HER2-amplified biliary tract cancer (~5-15% overall; enriched in gallbladder + extrahepat...
Deterministic view of the source YAML entity. Clinical authority remains with the cited source IDs and reviewer sign-off state.
| ID | BMA-HER2-AMP-CHOLANGIO |
|---|---|
| Type | Actionability |
| Status | reviewed 2026-05-08 | pending_clinical_signoff | actionability review required |
| Diseases | DIS-CHOLANGIOCARCINOMA |
| Sources | SRC-ESMO-BTC-2023 SRC-HERIZON-BTC-01-HARDING-2023 SRC-NCCN-HEPATOBILIARY |
Actionability Facts
| Biomarker | BIO-HER2-SOLID |
|---|---|
| Variant | amplification / overexpression — IHC 3+ or (IHC 2+ + ISH amplified, HER2/CEP17 ≥2.0); ~5-15% of biliary tract cancer (higher in gallbladder + extrahepatic CCA than intrahepatic CCA) |
| Disease | DIS-CHOLANGIOCARCINOMA |
| ESCAT tier | IIA |
| Recommended combinations | zanidatamab monotherapy 20 mg/kg IV q2w (2L+ post gemcitabine-based 1L per SRC-NCCN-HEPATOBILIARY) |
| Evidence summary | HER2-amplified biliary tract cancer (~5-15% overall; enriched in gallbladder + extrahepatic cholangiocarcinoma; ~3-5% intrahepatic CCA): zanidatamab (HER2-targeted biparatopic bispecific antibody) 20 mg/kg IV q2w produced confirmed ORR 41.3% (95% CI 30.4-52.8) in previously treated HER2 IHC 3+ or IHC 2+/ISH+ disease in HERIZON-BTC-01 (Harding et al., Lancet Oncol 2023; n=87). FDA accelerated approval November 2024 for HER2-positive (IHC 3+) BTC ≥2L. ESCAT tier IIA (FDA-approved disease-specific). NCCN category 2A. HER2 testing recommended at diagnosis for unresectable / metastatic BTC per SRC-NCCN-HEPATOBILIARY. Gastric-style scoring (Hofmann 2008 — basolateral / lateral membranous staining ≥10%) is generally applied given basolateral HER2 expression pattern in BTC. |
Notes
ESCAT IIA (FDA-approved disease-specific). HER2 testing (IHC + reflex ISH for IHC 2+) recommended at diagnosis for unresectable / metastatic BTC per SRC-NCCN-HEPATOBILIARY. Gastric-style scoring (Hofmann 2008 — basolateral / lateral membranous staining ≥10%) is generally applied. HER2 amplification frequency varies by anatomic subsite: highest in gallbladder + extrahepatic cholangiocarcinoma (~10-15%), lower in intrahepatic CCA (~3-5%). FDA accelerated approval Nov 2024 based on HERIZON-BTC-01; confirmatory study and traditional approval pending. UA access: zanidatamab not registered in UA (named-patient / EAP only as of 2026-05). Trastuzumab + pertuzumab combination has separate weak evidence in BTC (MyPathway Meric-Bernstam 2021 ORR ~23%) but is not the FDA-approved disease-specific combination — zanidatamab is the disease-specific actionable option.
Used By
No reverse references found in the YAML corpus.