HER2 Positive (IHC 3+) Metastatic Solid Tumors: 5 Questions to Discuss With Your Doctor

(BPT) - Sponsored by Daiichi Sankyo and AstraZeneca

While receiving a metastatic cancer diagnosis can be overwhelming, it is important to keep in mind that not all cancers are the same. Knowing what makes your cancer unique and understanding treatment options is helpful when speaking with your doctor.

In addition to understanding the stage of your disease, ask your doctor for information on biomarkers, or cancer genes and proteins. This will provide useful information about cancer cells, such as how they are likely to grow and spread and whether cancer treatment is working. It is important to work with your doctor to determine what biomarkers are causing your cancer to grow.

One example of a biomarker is human epidermal growth factor receptor 2, or HER2. This biomarker is commonly associated with breast cancer, but HER2 can be expressed in many solid tumors including biliary tract, lung, bladder, cervical, endometrial, ovarian, colorectal and pancreatic cancers.^[1]

To fully understand your cancer and appropriate treatment options, it is important to speak with your medical provider. But where do you start?

Here are five questions you may have that you should also ask your doctor about.

Question 1: What does it mean to have metastatic or unresectable cancer and can these cancers be treated?

Metastatic cancer means that cancer has spread from the part of your body where it first began growing to other parts of the body.^[2]Unresectable cancer means that the cancer is unable to be removed with surgery.^[3]

For cancers that are metastatic and/or unresectable, certain treatments may work to slow tumor growth.^[2]

It is important to talk to your doctor about your specific diagnosis, available treatment options and personal goals. Together, you and your doctor can create a customized plan based on your particular cancer.

Question 2: What is HER2, and which cancers can express high levels of it?

HER2 is a protein that tells cells to grow.^[4] When cells produce too much HER2, they can become cancerous.^[4]HER2 overexpression in cancer is linked to more aggressive diseases and poorer outcomes.^[5]

Many patients do not realize that overexpression of HER2 can be found in many different tumors beyond breast cancer, such as bladder, cervical, endometrial, ovarian and pancreatic cancers.^[1]

Ask your doctor if your cancer has been tested for HER2 or if you should have biomarker testing to determine if HER2 is present.

Question 3: How do I know if my cancer is overexpressing HER2?

To determine the presence of HER2 in cancer, a biomarker test is essential.^[4] There are different tests to measure presence of HER2, but in order to specifically identify HER2 overexpression, your doctor can use a testing method called immunohistochemistry, or IHC, which measures the amount of HER2 receptor protein on the surface of cells in a tissue sample. HER2 IHC scores range from IHC 0 to IHC 3+. HER2 positive includes tumors with an IHC 3+ score.^[4],[6]

If IHC testing determines that you have a HER2 positive (IHC 3+) metastatic solid tumor, talk to your doctor to see if a targeted treatment option may be right for you.

Question 4:What are targeted treatments and what should I know about them?

In recent years, treatments for metastatic cancer have provided benefits to many patients.^[7] Targeted therapies are used to precisely attack components in cancerous cells, which may have some impact on healthy cells as well.^[8] Some targeted therapies are used alongside traditional treatments like chemotherapy, surgery or radiation.^[8]

One type of targeted therapy is a class of drugs called antibody drug conjugates (ADCs), which are designed to bind to a specific target protein on the surface of cancer cells and deliver chemotherapy agents.^[9] Specifically, HER2 directed ADCs target and attach to HER2 on the cancer cell, releasing chemotherapy to destroy the cancer cells and other cells nearby.^[10]

Ask your doctor about targeted therapies like ADCs when discussing treatment options for your metastatic cancer.

Question 5: What is ENHERTU and am I eligible for this treatment?

ENHERTU^® (fam-trastuzumab deruxtecan-nxki) is a prescription medicine used to treat adults who have solid tumors that are HER2 positive (IHC 3+) and that cannot be removed by surgery or have spread to other parts of your body (metastatic), and who have received a prior treatment and have no other satisfactory treatment options. Your healthcare provider will perform a test to make sure ENHERTU is right for you.

ENHERTU was FDA approved for this use based on clinical studies that measured how many patients responded and how long they responded. ENHERTU is still being studied to confirm these results. It is not known if ENHERTU is safe and effective in children.

ENHERTU carries Boxed WARNINGS for interstitial lung disease and embryo-fetal toxicity, with risks of lung problems, low white blood cell count and heart problems. The most common adverse reactions (frequency greater than or equal to 20%), including laboratory abnormalities, were nausea, decreased white and red blood cell counts, decreased hemoglobin, decreased neutrophil count, decreased lymphocyte count, fatigue, decreased platelet count, increased aspartate aminotransferase, increased alanine aminotransferase, increased blood alkaline phosphatase, vomiting, alopecia, constipation, decreased blood potassium, decreased appetite, diarrhea, and musculoskeletal pain. Please see Important Safety Information below and consult with your healthcare provider.

ENHERTU was studied in three clinical trials of many different types of HER2 positive (IHC 3+) metastatic solid tumors.^[11] These studies only evaluated ENHERTU. There were no comparisons of results to other treatment options.

If you have a HER2 positive (IHC3+) metastatic solid tumor and have received prior systemic treatment, you may be eligible for ENHERTU, which is an infusion given once every three weeks either at your oncologist's office or at a nearby infusion center. When talking to your doctor about treatment options, ask if you are eligible for ENHERTU treatment.

Take an Active Role in Your Treatment Discussions

Remember, having open conversations with your healthcare team and asking informed questions is important for understanding your disease and treatment options. If you or a loved one is living with a metastatic solid tumor and exploring treatment options, use these five questions to guide discussions with your care team to make more informed decisions about your treatment plans together.

To learn more about treatment for certain eligible patients with HER2 positive (IHC 3+) metastatic cancer, visit ENHERTU.com.

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:
  • Cough
  • Trouble breathing or shortness of breath
  • Fever
  • Other new or worsening breathing symptoms (such as chest tightness, wheezing)
    
    
• Low white blood cell count (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
  • Coughing
  • 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.
  • Femaleswho 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
• Nausea
• Low red blood cell counts
• Feeling tired
• Low platelet counts
• Increased liver function tests
• Vomiting
• Hair loss
• Constipation
• Low levels of blood potassium
• Decreased appetite
• Diarrhea
• Muscle or bone pain

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 solid tumors that are HER2-positive (IHC 3+) and that cannot be removed by surgery or have spread to other parts of your body (metastatic), and who have received a prior treatment and have no other satisfactory treatment options. Your healthcare provider will perform a test to make sure ENHERTU is right for you.

• ENHERTU was FDA approved for this use based on clinical studies that measured how many patients responded and how long they responded. ENHERTU is still being studied to confirm these results.

It is not known if ENHERTU is safe and effective in children.

Please see fullPrescribing Information, including Boxed WARNINGS, andMedication Guide.

ENHERTU^® is a registered trademark of Daiichi Sankyo Company, Limited.

^©2025 Daiichi Sankyo, Inc. and AstraZeneca.

PP-US-ENTA-0319 10/25

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