Recombinant DNA-derived humanized monoclonal antibody that selectively binds with high affinity to the human epidermal growth factor receptor 2 protein, HER2.

The recommended initial loading dose of trastuzumab is 4 mg/kg administered as a 90-minute infusion.

The recommended weekly maintenance dose of trastuzumab is 2 mg/kg and can be administered as a 30-minute infusion if the initial loading dose was well tolerated.

Indicated as a single agent for the treatment of patients with metastatic breast cancer whose tumors overexpress the HER2 protein and who have received one or more chemotherapy regimens for their metastatic disease; indicated in combination with paclitaxel for treatment of patients with metastatic breast cancer whose tumors overexpress the HER2 protein and who have not received chemotherapy for their metastatic disease.

Approved as part of a treatment regimen containing doxorubicin, cyclophosphamide, and paclitaxel for the adjuvant treatment of women with node-positive, HER2-overexpressing breast cancer.

Chills, fever, nausea, vomiting, pain at tumor site, severe hypersensitivity reaction, and cardiac toxicity.

During the first infusion with trastuzumab, a symptom complex most commonly consisting of chills and/or fever was observed in about 40% of patients in clinical trials. The symptoms were usually mild to moderate in severity and were treated with acetaminophen, diphenhydramine, and meperidine (with or without reduction in the rate of trastuzumab infusion).

Do not administer by IV push or bolus.

Do not freeze reconstituted product.

Cardiac assessment is required pretreatment.