Sorafenib in Treating Patients With Metastatic or Recurrent Prostate Cancer

RATIONALE: Sorafenib may stop the growth of tumor cells by blocking the enzymes necessary for their growth. PURPOSE: This phase II trial is studying the effectiveness of sorafenib in treating patients who have metastatic or recurrent prostate cancer that has not responded to previous hormone therapy.

OBJECTIVES: * Determine the efficacy of sorafenib, as measured by prostate-specific antigen response, in patients with metastatic or recurrent hormone-refractory adenocarcinoma of the prostate. Secondary * Determine the objective response rate and duration of response in patients treated with this drug. * Determine the tolerability and toxicity of this drug in these patients. * Determine time to treatment failure and overall survival in patients treated with this drug. * Explore the relationship between measures of ras/raf pathway activation (pERK) and response to treatment in these patients. OUTLINE: This is a non-randomized, multicenter study. Patients receive oral sorafenib twice daily on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients are followed at 4 weeks after going off study treatment and then periodically for survival. Patients with stable or responding disease, when they go off study treatment, are followed every 3 months until relapse or progression. PROJECTED ACCRUAL: Approximately 15-25 patients will be accrued for this study within 12-18 months.