Why are HER2 antibody drugs used in HER2-targeted therapy?

HER2 is a protein on the surface of some cancer cells. When there is a high amount of HER2 or strong HER2 signalling, the cells may receive messages that support growth. Antibody drugs are designed to recognise and attach to this protein, making treatment more directed than medicines that act on cells without using a specific marker.

Depending on the drug, attachment can interrupt HER2 signalling, encourage immune cells to recognise the cancer cell, or help deliver another cancer medicine to the cell. Testing a tissue sample determines whether HER2 is present at a level that makes this treatment relevant. HER2 testing and the treatment choice are reviewed with the cancer type, stage, and previous therapy.

Before treatment, give the team your medicine list and mention heart disease, breathing problems, allergies, pregnancy or possible pregnancy, and previous cancer treatments. Keep scheduled infusions and monitoring visits. Tell the team about fever, diarrhoea, rash, shortness of breath, swelling, unusual tiredness, or changes in exercise tolerance; several side effects can be treated more effectively when reported early.

Seek urgent medical help for sudden breathing difficulty, chest pain, fainting, facial or throat swelling, or a severe infusion reaction. Contact the oncology team promptly for a new persistent cough, worsening breathlessness, ankle swelling, or a fast or irregular heartbeat. These symptoms can signal a reaction or effects on the heart or lungs and should not wait for the next appointment.

Ask how your HER2 result was measured, which antibody drug is planned, and whether it will be combined with chemotherapy or another targeted medicine. Discuss heart monitoring, infusion reactions, fertility and pregnancy planning, and how the team will judge whether the treatment is helping.