HER2 Inhibitors: 6 Medications That Fight HER2-Positive Breast Cancer
Key takeaways:
There are several human epidermal growth factor receptor 2 (HER2) inhibitors that treat HER2-positive breast cancer. Herceptin (trastuzumab), Perjeta (pertuzumab), and Tykerb (lapatinib) are just a few.
Which HER2 inhibitor you’re prescribed will depend on many factors, including the breast cancer stage, which medications you’ve already tried, and the potential for side effects.
There are ways to save on HER2 inhibitors. Some are available as lower-cost biosimilars or have copay savings opportunities. GoodRx can also help make your prescription more affordable.
Table of contents
Until the late 1990s, most cancer medications were nonspecific, meaning they destroyed cancer cells and healthy cells. This led to well-known side effects like nausea, mouth sores, and hair loss. But over time, researchers have helped advance the quality of cancer treatments by discovering specific targets involved in cancer growth.
Human epidermal growth factor receptor 2 (HER2) is one of those targets. It’s a protein found on the surface of breast cancer cells that helps them grow. In up to 20% of breast cancer cases, the cancer cells have too much HER2. This type of cancer, which is known as HER2-positive breast cancer, grows more quickly than HER2-negative breast cancer.
The good news is that there are a handful of medications available to fight HER2-positive breast cancer. If you’ve been prescribed a HER2 inhibitor, it’s important to know the specifics of the medication. This will help you know what to expect and feel assured that you’re receiving the best treatment.
Below, we compare six commonly prescribed HER2 inhibitors.
1. Herceptin
Herceptin (trastuzumab) was the first medication developed to specifically fight HER2-positive breast cancer. It’s an anti-HER2 monoclonal antibody, a lab-made protein that attaches to HER2 to slow down cancer growth.
This biologic medication is either given through an IV or as an injection under the skin (Herceptin Hylecta). The IV version is given once every 1 to 3 weeks. Herceptin Hylecta is meant to be given once every 3 weeks. However, it’s much quicker to receive Herceptin Hylecta (a 2 to 5 minute injection) compared to Herceptin (a 30 to 90 minute infusion).
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Both versions of Herceptin can treat early and metastatic (advanced) breast cancer. With early breast cancer, Herceptin is only given for 1 year. But for metastatic breast cancer, there isn’t a set treatment duration; the medication is taken for as long as it’s effective.
Herceptin is often combined with chemotherapy or other HER2 inhibitors, but it can also be given by itself.
Herceptin biosimilars
Herceptin has helped lengthen how long people live with HER2-positive breast cancer. But its price tag means it may not be accessible for everyone. That’s where Herceptin biosimilars come in.
Biosimilars are highly similar to the original (“reference”) biologic medications they’re based on. They’re expected to work the same way and have similar side effects to the reference medications. But biosimilars increase market competition, which ultimately helps drive prices down.
Herceptin currently has five biosimilars available:
Ogivri (trastuzumab-dkst)
Herzuma (trastuzumab-pkrb)
Ontruzant (trastuzumab-dttb)
Trazimera (trastuzumab-qyyp)
Kanjinti (trastuzumab-anns)
These Herceptin biosimilars haven’t been directly compared to each other in studies. So it’s not known if one is better than another. But based on how they’re made, there aren’t expected to be any meaningful differences between them.
Trastuzumab antibody-drug conjugates
Antibody-drug conjugates (ADCs) are unique combination treatments. Trastuzumab ADCs are IV medications that combine Herceptin and a chemotherapy medication. The benefit of these ADCs is that chemotherapy can be delivered directly to HER2-positive breast cancer cells without harming healthy cells. You can think of them like heat-seeking missiles.
There are currently two trastuzumab ADCs available for HER2-positive breast cancer: Kadcyla (ado-trastuzumab emtansine) and Enhertu (fam-trastuzumab deruxtecan).
Kadcyla: This medication is used to treat both early and metastatic breast cancer. If you have early breast cancer, it would be given if you still have cancer after initial treatment with chemotherapy, Herceptin, and surgery. In this scenario, you would receive up to 14 doses. If you have metastatic breast cancer, it would be given after you’ve been treated with Herceptin and a taxane (a class of chemotherapy medications that contain paclitaxel or docetaxel).
Enhertu: This medication is currently only used in cases of metastatic or advanced breast cancer that can’t be removed with surgery. Enhertu is given for as long as it's effective.
Each medication is given by IV every 3 weeks. With both, the first infusion is done over 90 minutes to make sure you can tolerate it. Subsequent infusions are done over 30 minutes. Given their design, these medications are not combined with other anti-HER2 or chemotherapy medications.
