The HER2 gene (also known as HER2/neu and ErbB2 gene) is overexpressed in 20-30% of human breast cancers and leads to a particularly aggressive form of the disease. Trastuzumab,a humanized anti-HER2/neu receptor monoclonal antibody, has been proved a valuable treatment for HER2-positive breast cancer patients.The combination of trastuzumab with chemotherapy has been shown to increase both survival and response rate, in comparison to trastuzumab alone. CMAB302, a biosimilar of trastuzumab, was developed by Shanghai CP Guojian Pharmaceutical Co.Ltd. Efficacy and safety of CMAB302 as a single agent or in combination with vinorelbine were evaluated in patients with HER2-overexpressing metastatic breast cancer.

The HER2 gene (also known as HER2/neu and ErbB2 gene) is overexpressed in 20-30% of human breast cancers and leads to a particularly aggressive form of the disease. Trastuzumab,a humanized anti-HER2/neu receptor monoclonal antibody, has been proved valuable treatment for HER2-positive breast cancer patients.The combination of trastuzumab with chemotherapy has been shown to increase both survival and response rate, in comparison to trastuzumab alone. CMAB302, a biosimilar of trastuzumab, was developed by Shanghai CP Guojian Pharmaceutical Co.Ltd. Previous Phase I study showed that CMAB302 was well tolerated as monotherapy and the pharmacokinetic data exhibited a non-linear profile over the dose range of 100 to 500 mg, similar to that of trastuzumab. In this study, efficacy and safety of CMAB302 as a single agent or in combination with vinorelbine were evaluated in patients with HER2-overexpressing metastatic breast cancer.

Inclusion Criteria:

• pathologic diagnosis breast cancer
• HER2+ status defined as IHC3+ Staining or in situ hybridization positive at least 1 measurable lesion as per RECIST criteria
• Adequate bone marrow function (absolute neutrophil count >1500/mm3, platelet count >100.000/mm3, hemoglobin >10gr/mm3)
• Adequate liver (bilirubin <1.0 times upper limit of normal and SGOT/SGPT <2.5 times upper limit of normal) and renal function (creatinine <1.5mg/dl)
• Adequate cardiac function (LVEF>50%). Normal electrocardiogram and absence of significant heart disease
• age from 18 to 70y
• Karnofsky performance score ≥ 60
• Life expectancy of greater than 3 months
• Negative HCG pregnancy test for premenopausal women of reproductive capacity and for women less than 12 months after the menopause.
• signed ICF

Exclusion Criteria:

• prior exposure vinorelbine for breast cancer
• prior exposure trastuzumab for breast cancer
• Prior chemotherapy and radiation therapy within the last 4 weeks before enrollment
• use of any other investigational agents within the last 4 weeks before enrollment
• symptomatic, central nervous system metastases
• Hypersensitivity to trial medications
• breastfeeding or pregnant