Trastuzumab usage and dosage in the treatment of breast cancer

For the treatment of metastatic breast cancer: Trastuzumab, alone or in combination with paclitaxel, is administered at an initial dose of 4 mg/kg as an intravenous infusion over 90 minutes, followed by 2 mg/kg as an intravenous infusion over 30 minutes once weekly until disease progression. For the treatment of adjuvant breast cancer, a total of 52 weeks of trastuzumab therapy is required, if administered in combination with paclitaxel, docetaxel, or docetaxel/carboplatin, at an initial dose of 4 mg/kg IV over 90 minutes during the first 12 weeks (paclitaxel or docetaxel) or 18 weeks (docetaxel/carboplatin) of chemotherapy, followed by 2 mg/kg IV over 30 minutes weekly. One week after the last weekly dose of trastuzumab, 6 mg/kg of trastuzumab is administered as an intravenous infusion over 30 to 90 minutes every three weeks.