ZANIDATAMAB-HRII INJ
Clinical Criteria Summary
Document 837: MON Zanidatamab hrii ZIIHERA Monograph Mar 2026
Indication & Patient Population
- Adults with previously treated, unresectable or metastatic biliary tract cancer (BTC)
- Age ≥ 18 years
- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
- Left ventricular ejection fraction ≥ 50%
Diagnostic & Disease State Requirements
- HER2-positive (IHC 3+) BTC, as detected by an FDA-approved test
- Confirmed HER2-amplified, unresectable, locally advanced, or metastatic BTC (gallbladder cancer [GBC], intrahepatic cholangiocarcinoma [ICC], or extrahepatic cholangiocarcinoma [ECC])
- Presence of ≥ 1 measurable target lesion
Prior Therapy & Treatment History
- Disease progression on ≥ 1 gemcitabine-based systemic therapy for unresectable, locally advanced, or metastatic disease
- Progression or recurrence within 6 months of completion in the neoadjuvant or adjuvant setting
- No prior treatment with HER2-targeting agents
Dosing & Administration Parameters
- 20 mg/kg by IV infusion once every 2 weeks
- Continue therapy until disease progression or unacceptable toxicity
Safety & Monitoring Considerations
- Boxed warning for embryofetal toxicity
- Other warnings include left ventricular dysfunction, infusion-related reactions, and diarrhea
- Discontinuation due to adverse events occurred in 2.5% of patients (Cohort 1)
- Serious treatment-related adverse events occurred in 8% overall
Place in Therapy & Formulary Context
- Subsequent-line therapy for BTC if disease progression
- Category 2A recommendation for HER2+ by IHC3+ per NCCN guidelines
- Indirect comparisons indicate no additional benefit over existing available therapies and a more inconvenient dosing schedule (every 2 weeks vs every 3 weeks)
- May be considered for patients unable to receive fam-trastuzumab deruxtecan due to concern for interstitial lung disease (ILD), though trastuzumab + tucatinib or trastuzumab + pertuzumab may be preferred for improved objective response rate and more convenient dosing
- Consider differences in study enrollment criteria when evaluating outcome comparisons across alternatives
Document 848: Zanidatamab ZIIHERA Criteria Mar 2026
Exclusion Criteria
- Left Ventricular Ejection Fraction < 50%
- Pregnancy
- Lactating
Inclusion Criteria
- Care provided by a VA or VA Community Care oncology provider
- Eastern Cooperative Oncology Group Performance Status 0 - 2
- Unresectable or metastatic biliary tract cancer
- Progressive disease on at least one prior chemotherapy regimen
- Patient is not a candidate for fam-trastuzumab deruxtecan, trastuzumab/tucatinib or trastuzumab/pertuzumab
Additional Inclusion Criteria
- For females who can become pregnant: Pregnancy should be excluded prior to receiving zanidatamab
- For females who can become pregnant: Counseling provided on potential risks vs benefits of treatment and the use of effective contraception during therapy and for 4 months after stopping treatment