zolbetuximab: clinical use

Prescribing considerations

• Confirm locally advanced unresectable or metastatic gastric or gastro-oesophageal junction adenocarcinoma and HER2-negative status.
• Confirm CLDN18.2 positivity using a validated assay; the licensed definition requires at least 75% of tumour cells to show moderate-to-strong membranous staining.
• Treatment should be initiated and supervised by a clinician experienced in anticancer therapy.
• Control pre-existing nausea or vomiting before the first infusion and provide antiemetic premedication.
• Administer zolbetuximab before accompanying chemotherapy when both are given on the same day.

Contraindications and cautions

• Hypersensitivity to zolbetuximab or any excipient.
• Use caution where there is a history of allergy to polysorbates.
• Clinical experience is limited in severe renal impairment and moderate hepatic impairment; severe hepatic impairment has not been studied.
• Safety and efficacy have not been established in children or adolescents.

Monitoring

• Observe during and after infusion for anaphylaxis, hypersensitivity and infusion-related reactions.
• Assess nausea and vomiting closely, particularly early in treatment.
• Monitor appetite, weight, oedema and albumin where clinically appropriate.
• Record the product name and batch number to maintain biological-medicine traceability.

Clinical pharmacology

Zolbetuximab is a chimeric mouse–human IgG1 antibody targeting CLDN18.2. It promotes antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity and is expected to be broken down into peptides and amino acids.

Formulation and product differences

• The authorised product is a white to off-white powder requiring reconstitution and dilution for intravenous infusion.
• The vial presentations differ in vial content but have the same excipients and reconstituted concentration.
• The formulation contains polysorbate 80, which can cause allergic reactions.