Herceptin
If you’ve been diagnosed with HER2-positive breast cancer that is either early-stage or advanced-stage/metastatic, your doctor may prescribe Herceptin (chemical name: trastuzumab).
Herceptin is a targeted therapy currently approved by the U.S. Food and Drug Administration (FDA):
to treat metastatic HER2-positive breast cancer to stop the cancer from growing
to treat early-stage breast cancer that is HER2-positive, either as part of a regimen with chemotherapy or alone after a chemotherapy regimen that includes an anthracycline
in combination with Perjeta (chemical name: pertuzumab) and Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel) — also known as THP chemo — to treat HER2-positive
in combination with Perjeta and chemotherapy after surgery to treat HER2-positive, early-stage breast cancer with a high risk of recurrence, known as TCHP chemo
How Herceptin works
Cancer cells grow in an uncontrolled fashion. Herceptin works on the surface of the cancer cell by blocking the chemical signals that can stimulate this uncontrolled growth.
Genes are like instruction manuals that tell each cell of your body how to grow, what kind of cell to become, and how to behave. Genes do this by ordering the cell to make special proteins that cause a certain activity — such as cell growth, rest, or repair.
Some breast cancer cells make too many copies of a gene called HER2. The HER2 gene makes a protein known as a HER2 receptor. HER2 receptors are like ears, or antennae, on the surface of all cells. These HER2 receptors receive signals that stimulate the cell to grow and multiply. But breast cancer cells with too many HER2 receptors can pick up too many growth signals. This causes them to start growing and multiplying too much and too fast. Breast cancer cells that overexpress the HER2 gene are said to be HER2-positive.
Herceptin works by attaching itself to the HER2 receptors on the surface of breast cancer cells and blocking them from receiving growth signals. By blocking the signals, Herceptin can slow or stop the growth of the breast cancer. Herceptin can also help fight breast cancer by alerting the immune system to destroy cancer cells to which it is attached.
Is Herceptin right for you?
Herceptin is used to treat breast cancers that are HER2-positive.
There are several tests used to find out if breast cancer is HER2-positive. Two of the most common tests are:
The IHC test uses a chemical dye to stain the HER2 proteins. The IHC gives a score of 0 to 3+ that measures the amount of HER2 proteins on the surface of cells in a breast cancer tissue sample. If the score is 0 to 1+, it’s considered HER2-negative. If the score is 2+, it's considered borderline. A score of 3+ is considered HER2-positive.
If the IHC test results are borderline, it’s likely that a FISH test will be done on a sample of the cancer tissue to determine if the cancer is HER2-positive.
The FISH test uses special labels that attach to the HER2 genes (unlike the IHC test, which attaches to the proteins made by the genes). The special labels have chemicals added to them so they change color and glow in the dark when they attach to the HER2 proteins. This test is the most accurate, but it is more expensive and takes longer to return results. This is why an IHC test is usually the first test done to see if a cancer is HER2-positive. With the FISH test, you get a score of either positive or negative (some hospitals call a negative test result “zero”). Learn more about HER2 status.
What to expect when taking Herceptin
Herceptin is usually given by intravenous (IV) infusion, which means it is delivered directly into your bloodstream through an IV or a port. The first dose of Herceptin takes about 90 minutes. After that, it only takes about 30 minutes to get other doses of Herceptin. Your Herceptin treatment schedule will depend on whether you’re receiving it with other medicines. You can talk to your doctor about your treatment schedule options.
If you’ve been diagnosed with early-stage HER2-positive breast cancer, you’ll likely receive Herceptin together with a chemotherapy regimen for a set number of rounds.
If you’ve been diagnosed with metastatic, HER2-positive breast cancer, you’ll keep being treated with Herceptin as long as you are getting benefits from the medicine and aren’t having troubling side effects.
It’s important to know that women who are pregnant or planning to get pregnant should not take Herceptin. Herceptin can harm the developing fetus. If there is any chance you can become pregnant, you must use effective birth control while you’re taking Herceptin and for at least 7 months after your last dose.
Also, women who are breastfeeding or plan to breastfeed shouldn’t take Herceptin. Together, you and your doctor will decide if you should take Herceptin or breastfeed.
