasn’t been treated with hormonal therapy yet, or that has grown while be treated with a different hormonal therapy. Kisqali is also a cyclin-dependent kinase 4/6 inhibitor like Ibrance. A kinase is a type of protein in the body that helps control cell division. Kisqali works by stopping cancer cells from dividing and growing.
Lynparza (chemical name: olaparib) is approved to treat metastatic, HER2-negative breast cancer with an inherited BRCA1 or BRCA2 mutation that has previously been treated with chemotherapy. Lynparza is a PARP inhibitor. The PARP enzyme fixes DNA damage in both healthy and cancer cells. Lynparza makes it very difficult for these cancer cells to fix DNA damage.
Perjeta (chemical name: pertuzamab) treats HER2-positive, locally advanced-stage or metastatic breast cancer that hasn’t been treated with either Herceptin or chemotherapy yet. Perjeta blocks the ability of HER2-positive breast cancer cells to receive signals that tell the cells to grow. Since Perjeta targets a different area on the cell than Herceptin does, it’s believed to be complementary to Herceptin. Perjeta is used in combination with Herceptin and the chemotherapy Taxotere. Perjeta can be used indefinitely to treat the cancer. The only reason to stop Perjeta is if the cancer no longer stays under control or side effects are severe.
Tykerb (chemical name: lapatinib) is given in combination with Xeloda, a type of chemotherapy, to treat locally advanced-stage or metastatic, HER2-positive breast cancer that has stopped responding to anthracyclines, taxanes, and Herceptin. Tykerb works against HER2-positive breast cancers by blocking certain proteins that can cause uncontrolled cell growth. Tykerb can also be given in combination with Femara (chemical name: letrozole), a type of hormonal therapy, to treat advanced-stage, HER2-positive, hormone-receptor-positive breast cancer. Sometimes, if breast cancer comes back or grows while taking Herceptin, doctors will add Tykerb and continue the Herceptin. Treatment with Tykerb can be continued indefinitely in order to keep the cancer under control. Your doctor would only recommend you stop taking Tykerb if the cancer stopped responding to it or if you experienced any severe side effects.
Verzenio (chemical name: abemaciclib) can be used alone or in combination to treat hormone-receptor-positive, HER2-negative metastatic breast cancer that has either progressed after hormonal therapy or has not been treated with hormonal therapy yet. Verzenio is a cyclin-dependent kinase 4/6 inhibitor, like Ibrance and Kisqali. A kinase is a type of protein in the body that helps control cell division. Verzenio works by stopping cancer cells from dividing and growing.
For more information on targeted therapies used to treat metastatic breast cancer, including side effects and what to expect, visit the Targeted Therapies section.