Targeted therapy, also called biologic therapy, uses the body's immune system or hormonal system to fight breast cancer cells. That does less harm to healthy cells, so the side effects aren’t usually as bad as from better-known treatments like chemotherapy.
One type of targeted therapy uses antibodies to kill cancer cells or block them from growing. Antibodies are a part of the immune system made by special white blood cells. They can be made in a lab and given as medicine.
Another type of this therapy uses drugs made of small molecules that block signals the cancer cells need to grow.
The type of targeted therapy your doctor might recommend depends on the type of breast cancer you have.
HER2-Positive Breast Cancer
A gene called HER2 makes too many copies of itself in about 20% of people with breast cancer. If you have that faulty version of the gene, your disease is called "HER2-positive."
Trastuzumab (Herceptin, Hercessi, Herzuma, Kanjinti, Ogivri, Ontruzan, Trazimera) is the standard treatment for this type of breast cancer. It's one example of a lab-made antibody. Experts think it stops cancer cells from growing in three ways:
- It sticks to certain areas on cancer cells, stopping them from growing.
- It signals the body's immune system to attack cancer cells.
- It can help chemotherapy work better for you.
Trastuzumab treats this type of breast cancer either alone or alone with chemotherapy drugs. Doctors commonly use it with drugs known as taxanes: docetaxel (Taxotere) and paclitaxel (Abraxane, Onxol).
Pertuzumab (Perjeta) is another antibody that treats HER2-positive breast cancer. Doctors use it along with docetaxel and trastuzumab. Pertuzumab may be harmful to a fetus, so women who are pregnant shouldn’t take it.
Another medication, ado-trastuzumab emtansine (Kadcyla), combines the antibody in trastuzumab with a chemotherapy drug. Doctors give it to people with HER2-positive, advanced breast cancer who were already treated with trastuzumab.
Margetuximab (Margenza) is a medication that is given by IV and is seen as an alternative to trastuzumab in those who have received previous treatment for their metastatic cancer.
Fam-trastuzumab deruxtecan-nxki (Enhertu) is an antibody treatment. Doctors can use fam-trastuzumab deruxtecan-nxki, known as an antibody drug conjugate (ADC) with pertuzumab, as a first-line treatment for HER2-positive metastatic or unresectable breast cancer, as well as for early-stage HER2-positive breast cancer as neoadjuvant (before surgery) or adjuvant (after surgery) treatment.
The drug attaches to HER-2 positive receptors outside the cell, then enters the cell and delivers cell-specific chemotherapy. This shows how treatment continues to evolve based on HER2 and other biomarkers.
One possible drawback of antibody treatment is that you generally need to get it as a shot.
Lapatinib (Tykerb) is an example of a small-molecule drug that you can take in a pill. Together with chemotherapy, it treats some advanced cases of HER2-positive breast cancer. Doctors often use it when other cancer medications haven't worked for someone.
Neratinib (Nerlynx) is a targeted therapy used to treat HER2-positive early breast cancer in some people who finished treatment with trastuzumab (Herceptin).
Palbociclib (Ibrance), a CDK4/6 inhibitor (cancer medication that blocks specific proteins), is a targeted therapy that's now FDA approved for use in combination with trastuzumab (with or without pertuzumab) and endocrine therapy for maintenance treatment of HR-positive, HER2-positive locally advanced or metastatic breast cancer (after induction treatment).
HER2-Negative Breast Cancer
If you don’t have the faulty version of the HER2 gene that makes too many copies of itself, your disease is "HER2-negative." You'll need different treatments.
If you've gone through menopause and have already tried certain treatments, your doctor might prescribe everolimus (Afinitor) with exemestane (Aromasin). Everolimus is for certain advanced cancers.
Some postmenopausal women with certain types of advanced breast cancer may get a prescription for Ibrance or ribociclib (Kisqali) along with hormone therapy. These drugs are used with an aromatase inhibitor such as anastrazole (Arimidex), exemestane (Aromisn), or letrozole (Femara).
The FDA approved abemaciclib (Verzenio) with the hormone therapy pill imlunestrant (Inluriyo) for adults with ER-positive, HER2-negative breast cancer that is advanced or has spread to other parts of the body. This combination is an option if the cancer grew or got worse after at least one hormone therapy and an FDA-authorized test confirms a change (mutation) in the ESR1 gene.
Gedatolisib (Revtorpyk) is a targeted therapy used with fulvestrant, with or without palbociclib, for adults with locally advanced or metastatic HR-positive, HER2-negative breast cancer without a detected PIK3CA mutation. The FDA approved it for use after the cancer progresses during or after at least one endocrine therapy for metastatic disease.
Olaparib (Lynparza) andtalazoparib (Talzenna) are drugs known as PARP inhibitors which are targeted therapy for women with BRCA gene mutations and are HER2 negative.
The FDA has approved the antibody -drug conjugate (ADC) datopotamab deruxtecan (Datroway) to treat certain types of breast cancer that are hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2-) or some triple-negative breast cancers.
Another ADC, sacituzumab govitecan-hziy (Trodelvy) is approved for triple-negative breast cancer that has spread to other parts of the body or cannot be removed with surgery. It can be used on its own or combined with pembrolizumab (Keytruda) or pembrolizumab and berahyaluronidase alfa-pmph (Keytruda Qlex), depending on whether the tumor has a specific protein marker called PD-L1. Like datopotamab deruxtecan, sacituzumab govitecan-hziy targets cancer cells that have a specific protein called TROP-2 on their surface. The antibody attaches to TROP-2 and delivers a chemo drug directly into the cancer cell, killing it. This can keep the cancer from growing and may cause it to shrink in size.
A new targeted therapy, vepdegestrant (Veppanu) is the first FDA-approved proteolysis targeting chimera (PROTAC), a targeted protein degrader. It is an oral cancer drug taken once daily with food for people with estrogen receptor-positive (ER+) HER2-, estrogen receptor 1 (ESR1)-mutated advanced or metastatic breast cancer, whose disease has progressed after at least one prior hormone (endocrine) therapy. An FDA-authorized test confirming ESR1 mutation must be given before starting treatment.
Other Types of Targeted Treatment
Researchers are studying more ways to fight breast cancer.
Angiogenesis inhibitors. These antibodies prevent the growth of new blood vessels, cutting off the supply of oxygen and nutrients to cancer cells. To date, the only such drug used for breast cancer, bevacizumab (Avastin, Mvasi), lost its FDA approval because the risks outweighed its benefits and it didn't improve how long people with breast cancer lived.
Signal transduction inhibitors. These antibodies block signals inside the cancer cell that help the cells divide, stopping the cancer from growing.
Side Effects
These differ from one medicine to another. They can include:
- Allergic reactions
- Trouble breathing
- Swelling
- Nausea
- Rashes
- Diarrhea
- Fever
- Chills
- Dizziness
- Weakness
Tell your doctor about any side effects you have. They may be able to ease them.
Recognize an Emergency
Call your nurse or doctor if you have:
- A temperature over 100.4 F. If you have any fever and chills, tell your doctor immediately. If you can't reach your doctor, go to the emergency room.
- New mouth sores or patches, a swollen tongue, or bleeding gums
- A dry, burning, scratchy, or "swollen" throat
- A cough that is new or persistent
- Feeling the need to pee more often, stronger urges than usual, a burning feeling while peeing, or blood in your urine
- Heartburn, nausea, vomiting, constipation, or diarrhea that is severe or lasts longer than 2 or 3 days
- Blood in your stools
- Shortness of breath
- Swelling in feet or ankles
- Severe tiredness or fatigue
