• First-line treatment of metastatic breast cancer (with paclitaxel) that displays overexpression of the human epidermal growth factor receptor 2 (HER2) protein.

• Treatment of HER2–overexpressing metastatic breast cancer (as monotherapy) in patients who have already received other chemotherapy regimens.

• Adjuvant treatment of HER2–overexpressing node positive or node negative breast cancer (to be used alone after multi-modality anthracycline-based therapy or as part of one of the following regimens: doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel; with docetaxel and carboplatin).

• Treatment of HER2–overexpressing metastatic gastric or gastroesophageal adenocarcinoma (with cisplatin and capecitabine or 5–fluorouracil) in patients who have not received prior treatment for metastatic disease.