3.1
Trastuzumab is a recombinant humanised monoclonal antibody that specifically targets the HER2 protein. It is licensed for 2 indications for the treatment of MBC overexpressing HER2 at level 3 or more. Firstly, it is licensed in combination with paclitaxel for patients with MBC who have not received chemotherapy for metastatic disease and in whom an anthracycline is unsuitable. Secondly, it is licensed as a monotherapy for patients who have received at least 2 chemotherapy regimens for MBC; prior chemotherapy must have included at least an anthracycline and a taxane, unless these treatments are inappropriate; patients who are oestrogen receptor-positive must also have failed to respond to appropriate hormonal therapy.