When you or a loved one has breast cancer, your doctor will figure out the best treatment options to offer you based on your particular tumor, your age, other conditions you have, and your wishes. Breast cancer treatment usually Includes a combination of surgery, chemotherapy, and radiation.
One treatment option for breast cancer is called targeted therapy. Trastuzumab (Herceptin) is an example of one of these. Other medicines used for targeted therapy include trastuzumab-anns (Kanjinti), trastuzumab-pkrb (Herzuma), trastuzumab-dkst (Ogivri), trastuzumab-dttb (Ontruzant), and trastuzumab-qyyp(Trazimera). You may see these drugs called biosimilars because they are biological copies of Herceptin.
Targeted therapies work by going after and controlling specific proteins that help certain breast cancer cells grow and spread. For these to work, a cancer has to have plenty of the protein that the medicine targets. While this means that they won’t work for every cancer, targeted medicines can work even when chemo or other treatments don’t. You also can use them along with chemo or other treatments.
Herceptin (trastuzumab) is one of these targeted medicines for breast cancer. It works against a protein called HER2 (also sometimes referred to as HER2/neu), which is short for human epidermal growth factor receptor 2. Herceptin can treat early lymph node-positive and more advanced/metastatic breast cancers that make too much HER2. This subtype of invasive breast cancer is known as HER2-positive breast cancer.
How Does Herceptin Work?
The HER2 protein is a receptor. Receptors are found in and on cancer cells, where they affect how the cells respond to other substances in your body. In normal cells, HER2 is involved in healthy cell growth. But some cancer cells have extra copies of the gene that makes HER2. As a result, they make too much HER2 protein. When cancer cells make too much HER2, they pick up too many signals that tell them to grow and they grow faster.
Herceptin is an antibody. You’re probably familiar with antibodies as proteins that help your immune system fight infections by attaching to an antigen. In this case, scientists create a special antibody that will attach to the antigen on the HER2 receptors. When given to women with HER2-positive breast cancer, the antibodies attach to HER2 receptors on cancer cells. This blocks growth signals and helps slow the cancer cells' growth and progression. Herceptin may also help your immune system fight your cancer.
Is Herceptin Right for My Breast Cancer?
If your breast cancer is HER2-negative, then Herceptin won’t work for you. Most breast cancers are HER2 negative. About 20% of breast cancers are HER2-positive and may respond to treatment with Herceptin. Doctors use Herceptin for both early and more advanced HER2-positive breast cancers.
If your breast cancer is at an early stage and makes too much HER2, your doctor may treat it with Herceptin after surgery to remove as much of the cancer as they can. You might take Herceptin together with endocrine (anti-estrogen hormone) therapy and/or chemo. You might also take Herceptin together with other HER2 targeted medicines such as Perjeta (pertuzumab).
It’s more likely that you’ll take Herceptin for an early stage cancer if your tumor is larger or has spread to lymph nodes. Your doctor also might suggest it if there’s reason to think your cancer will grow faster or come back. Herceptin can help to keep early stage HER2-positive cancer from coming back after surgery.
If tests show your cancer can’t be removed with surgery, Herceptin and other treatments may help shrink it enough to make surgery possible. If your HER2-positive breast cancer has spread to distant parts of your body, Herceptin can help to stop or slow its growth.
Herceptin isn’t the only treatment for breast cancer that works on HER2. If your HER2-positive breast cancer grows while you’re taking Herceptin, there may be other targeted treatments you could try. You should talk with your doctor about which treatment or combination of treatments they recommend for you and why.
What to Expect if You’re Taking Herceptin
You’ll get Herceptin in an intravenous (IV) infusion. The medicine has to go right into your bloodstream so that it can reach the cancer. Each infusion will take about 30 to 90 minutes.
There’s also an injectable form of Herceptin. It’s called Herceptin Hylecta and includes an extra enzyme. A clinical trial showed that Herceptin Hylecta works as well as Herceptin. Ask your doctor which version you should take.
How often and how long you will get Herceptin depends on how advanced your breast cancer is and what other medicines you’re taking. If doctors found your breast cancer at an early stage, you’ll likely get Herceptin along with chemo or other medicines. You’ll take it for a limited time after surgery to remove the cancer.
If your HER2-positive breast cancer is advanced (metastatic), you’ll keep taking Herceptin for as long as it’s working to slow the cancer unless you have a serious or troubling side effect. Your doctor will run tests to make sure your heart is working well before you start taking Herceptin. They’ll also monitor your heart while you’re taking it to make sure it’s not affecting your heart.
What Are Herceptin's Side Effects?
The most common side effects of Herceptin include:
- Headache
- Diarrhea
- Nausea
- Fever or chills
- Infection
- Trouble sleeping
- Cough
- Rash
Some people taking Herceptin will get serious heart problems. It may also cause problems in your lungs. Ask your doctor what symptoms to watch out for and when you need to call them.
There are many other side effects of Herceptin that happen less often. You can’t take Herceptin if you’re pregnant or might get pregnant.
How Well Does Herceptin Work?
Herceptin has made a big difference in treating advanced HER2-positive breast cancers since its approval in 1998. When given alone or with chemo, Herceptin can help to slow the growth of HER2-positive breast cancer.
Studies have shown that it improves survival in advanced breast cancers with extra HER2. It also helps to keep cancer from growing and spreading and keeps treatment working longer. But Herceptin won’t work for all advanced HER2-positive breast cancers. Sometimes it works for a while and then stops working. Most advanced HER2-positive breast cancers treated with Herceptin still progress within a year.
In early stage HER2-positive breast cancer, adding Herceptin to chemo after surgery cuts the risk that the cancer will come back by about 50%. More women who take Herceptin with chemo will remain free of cancer. Overall survival also improves with Herceptin.
A study that looked at outcomes in early stage HER2-positive breast cancer for up to 11 years found that more women who took Herceptin for 1 year were alive and cancer free. It didn’t help to take Herceptin for a second year. More recent studies suggest taking Herceptin for 6 months, or perhaps less, also can help keep many early, HER2-positive breast cancers from coming back. Taking Herceptin for less time might be an option if you are worried about side effects.
Your treatment for breast cancer will depend on many factors related to your cancer and other aspects of your health. Ask your doctor about what treatment options they suggest for you.
