Zoledronic acid: an advance in tumour bone disease therapy and a new hope for osteoporosis.

The two main therapeutic applications of bisphosphonates are tumour bone disease and osteoporosis. They constitute the standard treatment for cancer hypercalcaemia, and placebo-controlled trials have shown that the prolonged administration of bisphosphonates, such as pamidronate or clodronate, can reduce the frequency of complications from tumour bone disease due to metastatic breast cancer or myeloma by a quarter to one-half. The results obtained with the intravenous route appear to be more impressive and more rapidly obtained than with oral compounds. Both agents can reduce the risk of vertebral, wrist and hip fractures by 30 - 50%, whereas other antiresorptive agents, such as raloxifene (Eli Lilly & Co.) or calcitonin (Unigene Laboratories Inc.), have only been demonstrated to reduce the incidence of vertebral fractures. The short infusion time (4 mg over 15 min) offers a convenient therapy and constitutes the most evident advantage of zoledronic acid, which will improve patients' quality of life. Zoledronic acid has the potential to change the treatment of osteoporosis dramatically.