Trastuzumab - Use | Dosage | Side Effects
Trastuzumab (HerceptinR) is a type of targeted therapies for breast cancer. Trastuzumab is a monoclonal antibody, which is one type of biological cancer therapy. A monoclonal antibody is an antibody that can be made in large quantities in the laboratory. Antibodies are molecules that naturally produced by our immune system.Naturally, their role is to look for the cell (bacteria and viruses) and kill them. Antibodies made in the laboratory can be designed to look for certain human cells. Trastuzumab target the breast cancer cells. Somewhere between 15 and 25 out of 100 patients with breast cancer is likely to respond to treatment of the medicine. Their cancer cells have a high level of protein, known as erbB2 or HER2Neu. This protein is the receptor of growth factors. It transmits signals from the outside to the interior of the cell, which makes it grow cells. Trastuzumab is attached to a protein receptor and block it so cancer cells can not grow. This medicine, also enhances the effect of chemotherapy medicines on cancer cells.
Mechanism of action
The mechanism of action of trastuzumab is based on binding of antibody to HER2 receptor (which is present in 15-20% of patients). There are four mechanisms of action of medicine against cancer:
- Powered by antibody-dependent cell-mediated cytotoxicity and (ADCC)
- Prevents p95HER2 fragments, which further limits the transmission of signals for malignant transformation.
- It causes downregulation of receptor endocytosis and limiting signal for further growth and division.
- Inhibits HER2 - regulated angiogenesis
Trastuzumab use in early breast cancer
Trastuzumab is recommended as a method for the treatment of women with HER2-positive early breast cancer. Women who are suitable for treatment with trastuzumab intravenously receive every three weeks in one year. Trastuzumab for early breast cancer can be used if:
- The cells were positive for HER2
- After completion of surgery and chemotherapy (and sometimes radiotherapy)
- If the test results are satisfactory heart
- If there is a cardiac disease (congestive heart attack, angina, uncontrolled high blood pressure, evidence of a heart attack on the ECG, arrhythmia, etc..).
In these cases, the treatment is not safe enough. Before you move to the implementation of trastuzumab perform the appropriate tests for the heart, which can perform again every three months during treatment with trastuzumab. If the during the use of trastuzumab occurs cardiac arrhythmia, the treatment should be discontinued.
Application and adverse reactions
Trastuzumab is administered intravenously dropwise during 30 to 60 minutes. Early breast cancer therapy is recommended every three weeks. For advanced breast cancer trastuzumab is administered once weekly.
The most severe side effect of trastuzumab is cardiotoxicity. Therefore, it is imperative that patients have a heart examination every three months during treatment. Other common adverse events were fatigue, light allergic reactions like itching, fever, shortness of breath, nausea, diarrhea and pain.
The form and terms of storage
Trastuzumab is used as a powder for the concentrate for solution for infusion. Trastuzumab is a white to pale yellow powder. It is kept in the refrigerator at 2-8C.
Trastuzumab is dosed as follows:
- 2 mg / kg / week (the first dose of 4 mg / kg)
- 6 mg / kg / week 3 (the first dose of 8 mg / kg)