This Study is to Assess the Efficacy and Safety of ZD6474 in Subjects With Metastatic Breast Cancer

Inclusion Criteria:

* Histological and/or cytological confirmation of metastatic breast cancer which is refractory to anthracycline, taxane, with or without capecitabine therapies;
* WHO performance status 0, 1 or 2 on the day of registration;
* Females, aged \>= 18 years;
* No Gastrointestinal pathology which could affect the bioavailability of ZD6474.

Exclusion Criteria:

* Any evidence of severe or uncontrolled systemic diseases including known cases of Hepatitis B or C or human immunodeficiency virus (HIV).
* Significant cardiac event (including symptomatic heart failure or unstable angina) within 3 months of entry or any cardiac disease that in the opinion of the investigator increases risk for ventricular arrhythmia;
* History of clinically significant cardiac arrhythmia (multifocal PVCs, bigeminy, trigeminy, ventricular tachycardia), which is symptomatic or requires treatment (CTC grade 3) or asymptomatic sustained ventricular tachycardia;
* Chronic atrial fibrillation;
* Previous history of QT / QTc prolongation with other medication;
* Congenital long QT syndrome;
* Systemic anti-cancer therapy or other investigational agent within the last 4 weeks (6 weeks for nitrosoureas, mitomycin C, or suramin);
* Currently receiving drugs with known significant 3A4 inhibitory (ie, ketoconazole, itraconazole, troleandomycin, erythromycin, diltiazem, verapamil) or stimulatory (ie, phenytoin, carbamazepine, barbiturates, rifampicin) effects;
* Currently receiving therapeutic doses of warfarin (Coumadin?)