A targeted therapy is a drug designed to attack a certain molecular agent or pathway involved in the development of cancer. For example, the drug trastuzumab (Herceptin) targets a certain gene's protein called HER2/neu that is found on the surface of some cancer cells.
Unlike chemotherapy drugs, targeted therapies kill cancer cells with little harm to healthy cells. One of the drawbacks of these therapies is they only work on cancers that have the specific markers they were designed to target. Therefore, many people cannot use these drugs.
Targeted therapies offer promise for current and future breast cancer treatments.
To learn more about a specific targeted therapy drug, visit the National Institutes of Health’s Medline Plus website.
The drug trastuzumab (Herceptin) is used to treat metastatic breast cancer and early breast cancer (including lymph node-positive and some lymph node-negative cancers).
Some breast cancers have high amounts of a protein called HER2/neu on the surface of the cancer cells (called HER2/neu-positive (HER2-positive) breast cancer). The HER2/neu protein is important for cancer cell growth.
Trastuzumab is a specially made antibody that targets HER2-positive cancer cells. When attached to the HER2/neu protein, trastuzumab can slow or stop the growth of these cancer cells.
The HER2/neu status of a tumor is determined by testing tissue removed during a biopsy. All newly diagnosed breast cancers are tested for HER2/neu status.
About 15 to 20 percent of breast cancers are HER2-positive [78-79]. These breast cancers can be treated with trastuzumab.
Learn more about tumor characteristics like HER2/neu status.
Studies show chemotherapy plus trastuzumab cuts the risk of breast cancer recurrence in half compared to chemotherapy alone among women with HER2-positive cancers [80-83].
Trastuzumab is only used to treat HER2-positive cancers and has no role in the treatment of HER2/neu-negative cancers.
For a summary of research studies on trastuzumab and overall survival in early breast cancer, visit the Breast Cancer Research section.
If you have HER2-positive breast cancer, neoadjuvant trastuzumab (Herceptin) and pertuzumab (Perjeta) may be added to your neoadjuvant chemotherapy.
If you have neoadjuvant trastuzumab, you will likely also have trastuzumab after surgery (adjuvant trastuzumab). However, pertuzumab is only used as a neoadjuvant therapy and is not given after surgery.
Trastuzumab is not usually given at the same time as anthracycline-based chemotherapy, neither in the neoadjuvant nor the adjuvant setting.
Learn about trastuzumab and pertuzumab as part of neoadjuvant treatment of early and locally advanced breast cancer.
Trastuzumab (Herceptin) is a specially made antibody that targets HER2/neu-positive (HER2/neu+) cancer cells. When attached to the HER2/neu protein, trastuzumab slows or stops the growth of these cells. Trastuzumab is only used to treat HER2/neu+ breast cancers. It is given through an IV (intravenously). Clinical trials in women with HER2/neu+ metastatic breast cancer have shown trastuzumab can shrink tumors and slow cancer growth when used alone or combined with chemotherapy [11-15]. Trastuzumab is used as a first treatment for HER2/neu+ metastatic breast cancer as well as a treatment for HER2/neu+ metastatic cancer that has started to progress with chemotherapy [11-15]. In some cases, HER2/neu+ tumors may spread to the brain. Because trastuzumab is not able to cross the blood-brain barrier, it is not used to treat brain metastases.Learn about trastuzumab, lapatinib and other targeted therapies in the treatment of metastatic breast cancer.
Trastuzumab use is linked to congestive heart failure, a serious heart condition. In clinical trials, about two to three percent of those treated with chemotherapy plus trastuzumab had heart failure, compared to fewer than one percent of those treated with chemotherapy alone [81-83]. This risk of heart problems may be higher with chemotherapy regimens containing an anthracycline than with regimens without an anthracycline . For most people who develop a heart problem while taking trastuzumab, the condition improves after stopping trastuzumab. For a few people, however, the heart problem may be permanent.
