Zanidatamab: clinical use

Prescribing considerations

• Confirm HER2 IHC3+ tumour status using an appropriately validated diagnostic test.
• Initiation should be by a physician experienced in biliary tract cancer; administration requires trained staff and immediate access to resuscitation equipment.
• Use premedication and monitor for infusion-related reactions.
• Consider embryo-fetal toxicity, cardiac history, pulmonary symptoms and limited evidence in severe renal or moderate-to-severe hepatic impairment.
• This product has conditional authorisation and is subject to additional monitoring.

Contraindications and cautions

• Hypersensitivity to zanidatamab or any formulation excipient.

Monitoring

• Pregnancy status before treatment where relevant.
• Left ventricular ejection fraction before treatment and regularly thereafter.
• Infusion reactions during administration and as clinically indicated afterwards.
• New cough, breathlessness or other evidence of pneumonitis.
• Clinical toxicity and relevant laboratory abnormalities, including diarrhoea, anaemia and increased liver enzymes.
• Record the product name and batch number for traceability.

Clinical pharmacology

A humanised bispecific IgG1 antibody binding extracellular HER2 domains 2 and 4 on separate HER2 molecules. It promotes receptor internalisation, complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis.

Formulation and product differences

• The product is a single-use powder for concentrate that must be reconstituted and diluted before intravenous infusion. It contains polysorbate 20 and is essentially sodium-free.

Solution for infusion

Route: Intravenous

Strengths: 300 mg