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.

Inclusion criteria

• Must have a histologic diagnosis of adenocarcinoma of the prostate.
• For patients without clinical metastasis treated by surgery, serum PSA values must be > 0.2 ng/ml by two measurements at least two weeks apart. In patients treated with ablative radiation therapy without clinical metastasis, three consecutive increases in serum PSA must be documented, with at least a one-month interval between values with the final PSA > 2ng/m as evidence of biochemical PSA failure. P
• Patients who have not had prior primary therapy such as radiation or surgery, are required to have a detectable PSA of at least 0.2 ng/ml.
• Patients with evidence of metastatic disease are eligible irrespective of serum PSA level.
• Prior history of a second malignancy is allowed if treated with curative intent and patient has been free of disease greater than five years
• ECOG performance status of < 2.

Exclusion criteria

• Prior treatment with a GnRH analogue or anti-androgen.
• Evidence of immunosuppression or have been treated with immunosuppressive therapy, such as chemotherapy, chronic treatment dose corticosteroids, or radiation therapy to bones, within 6 months of study enrollment
• Current or treatment within 4 weeks with estrogen or estrogenic agents (including herbal compound PC-SPES)
• Current or treatment within 4 weeks with herbal compounds for prostate cancer such as PC-SPES or saw palmetto
• Current or treatment within 4 weeks with megestrol
• Current or prior treatment with a bisphosphonate, calcitonin, or other bone resorptive/anabolic agents
• Current use of oral corticosteroids or any such use within the past 6 months
• Current use of potentially bone-toxic anticonvulsants (phenytoin, or carbamazepine)
• History of orchiectomy
• Hypocalcemia