Prescription medicine
Zanidatamab Brand names: Ziihera
Zanidatamab (Ziihera) is a prescription medicine. No generic is listed in FDA's NDC Directory.
- No generic listed
- Boxed warning
Check it at the source: the zanidatamab FDA label on DailyMed (effective August 24, 2026); every zanidatamab label on DailyMed.
Highlights of the record
FDA label of August 24, 2026; NDC Directory, Drugs@FDA and Orange Book, October 8, 2026
DIARRHEA AND EMBRYO-FETAL TOXICITY ZIIHERA,.
in combination with fluoropyrimidine- and platinum-containing chemotherapy, with or without tislelizumab-jsgr, can cause severe diarrhea, including life threatening and fatal cases. Use antidiarrheal prophylaxis during the first cycle when ZIIHERA is given in combination with these drugs. Manage with antidiarrheals and supportive measures as clinically indicated. Interrupt, reduce the dose or discontinue ZIIHERA based on severity [see Dosage and Administration ( 2.4 ), Warnings and Precautions ( 5.1 ), Use in Specific Populations ( 8.5 )]. Embryo-Fetal Toxicity: Exposure to ZIIHERA during pregnancy can cause embryo-fetal harm. Advise patients of the risk and need for effective contraception [see Warnings and Precautions ( 5.2 ), Use in Specific Populations ( 8.1 , 8.3 )]. WARNING: DIARRHEA and EMBRYO‑FETAL TOXICITY See full prescribing information for complete boxed warning.
ZIIHERA, in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr can cause severe diarrhea, including life threatening, and fatal cases. Use antidiarrheal prophylaxis during the first cycle when ZIIHERA is given in combination with these drugs. Manage with antidiarrheals and supportive measures as clinically indicated. Interrupt, reduce the dose or discontinue ZIIHERA based on severity. […]
Used for
From the label: indications and usageZIIHERA is a bispecific HER2-directed antibody indicated for: Gastroesophageal Adenocarcinoma (GEA)
in combination with fluoropyrimidine- and platinum-containing chemotherapy, and tislelizumab-jsgr, as first-line treatment of adult patients with HER2-positive (IHC 3+ or IHC 2+/ISH+) unresectable locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma, as detected by an FDA-au
Forms and strengths
- 50 mg/ml
Injection (powder) (lyophilized) for solution.
On the market
- Generic approvals
- No generic approved
- Labelers listed (NDC)
- 1 of which 0 under generic applications, 1 under brand applications, repackagers included
Supply and safety
- Pharmacy cost (NADAC)
- Not in the survey
- Shortage (FDA)
- No current entry
- Recalls by its makers (FDA)
- No recall recorded
- FAERS reports
- 51 through July 30, 2026
What is zanidatamab used for?
From the label: indications and usageZIIHERA is a bispecific HER2-directed antibody indicated for: Gastroesophageal Adenocarcinoma (GEA)
in combination with fluoropyrimidine- and platinum-containing chemotherapy, and tislelizumab-jsgr, as first-line treatment of adult patients with HER2-positive (IHC 3+ or IHC 2+/ISH+) unresectable locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma, as detected by an FDA-authorized test. […]
FDA pharmacologic class: Bispecific HER2-directed Antibody.
Source: FDA drug label (ZIIHERA), Jazz Pharmaceuticals, Inc., effective August 24, 2026 (SPL set ae5d9425-fae5-4541-a158-150998343348), via openFDA; the full label on DailyMed
What does the patient leaflet for zanidatamab say first?
The FDA-approved Medication Guide or Patient Information that comes with the medicine, in its own words.
From the patient leaflet: What is the most important information I should know about ZIIHERA?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: o will tell you to drink more fluids. o start you on an antidiarrheal medicine such as loperamide or other treatment, as needed. o 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: o Your healthcare provider should do a pregnancy test before you start treatment with ZIIHERA. o Use effective birth control (contraception) during treatment with ZIIHERA and for 4 months after the last dose. See “What are the possible side effects of ZIIHERA?” for more information about side effects.
Source: FDA drug label (ZIIHERA), Jazz Pharmaceuticals, Inc., effective August 24, 2026 (SPL set ae5d9425-fae5-4541-a158-150998343348), via openFDA; the full label on DailyMed
Is there a generic for zanidatamab (Ziihera)?
No generic zanidatamab is approved (Drugs@FDA, October 8, 2026).
Source: Drugs@FDA, FDA NDC Directory and the Orange Book (openFDA bulk files, October 8, 2026)
What does the zanidatamab label say about other medicines?
The zanidatamab label names 3 other medicines in its interaction, contraindication or warning sections. The sentences are the labels' own; a label lists what its studies and reports found, not every interaction.
| Medicine named | Section | What the label says |
|---|---|---|
| Fluorouracil | warnings and precautions | In a Phase 2 study evaluating ZIIHERA in combination with FOLFOX in patients with GEA, 57% of patients who received a fluorouracil bolus without loperamide prophylaxis (N=14), experienced Grade 3 diarrhea, while 30% of patients who did not receive a fluorouracil bolus but received loperamide prophylaxis (N=10) … |
| Loperamide | warnings and precautions | When ZIIHERA is used in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr, severe, life threatening, and fatal cases of diarrhea can occur despite loperamide prophylaxis [see Adverse Reactions ( 6.1 ), Use in Specific Populations ( 8.5 )]. |
| Tislelizumab | warnings and precautions | Gastroesophageal Adenocarcinoma (GEA) In Combination with fluoropyrimidine- and platinum-containing chemotherapy and tislelizumab: |
Source: FDA drug label (ZIIHERA), Jazz Pharmaceuticals, Inc., effective August 24, 2026 (SPL set ae5d9425-fae5-4541-a158-150998343348), via openFDA; the full label on DailyMed
What do FAERS reports show for zanidatamab?
The FDA Adverse Event Reporting System holds 51 reports that list zanidatamab among the medicines taken, through July 30, 2026, each a report of something that happened, not proof the medicine caused it; 7 are coded as a death and 4 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is.
The most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026
What next?
- Zanidatamab side effects
- the label's list beside FAERS reports
- Check an interaction
- what two or more labels say about each other