The Who, What, Where, When and Sometimes, Why.

HER2-Targeted Therapies

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 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 10-20 percent of newly diagnosed breast cancers are HER2-positive [136-137]. 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)?


Herceptin (IV drug), Herceptin Hylecta (injection)

Early and metastatic breast cancer

IV drug or injection


Perjeta (IV drug) and Phesgo (injection combined with trastuzumab)

Early and metastatic breast cancer

IV drug or injection



Metastatic breast cancer

IV drug

Ado-trastuzumab emtansine (T-DM1)


Early and metastatic breast cancer

IV drug

Trastuzumab deruxtecan (fam-trastuzumab deruxtecan)


Metastatic breast cancer

IV drug



Metastatic breast cancer




Early and metastatic breast cancer




Metastatic breast cancer


*Biosimilar forms of trastuzumab include: trastuzumab-anns (Kanjinti), trastuzumab-dkst (Ogivri), trastuzumab-dttb (Ontruzant), trastuzumab-pkrb (Herzuma) and trastuzumab-qyyp (Trazimera).

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

Treatment guidelines

Although the exact treatment for breast cancer varies from person to person, evidence-based guidelines help ensure high-quality care. 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 use.

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 option has risks and benefits to consider along with your own values and lifestyle. 

Susan G. Komen® Support Resources

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.

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 more about insurance plans and prescription drug 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.

Funding is available for eligible individuals undergoing breast cancer treatment at any stage or living with metastatic breast cancer (stage 4).

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

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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.

 Updated 06/30/23