Inclusion Criteria:

- Diagnosis of breast cancer with locally advanced or metastatic (stages IIIB, IIIC or
IV according to TNM classification), confirmed histologically with no intention to
curative treatment by radiotherapy or surgery;

- Clinical or radiological progression after one or two lines of previous hormone
treatment, including adjuvant treatment;

- Positive for ER and / or PR expression documented by IHC;

- Confirmed expression of Lewis Y antigen by IHC;

- Presenting the performance status of 0 or 1 according to Eastern Cooperative Oncology
Group (ECOG);

- Have a measurable or evaluable disease by Response of Evaluation Criteria in Solid
Tumors (RECIST);

- Adequate organ function, assessed by laboratory tests obtained at least 2 weeks
before the first day of treatment and within the following parameters:

absolute neutrophil count ≥ 1.5 x 109 / L; platelet count ≥ 100 x 109 / L; serum bilirubin
≤ 2.0 mg / dL; AST/ALT ≤ 2.5 x upper limit of normal; serum creatinine ≤ 2.0 mg / dL;

- Expected survival > 12 weeks;

- In patients with childbearing potential: Negative pregnancy confirmed by test done 21
days before the date of study treatment initiation;

- Willingness and ability to comply with the protocol for the duration of the study.

Exclusion Criteria:

- Patients subjected previously to more than two lines of hormonal therapy, including
adjuvant treatment;

- Presenting the amplification or overexpression of HER-2;

- Systemic corticosteroids or immunosuppressive agents used concomitantly with the
study or have used systemic corticosteroids or immunosuppressants in the last 14 days
before the first dose of the investigational drug;

- Visceral metastatic disease with life-threatening (as defined by extensive liver
involvement), or symptomatic pulmonary lymphangitic carcinomatosis or any degree of
cerebral or leptomeningeal involvement;

- Previous or current history of clinically significant cardiac disease (class III or
IV according to New York Heart Association);

- Clinically significant arrhythmia;

- History of myocardial infarction within the last 6 months;

- Previous or current history of other severe diseases (eg, severe ascites requiring
repeated drainage, active infections requiring antibiotics, bleeding, inflammatory
bowel disease or chronic diseases that may interfere with obtaining accurate results
of the study);

- Previous chemotherapy for metastatic disease (adjuvant chemotherapy is acceptable, if
more than four weeks between its completion and inclusion in the study;

- Radiotherapy within 4 weeks before inclusion in the study or with no recovery from
the toxic effects of radiotherapy when done up to 6 weeks before inclusion in the
study, except for palliative radiotherapy for bone metastases involving <25 % bone
marrow;

- Treatment with biological agents, immunotherapy or surgery within 4 weeks before
inclusion in the study or with no recovery from the toxic effects of these treatments
when made until six weeks prior to study entry (prior treatment with bisphosphonates
is allowed, it can be continued after inclusion in the study);

- Any investigational agent treatment within 12 months prior to study entry, unless the
investigator considers that the participation in the study may benefit the patient;

- Previous or current history of another type of tumor, excluding skin cancer,
melanoma, in situ cervix carcinoma or in situ ductal carcinoma or lobular breast if
properly treated;

- Uncontrolled hypercalcemia (defined as total calcium> 11.5 mg / dL)