Targeted therapy drugs interfere with signals that tell the cancer cells to grow. Some drugs also stop the cancer from developing new blood vessels. There are different types that work in slightly different ways. Targeted therapies are sometimes called biological therapies.
You usually have targeted therapy drugs with chemotherapy. They are also occasionally given with hormonal therapy.
Trastuzumab (Herceptin®) is the only targeted therapy drug widely available through the NHS to treat secondary breast cancer. Even if you have had treatment with trastuzumab previously, your cancer doctor may still recommend further treatment with it. This usually depends on how long ago you had it.
Trastuzumab and other targeted therapy drugs are sometimes given in clinical trials.