The purpose of this trial with Zometa is to investigate the effect ZOMETA 4 mg (zoledronic acid for injection in 100mg solution ) has in preventing associated bone loss in prostate cancer patients with bone metastasis when administered in conjunction with hormonal cancer therapy. This trial will seek to determine the effect of ZOMETA in stabilizing and increasing bone mineral density in these patients.

This prospective, open-label, single arm, multicenter study will enroll approximately 200 prostate cancer patients with a history of at least one documented bone lesion documented by bone scan or radiograph. Patients must already be receiving hormone therapy and meet the following additional criteria:

• 18 years of age or older
• Histologically confirmed diagnoses of prostate cancer
• Confirmed objective evidence of metastatic bone disease as evidenced by bone scan or radiograph
• Received or will receive hormonal treatment also know as androgen deprivation therapy with an LHRH agonist or other hormonal treatments

Throughout the course of this 12-month trial, patients will be identified based on the duration of established hormonal treatment at the time of enrollment. Each patients duration of participation will be up to 56 weeks including a 4 week screening, 48 week treatment and a 4 week follow up.

Inclusion criteria:

• Signed informed consent
• Age > 18 years
• Histologically confirmed diagnosis of carcinoma of the prostate
• Objective evidence of metastatic disease to the bone as evidenced by bone scan or radiograph at any point since their diagnosis of prostate cancer
• Currently receiving, or will begin receiving, hormonal therapy with an LHRH agonist or other hormonal treatments for either < 6 months or > 6 months
• ECOG performance status of 0, 1, or 2

Exclusion criteria:

• Patients who are hormone sensitive without metastatic disease to the bone
• Patients who are hormone refractory typically defined as two or three consecutive increases in PSA measured at least one month apart while on hormone therapy
• Patients who are not treated with LHRH agonist or other hormonal treatments
• Patients who are currently receiving diethylstilbestrol (DES) or PC-SPES
• Patients with another nonmalignant disease which would confound the evaluation of primary endpoints or prevent the patient complying with the protocol.
• Patients with abnormal renal function as evidenced by either a serum creatinine greater than 2 mg/dL 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)