Study of Samarium Sm-153 Lexidronam Combined With Docetaxel for Patients With Prostate Cancer

Inclusion Criteria: * Have histological evidence of adenocarcinoma of the prostate. * Have progressive castrate metastatic disease. * Castrate levels of testosterone (\<50 ng/ml). Treatment to maintain castrate levels of testosterone must be continued. * Must have evidence of at least 3 bone metastases on bone scan. * Patients for whom initial hormone treatment (exclusive of neoadjuvant hormone therapy) was a combined androgen blockade approach, must show progression of disease following withdrawal of the anti-androgen prior to enrollment. * Patients undergoing prior bisphosphonate treatments are eligible. * Patients who have received one prior treatment with 153Sm lexidronam or 89Sr are eligible provided it is at least 12 weeks from treatment with 153Sm lexidronam or 24 weeks from treatment with 89Sr. * Life expectancy of at least 12 weeks (based on co-morbidity). * KPS\>60. * Lab requirements: * White Blood Count (WBC) ≥ 3,000/mm3; * Absolute Neutrophil Count (ANC) ≥ 1,500/ mm3; * Platelet (PLT) ≥ 100,000/mm3; * Hemoglobin (HGB) ≥ 10 mg/dl; * Bilirubin ≤ 2.0 mg/dl; * ALT/AST≤ 3 times the upper limit of normal; * Serum creatinine ≤ 2.0 mg/dl. * Patients must sign an informed consent. Exclusion Criteria: * Patients with small cell carcinoma. * Patients with predominant visceral metastases (\>3 lung or liver lesions) or symptomatic lymphadenopathy (scrotal or pedal edema). * Patients who have received more than one course of external beam radiation therapy directed at bone lesions. * Clinically significant cardiac disease (New York Heart Association Class III/IV). * History of other malignancies (other than non-melanoma skin cancer), unless in complete remission or off therapy for that disease for at least five years. * Have or are participating in a research study protocol or clinical trial protocol within 30 days of the date of the baseline visit.