Inclusion Criteria

Inclusion Criteria (major highlights):

- Patient is an adult female with histologically or cytologically confirmed carcinoma
of the breast for whom single-agent cytotoxic chemotherapy is indicated

- Patient can have either measurable or non-measurable disease by RECIST.

- Patient has received prior therapy (administered in the neoadjuvant, adjuvant and/or
metastatic setting) with an anthracycline, a taxane and capecitabine

- Patient has minimum of 2 and a maximum of 5 prior cytotoxic chemotherapy regimens
with the last dose administered within 6 months. A minimum of two chemotherapy
regimens had to be for locally recurrent and/or metastatic disease. All therapy
received prior to a diagnosis of metastatic disease (eg, neoadjuvant, adjuvant or
repeated adjuvant therapy following a second resection) is counted as one regimen.

- Patient has Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

- Adequate hematopoietic, liver and kidney functions.

Exclusion Criteria (major highlights):

- Patient with chemotherapy within 21 days, radiotherapy within 14 days, biological
therapy with 14 days, hormonal therapy within 7 days and investigational therapy
within 21 days prior to randomization.

- Patient with any major surgery within 28 days prior to randomization.

- Patient with concurrent use of biologic agents for the treatment of cancer including
antibodies or any investigational agent(s).

- Patient with prior treatment for cancer with a camptothecin derivative.

- Patient with chronic or acute GI disorders resulting in diarrhea of any severity
grade; patients who are using chronic anti-diarrheal supportive care to control
diarrhea in the 28 days prior to randomization.

- Patient received pharmacotherapy for hepatitis B or C, tuberculosis or HIV.

- Patient with known cirrhosis diagnosed with Child-PUGH Class A or higher liver
disease.

- Patient with prior malignancy (other than breast cancer) except for non-melanoma skin
cancer and carcinoma in situ (of the cervix or bladder), unless diagnosed and
definitively treated more than 5 years prior to randomization.

- Patient requiring daily use of oxygen supplementation in the 28 days prior to
randomization.

- Patients with significant cardiovascular impairment.