Abstract

Zoledronic acid in Paget\'s disease

Author(s): David Hosking

Paget’s disease is characterized by increased bone turnover, and treatment has been revolutionized by the introduction of bisphosphonates. Zoledronic acid is the latest compound to be introduced into clinical practice. It has increased potency in terms of inhibiting critical enzymes needed for osteoclastic bone resorption. This means that small amounts of the drug can be given as a 15-min intravenous infusion with the potential for improved compliance compared with oral therapy. The strong adherence of this bisphosphonate for hydroxyapatite results in prolonged control of bone turnover/disease activity. Recent clinical trials comparing the effect of a 5-mg infusion of zoledronic acid with oral risedronate 30 mg for 2 months showed rapid control of bone turnover in almost 90% of patients treated intravenously. Control of bone turnover persisted in an (ongoing) extended observation study for up to 24 months after the initiation of treatment. Most patients treated with zoledronic acid experienced little increase from the post-treatment nadir bone turnover. The hope is that the ability to control Paget’s disease in the long term will reduce the risk of long-term complications. It will also facilitate the shift of long-term management from secondary to primary care. The reduced requirement for re-treatment also makes this bisphosphonate a cost-effective drug of first choice for the treatment of Paget’s disease.