A study reported during the 2008 American Society of Clinical Oncology (ASCO) Breast Cancer Symposium found that about one-third of HER2-positive breast cancers that stop responding or don't respond to Herceptin may do so because the cancers change from being HER2-positive at diagnosis to HER2-negative during treatment.
The small study looked at 143 women diagnosed with early-stage, HER2-positive breast cancer. All of the women received two types of chemotherapy — a taxane and an anthracycline — and Herceptin before surgery. The cancers in about half of the women responded completely to chemotherapy and Herceptin (meaning no cancer was found in the breast or the underarm (axillary) lymph nodes during surgery). The cancers in the other half of the women didn't completely respond to chemotherapy and Herceptin (meaning cancer was found in the breast or in the underarm lymph nodes during surgery).
The researchers analyzed the cancer found during surgery and discovered that in about one-third of the women (30.4%), the cancer wasn't HER2-positive anymore — it had changed from HER2-positive at diagnosis to HER2-negative some time while the women were receiving chemotherapy and Herceptin.
If you are receiving Herceptin for advanced stage (metastatic) breast cancer and the treatment stops working, your doctor may recommend a biopsy of an area of cancer to see if it has changed to HER2-negative breast cancer.
Herceptin side effects
Like almost all medicines, Herceptin can cause side effects, some of them severe. The most common side effects of Herceptin are:
If you are receiving Herceptin with chemotherapy, you may also experience chemotherapy side effects.
Herceptin may also cause serious side effects, including:
Heart problems: Herceptin may cause serious heart problems, including some that don’t have symptoms (such as reduced heart function) and some that do (such as congestive heart failure). Symptoms to watch for include swelling of the ankles or legs, shortness of breath, cough, or weight gain of more than five pounds in less than 24 hours. Contact your doctor immediately if you have any of these symptoms.
Your risk of heart problems is higher if you are receiving Herceptin in combination with anthracycline chemotherapy. Before starting Herceptin therapy, you’ll likely receive a heart test to check how well your heart is functioning. Your doctor will continue to monitor your heart function while you are receiving Herceptin, as well as after you complete treatment.
Lung problems: Herceptin may cause inflammation of the lungs, which can be life-threatening. Symptoms include trouble breathing, cough, tiredness, and fluid in the lungs.
Herceptin Hylecta (injectable Herceptin)
Herceptin Hylecta (chemical name: trastuzumab and hyaluronidase-oysk) is an injectable form of Herceptin. It is a combination of Herceptin and hyaluronidase, an enzyme that helps your body use the Herceptin.
Unlike traditional Herceptin, which is given by infusion into an IV or port, Herceptin Hylecta is given subcutaneously, which means it is injected under your skin using a hypodermic needle, much like a vaccine. The injection takes about two to five minutes and is given in your thigh, alternating between left and right for each dose.
It’s important to know that Herceptin Hylecta is given in different doses than IV Herceptin. Herceptin Hylecta is given at a fixed dose of 600 milligrams, while the dose of IV Herceptin is based on your weight.
You can receive a Herceptin Hylecta injection at an infusion center along with a chemotherapy regimen. If you are being treated with only Herceptin Hylecta, you may be able to receive the injection at your doctor’s office.
Herceptin Hylecta is approved to treat HER2-positive breast cancer that has spread to the lymph nodes (node-positive) or is not in the lymph nodes but is considered to be at high risk of recurrence:
after surgery as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin), Cytoxan (chemical name: cyclophosphamide), and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
after surgery as part of a treatment regimen with Taxotere and carboplatin
after surgery as a single treatment for people who have been treated with a chemotherapy regimen that includes an anthracycline
Herceptin Hylecta is also approved to treat metastatic HER2-positive breast cancer:
in combination with Taxol as the first treatment for metastatic disease
as a single treatment for people who have been treated with one or more chemotherapy regimens for metastatic disease
Like Herceptin, Herceptin Hylecta can cause side effects, some of them severe. Common Herceptin Hylecta side effects include:
upper respiratory tract infection
flushing
chills
Like Herceptin, less common but more severe side effects of Herceptin Hylecta include weakening of the heart muscle and other heart problems, as well as serious lung problems.
