“Finding a lump was scary and I knew it was something I needed to take seriously, so I immediately scheduled an appointment with my doctor,” Lisa said.
After having a scan and biopsy, Lisa was told she had de novo metastatic breast cancer (mBC), an advanced form of the disease in which cancer has already spread beyond the breast to other parts of the body at the time of initial diagnosis.1 A de novo mBC diagnosis is very rare – most breast cancers are detected before the disease has spread, while approximately five percent of new diagnoses are de novo mBC.1
Lisa knew her life was forever changed, as she was now one of the more than 168,000 women living with mBC, a disease that has many different subtypes defined by unique characteristics.2,3 She learned early on that it is important for people with mBC to know their subtype, as this can help determine appropriate treatment options.4
“At first, my family and I were overwhelmed, afraid and anxious,” said Lisa. “But I tried my best to stay focused and approached the situation from a practical, solution-oriented way. My oncologist and I agreed I should receive biomarker testing in order to learn my subtype and discuss a treatment plan that was right for me.”
To discover a person’s breast cancer subtype, doctors conduct testing on cancer cells to help identify which biomarkers, including genes, proteins or hormones, may be causing the cancer to grow.4 One common biomarker that doctors look for in breast cancer is the human epidermal growth factor 2 (HER2) protein.5
Cancer cells that make too much HER2 tend to grow faster and are more likely to spread to other parts of the body than other types of breast cancer.5 These cancers can be treated with medicines that specifically target the HER2 protein to try to slow the progression of disease.5
Research shows that even cancer cells that express low levels of HER2 can potentially be treated with this form of targeted treatment.5,6 These breast cancers are now classified as HER2-low and they are quite common – approximately 50% of all breast cancers are considered HER2-low.7 Sometimes a person’s HER2 status can change over time, which is why it may be necessary to conduct new biomarker testing upon initial diagnosis and treatment progression.8,9
“When I was diagnosed with metastatic breast cancer, I was not told my cancer was HER2-low – there was just very little awareness of it at the time,” said Lisa. “Since then, I’ve learned that my cancer does fall into the classification of HER2-low. After disease progression on other treatment options, including chemotherapy, I started treatment with ENHERTU to specifically treat my form of metastatic breast cancer.”
In 2022, ENHERTU® (fam-trastuzumab deruxtecan-nxki) was approved by the U.S. Food and Drug Administration (FDA) as the first HER2 directed medicine for the treatment of adult patients with unresectable (unable to be removed surgically) or metastatic HER2-low (immunohistochemistry [IHC] test score of 1+ or IHC score of 2+/in-situ hybridization [ISH]-) breast cancer. Eligible patients must also have received a prior chemotherapy in the metastatic setting or developed disease recurrence (meaning their cancer came back) during or within six months of completing adjuvant chemotherapy (which is given after surgery).10
ENHERTU is what is known as an antibody drug conjugate. It is made up of a monoclonal antibody connected to a cancer-killing medicine and works by using HER2 as a target to deliver the cancer-killing medicine to the cancer cells.
The FDA approved ENHERTU in this setting based on research from the DESTINY-Breast04 clinical trial of people with HER2-low mBC who had already received other types of treatment. The study found that ENHERTU nearly doubled the time that people lived without their cancer growing or spreading, compared to chemotherapy (9.9 months versus 5.1 months, respectively).10 The study also showed that ENHERTU increased overall survival by more than six months versus chemotherapy (23.4 versus 16.8 months, respectively), making it the first study to show a survival benefit from a HER2 targeted therapy for people living with HER2-low mBC.10
ENHERTU can cause serious side effects, including lung problems that may be severe, life threatening, or that may lead to death; low white blood cell count; heart problems that may affect your heart’s ability to pump blood; or harm to an unborn baby. Your healthcare provider may follow you more closely if you have liver or kidney problems. Moreover, in clinical trials, more serious lung problems were seen in patients with certain kidney problems. See Important Safety Information below.
“One of the most important things I’ve learned while living with metastatic breast cancer is that building a good partnership with your oncologist is critical. Ask a lot of questions, learn as much as you can and make sure you understand what subtype you have so you can develop your treatment plan together,” said Lisa. “And remember, cancer research is always advancing, so keep the lines of communication open with your healthcare team to stay informed of new discoveries that may apply to your treatment.”
Learn more about HER2-low mBC and ENHERTU at www.ENHERTU.com. If you or someone you know has been diagnosed with hormone receptor positive (HR+), HER2 negative or triple negative mBC, download the discussion guide to help you talk with your doctor about your biomarker testing results. Testing may reveal that you are one of the many people whose cancer cells have low HER2 expression, which may give you additional treatment options to consider.
Important Safety Information
What is the most important information I should know about ENHERTU?
