Inclusion Criteria:

- Patients older than 18 years and less than 80 years

- Histologically-proven adenocarcinoma of the prostate

- Evidence of bone metastases and progressive, hormone-refractory, disease

- No previous chemotherapy

- No previous radiotherapy, except radiotherapy directed to the prostate and/or to a
single bony lesion

- No previous carcinoma, except basal-cell carcinoma of the skin

- Adequate renal function: measured or calculated creatinine clearance > 60 ml/min

- Absolute granulocyte count ≥ 1,500/mm3, platelets ≥ 100,000 mm3, bilirubin ≤ 1.5 fold
the upper normal value

- Signed informed consent.

Exclusion Criteria:

- Patients infected by the Human Immunodeficiency Virus (HIV)

- Patients who do not fit inclusion criteria