Phase II Study of Cabazitaxel as 2nd Line Treatment in Patients With HER-2 Negative Metastatic Breast Cancer Previously Treated With Taxanes

• Written informed consent

• Female patients aged 18 to 75 years

• Patients must have received 1st-line chemotherapy for locally recurrent / metastatic disease

• Prior taxane-containing treatment (paclitaxel, docetaxel or nab-paclitaxel), either for advanced disease or as neoadjuvant/adjuvant chemotherapy. In case of early relapse (relapse during neoadjuvant/adjuvant chemotherapy or disease-free interval less than 6 months), neoadjuvant/adjuvant chemotherapy will be considered as 1st-line treatment

• Diagnosis of HER-2 negative (HER-2 \<2+ by immunohistochemistry and/or FISH or CISH negative) metastatic breast adenocarcinoma confirmed by the pathology department of the enrolling institution

• Eastern Cooperative Oncology Group performance status (PS) of 0-1

• Life expectancy of at least 12 weeks

• Measurable disease by the Response Criteria in Solid Tumors 1.1 (RECIST 1.1) method (at least one measurable lesion)

• Laboratory values within the specified ranges within 1 week of study enrolment:

‣ Hemoglobin ≥ 9.0 g/dL

⁃ Absolute neutrophil count of ≥ 1.5 x 10\^9/L

⁃ Thrombocyte count of ≥ 100 x 10\^9/L

⁃ Serum creatinine ≤ 1.5 upper limit of normal (ULN). If creatinine 1.0 - 1.5 x ULN, creatinine clearance will be calculated according to CKD-EPI formula and patients with creatinine clearance \<60 mL/min should be excluded

⁃ SGOT (AST), SGPT (ALT) ≤ 2.5 x ULN and alkaline phosphatase ≤ 2.5 x ULN, total bilirubin ≤ ULN (the same limits also refer to patients with liver metastases)

• Previous treatment for loco-regional disease is allowed, including surgical procedures or palliative radiotherapy (such treatments must have been completed at least 4 weeks before enrolment)

• Compliance of the patient regarding scheduled visits, treatment plan, laboratory tests and other procedures of the study.

• The enrolment of patients with controlled brain metastases is allowed (metastases that have been treated with radiotherapy and remained stable for at least 4 weeks following the completion of radiation treatment)