Generic name: zanidatamab
Brand name: Ziihera
Dosage form: intravenous powder for injection (hrii 300 mg)
Drug class: HER2 inhibitors

Medically reviewed by Drugs.com on Jan 13, 2025. Written by Cerner Multum.

What is zanidatamab?

Zanidatamab is used in adults to treat a certain type of bile duct or gallbladder cancer called biliary tract cancer.

Zanidatamab is used when the cancer was previously treated, has spread to other parts of the body (metastatic), or cannot be removed with surgery.

Your doctor will make sure you have the correct tumor type to be treated with zanidatamab.

Zanidatamab may also be used for purposes not listed in this medication guide.

Zanidatamab side effects

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Some side effects may occur during or after the infusion. Tell your medical caregiver if you feel dizzy, nauseated, light-headed, itchy, sweaty, or have a headache, chest tightness, back pain, trouble breathing, or swelling in your face.

Zanidatamab may cause serious side effects. Call your doctor at once if you have:

• new or worsening shortness of breath;

• feeling very tired;

• loss of consciousness;

• a new or a worsening irregular heartbeat pattern;

• dizziness, feeling light-headed;

• swelling or rapid weight gain; or

• severe diarrhea.

Your cancer treatments may be delayed, changed, or permanently discontinued if you have certain side effects.

Common side effects of zanidatamab may include:

• infusion related reaction;

• diarrhea;

• stomach pain; or

• feeling tired.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Related/similar drugs

Warnings

May harm an unborn baby. Do not use if you are pregnant. Use effective birth control while using zanidatamab and for at least 4 months after your last dose. Tell your doctor if you become pregnant.

Before taking this medicine

Tell your doctor if you have or have ever had:

• heart problems.

You may need to have a negative pregnancy test before starting this treatment.

May harm an unborn baby. Do not use if you are pregnant. Use effective birth control while using zanidatamab and for at least 4 months after your last dose. Tell your doctor if you become pregnant.

Ask a doctor if it is safe to breastfeed while using zanidatamab.

How is zanidatamab given?

Zanidatamab is given as a slow infusion into a vein. A healthcare provider will give you this injection.

Zanidatamab usually given once every 2 weeks. Your doctor will determine your treatment schedule.

You will be watched for a short time to make sure you do not have an allergic reaction.

Your heart function and blood will need to be tested before and during treatment. Your treatment may be changed based on the results.

You may be given other medications to help prevent serious side effects or an allergic reaction. Keep using these medicines for as long as your doctor has prescribed.

Zanidatamab dosing information

Usual Adult Dose for Cholangiocarcinoma of biliary tract:

20 mg/kg IV every 2 weeks
Duration of therapy: Until disease progression or unacceptable toxicity

Comments:
-Approved under accelerated approval based on overall response rate and duration of response; continued approval may depend on verification and description of clinical benefit in confirmatory trials.
-Patients should be selected based on HER2-positive (immunohistochemistry [IHC] 3+) tumor specimens, as detected by a US FDA-approved test.
-Duration of infusion:
---First and second: 120 to 150 minutes
---Third and fourth: 90 minutes (if previous infusions were well-tolerated)
---Subsequent: 60 minutes (if previous infusions were well-tolerated)

Use: For the treatment of patients with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer, as detected by a US FDA-approved test

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your zanidatamab infusion.

What happens if I overdose?

In a medical setting an overdose would be treated quickly.

What should I avoid while taking zanidatamab?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect zanidatamab?

Other drugs may affect zanidatamab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.

Zanidatamab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for zanidatamab.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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