Zoledronic acid (
Zometa), a parenteral
bisphosphonate, is an inhibitor of osteoclast-mediated
bone resorption and is used in the management of patients with
cancer.
Zoledronic acid 4 mg is administered as an
intravenous infusion over 15 minutes. In the treatment of bone
metastases,
zoledronic acid is the first and only
bisphosphonate to demonstrate efficacy in patients with a broad range of tumour types and in
multiple myeloma. In well-designed trials, a single 4 mg dose of
zoledronic acid showed good efficacy in the treatment of patients with hypercalcaemia of
malignancy.
Zoledronic acid 4 mg was superior to
pamidronic acid 90 mg, administered as a 2-hour infusion, as assessed by normalised serum
calcium concentrations 10 days after administration. In conjunction with
antineoplastic therapy,
zoledronic acid was an effective long-term (up to 25 months) treatment for skeletal-related events in patients with bone
metastases associated with
multiple myeloma or solid tumours. In patients with bone
metastases secondary to
breast cancer or bone lesions from myeloma,
zoledronic acid was at least as effective as
pamidronic acid, based on assessments of skeletal-related events 25 months after the start of treatment. In addition, compared with
pamidronic acid, the overall risk of developing skeletal complications, including hypercalcaemia of
malignancy, was significantly reduced in recipients of
zoledronic acid. Compared with
pamidronic acid,
zoledronic acid reduced the risk of patients with
breast cancer developing a skeletal-related event by an additional 20%.
Zoledronic acid was significantly more effective than placebo on most efficacy measures in patients with bone
metastases secondary to other solid tumours (e.g. lung, prostate) and showed sustained efficacy for up to 15 months. Preliminary data indicate that its efficacy in these patients is sustained for up to 24 months. Estimates of the cost effectiveness of
zoledronic acid in the treatment of
prostate cancer were consistent with those of other
bisphosphonates, and cost-effectiveness ratios were within limits considered acceptable economic value.
Zoledronic acid was generally well tolerated, with a tolerability profile similar to that of
pamidronic acid and placebo. As with other
bisphosphonates, deterioration of renal function has occasionally been reported in patients receiving
zoledronic acid and monitoring of serum
creatinine is recommended during treatment. The efficacy of
zoledronic acid is therefore well established in patients with hypercalcaemia of
malignancy and, for up to 25 months, in the treatment of complications arising from metastatic
bone disease in patients with
multiple myeloma or solid tumours. The clinical profile of
zoledronic acid compares favourably with that of
pamidronic acid in patients with
cancer and
zoledronic acid has a more convenient administration schedule with the potential for better compliance. Thus,
zoledronic acid is an effective
bisphosphonate and is positioned to play an important role in the management of advanced
cancer patients with bone
metastases.