What's so special about [symbol: see text] trastuzumab?

The growth and multiplication of cells are regulated, in part, by polypeptide growth factors that bind to high-affinity receptors typically found on the plasma membrane. One such receptor is human epidermal growth factor receptor 2 (HER2). In around a quarter of all primary breast cancers, cells possess abnormally high numbers of (overexpress) HER2. [symbol: see text] Trastuzumab (pronounced tra-stoo-zoo-mab; Herceptin-Roche), a recombinant humanised mouse monoclonal antibody directed against HER2, is available as a treatment for certain patients with metastatic breast cancer. It is licensed as a first-line treatment in combination with [symbol: see text] paclitaxel for those whose cancer cells overexpress HER2 and for whom an anthracycline is unsuitable, and as a third-line treatment used alone when treatment with (where appropriate) an anthracycline, a taxane and hormonal therapy has failed. The National Institute for Clinical Excellence (NICE) has recommended trastuzumab as a treatment option for metastatic breast cancer in accordance with the licensed indications. What does trastuzumab offer?