This is a monoclonal antibody directed against a cell surface protein produced by the human epidermal growth factor receptor 2 (HER2) gene which is overexpressed in about one-third of all breast cancers.

Indications: As monotherapy for metastatic breast cancer or in combination with docetaxel or paclitaxel.

Cautions: Concomitant use of trastuzmab with anthracyclines is associated with cardiotoxicity. It has been advised that the use of anthracyclines even after stopping trastuzumab may carry a higher risk of cardiotoxicity and if possible should be avoided for up to 22 weeks. If anthracyclines need to be used, cardiac functions should be monitored.

Contra-indications: Severe dyspnea at rest; breast feeding

Side effect: Infusion-related side effects including chills, fever, hypersensitivity reactions such as anaphylaxis, urticaria and angioedema, pulmonary events (possibly delayed onset); cardiotoxicity, gastrointestinal symptoms, asthenia, headache, chest pain, arthralgia, myalgia, hypotension.

Dose: 4mg/Kg initially, by intravenous infusion in 0.9% sodium chloride over 90 minutes. This may be followed by 2mg/Kg over 30 minutes at weekly intervals.