Zumab

Indications

Trastuzumab (sometimes misspelt Trustuzumab) is a targeted anticancer medicine used to treat HER2-positive breast cancer, both early breast cancer (before or after surgery) and breast cancer that has spread. It is also used for HER2-positive advanced stomach (gastric) or gastro-oesophageal junction cancer. A test on the tumour must first confirm that it is HER2-positive.

How It Works

Trastuzumab is a monoclonal antibody, a laboratory-made protein that attaches to the HER2 receptor on the surface of some cancer cells. HER2 sends signals that make these cells grow and divide. By blocking HER2, Trastuzumab slows cancer growth, and it also marks the cancer cells so the immune system can attack them.

Dosage and Administration

Trastuzumab is given in hospital by a doctor or nurse, either as an infusion into a vein or as an injection under the skin, depending on the product. The dose and schedule (usually every 1 or 3 weeks) are set by the oncologist based on body weight and the treatment plan, and it is often given together with chemotherapy. The intravenous and under-the-skin forms are not interchangeable without the doctor's decision.

Interactions

Giving Trastuzumab together with or soon after anthracycline chemotherapy (such as Doxorubicin or Epirubicin) increases the risk of heart problems, so the doctor plans the timing carefully. Tell the cancer team about all other medicines and supplements you take.

Contraindications

• Allergy to Trastuzumab, to proteins from Chinese hamster cells, or to any ingredient.
• Severe breathlessness at rest caused by advanced cancer or needing oxygen therapy.

Side Effects

Common side effects include infusion reactions (fever, chills, rash, nausea) especially with the first dose, tiredness, diarrhoea, headache, muscle or joint pain, a runny nose and low blood counts when given with chemotherapy. Trastuzumab can weaken the heart muscle.

Tell the doctor or nurse at once, or get urgent medical help, for shortness of breath, swelling of the ankles or legs, rapid weight gain, a fast or irregular heartbeat, chest pain, wheezing, swelling of the face or throat during or after the infusion, or fever with signs of infection.

Pregnancy and Lactation

Trastuzumab can harm the unborn baby, for example by reducing the fluid around the baby. Women who could become pregnant should use effective contraception during treatment and for 7 months after the last dose. Do not breastfeed during treatment and for 7 months after the last dose.

Precautions and Warnings

Heart function is checked with a scan (echocardiogram or MUGA) before starting and regularly during treatment and after. Tell your doctor about heart disease, high blood pressure, previous anthracycline treatment or lung disease. Patients are watched closely during infusions for reactions.

Overdose

Overdose is unlikely because it is given by health professionals. If too much is given, the patient is monitored and given supportive care.

Therapeutic Class

Antineoplastic agent; anti-HER2 monoclonal antibody.

Storage

Store in a refrigerator at 2 to 8°C; do not freeze. Keep in the original carton to protect from light. Hospital use only; as directed on the pack.