# Zanidatamab

Source: https://onco.cc/drugs/zanidatamab/  
OnCo record `zanidatamab` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Zanidatamab (Ziihera) is an antibody that grabs HER2 at two different spots, approved for HER2+ bile duct cancer.

## Summary

Accelerated approval November 2024 for HER2+ biliary tract cancer (HERIZON-BTC-01). HERIZON-GEA-01 phase 3 in first-line HER2+ gastro-oesophageal cancer with chemotherapy ± tislelizumab was positive (2025). Jazz (ex-Asia) and BeOne. Biparatopic binding drives receptor clustering and internalisation, the basis of the ADC zanidatamab zovodotin.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-04
- Brand: Ziihera
- Modality: Biparatopic bispecific antibody (HER2)
- Mechanism: Binds ECD2 and ECD4 of HER2 simultaneously; clustering, internalisation, ADCC.
- Approvals: US 2024: HER2+ (IHC 3+) unresectable/metastatic biliary tract cancer, previously treated; EU 2025: HER2+ biliary tract after ≥1 line; 27 Jun 2025 (conditional); UK 2026: HER2-positive (IHC 3+) unresectable locally advanced or metastatic biliary tract cancer after at least one line of systemic treatment; MHRA 19 February 2026, NICE TA1153 published 7 May 2026 with a commercial arrangement
- Dosing: IV infusion; 20 mg/kg every 2 weeks

## Notes

- Gallbladder cancer was the largest anatomical subgroup in HERIZON-BTC-01, which required ERBB2 amplification by central ISH and reported a 41.3% confirmed response rate in the 80 IHC 2+ or 3+ patients (Harding 2023); the FDA label restricts use to IHC 3+ on the Ventana PATHWAY 4B5 assay.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Zanidatamab
- FDA label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?query=Zanidatamab

