Zanidatamab
Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.
| ID | DRUG-ZANIDATAMAB |
|---|---|
| Type | Drug |
| Aliases | ZiiheraЗанідатамаб |
| Status | reviewed 2026-05-08 | pending_clinical_signoff |
| Diseases | DIS-CHOLANGIOCARCINOMA |
| Sources | SRC-ESMO-BTC-2023 SRC-HERIZON-BTC-01-HARDING-2023 SRC-NCCN-HEPATOBILIARY |
Drug Facts
| Class | HER2-targeted bispecific (biparatopic) IgG1 monoclonal antibody (binds HER2 ECD2 + ECD4) |
|---|---|
| Mechanism | Humanized bispecific (biparatopic) IgG1-like monoclonal antibody binding two distinct non-overlapping HER2 (ERBB2) extracellular epitopes — subdomain ECD2 (the pertuzumab-like dimerization arm) and ECD4 (the trastuzumab-like membrane-proximal arm) — simultaneously on the same HER2 molecule and across HER2 molecules. Mechanisms: (1) enhanced HER2 receptor clustering, internalization, and lysosomal degradation (downregulation of surface HER2 distinct from trastuzumab); (2) potent antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) via Fc-FcγR engagement; (3) complement- dependent cytotoxicity (CDC); (4) blockade of ligand-independent HER2 homo- and heterodimerization and downstream PI3K/AKT and MAPK signaling. Dual-epitope binding produces activity in some trastuzumab-resistant HER2-amplified tumors. Activity requires HER2 IHC 3+ or ISH-ampl... |
| Typical dosing | 20 mg/kg IV infusion every 2 weeks (q2w) until disease progression or unacceptable toxicity. First infusion over 60-90 min; subsequent infusions may be shortened to ~30 min if first infusion well-tolerated. Premedication: antihistamine + acetaminophen + corticosteroid for infusion reaction prophylaxis (especially first 2-3 infusions). Cardiac monitoring: baseline LVEF (echo or MUGA) before initiation, then q3 months during therapy. Antidiarrheal prophylaxis advised given ~40% any-grade diarrhea. |
| Ukraine registered | False |
| NSZU reimbursed | False |
| Ukraine last verified | 2026-05-08 |
Warnings
- Embryo-fetal toxicity (HER2-targeted class effect — effective contraception required during therapy and ≥4 months after last dose)
Notes
HER2-targeted biparatopic bispecific antibody (Jazz Pharmaceuticals / Zymeworks). FDA accelerated approval November 2024 for HER2-positive (IHC 3+) previously treated unresectable / locally advanced / metastatic biliary tract cancer based on HERIZON-BTC-01 (Harding et al., Lancet Oncol 2023; n=87 cohort 1; ORR 41.3%, DCR 68.8%, median DoR 14.9 mo). ESCAT tier IIA (FDA-approved disease-specific HER2-amplified BTC 2L+). Distinct from trastuzumab in dual-epitope binding (ECD2 + ECD4) which produces enhanced HER2 receptor clustering, internalization, and degradation; mechanistically retains activity in some trastuzumab- experienced HER2+ tumors. Diarrhea (~40%) is the dominant clinically- relevant non-cardiac toxicity — antidiarrheal prophylaxis advised. Cardiac surveillance per HER2-targeted class. Active development in HER2+ gastric/GEJ (HERIZON-GEA-01 phase 3, with chemotherapy ± tislelizumab — pending readout); HER2-amplified colorectal; breast. EMA review pending. UA access: named-patient / EAP only as of 2026-05.
Used By
Regimens
REG-ZANIDATAMAB- Zanidatamab — 2L+ HER2-amplified biliary tract cancer (HERIZON-BTC-01)