Pertuzumab / Trastuzumab

What it is and how it works

Pertuzumab binds the extracellular dimerisation domain II of HER2 and blocks ligand-dependent heterodimerisation with other HER receptors, while trastuzumab binds domain IV and inhibits ligand-independent HER2 signalling and mediates antibody-dependent cellular cytotoxicity. Together they produce a more complete blockade of HER2 signalling.

Indications

HER2-positive early breast cancer (neoadjuvant and adjuvant treatment in patients at high risk of recurrence) and HER2-positive metastatic or locally recurrent unresectable breast cancer, in combination with chemotherapy.

Dosage and administration (summary)

For the fixed-dose subcutaneous combination: loading dose pertuzumab 1200 mg/trastuzumab 600 mg, then pertuzumab 600 mg/trastuzumab 600 mg every 3 weeks; intravenous co-administered products are dosed per their own labels.

Contraindications

Hypersensitivity to pertuzumab, trastuzumab or any excipient.

Warnings and precautions

May reduce left ventricular ejection fraction and cause heart failure; assess LVEF before and regularly during treatment. Injection- or infusion-related and hypersensitivity reactions, including anaphylaxis, may occur. Diarrhoea and, with chemotherapy, febrile neutropenia are common.

Pregnancy

Avoid: may cause embryo-fetal toxicity including oligohydramnios; effective contraception is required during and for 7 months after the last dose.

Storage and supply

Store at 2–8 °C in a refrigerator; do not freeze; keep in the outer carton to protect from light.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.