Your heart will be checked before and during treatment with trastuzumab to help ensure there are no problems. To help protect the heart while taking trastuzumab, it may be helpful to adopt a lifestyle that includes a healthy diet, regular exercise and for those who smoke, quitting smoking .
Because of the risk of heart problems, trastuzumab is usually only recommended for people with breast tumors that are larger than one centimeter. There is controversy as to whether very small (smaller than one centimeter), lymph node-negative tumors should be treated with trastuzumab.
To learn more about trastuzumab, visit the National Institutes of Health’s Medline Plus website.
Pertuzumab (Perjeta) is an antibody that targets HER2/neu-positive (HER2/neu+) cancer cells in a different way than trastuzumab. Pertuzumab is FDA-approved for the treatment of HER2/neu+ metastatic breast cancers that have not been treated with chemotherapy, trastuzumab or lapatinib. It is given through an IV.
Findings from a randomized controlled trial showed pertuzumab in combination with trastuzumab and chemotherapy slowed the growth of HER2/neu+ metastatic breast cancer and increased survival better than trastuzumab and chemotherapy alone [14,27].
Possible side effects of pertuzumab include diarrhea, rash, mouth sores, low white blood cell count and dry skin .
Tyrosine-kinase inhibitors, such as lapatinib (Tykerb), are a class of drugs that target enzymes important for cell functions (called tyrosine-kinase enzymes). These drugs can block tyrosine-kinase enzymes at many points along the cancer growth pathway.
Lapatinib is FDA-approved for the treatment of HER2/neu-positive (HER2/neu+) metastatic breast cancer in women who have already had chemotherapy and trastuzumab. Lapatinib is taken in pill form.
Lapatinib combined with chemotherapy can increase time to cancer spread and improved overall survival compared to chemotherapy alone in women with HER2/neu+ metastatic breast [18-19].
Some studies have shown lapatinib combined with the aromatase inhibitor letrozole may increase time to cancer spread compared to the use of letrozole alone in women with hormone receptor-positive, HER2/neu+ metastatic breast cancer [20-21].
One clinical trial found lapatinib combined with trastuzumab may increase time to cancer spread compared to the use of trastuzumab alone in women with HER2/neu+ metastatic breast cancer .
Early findings show lapatinib holds promise for HER2/neu+ metastatic cancer with brain metastases as it can pass through the blood-brain barrier [22-24]. Most therapies, including trastuzumab, cannot cross the blood-brain barrier. In rare cases, lapatinib can help shrink or slow the growth of brain metastases [22-24].
Side effects of lapatinib include diarrhea, nausea, vomiting, rash and fatigue. In rare cases, it has been linked to liver and lung problems [15,18-21].
Although the exact treatment for breast cancer varies from person to person, guidelines help ensure quality care. These guidelines are based on the latest research and the consensus of experts. The National Comprehensive Care Network (NCCN) and American Society of Clinical Oncology (ASCO) are two respected organizations that regularly update and post their guidelines online. The National Cancer Institute (NCI) also has overviews of treatment options.
Komen Support Resources
Targeted therapy drug costs can quickly become a financial burden for you and your family. Medicare and many insurance providers offer prescription drug plans. One may already be included in your policy or you may be able to buy an extra plan for prescriptions.
You may also qualify for assistance from programs that help with drug costs or offer low-cost or free prescriptions.
Learn more about insurance plans and prescription drug assistance programs.
Susan G. Komen® position on fairness in breast cancer medication coverage
Medications taken by mouth (oral) are usually covered under a health insurance plan’s prescription drug benefit rather than the plan’s medical benefit. As a result, people often find themselves facing high out-of-pocket costs when filling their prescriptions (sometimes costing thousands of dollars per month). High prescription drug costs are a barrier to care. High costs can prevent people from getting the medications prescribed by their health care provider.
Komen supports efforts at the state and federal level to require insurers to provide equal (or better) coverage for oral breast cancer medications as they provide for IV medications to ensure people have access to affordable, appropriate treatment for their cancer.
Targeted Therapy Video
Facts for Life: Targeted Therapies
Breast Cancer 101 - Targeted Therapy
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