The purpose of the study is to examine the safety and effectiveness of the drug combination of Myocet, paclitaxel and trastuzumab compared to paclitaxel and trastuzumab without Myocet, as first line treatment for patients with metastatic HER2+ breast cancer.

Inclusion Criteria:

• Metastatic Her2+ Breast cancer by FISH analysis
• No prior chemotherapy for metastatic disease
• Measurable disease
• normal left ventricular ejection fraction

Exclusion Criteria:

• prior doxorubicin treatment exceeding 300 mg/m2 or epirubicin exceeding 600 mg/m2
• relapse within 12 months of completion of adjuvant trastuzumab, taxane or anthracycline therapy