AZD2171 to Treat Prostate Cancer

Background: * AZD2171 (Cediranib) is an oral potent inhibitor of receptor tyrosine kinases which impact vascular endothelial growth factor-A (VEGF). * VEGF appears important in blood vessel formation and disease progression in prostate cancer. * No known effective therapy in patients with progressive androgen-independent prostate cancer after treatment with docetaxel. Objectives: * Primary objective of this study is to determine if AZD2171 is associated with a 30% 6 month probability of progression free survival in patients with metastatic androgen independent prostate cancer (AIPC) as determined by clinical and radiographic criteria. * Secondary objective of this study will be demonstration of biologic effect by the drug in the patient and on the tumor (when possible). Correlative studies will be conducted on serially obtained tissue biopsies and white blood cell collections. * Laboratory correlates will include elucidation of activation of components of the VEGFR2 and angiogenesis pathways and evaluation of endothelial cell adhesion molecules (released by damaged cells) using enzyme-linked immunosorbent assay (ELISA), pharmacogenetic analysis of kinase insert domain receptor (KDR) variants and single nucleotide polymorphisms, and pharmacokinetic characterization of AZD2171 activity. Eligibility: * Metastatic progressive androgen-independent prostate cancer. * Prior treatment with docetaxel. * May not have corrected QT interval (QTc ) greater than 470 msec or greater than 1+ proteinuria on 2 consecutive dipsticks no less than 1 week apart. Design: * Phase II trial with a two stage design. 12 patients enrolled in first cohort, if 2 or more are progression free at 6 months than enroll up to 35 evaluable patients. The ceiling will be set at 37 to allow for inevaluable patients. * Starting dose 20 mg QD (every day) for all patients. * Once two stage design is complete then prednisone 10 mg once per day will be given in combination with AZD2171. The total number of patients will be 23 for this portion of the protocol.