Biological therapies are drugs that recognise and lock onto specific proteins (receptors) that are present in particular cancer cells. There are different types of biological therapies that work in slightly different ways.

Trastuzumab (also known as Herceptin®) is a type of drug known as a monoclonal antibody. It works by binding to particular proteins – HER2 receptors – on the surface of breast cancer cells. This slows down or stops the cancer cells dividing.

Herceptin® can only control a breast cancer if the breast cancer cells have a large number of the HER2 receptors on their surface (see treatment overview). Around 1 in 5 (20%) of women will have a large number of receptors − this is known as being HER2-positive. Your doctor may have your cancer cells tested for HER2 protein.

The National Institute for Health and Clinical Excellence (NICE), recommend that women with secondary (advanced) breast cancer can be given:

• Herceptin® in combination with paclitaxel (Taxol®) chemotherapy. This combination is only given if you haven’t previously been treated with chemotherapy for advanced breast cancer, and if you aren’t suitable to be treated with chemotherapy drugs known as anthracyclines, such as epirubicin and doxorubicin.

• Herceptin® on its own if you have already had at least two different courses of chemotherapy for advanced breast cancer, including an anthracycline chemotherapy and a taxane chemotherapy, such as paclitaxel (Taxol) or docetaxel (Taxotere®). Hormonal therapy should also have been tried if appropriate.

Herceptin® is usually given once every three weeks. It is given as a drip (infusion) into a fine tube (cannula) inserted into a vein.

Lapatinib is a newer type of biological therapy known as a growth inhibitor that is effective against cancers that have large numbers of HER2 receptors on the surface. Growth inhibitors interfere with the way that cancer cells 'communicate' with each other and can affect the cancer’s ability to develop.

Lapatinib is a tablet. It is given in combination with the chemotherapy drug capecitabine (Xeloda®), which is also a tablet. The National Institute for Health and Clinical Excellence (NICE) has not yet recommended the use of lapatinib in the treatment of advanced breast cancer. As a result it may not be possible to get the drug on the NHS.