Inclusion Criteria:

- Female patients, >/= 18 years of age

- Locally recurrent/metastatic breast cancer (relapse in supra- or infraclavicular
lymph nodes is regarded as metastatic disease)

- HER2-positive primary disease

- Patients must have received Herceptin in the adjuvant and/or neoadjuvant setting

- Relapsed breast cancer >/= 6 months after discontinuing last drugs of Herceptin
and/or chemotherapy in the adjuvant and/or neoadjuvant setting for HER2-positive
breast cancer

- Measurable disease according to RECIST 1.0

- Eastern Cooperative Oncology Group (ECOG) performance status 0-2

- Maximum cumulative dose of doxorubicin or no prior anthracyclines

- At least 3 weeks after prior surgery or radiotherapy

Exclusion Criteria:

- Pregnant or breastfeeding women

- Previous chemotherapy for metastatic breast cancer (prior endocrine therapy till
progressive disease is allowed)

- Pleural effusions, ascites or bone lesions as only manifestation of disease

- Brain metastases

- Invasive malignancy other than metastatic breast cancer

- Inadequate bone marrow, hepatic or renal function

- Prior treatment with anti-HER therapies other than (neo)adjuvant Herceptin