What should you know about side effects?

Knowing what to expect helps you prepare for your treatment

ZIIHERA can cause serious side effects, including:

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  • Diarrhea. Diarrhea during treatment with ZIIHERA can be severe, life threatening, and can lead to death. Diarrhea may cause loss of fluids and body salts (electrolytes)Follow all of your care team's instructions to help with your diarrhea.
  • Harm to an unborn baby. Taking ZIIHERA during pregnancy or within 4 months before pregnancy can harm your unborn baby
  • Heart problems that may affect how well your heart pumps blood
  • Infusion-related reactions

More severe or worse side effects occurred more often in people who were 65 years or older who received ZIIHERA + tislelizumab (immunotherapy) + chemotherapy (87%) compared to people younger than 65 years (80%).

ZIIHERA may cause other side effects

Other common side effects when ZIIHERA is given in combination with chemotherapy and tislelizumab include:

  • diarrhea
  • nausea
  • decreased appetite
  • low levels of blood potassium
  • vomiting
  • feeling tired
  • numbness, pain, tingling, or burning in your hands or feet
  • rash
  • infusion-related reactions

Other common side effects when ZIIHERA is given in combination with chemotherapy include:

  • diarrhea
  • nausea
  • vomiting
  • numbness, pain, tingling, or burning in your hands or feet
  • decreased appetite
  • feeling tired
  • low levels of blood potassium
  • infusion-related reactions
  • rash

These are not all of the possible side effects of ZIIHERA. See the Medication Guide for more information about side effects and discuss with your doctor.

Managing diarrhea

Diarrhea is the most common side effect with ZIIHERA. With ZIIHERA treatment plans, about 4 out of 5 people experienced diarrhea in the clinical trial.

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  • Your care team will instruct you to take an over-the-counter medicine called loperamide (Imodium®) before you receive ZIIHERA to help manage diarrhea. It's important you take this medicine (4 mg) twice daily for at least the first 7 days of your first round of treatment with ZIIHERA, and as directed by your care team afterward
  • Less than 5% of people had to stop taking ZIIHERA because of diarrhea. For most people, diarrhea typically happened during the first round of treatment and got better within 3 weeksgot better within 3 weeks
  • Drinking extra fluids is also important since diarrhea can cause your body to lose fluids and salts
  • If you get new or worsening diarrhea, notify your care team right away
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Here are some tips to help you manage diarrhea:

Act early

Take antidiarrheal medicine, loperamide (Imodium®), before your treatment, for at least the first 7 days of your first round. Take it again at the first sign of loose stools, as instructed by your care team

Inform your care team

Call your care team right away if you experience more frequent or loose stools, or if anything feels unmanageable

Manage day by day

Keep loperamide with you and take it as instructed by your care team if diarrhea happensDrink plenty of fluids since diarrhea can make you lose fluids and salts

Managing side effects starts before your first infusion. Being prepared ahead of time may help support you on your treatment journey with ZIIHERA. Remember, you are not alone—your care team is there to help you through any challenges along the way.

Your care team is your partner through this. Reach out as often as you need

Explore details about what your treatment visits may involve.

How will you receive ZIIHERA?

What is ZIIHERA?

ZIIHERA (zanidatamab-hrii) 50 mg/mL is a prescription medicine used to treat adults with gastroesophageal cancer (GEA) including gastric cancer, esophageal cancer, and gastroesophageal junction (GEJ) cancer. ZIIHERA is used in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr as the first treatment when your GEA:

  • cannot be removed by surgery or has spread to other parts of your body (metastatic); and
  • your tumor tests positive for human epidermal growth factor receptor 2 (HER2 IHC 3+ or IHC 2+/ISH+).

Your healthcare provider will perform a test to make sure ZIIHERA is right for you.

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

IMPORTANT SAFETY INFORMATION

ZIIHERA can cause serious side effects, including:

  • Diarrhea. Diarrhea during treatment with ZIIHERA can be severe, life threatening, and can lead to death. Diarrhea may cause loss of fluids and body salts (electrolytes). To help prevent or reduce diarrhea during treatment with ZIIHERA, your healthcare provider:
    • will tell you to drink more fluids.
    • start you on an antidiarrheal medicine such as loperamide or other treatment, as needed.
    • may temporarily stop, reduce your dose or permanently stop treatment with ZIIHERA, or other medicines you take.

If you get new or worsening diarrhea, tell your healthcare provider right away and take antidiarrheal medicine as prescribed. Follow all of your healthcare providers instructions to help with your diarrhea.

  • Harm to your unborn baby. Taking ZIIHERA during pregnancy or within 4 months before pregnancy can harm your unborn baby. Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with ZIIHERA.

Females who are able to become pregnant:

  • Your healthcare provider should do a pregnancy test before you start treatment with ZIIHERA.
  • Use effective birth control (contraception) during treatment with ZIIHERA and for 4 months after the last dose.

  • Heart problems that may affect how well your heart pumps blood. Your healthcare provider will check your heart function before and during treatment with ZIIHERA. Tell your healthcare provider right away if you get any of the following signs and symptoms of a heart problem:

    • new or worsening shortness of breath
    • feeling more tired than usual
    • swelling of your ankles or feet
    • loss of consciousness
    • irregular heartbeat
    • sudden weight gain
    • dizziness or feeling light-headed

  • Infusion-related reactions. Your healthcare provider will check for side effects during your infusions. Tell your healthcare provider right away if you get any of the following symptoms during or after your infusions of ZIIHERA:

    • shortness of breath or trouble breathing
    • fever
    • chills
    • rash
    • flushing
    • nausea or vomiting
    • dizziness or feeling light-headed
    • chest discomfort

Before receiving ZIIHERA, tell your healthcare provider about all of your medical conditions, including if you:

  • have or have had any heart problems.
  • are breastfeeding or plan to breastfeed. It is not known if ZIIHERA passes into your breastmilk. Talk to your healthcare provider about the best way to feed your baby if you receive treatment with ZIIHERA.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Other common side effects when ZIIHERA is given in combination with chemotherapy and tislelizumab-jsgr include:

  • diarrhea
  • nausea
  • decreased appetite
  • low levels of blood potassium
  • vomiting
  • feeling tired
  • numbness, pain, tingling, or burning in your hands or feet
  • rash
  • infusion-related reactions

Other common side effects when ZIIHERA is given in combination with chemotherapy include:

  • diarrhea
  • nausea
  • vomiting
  • numbness, pain, tingling, or burning in your hands or feet
  • decreased appetite
  • feeling tired
  • low levels of blood potassium
  • infusion-related reactions
  • rash

These are not all the possible side effects of ZIIHERA. Call your doctor for medical advice about side effects.

Tell your healthcare provider if you have any side effect that bothers you or that does not go away. You may report side effects to FDA at 1-800-FDA-1088 or www.fda.gov/medwatch

Please see the full Prescribing Information, including BOXED WARNINGS and Medication Guide, and discuss with your doctor.