A Phase 2 Study of EZN-2208 in Patients With Metastatic Breast Cancer

EZN-2208 will be administered by i.v. infusion weekly for 3 weeks in 4-week cycles. Study
treatment will be continued until evidence of disease progression, unacceptable toxicity, or
withdrawal of the patient's consent for participation in the study.

Approximately 160 patients with previously treated MBC will be enrolled in this study.
Eighty patients in each of two cohorts will be evaluated as follows:

1. AT Cohort - Patients treated with prior anthracycline and taxane as adjuvant or
metastatic therapy; no more than 2 prior chemotherapy regimens for MBC

2. ATX Cohort - Patients treated with prior anthracycline, taxane, and Xeloda®
(capecitabine) as adjuvant or metastatic therapy; no more than 4 prior chemotherapy
regimens for MBC

After discontinuation of study treatment, patients will receive care as considered
appropriate by the investigator. Patients will continue to be followed for disease
progression, subsequent anticancer therapy, and survival for at least 6 months after
enrollment of the last patient in the study