Window Study of ZD4054 in Metastatic Prostate Cancer

This is a prospective study in which patients with castrate-resistant prostate cancer and bone metastases will undergo imaging, donate blood, bone marrow and urine samples, and where possible primary tumour and bone metastatic tissue, before and during treatment with ZD4054, an orally active specific endothelin-A antagonist. The samples will be used primarily for biomarker studies, and it is hypothesized that these will inform on the mechanism of action of this drug. Magnetic Resonance Imaging (MRI) will be performed to evaluate emerging functional imaging endpoints as markers of early response in bone metastatic prostate cancer.