Vinorelbine (Oral) Plus Trastuzumab for 1st-line Treatment of HER2/Neu Overexpressing Breast Cancer

Inclusion Criteria: * Histologically proven, metastatic breats cancer. * HER2-neu overexpression (IHC3+ or IHC2+/FISH+) * Written informed consent * no previous therapy with vinorelbine or trastuzumab * Age \* 18 and \* 75 years * Karnofsky-Performance status \> 70% * Life expectance 16 weeks and more * Availability of at least one target lesion according to RECIST-criteria. Target lesions need to be outside of radiation fields. Bone metastases are excluded as indicator leasions * Exclusion of pregnancy and adequte contraception during childbearing age. * Adequate hematological, renal, and hepatic function * Normal cardiac function. LVEF should not be \>10% below normal. * Adequate compliance to perform treatment and subsequent follow-up visits Exclusion Criteria: * Locoregional recurrence of breast cancer only or development of contralateral breast cancer * Pregnancy or lactation * Symptomatic brain- or meningeal metastasis * Concurrent endocrine antitumor therapy * Other malignancies except basal cell cancer of the skin or in-situ carcinoma of the cervix * Peripheral neuropathy \>= NCI CTC Grade 2. * other severel disease which preclude adequate treatment * Participation in a clinical trial within the last 30 days. * Psychological, familial, sociological or geographical conditions which preclude treatment according to the protocol or the planned follow-up