Development of an active second-line treatment option for metastatic breast cancer patients previously pre-treated with anthracyclines and taxanes in neoadjuvant, adjuvant or palliative settings. For each randomisation arm, 100 patients will be included. The trial was performed as a 2-stage phase II study according to the optimal design by Simon with overall response rate as the primary objective.

Study Design:

Arm A: Vinorelbine 25 mg/m2 d1,8; Carboplatin AUC=6 d1 q 3 weeks; Arm B: Gemcitabine 1000 mg/m2 d1,8; Carboplatin AUC=6 d1 q 3 weeks;

Inclusion Criteria:

1. Histologically confirmed metastatic breast cancer;
2. All patients were required to give written informed consent;
3. To have received a previous treatment with anthracyclines and taxanes;
4. Previous radiotherapy is allowed, whenever the radiated area is not the only disease location;
5. At least 4 weeks since the last previous antineoplastic treatment;
6. Patients must have recovered from all previous toxicities;
7. Karnofsky Performance status >= 70%;
8. Adequate hematological, renal, cardiac and hepatic function;
9. Life expectancy of at least 12 weeks;
10. Patients able to comply and to receive an adequate follow-up;

Exclusion Criteria:

1. Only bone metastases;
2. Active infection;
3. Previous treatment with one of the study drugs;
4. Application of other cytotoxic chemotherapy;
5. Insufficient renal function (creatinine clearance < 60ml/min);
6. Clinically unstable brain metastasis;
7. Pregnancy or lactation;
8. Other primary malignancies (other than carcinoma-in-situ of the cervix or adequately treated basal cell cancer of the skin);
9. Abnormal liver function (bilirubin > 2.0-fold upper normal limit (UNL); Alanine aminotransferase and aspartate aminotransferase >2.5-fold UNL). In patients with hepatic metastasis, a value of Alanine aminotransferase and aspartate aminotransferase of up to 5-fold UNL is permitted;
10. Males;
11. Second malignancy (except for cervix carcinoma in situ or skin carcinoma - no melanoma- with an adequate treatment). Previous malignancies are allowed if disease-free survival is superior to 5 years, except for renal carcinoma or melanoma;