HER2 Antibody Drugs: How Targeted Treatment Works

HER2 antibody drugs are laboratory-made proteins designed to recognise a particular protein on, or near, a cancer cell. HER2 can send growth signals when present or active in excess. An antibody may block those signals, mark cells for immune attack, or interfere with the way HER2 receives messages. The exact action depends on the medicine and the cancer's test results.

These medicines are targeted, but they do not affect only cancer cells. HER2 is also found in some normal tissues, so treatment can affect healthy organs. Some antibodies are given through a vein, while others may be given under the skin. Testing of tumour tissue or another sample helps determine whether HER2-directed treatment is appropriate.

HER2-directed antibodies may be used for selected breast, stomach or gastro-oesophageal cancers, and other cancers when testing shows a relevant HER2 finding. They can be used before surgery, after surgery, for advanced disease or with other medicines, depending on the clinical plan. A pathology report helps the team match treatment to the tumour's biology.

Depending on the tumour, alternatives may include chemotherapy, hormone therapy, immunotherapy, another HER2-directed medicine, radiation or surgery. These approaches work through different mechanisms and may be combined. The choice is shaped by biomarker results, previous treatments, the location of disease, symptoms and how your body is coping.

Treatment is given on a planned schedule, with the route and setting depending on the medicine. Infusion-related symptoms can occur during or soon after some intravenous doses, so the team may observe you. Tell staff about breathlessness, swelling, palpitations, new cough or marked fatigue. These symptoms can have several causes, but they deserve timely assessment during HER2 treatment.

Your oncology team may check heart function before and during treatment because some HER2 medicines can affect the heart's pumping ability. They may also review blood tests, symptoms and any reactions around treatment. Keep a record of new symptoms and medicines, and discuss pregnancy or breastfeeding before therapy begins. The team will explain when to seek urgent help and how follow-up is arranged.