An Open-label Phase II Study With SUTENT in Patients Suffering From Hormone Refractory Prostate Cancer

* Antitumor efficacy of sunitinib will be assessed as follows: * PSA response rate and PSA progression according Working Group Criteria, * Variation of PSA doubling time (PSADT) before and after initiation of the treatment, * Objective response rate (ORR) according to RECIST criteria, * Clinical benefit, * Overall survival (OS). * Pharmacokinetic endpoints will include sunitinib and its metabolite, SU012662, plasma levels and estimation of the population pharmacokinetic parameters as well as the inter-individual variability of these parameters, for a subgroup of 30 patients. * The biological effects of sunitinib in patients with metastatic prostate carcinoma will be evaluated by measurements of the different biological markers that could be modulated by this antiangiogenic therapeutic, and could then predict and monitor disease progression and response to treatment: * Bone tumor markers: bone resorption markers (uCTX, uCTX, ICTP, CTX-MMP and TRACP-5b), bone formation markers (OC, PINP and BALP), osteoclastogenesis markers (OPG and RANKL) and parameters as calcium, phosphate, creatinine, albumin, PTH and 25(OH)D. * Angiogenesis markers: bFGF, SDF-1, VEGF-A, VEGFR1 and VEGFR2, CECs and CEPs, endothelial and platelet microparticles.