Also like Herceptin, women who are pregnant or planning to get pregnant should not be treated with Herceptin Hylecta. Herceptin Hylecta can harm the developing fetus. If there is any chance you can become pregnant, you must use effective birth control while you’re being treated with Herceptin Hylecta and for at least 7 months after your last dose.
Herceptin biosimilars
Herceptin is a biologic medicine. Biosimilars are almost identical to a biologic medicine that is already approved by the U.S. Food and Drug Administration (or similar organizations in other countries). Biologics — including monoclonal antibodies, such as Herceptin — are medicines that are made from or contain parts of living cells. It can help to think of a biosimilar as a generic version of a biologic drug, though that comparison isn’t completely accurate.
There are six Herceptin biosimilars that have been approved by the FDA:
Hercessi (chemical name: trastuzumab-strf)
Herzuma (chemical name: trastuzumab-pkrb)
Kanjinti (chemical name: trastuzumab-anns)
Ogivri (chemical name: trastuzumab-dkst)
Ontruzant (chemical name: trastuzumab-dttb)
Trazimera (chemical name: trastuzumab-qyyp)
Hercessi is approved to treat early-stage HER2-positive breast cancer after surgery. It may be prescribed:
as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin); Cytoxan (chemical name: cyclophosphamide); and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
as part of a regimen that includes Taxotere and carboplatin
alone, after a chemotherapy regimen that includes an anthracycline, such as Adriamycin
Hercessi is also approved for metastatic breast cancer:
in combination with Taxol as a first treatment for metastatic HER2-positive breast cancer
alone to treat metastatic HER2-positive breast cancer that has been treated with one or more chemotherapy regimens
Common Hercessi side effects include:
Like Herceptin, Hercessi may cause serious heart problems, such as a decrease in heart function and congestive heart failure.
Herzuma is approved to treat non-metastatic HER2-positive breast cancer that has spread to the lymph nodes (node-positive) or is not in the lymph nodes but is considered to be at high risk of recurrence:
after surgery as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin), Cytoxan (chemical name: cyclophosphamide), and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
after surgery as part of a treatment regimen with Taxotere and carboplatin
Herzuma is also approved to treat metastatic HER2-positive breast cancer:
in combination with Taxol as the first treatment for metastatic disease
as a single treatment for people who have been treated with one or more chemotherapy regimens for metastatic disease
Common Herzuma side effects include:
Serious side effects include worsening of neutropenia (low white blood cell count) caused by chemotherapy.
Like Herceptin, less common but more severe side effects of Herzuma include weakening of the heart muscle and other heart problems.
Kanjinti is approved to treat non-metastatic HER2-positive breast cancer that has spread to the lymph nodes (node-positive) or is not in the lymph nodes but is considered to be at high risk of recurrence:
after surgery as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin), Cytoxan (chemical name: cyclophosphamide), and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
after surgery as part of a treatment regimen with Taxotere and carboplatin
as a single treatment after people have been treated with anthracycline-based chemotherapy
Kanjinti is also approved to treat metastatic HER2-positive breast cancer:
in combination with Taxol as the first treatment for metastatic disease
as a single treatment for people who have been treated with one or more chemotherapy regimens for metastatic disease
Kanjinti can also be used to treat metastatic, HER2-positive stomach cancer.
Common Kanjinti side effects include:
Serious side effects include worsening of neutropenia (low white blood cell count) caused by chemotherapy.
Like Herceptin, less common but more severe side effects of Kanjinti include weakening of the heart muscle and other heart problems.
Ogivri is approved to treat non-metastatic HER2-positive breast cancer that has spread to the lymph nodes (node-positive) or is not in the lymph nodes but is considered to be at high risk of recurrence:
after surgery as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin), Cytoxan (chemical name: cyclophosphamide), and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
after surgery as part of a treatment regimen with Taxotere and carboplatin
as a single treatment after people have been treated with anthracycline-based chemotherapy
Ogivri is also approved to treat metastatic HER2-positive breast cancer:
in combination with Taxol as the first treatment for metastatic disease
as a single treatment for people who have been treated with one or more chemotherapy regimens for metastatic disease
Ogivri can also be used to treat metastatic, HER2-positive stomach cancer.
