Targeted therapies are a relatively new form of treatment for breast cancer and may be used alone or in combination with other treatments. Unlike traditionalchemotherapy, which attacks any rapidly growing cells, targeted therapies directly target cancer cells or signaling pathways that contribute to the growth of cancer cells. For this reason, many of the drugs may have fewer side effects than chemotherapy.
Targeted therapies are available for the treatment of estrogen receptor-positive breast cancers,HER2-positive breast cancers, andtriple-negative breast cancer.
These drugs can work very well, but like the other medications used to treat metastatic breast cancer, resistance usually develops over time. Some of these drugs are used for both early-stage and metastatic breast cancer, whereas others are used primarily for treating metastatic breast cancer.
For HER2-Positive Cancer
In around 25% of breast cancers, a gene known as human epidermal growth receptor 2 (or HER2/neu) results in the overexpression of the HER2 protein (receptors) on the surface of breast cancer cells.
The presence of HER2 receptors may result in the growth and proliferation of HER2-positive cancers. Thus, medications that interfere with these receptors interfere with the signal to these cancer cells, limiting their growth.
Medications that target HER2 include:
Verywell / Gary Ferster
Your healthcare provider may check your heart function before treatment, and again while you are taking the drug. Let your healthcare provider know if you develop symptoms such as shortness of breath, leg swelling, and severe fatigue.
HER2 Status and Breast Cancer
For Estrogen Receptor-Positive Cancer
These drugs are used for the treatment of breast cancer for females who are postmenopausal (or who are premenopausal and have received ovarian suppression therapy) to make hormonal therapies more effective.
For Women With BRCA Gene Mutations
Drugs known as PARP inhibitors are used for women with BRCA1 and BRCA2 gene mutations. They come in pill form and includeLynparza (olaparib)andTalzenna (talazoparib).
Poly ADP ribose polymerase (PARP) proteins normally help repair damaged DNA inside cells. The BRCA genes (BRCA1 and BRCA2) also help repair DNA (in a slightly different way), but mutations in one of those genes can stop this from happening.
Olaparib and talazoparib can be used to treat metastatic, HER2-negative breast cancer in people with a BRCA mutation who have already gotten chemotherapy.Olaparib can also be used to treat high-risk early-stage breast cancer in people who have been treated with chemotherapy. Olaparib can be used in women who have already received hormone therapy if the cancer is hormone receptor-positive.
Side effects can include nausea, vomiting, diarrhea, fatigue, loss of appetite, taste changes, low red blood cell counts (anemia), low platelet counts, low white blood cell counts, belly pain, and muscle and joint pain.Rarely, some people treated with a PARP inhibitor have developed a blood cancer, such asmyelodysplastic syndrome (MDS)oracute myeloid leukemia (AML).
BRCA Mutations and Breast Cancer
For Triple-Negative Breast Cancer
Tumors that are estrogen receptor negative, progesterone receptor negative, and HER2 negative result in what’s known as triple-negative breast cancer. This form can be more of a challenge to treat, as hormonal therapies and HER2 therapies are usually ineffective.
Trodelvy (sacituzumab)is used to treat metastatic or inoperable triple-negative breast cancer for people who have received two or more prior treatments, including at least one treatment for metastatic disease. It binds to the antigen Trop-2 and inhibits DNA replication and stimulates cell death.
Triple-Negative Breast Cancer
A Word From Verywell
In addition to targeted therapy,immunotherapy for breast canceris also an option that works a little differently—immunotherapy involves a procedure that stimulates your body’s immune system to fight cancer. With medicine changing so rapidly, it’s important to keep up with the latest treatments and understand options for your particular type of cancer. Armed with that information, you’ll be able to have a more productive conversation with your oncologist about the therapies that will be most effective for you.
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4 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Liedtke C, Kolberg HC.Systemic Therapy of Advanced/Metastatic Breast Cancer - Current Evidence and Future Concepts.Breast Care (Basel).2016;11(4):275-281. doi:10.1159/000447549Breastcancer.org.Women Treated With Herceptin Need Heart Monitoring No Matter Their Age.Food and Drug Administration.Fda approves first targeted therapy for her2-low breast cancer.Yi M, Dong B, Qin S, Chu Q, Wu K, Luo S.Advances and perspectives of PARP inhibitors.Exp Hematol Oncol. 2019;8:29. doi:10.1186/s40164-019-0154-9Additional ReadingDeVita, Vincent., et al. Cancer: Principles & Practice of Oncology. Cancer of the Breast. Wolters Kluwer, 2016.
4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Liedtke C, Kolberg HC.Systemic Therapy of Advanced/Metastatic Breast Cancer - Current Evidence and Future Concepts.Breast Care (Basel).2016;11(4):275-281. doi:10.1159/000447549Breastcancer.org.Women Treated With Herceptin Need Heart Monitoring No Matter Their Age.Food and Drug Administration.Fda approves first targeted therapy for her2-low breast cancer.Yi M, Dong B, Qin S, Chu Q, Wu K, Luo S.Advances and perspectives of PARP inhibitors.Exp Hematol Oncol. 2019;8:29. doi:10.1186/s40164-019-0154-9Additional ReadingDeVita, Vincent., et al. Cancer: Principles & Practice of Oncology. Cancer of the Breast. Wolters Kluwer, 2016.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Liedtke C, Kolberg HC.Systemic Therapy of Advanced/Metastatic Breast Cancer - Current Evidence and Future Concepts.Breast Care (Basel).2016;11(4):275-281. doi:10.1159/000447549Breastcancer.org.Women Treated With Herceptin Need Heart Monitoring No Matter Their Age.Food and Drug Administration.Fda approves first targeted therapy for her2-low breast cancer.Yi M, Dong B, Qin S, Chu Q, Wu K, Luo S.Advances and perspectives of PARP inhibitors.Exp Hematol Oncol. 2019;8:29. doi:10.1186/s40164-019-0154-9
Liedtke C, Kolberg HC.Systemic Therapy of Advanced/Metastatic Breast Cancer - Current Evidence and Future Concepts.Breast Care (Basel).2016;11(4):275-281. doi:10.1159/000447549
Breastcancer.org.Women Treated With Herceptin Need Heart Monitoring No Matter Their Age.
Food and Drug Administration.Fda approves first targeted therapy for her2-low breast cancer.
Yi M, Dong B, Qin S, Chu Q, Wu K, Luo S.Advances and perspectives of PARP inhibitors.Exp Hematol Oncol. 2019;8:29. doi:10.1186/s40164-019-0154-9
DeVita, Vincent., et al. Cancer: Principles & Practice of Oncology. Cancer of the Breast. Wolters Kluwer, 2016.
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