Zometa on Bone Mineral Density in Prostate Cancer Patients Undergoing Androgen Ablation Therapy

Castration by GnRH agonist therapy with or without androgen antagonists has been a mainstay for advanced prostate cancer. One of the most significant side effects of the use of androgen ablative therapies has been a decrease in bone mineral density, potentially placing patients at greater risk of osteoporosis and bone fractures. It is prudent to anticipate this adverse effect of therapy and to minimize its severity with appropriate and timely pharmacologic intervention. Zometa is a bisphosphonates and bisphosphonates are effective inhibitors of osteoclastic bone resorption. Recent studies have shown that other bisphosphonates were able to reduce the bone loss observed after 24 and 48 weeks of treatment with a GnRH analogue. An unanswered question remains, however, in how frequently these agents should be employed in clinical practice. This is a three-arm randomized trial of Zometa® on bone mineral density in subjects with stage D prostate cancer undergoing androgen ablation therapy. If subjects are enrolled in Arm 1, the GnRH analogue would be administered every 3 months for 1 year. Four milligrams of Zometa® would be administered IV over 15 minutes 7 days prior to beginning androgen deprivation therapy. If subjects are enrolled in Arm 2, the GnRH analogue would be administered every 3 months for one year, and 4 mg of Zometa® would be administered IV over 15 minutes at month 6. If subjects are enrolled in Arm 3, the GnRH analogue is administered every 3 months for 1 year, with 4 mg of Zometa® administered IV over 15 minutes monthly for 6 months, beginning at month 6.