The bisphosphonate zoledronic acid(Drug information on zoledronic acid) (Zometa) is effective in the treatment of skeletal-related events from bone metastases in prostate cancer patients, according to data presented at the 97th annual meeting of the American Urological Association. Patients with advanced prostate cancer are at high risk for bone complications, including bone pain, pathologic fractures, need for radiation or surgery to bone, and spinal cord compression. This study marks the first time a bisphosphonate has demonstrated efficacy in the treatment of bone metastases in this patient population.
"Bone metastases can result in debilitating pain, fractures, and compression of the spine and are a significant problem for patients with advanced prostate cancer. Until now, there were few effective therapies available for these patients," said Fred Saad, md, associate professor of urology and director of urologic oncology at the Montreal Cancer Institute, University of Montreal. "Zometa represents a significant advance in the overall treatment of advanced prostate cancer patients."
The study was designed to investigate the efficacy of zoledronic acid in patients with bone complications resulting from prostate cancer, particularly with respect to reducing the proportion of patients with skeletal-related events and delaying the time to the first such event. A total of 643 patients who progressed through hormonal therapy with at least one bone metastasis participated in the multicenter, randomized, placebo-controlled trial. The final analysis was based on an evaluation of zoledronic acid, 4 mg in 100 mL of solution, compared to placebo, at an infusion rate of 15 minutes, given every 3 weeks for 15 months.
Improvements Evident at 15 Months
The 15-month data demonstrated that 25% fewer patients taking 4 mg of zoledronic acid experienced any skeletal-related event compared to patients taking placebo (33% vs 44%, P = .021). The data also demonstrated that fewer patients taking zoledronic acid had a pathologic fracture compared to patients taking placebo (13% vs 22%, P = .015).
Patients taking zoledronic acid showed a slower rate of pain progression compared with placebo. All patients experienced a mean increase from baseline in composite Brief Pain Inventory pain scores over time. However, the increases were lower at every time point for patients treated with zoledronic acid compared with placebo (and were statistically significant at months 3 and 9).