Common side effects of Ogivri include:
Less common but more severe side effects of Ogivri include heart damage and lung damage.
Ontruzant is approved to treat non-metastatic HER2-positive breast cancer that has spread to the lymph nodes (node-positive) or is not in the lymph nodes but is considered to be at high risk of recurrence:
after surgery as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin), Cytoxan (chemical name: cyclophosphamide), and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
after surgery as part of a treatment regimen with Taxotere and carboplatin
as a single treatment after people have been treated with anthracycline-based chemotherapy
Ontruzant is also approved to treat metastatic HER2-positive breast cancer:
in combination with Taxol as the first treatment for metastatic disease
as a single treatment for people who have been treated with one or more chemotherapy regimens for metastatic disease
Ontruzant also can be used to treat metastatic, HER2-positive stomach cancer.
Ontruzant can only be given by intravenous (IV) infusion, which means it is delivered directly into your bloodstream through an IV or a port.
Common side effects of Ontruzant include:
Like Herceptin, less common but more severe side effects include heart damage and lung damage.
It’s important to know that women who are pregnant or planning to get pregnant should not take Ontruzant. Ontruzant can harm the developing fetus. If there is any chance you can become pregnant, you must use effective birth control while you’re taking Ontruzant and for at least 7 months after your last dose.
Trazimera is approved to treat non-metastatic HER2-positive breast cancer that has spread to the lymph nodes (node-positive) or is not in the lymph nodes but is considered to be at high risk of recurrence:
after surgery as part of a treatment regimen that includes Adriamycin (chemical name: doxorubicin), Cytoxan (chemical name: cyclophosphamide), and either Taxol (chemical name: paclitaxel) or Taxotere (chemical name: docetaxel)
after surgery as part of a treatment regimen with Taxotere and carboplatin
as a single treatment after people have been treated with anthracycline-based chemotherapy
Trazimera is also approved to treat metastatic HER2-positive breast cancer:
in combination with Taxol as the first treatment for metastatic disease
as a single treatment for people who have been treated with one or more chemotherapy regimens for metastatic disease
Trazimera also can be used to treat metastatic, HER2-positive stomach cancer.
Common Trazimera side effects include:
Real patient reviews
Members of our community discuss their experiences with Herceptin in the community forum. Here are some of their comments. Remember, it's very important to talk to your doctor about any side effects you're having and ask about ways to manage them.
“My side effects kicked in early on. Within the first week of treatment, I had severe abdominal pain and cramping. My side effects up to this week were focused mainly on digestive issues and body aches. I have not had much nausea. I have also experienced loss of appetite and heartburn. I have lost weight, cause I couldn't eat much. I generally love food but just couldn't eat it without abdominal pain and diarrhea. I am happy to say that for the last couple of days, I have been able to eat real food! I hope that I can continue to eat after this week's treatment.” — lumary
“I've gotten a sore throat after every infusion. My counts are very good, thank God. I gargle, and it goes away within a couple of days. I attribute it to the post-nasal drip from the constant runny nose.” — DaniellaD
“I finished my year of Herceptin in January. I did not do any chemo. My nails would split in the middle and peel down. Reaching into my purse would cause my fingertips to bleed. I started taking biotin about three weeks ago, and am slowly seeing improvement. Nails are now almost brittle rather than paper-thin. My nails look pinker and thicker. They are short still, but feel stronger. Only my thumb nails are still in terrible shape.” — juliejfrs
Read more in our Herceptin discussion forum.
Paying for Herceptin
If your doctor prescribes Herceptin and you face any difficulties getting it covered by insurance, or you don't have insurance, you can get in touch with Access Solutions, sponsored by Genentech (the maker of Herceptin). Access Solutions can help investigate your insurance coverage benefits, appeal denied claims, and provide other assistance. You can also reach Access Solutions at 1-888-249-4918.
Learn more about financial assistance and medicine cost-lowering tips.
— Last updated on July 1, 2025 at 8:44 PM
