Trastuzumab
Indications
Trastuzumab is used to treat breast cancer and advanced stomach (gastric) cancer in which the cancer cells make too much of a protein called HER2 (HER2-positive). It may be used before or after surgery for early breast cancer, or for cancer that has spread, often together with chemotherapy or other cancer medicines.
How It Works
Trastuzumab is a monoclonal antibody, a laboratory-made protein that attaches to the HER2 protein on the surface of cancer cells. This blocks growth signals and helps the immune system recognise and destroy the cancer cells.
Dosage and Administration
Trastuzumab is given by a doctor or nurse in hospital, usually as a drip into a vein (intravenous infusion), and some forms are given as an injection under the skin. The dose depends on body weight and the treatment plan and is given as prescribed, commonly every 1 or 3 weeks. The first infusion is given slowly and you will be watched for reactions. HER2 testing must confirm the cancer is HER2-positive before treatment.
Interactions
Using Trastuzumab with, or soon after, anthracycline chemotherapy such as Doxorubicin or Epirubicin increases the risk of heart damage, so doctors plan the timing carefully. Tell your doctor about all medicines you take.
Contraindications
Do not use if you are allergic to Trastuzumab or to mouse or hamster proteins, or if you have severe breathing difficulty at rest due to advanced cancer or other lung problems.
Side Effects
Common side effects include infusion reactions (fever, chills, shivering), tiredness, headache, diarrhoea, nausea, muscle or joint pain, rash, sore mouth, cough, and lower blood counts when combined with chemotherapy. Trastuzumab can weaken the heart muscle.
Get urgent medical help if you have breathlessness, swelling of the legs or ankles, a fast or irregular heartbeat, chest pain, wheezing, swelling of the face or throat, or a severe reaction during or after an infusion.
Pregnancy and Lactation
Trastuzumab can harm an unborn baby, including by reducing the fluid around the baby. Use effective contraception during treatment and for 7 months after the last dose. Do not breastfeed during treatment and for 7 months afterwards unless your doctor advises otherwise.
Precautions and Warnings
Your heart function is checked with a scan (echocardiogram or MUGA) before and regularly during treatment. Tell your doctor if you have heart disease, high blood pressure or lung problems. Different Trastuzumab products (including biosimilars and the form for under-the-skin use) are not automatically interchangeable; your doctor will choose one.
Overdose
Overdose is unlikely as it is given in hospital. If too much is given, you will be monitored and treated for any symptoms.
Therapeutic Class
Antineoplastic, monoclonal antibody (anti-HER2).
Storage
Store in a refrigerator at 2 to 8°C, do not freeze, keep in the original pack and away from light. In hospital it is stored and prepared as directed on the pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.
All brands of Trastuzumab