## Connected records

- biomarkers: [HER2 IHC 3+ (HER2-positive by immunohistochemistry)](https://onco.cc/biomarkers/her2-ihc-3-plus/)
- cancers: [Biliary tract cancer (all types)](https://onco.cc/cancers/biliary-tract-cancer/), [Biliary tract cancer (cholangiocarcinoma)](https://onco.cc/cancers/cholangiocarcinoma/), [Early HER2-positive breast cancer](https://onco.cc/cancers/her2-positive-early-breast-cancer/), [Extrahepatic cholangiocarcinoma (perihilar and distal)](https://onco.cc/cancers/extrahepatic-cholangiocarcinoma/), [Gallbladder adenocarcinoma](https://onco.cc/cancers/gallbladder-adenocarcinoma/), [Gallbladder cancer](https://onco.cc/cancers/gallbladder/), [Gastric & gastro-oesophageal junction cancer](https://onco.cc/cancers/gastric/), [HER2-amplified colorectal cancer](https://onco.cc/cancers/her2-amplified-colorectal/), [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [HER2-positive breast cancer with brain metastases](https://onco.cc/cancers/her2-positive-breast-brain-metastases/), [HER2-positive gastric cancer](https://onco.cc/cancers/gastric-her2-positive/), [Intrahepatic cholangiocarcinoma](https://onco.cc/cancers/intrahepatic-cholangiocarcinoma/), [Oesophageal cancer](https://onco.cc/cancers/esophageal/)
- technologies: [Bispecific antibodies](https://onco.cc/technologies/bispecific-antibody/)
- targets: [HER2](https://onco.cc/targets/her2/)
- companies: [BeOne Medicines (formerly BeiGene)](https://onco.cc/companies/beone/), [Jazz Pharmaceuticals](https://onco.cc/companies/jazz/), [Zai Lab](https://onco.cc/companies/zai-lab/), [Zymeworks](https://onco.cc/companies/zymeworks/)
- terms: [Epitope](https://onco.cc/terms/epitope/), [HER2 and genomic testing for biliary cancer on the NHS](https://onco.cc/terms/genomic-testing-biliary-uk/), [HER2 testing in biliary tract cancer (IHC, ISH and NGS)](https://onco.cc/terms/her2-testing-in-biliary-cancer/)
- trials: [A Phase 2 Neoadjuvant Study of Zanidatamab in Combination With Chemotherapy in Participants With HER2-positive Breast Cancer](https://onco.cc/trials/nct07102381/), [A Phase 2 Study of Zanidatamab in Patients With HER2-expressing Tumors](https://onco.cc/trials/nct06695845/), [A Study Comparing the Efficacy and Safety of Zanidatamab to Trastuzumab, Each in Combination With Physician's Choice Chemotherapy, for the Treatment o](https://onco.cc/trials/nct06435429/), [An Exploratory Study of Zanidatamab in HER2-positive Advanced Tumor After at Least One Line of Standard Therapy](https://onco.cc/trials/nct07631871/), [Clinical Trial Evaluating the Activity of Zanidatamab for the Treatment of Patients With Solid Tumors With an Alteration of the HER2 Gene.](https://onco.cc/trials/nct07192068/), [HERIZON-BTC-01](https://onco.cc/trials/herizon-btc-01/), [HERIZON-BTC-302](https://onco.cc/trials/herizon-btc-302/), [HERIZON-GEA-01](https://onco.cc/trials/herizon-gea-01/), [Investigating Precision Medicine in the Adjuvant Setting in Biliary Tract Cancer](https://onco.cc/trials/nct07745296/), [Phase II Basket Trial: Zanidatamab Plus Tislelizumab in HER2-Positive GI Tumors (UNION-HER2-BASKET)](https://onco.cc/trials/nct07243938/), [PRE-ISPY Phase I/II Oncology Platform Program](https://onco.cc/trials/nct05868226/), [SAFIR-ABC10](https://onco.cc/trials/safir-abc10/), [Zanidatamab Before Surgery for the Treatment of HER2 Positive Colon and Rectal Cancer in Patients Planned for Curative Intent Treatment](https://onco.cc/trials/nct07405476/)
- key papers: [Clinical and genomic characterization of ERBB2-altered gallbladder cancer: exploring differences between an American and a Chilean cohort](https://onco.cc/key-papers/paper-mondaca-erbb2-gallbladder-us-chile-jco-go-2024/), [HER2 status in extrahepatic cholangiocarcinoma and gallbladder carcinoma: concordance between immunohistochemistry and chromogenic in situ hybridization in 140 cases](https://onco.cc/key-papers/paper-angerilli-her2-ihc-cish-biliary-hum-pathol-2026/), [Zanidatamab for HER2-amplified, unresectable, locally advanced or metastatic biliary tract cancer (HERIZON-BTC-01): a multicentre, single-arm, phase 2b study](https://onco.cc/key-papers/paper-harding-lancet-oncol/)
- pairings: [HER2 sequence in gastric cancer: zanidatamab/trastuzumab + chemo ± PD-1 → T-DXd](https://onco.cc/pairings/her2-gastric-sequence/)
- ideas: [Biomarker-directed first-line quadruplets in gastric cancer](https://onco.cc/ideas/idea-biomarker-quadruplet-gastric/), [Reflex HER2 testing of every advanced gallbladder and extrahepatic biliary cancer](https://onco.cc/ideas/idea-gbc-reflex-her2-testing-advanced-biliary/)
- roadmaps: [Gallbladder cancer roadmap: from a chance finding at gallstone surgery to a disease with its own trials](https://onco.cc/roadmaps/gallbladder-cancer-roadmap/)
- people: [Jeeyun Lee](https://onco.cc/people/lee-jeeyun/)
- pathways: [Gastric cancer (KEGG map)](https://onco.cc/pathways/gastric-cancer-signalling/), [Receptor tyrosine kinase activation](https://onco.cc/pathways/rtk-activation/)
- drugs: [Zanidatamab zovodotin](https://onco.cc/drugs/zanidatamab-zovodotin/)

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