2. Perjeta
Like Herceptin, Perjeta (pertuzumab) is an anti-HER2 monoclonal antibody that’s used to treat both early and metastatic breast cancer. It attaches to the HER2 protein, but at a different spot than Herceptin does. It isn’t that effective by itself, but it does help boost Herceptin’s ability to block HER2. This is why you wouldn’t take it by itself; it’s always given in combination with Herceptin (or a Herceptin biosimilar).
Perjeta is usually given by IV every 3 weeks. The first infusion is administered over 1 hour to make sure you can tolerate it. And subsequent infusions are given over 30 minutes. It’s also available as an under-the-skin injection that combines pertuzumab with Herceptin, called Phesgo. This version only takes 5 to 8 minutes to administer.
Good to know: Unlike Herceptin, Perjeta doesn’t have any biosimilars or ADCs available. It’s only available in its original form.
3. Margenza
Margenza (margetuximab) is the newest anti-HER2 monoclonal antibody. Compared to Herceptin and Perjeta, Margenza is designed to cause a stronger immune response to HER2-positive breast cancer cells.
This medication is available as an IV infusion that’s given every 3 weeks. The first infusion is given over 2 hours to make sure you can tolerate it, and subsequent infusions are given over 30 minutes. There aren’t any Margenza biosimilars or ADCs available.
Margenza is only used in cases of metastatic breast cancer and in combination with chemotherapy. It’s an option for later in the breast cancer journey, after at least two or more HER2 inhibitors have been tried. Then, it’s given for as long as it’s effective.
4. Tykerb
Some HER2 inhibitors come in an oral formulation. These medications are known as tyrosine kinase inhibitors (TKIs). They’re different from monoclonal antibodies and ADCs because they deactivate the HER2 protein from inside of cells, rather than interfering with them from the outside.
Tykerb (lapatinib) was the first TKI approved to treat HER2-positive breast cancer. And it’s been around long enough that there is a generic version available. It’s only used in cases of advanced or metastatic breast cancer and is typically given in combination with other oral breast cancer medications.
Tykerb comes as a 250 mg tablet. Depending on your situation, you may have to take 5 to 6 tablets a day. The medication should be taken on an empty stomach.
5. Nerlynx
Nerlynx (neratinib) is another oral TKI approved to treat HER2-positive breast cancer. It’s used to treat both early and metastatic HER2-positive breast cancer. With early breast cancer, it’s given by itself after a person has taken Herceptin for a year.
In cases of metastatic breast cancer, Nerlynx is given later on in the treatment process, usually in combination with an oral chemotherapy called Xeloda (capecitabine). This is done after two or more HER2 inhibitors have been tried first. And then it’s given for as long as it’s effective.
Nerlynx is available as a 40 mg tablet, and there isn’t a generic available. You have to take 6 tablets once a day to get the full dose. But your healthcare provider may prescribe you a low Nerlynx dose at first, and then slowly increase it to minimize the risk of side effects. The medication should be taken with food.
6. Tukysa
Tukysa (tucatinib) is the newest oral TKI for HER2-positive breast cancer. But it’s only used to treat advanced or metastatic breast cancer, and it’s never taken alone. It’s typically prescribed alongside Herceptin and Xeloda, after a person has already tried at least one HER2 inhibitor.
Tukysa is available as a 150 mg tablet, and there isn’t a generic available. You have to take 2 tablets twice a day to get the full dose. And you can take it with or without food.
How do I know which HER2 inhibitor is right for me?
There is no best HER2 inhibitor for everyone. Nearly everything about cancer treatment, including which HER2-positive breast cancer medication is recommended, is personalized.
While Herceptin tends to be the most commonly prescribed HER2 inhibitor, your healthcare provider may recommend a different medication depending on the stage of breast cancer, which medications you’ve already tried, and the potential for side effects. It will also depend on insurance coverage status and whether you’re able to take oral medications.
Bottom line, your healthcare provider will work with you to determine the best HER2 inhibitor for your situation.
How to save on HER2 inhibitors
There are ways to save on your HER2 inhibitor medication. GoodRx can help you navigate your options, which could include a copay savings card or patient assistance program. As mentioned, there are also lower-cost Herceptin biosimilars and certain generics available. Your cancer care team can also help you navigate savings opportunities.
The bottom line
There are many different HER2 inhibitors available to treat HER2-positive breast cancer. Herceptin (trastuzumab), Perjeta (pertuzumab), and Tykerb (lapatinib) are some most commonly prescribed examples. But which HER2 inhibitor your healthcare provider recommends will depend on the stage of your cancer and what you’ve already tried.
When recommending a HER2 inhibitor, your healthcare provider will also take into account your insurance status and the different medications’ side effects to determine the best treatment for you.
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