ENHERTU can cause serious side effects, including:
Lung problems that may be severe, life-threatening or that may lead to death. If you develop lung problems your healthcare provider may treat you with corticosteroid medicines. Tell your healthcare provider right away if you get any of the following signs and symptoms:
• Trouble breathing or shortness of breath
• Other new or worsening breathing symptoms (e.g., chest tightness, wheezing)
Low white blood cell counts (neutropenia). Low white blood cell counts are common with ENHERTU and can sometimes be severe. Your healthcare provider will check your white blood cell counts before starting ENHERTU and before starting each dose. Tell your healthcare provider right away if you develop any signs or symptoms of an infection or have fever or chills during treatment with ENHERTU.
Heart problems that may affect your heart’s ability to pump blood. Your healthcare provider will check your heart function before starting treatment with ENHERTU. Tell your healthcare provider right away if you get any of the following signs and symptoms:
• New or worsening shortness of breath
• Feeling tired
• Swelling of your ankles or legs
• Irregular heartbeat
• Sudden weight gain
• Dizziness or feeling light-headed
• Loss of consciousness
Your healthcare provider will check you for these side effects during your treatment with ENHERTU. Your healthcare provider may reduce your dose, delay treatment or completely stop treatment with ENHERTU if you have severe side effects.
Harm to your unborn baby. Tell your healthcare provider right away if you become pregnant or think you might be pregnant during treatment with ENHERTU.
• If you are able to become pregnant, your healthcare provider should do a pregnancy test before you start treatment with ENHERTU.
• Females who are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for 7 months after the last dose.
• Males who have female partners that are able to become pregnant should use effective birth control (contraception) during treatment with ENHERTU and for 4 months after the last dose.
Before you receive ENHERTU, tell your healthcare provider about all of your medical conditions, including if you:
• Have lung or breathing problems.
• Have signs or symptoms of an infection.
• Have or have had any heart problems.
• Are breastfeeding or plan to breastfeed. It is not known if ENHERTU passes into your breast milk. Do not breastfeed during treatment with ENHERTU and for 7 months after the last dose.
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
How will I receive ENHERTU?
• You will receive ENHERTU into your vein through an intravenous (IV) line by your healthcare provider.
• ENHERTU is given 1 time every three weeks (21-day treatment cycle).
• Your healthcare provider will decide how many treatments you need.
• Your healthcare provider will give you medicines before your infusion to help prevent nausea and vomiting.
• Your healthcare provider may slow down or temporarily stop your infusion of ENHERTU if you have an infusion-related reaction, or permanently stop ENHERTU if you have severe infusion reactions.
• If you miss a planned dose of ENHERTU, call your healthcare provider right away to schedule an appointment. Do not wait until the next planned treatment cycle.
What are the possible side effects of ENHERTU?
ENHERTU can cause serious side effects. See “What is the most important information I should know about ENHERTU?”
The most common side effects of ENHERTU when used at the 5.4 mg/kg dose include:
• Low white blood cell counts
• Low red blood cell counts
• Feeling tired
• Low platelet counts
• Increased liver function tests
• Hair loss
• Muscle or bone pain
• Decreased appetite
• Low levels of blood potassium
ENHERTU may cause fertility problems in males, which may affect the ability to father children. Talk to your healthcare provider if you have concerns about fertility.
These are not all of the possible side effects of ENHERTU. Call your doctor for medical advice about side effects. You may report side effects to Daiichi Sankyo at 1-877-437-7763 or to FDA at 1-800-FDA-1088.
What is ENHERTU?
ENHERTU is a prescription medicine used to treat adults who have:
• HER2-low breast cancer that cannot be removed by surgery or that has spread to other parts of your body (metastatic), and who have received a prior chemotherapy:
· for metastatic disease,
· your disease has returned during or within 6 months of completing adjuvant chemotherapy (after surgery). Your healthcare provider will perform a test to make sure ENHERTU is right for you
It is not known if ENHERTU is safe and effective in children.
ENHERTU® is a registered trademark of Daiichi Sankyo Company, Limited.
©2023 Daiichi Sankyo, Inc. and AstraZeneca.
1 Liu W, et al. Nature. 2022 March; 12: 3597
2 Susan G. Komen. Metastatic Breast Cancer. Accessed September 2023.
3 American Cancer Society. Treatment of Stage IV (Metastatic) Breast Cancer. Accessed September 2023.
4 American Cancer Society. Biomarker Tests and Cancer Treatment. Accessed September 2023.
5 American Cancer Society. Breast Cancer HER2 Status. Accessed September 2023.
6 National Cancer Institute. Enhertu Improves Survival for Metastatic “HER2-Low” Breast Cancer. Accessed September 2023.
7 Tarantino P, et al. Cancer Discovery. 2022; 12:2026-30
8 Bergeron A, et al. Nature. 2023; 129:122-134
9 Breastcancer.org. Breast Cancer’s Hormone Receptor and HER2 Status Can Change After Diagnosis. Accessed September 2023.
10 ENHERTU Prescribing Information. Accessed September 2023.