HER2-Targeted Therapies
HER2-positive breast cancers have a lot of the protein called HER2 on the surface of their cells. The HER2 protein is an important driver of cell growth and survival.
HER2-targeted therapies are used to treat HER2-positive breast cancers. They have no role in the treatment of HER2-negative cancers.
Testing for HER2 status
The HER2 status of a tumor is determined by testing tissue removed during a biopsy. All breast cancers are tested for HER2 status.
About 10% to 20% of newly diagnosed breast cancers are HER2-positive [160-161]. HER2-positive breast cancers can be treated with HER2-targeted therapies.
Learn more about HER2 status.
HER2-targeted therapies
The table below lists the HER2-targeted therapies used to treat breast cancers.
Drug name | Brand name(s) | Used to treat early or metastatic breast cancer? | Pill, injection under the skin, or IV drug (given by vein through an IV)? |
Trastuzumab* | Herceptin (IV drug) and Herceptin Hylecta (injection) | Early and metastatic breast cancer | IV drug or injection |
Pertuzumab* | Perjeta (IV drug) and Phesgo (injection combined with trastuzumab) | Early and metastatic breast cancer | IV drug or injection |
Margetuximab | Margenza | Metastatic breast cancer | IV drug |
Ado-trastuzumab emtansine (T-DM1) | Kadcyla | Early and metastatic breast cancer | IV drug |
Trastuzumab deruxtecan (fam-trastuzumab deruxtecan) | Enhertu | Metastatic breast cancer | IV drug |
Tucatinib | Tukysa | Metastatic breast cancer | Pill |
Neratinib | Nerlynx | Early and metastatic breast cancer | Pill |
Lapatinib | Tykerb | Metastatic breast cancer | Pill |
*Biosimilar forms of trastuzumab include: trastuzumab-anns (Kanjinti), trastuzumab-dkst (Ogivri), trastuzumab-dttb (Ontruzant), trastuzumab-pkrb (Herzuma) and trastuzumab-qyyp (Trazimera). There is one biosimilar form of pertuzumab: pertuzumab-dpzb (Poherdy).
To learn more about a specific HER2-targeted therapy drug, visit the National Institutes of Health’s Medline Plus website.
HER2-targeted therapies and breast cancer treatment
Click on the topics below to learn more.
Watch our video on HER2 status and how HER2-targeted therapies work to treat breast cancer.
Treatment guidelines
Although the exact treatment for breast cancer varies from person to person, evidence-based guidelines help make sure high-quality care is given. These guidelines are based on the latest research and agreement among experts.
The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are respected organizations that regularly review and update their guidelines.
In addition, the National Cancer Institute (NCI) has treatment overviews.
Talk with your health care team about which treatment guidelines they follow.
After you get a recommended treatment plan from your health care team, study your treatment options. Together with your health care team, make thoughtful, informed decisions that are best for you. Each treatment has benefits and risks to consider along with your own values and lifestyle.
Susan G. Komen® Support Resources |
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Financial assistance
Costs related to breast cancer treatment can quickly become a financial burden for you and your family. Dealing with finances and insurance can be overwhelming.
Many hospitals have financial counselors who can discuss insurance and cost coverage with you. They may be able to arrange a payment plan for hospital-related costs.
You may qualify for financial assistance from federal, state or local programs. A financial counselor or social worker at your hospital can help you learn about financial assistance programs.
Learn more about financial assistance programs.
Prescription drug assistance
Most chemotherapy drugs are given through an IV into a vein, so they are covered under your health insurance plan’s medical benefit. However, some chemotherapy drugs are pills and are covered under your plan’s prescription drug benefit. This means there are usually out-of-pocket costs, which can add up over time.
Medicare and many insurance companies offer prescription drug plans. One may already be included in your policy, or you may be able to buy an extra plan for prescriptions.
Some drugs are off-patent and may have a generic form. Generic drugs cost less than the name brands but are just as effective.
Many hospitals have financial counselors who can discuss insurance and cost coverage with you.
You may qualify for programs that help with drug costs or offer low-cost or free prescription drugs. A financial counselor or social worker at your hospital can help you learn about these programs.
Learn more about insurance plans and prescription drug assistance programs.
Learn more about other financial assistance programs.
Komen Financial Assistance Program |
Susan G. Komen® created the Komen Financial Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals. To learn more about this program and other helpful resources, call the Komen Patient Care Center at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org. Se habla español. Learn about other financial assistance programs. |
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Susan G. Komen®‘s position on fairness in oral cancer drug coverage |
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Insurance coverage of oral cancer drugs Cancer medications given through an IV into a vein or by an injection (under the skin or into a muscle) are usually covered under a health insurance plan’s medical benefit. However, oral cancer drugs (cancer medications that are pills) are usually covered under a health insurance plan’s prescription drug benefit. As a result, people often find themselves facing high out-of-pocket costs when filling prescriptions for oral cancer drugs. Sometimes these costs can be thousands of dollars a month. The impact of high cost-sharing High prescription drug costs and the resulting out-of-pocket burden on patients are a barrier to health care. They can prevent people from getting the medications prescribed by their health care providers. No one should be forced to get less appropriate treatment because an insurer gives more coverage for IV and injectable drugs than for pills. Efforts to increase fairness in drug coverage Komen supports state and federal efforts to require insurers to provide the same or better coverage for oral cancer drugs as they do for IV and injectable cancer drugs. This would help make sure patients have access to affordable, appropriate treatment. Become a Komen Advocacy Insider Sign up to be a Komen Advocacy Insider and get informed when action is needed on oral drug coverage parity at the state or national level. |
Updated 03/19/26
This content is regularly reviewed by an expert panel including researchers, practicing clinicians and patient advocates.
