The purpose of this study is to assess the efficacy and tolerability of zoledronic acid in preventing skeletal-related events in patients with prostate cancer

Inclusion Criteria:

• Written informed consent must be obtained
• Age > 18 years
• Histologically confirmed diagnosis of carcinoma of the prostate
• Current (or previous) objective evidence of metastatic disease to the bone
• Currently receiving 1st line hormonal therapy with LHRH agonists or other hormonal treatments
• ECOG performance status of 0, 1, or 2

Exclusion Criteria:

• Patients with abnormal renal function as evidenced by either a serum creatinine determination 1.5 x or greater above the upper limit of normal or by a calculated creatinine clearance of 60 ml/minute or less
• Corrected (adjusted for serum albumin) serum calcium concentration < 8.0 mg/dl (2.00 mmol/L)
• WBC<3.0x1'000'000'000, ANC < 1500/mm3, Hgb<8.0 g/dL, platelets < 75 x 1'000'000'000/L.
• Liver function tests >2.5 ULN, serum creatinine >1.5 ULN.
• Patients with another nonmalignant disease which would confound the evaluation of primary endpoints or prevent the patient complying with the protocol.
• Known hypersensitivity to zoledronic acid or other bisphosphonates
• Subjects who, in the opinion of the investigator, are unlikely to cooperate fully during the study

Other protocol-defined inclusion / exclusion criteria apply.