HER2-Targeted Therapies for Early Breast Cancer

This section discusses HER2-targeted therapies for early and locally advanced breast cancer.

Learn about HER2-targeted therapies for metastatic breast cancer (also called advanced or stage IV breast cancer).

HER2-targeted therapies and HER2-positive breast cancer

HER2-positive breast cancers have a lot of a 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 designed 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 newly diagnosed breast cancers are tested for HER2 status.

About 10% to 20% of newly diagnosed breast cancers are HER2-positive [136-137]. These breast cancers can be treated with HER2-targeted therapies.

Trastuzumab (Herceptin)

How does trastuzumab work?

Trastuzumab is an antibody drug specially made to target HER2-positive cancer cells.

Trastuzumab attaches to the HER2 protein on the surface of HER2-positive breast cancer cells. This can slow or stop their growth.

Breast cancer treatment

For women with HER2-positive early breast cancer, chemotherapy plus trastuzumab cuts the risk of recurrence (a return of breast cancer) in half compared to chemotherapy alone [138-140].

Trastuzumab is given by vein (through an IV) or by injection under the skin every 3 weeks for one year.

Treatment with trastuzumab may begin before breast cancer surgery (neoadjuvant therapy) or after surgery (adjuvant therapy).

Trastuzumab is also used to treat HER2-positive metastatic breast cancers.

Learn about neoadjuvant treatment with trastuzumab.

Learn more about treatment for HER2-positive metastatic breast cancers.

 

For a summary of research studies on trastuzumab and overall survival in early breast cancer, visit the Breast Cancer Research Studies section.

 

For a summary of research studies on trastuzumab and treatment for metastatic breast cancer, visit the Breast Cancer Research Studies section.

Side effects of trastuzumab

Side Effects

Trastuzumab

Possible side effects include headache, fever and chills.

Trastuzumab can cause serious heart problems. Your heart will be checked before and during treatment to help make sure there are no problems.

Adapted from select sources [8,138,141].

Trastuzumab doesn’t cause hair loss, nausea or vomiting, and has no effect on bone marrow.

Before you begin treatment with trastuzumab, talk with your health care provider about possible side effects and how to manage them.

Heart problems linked to trastuzumab

Trastuzumab use is linked to congestive heart failure, a serious heart condition.

In clinical trials, about 2% to 3% of those treated with chemotherapy plus trastuzumab had heart failure, compared to fewer than 1% of those treated with chemotherapy alone [138,141].

This risk of heart problems is higher with chemotherapy regimens that include an anthracycline drug compared to regimens without an anthracycline drug [8,138].

The risk of heart problems may also be higher for women over 60 and for those who already have heart problems [8,141].

For most people who develop a heart problem while taking trastuzumab, the condition improves after stopping trastuzumab. For a few, it may be permanent.

Avoiding heart problems

Your heart will be checked before and during treatment with trastuzumab. This is to help make sure there are no problems, or if there are problems, they’re caught early.

Adopting a lifestyle that includes a healthy diet, regular exercise and for those who smoke, quitting smoking is a good way to help avoid heart problems related to treatment.

To learn more about trastuzumab, visit the National Institutes of Health’s Medline Plus website.

Biosimilar trastuzumab

A biosimilar drug is a “generic-like” version of a drug that contains biological products (biologics) such as antibodies or proteins. Trastuzumab is a biologic drug.

There are some FDA-approved biosimilar forms of trastuzumab. These biosimilars are safe and effective treatments for early and metastatic HER2-positive breast cancers.

Learn more about biosimilars.

Ado-trastuzumab emtansine (Kadcyla, T-DM1, trastuzumab emtansine)

How does ado-trastuzumab emtansine work?

Ado-trastuzumab emtansine (Kadcyla, T-DM1, trastuzumab emtansine) is an antibody-drug conjugate.

Ado-trastuzumab emtansine consists of the HER2-targeted antibody drug trastuzumab (Herceptin) and a chemotherapy called DM1 (so it’s sometimes called T-DM1). The combination of drugs allows the targeted delivery of chemotherapy to HER2-positive cancer cells.

Breast cancer treatment

Ado-trastuzumab emtansine is used to treat some women with HER2-positive early breast cancer who have cancer remaining in their breast or lymph nodes after neoadjuvant therapy (given before surgery) [8]. The use of ado-trastuzumab emtansine in these women can reduce the risk of breast cancer recurrence (a return of breast cancer) and breast cancer death by 50% compared to treatment with trastuzumab [142].

Ado-trastuzumab emtansine is given by vein (through an IV) every 3 weeks for 14 cycles. Treatment with ado-trastuzumab emtansine begins after breast surgery.

Ado-trastuzumab emtansine is under study for use in the neoadjuvant setting [143].

Learn about ado-trastuzumab emtansine and metastatic breast cancer treatment.

Side effects of ado-trastuzumab emtansine

Side Effects

Ado-trastuzumab emtansine

Possible side effects include nausea, fatigue, muscle and joint pain, constipation, neuropathy (nerve damage that may cause pain or numbness, usually in the fingers or toes), low platelet counts and headache.

It can also cause liver problems. Your liver will be checked before and during treatment to help make sure there are no problems.

Because ado-trastuzumab emtansine contains trastuzumab, it can cause serious heart problems. Learn more about this risk and steps taken to monitor your heart during treatment.

Adapted from select sources [142,144].

Ado-trastuzumab emtansine doesn’t usually cause hair loss.

Before you begin treatment with ado-trastuzumab emtansine, talk with your health care provider about possible side effects and how to manage them.

