Trastuzumab deruxtecan in HER2-mutant non-small cell lung cancer

HER2 is a protein involved in cell signals. A mutation in the HER2 gene can help some lung cancer cells grow. Trastuzumab deruxtecan combines an antibody that recognises HER2 with a chemotherapy medicine. After binding to a cancer cell, it can carry the medicine into that cell. This is different from immunotherapy, which helps the immune system recognise or attack cancer cells.

Your team may review the tumour biopsy or another validated sample to confirm the HER2 change and assess whether this medicine fits your cancer, previous treatments, general health and treatment goals.

Treatment is given by infusion at a cancer centre. Before and during treatment, your team may check blood counts, liver function, heart health and breathing symptoms. Tell them about lung disease, heart problems, pregnancy plans, medicines and previous reactions to infusions.

Possible effects include nausea, tiredness, reduced appetite, low blood counts, hair changes and infusion reactions. Anti-sickness medicines can help. Do not start a supplement or new medicine without checking its compatibility with your oncology team. Other options may include targeted therapy, immunotherapy, radiotherapy or surgery, depending on where the cancer is and how it behaves.

Contact your cancer team promptly for new or worsening cough, shortness of breath, chest discomfort, fever, severe weakness, unusual bleeding or signs of an infusion reaction. Breathlessness can signal inflammation in the lungs and needs urgent assessment. Seek emergency help for severe breathing difficulty, fainting, confusion or swelling of the face or throat.

Ask which HER2 test confirmed the mutation, why this treatment is being recommended, how infusion visits will work, which symptoms should be reported the same day, and how response will be assessed. You can also ask whether [Targeted Therapy](/treatments/systemic-therapy/targeted-therapy/) or [Immunotherapy](/treatments/systemic-therapy/immunotherapy/) has a role, and whether [Stereotactic Body Radiotherapy](/treatments/radiation-oncology/stereotactic-body-radiotherapy/) or [Lung Lobectomy](/treatments/surgical-oncology/lung-lobectomy/) might be relevant.