To learn more about ado-trastuzumab emtansine, visit the National Institutes of Health’s Medline Plus website.

Pertuzumab (Perjeta)

How does pertuzumab work?

Pertuzumab is an antibody drug that targets HER2-positive cancer cells, but in a different way than trastuzumab.

Breast cancer treatment

Pertuzumab is used in combination with trastuzumab and chemotherapy to treat some HER2-positive breast cancers [8].

In people with HER2-positive early breast cancers at high risk of recurrence, adding pertuzumab to treatment with trastuzumab and chemotherapy can reduce the risk of recurrence by about 20% [145].

Pertuzumab is always given in combination with trastuzumab. It’s not given on its own. The combination of drugs is given by vein (through an IV) or by injection under the skin every 3 weeks for up to one year.

Treatment with pertuzumab and trastuzumab may begin before breast cancer surgery (neoadjuvant therapy) or after surgery (adjuvant therapy).

Learn about neoadjuvant treatment with pertuzumab and trastuzumab.

Learn about pertuzumab and metastatic breast cancer treatment.

Side effects of pertuzumab

Side Effects

Pertuzumab

Possible side effects include diarrhea, nausea, fatigue and rash.

Pertuzumab is always given in combination with trastuzumab. Trastuzumab can cause serious heart problems. Learn more about this risk and steps taken to monitor your heart during treatment.

Adapted from select sources [146].

Before you begin treatment with pertuzumab, talk with your health care provider about possible side effects and how to manage them.

To learn more about pertuzumab, visit the National Institutes of Health’s Medline Plus website.

Neratinib (Nerlynx)

How does neratinib work?

Tyrosine-kinase inhibitors, such as neratinib, are drugs that target tyrosine-kinase enzymes, which are important for cell functions. These drugs can block tyrosine-kinase enzymes at many points along the cancer growth pathway.

Breast cancer treatment

Neratinib is used to treat HER2-positive early breast cancer in some women who have completed treatment with trastuzumab (Herceptin) [8].

Treatment with neratinib may reduce the risk of breast cancer recurrence in some people [147].

Neratinib is a pill taken every day for one year.

Learn about neratinib and the treatment of metastatic breast cancer.

Side effects of neratinib

Side Effects

Neratinib

The most common side effect is diarrhea. Your health care provider will recommend medications to help prevent and control the diarrhea.

Other possible side effects include nausea, vomiting, fatigue, abdominal pain and rash.

In rare cases, neratinib has been linked to liver problems. Your liver function will be checked throughout your treatment to help make sure there are no problems.

Adapted from select sources [148].

Before you begin taking neratinib, talk with your health care provider about possible side effects and how to manage them.

To learn more about neratinib, visit the National Institutes of Health’s Medline Plus website.

Prescription drug assistance

Prescription drug costs can quickly become a financial burden for you and your family.

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.

Although most HER2-targeted therapies for early breast cancer are given by vein (through an IV) or by injection, neratinib (Nerlynx) is a pill. So, neratinib is covered under your health insurance plan’s prescription drug benefit rather than the plan’s medical benefit. This means there are usually out-of-pocket costs, which can add up over time.

You may qualify for programs that help with drug costs or offer low-cost or free prescriptions.

Many cancer centers have patient financial counselors who can discuss insurance and cost coverage with you.

Learn about insurance plans and prescription drug assistance programs.

Learn 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 Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email helpline@komen.org.

Se habla español.

Susan G. Komen®‘s position on fairness in oral cancer drug coverage

Insurance coverage of oral cancer drugs

Cancer medications given by vein (through an IV) or injection (under the skin or into a muscle) are usually covered under a health insurance plan’s medical benefit. However, cancer medications that are pills (oral cancer drugs) 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 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 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 drug coverage issues at the state or national level.

Clinical trials

Research is ongoing to improve all areas of treatment for breast cancer.

New therapies are being studied in clinical trials. The results of these studies will decide whether these therapies become part of the standard of care.

After discussing the benefits and risks with your health care provider, we encourage you to consider joining a clinical trial.

Susan G. Komen® Patient Care Center

If you or a loved one needs information or resources about clinical trials, the Patient Care Center can help. Contact the Komen Breast Care Helpline at 1-877-465-6636 or email clinicaltrialinfo@komen.org.

Se habla español.

BreastCancerTrials.org in collaboration with Komen offers a custom matching service to help find clinical trials that fit your needs.

Learn what Komen is doing to help people find and participate in breast cancer clinical trials, including trials supported by Komen.

Learn more about clinical trials.

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Susan G. Komen® Support Resources

  • Do you need help? We’re here for you. The Komen Patient Care Center is your trusted, go-to source for timely, accurate breast health and breast cancer information, services and resources. Our navigators offer free, personalized support to patients, caregivers and family members, including education, emotional support, financial assistance, help accessing care and more. Get connected to a Komen navigator by contacting the Breast Care Helpline at 1-877-465-6636 or email helpline@komen.org to get started. All calls are answered Monday through Thursday, 9 a.m to 7 p.m. ET and Friday, 9 a.m. to 6 p.m. ET. Se habla español.
  • The Komen Breast Cancer and Komen Metastatic (Stage IV) Breast Cancer Facebook groups are places where those with breast cancer and their family and friends can talk with others for friendship and support.
  • Our fact sheets, booklets and other education materials offer additional information.

*Please note, the information provided within Komen Perspectives articles is only current as of the date of posting. Therefore, some information may be out of date.

Updated 12/28/23