Remission Over 3 Years in Patients with Paget Disease of Bone Treated with a Single Intravenous Infusion of 5 mg Zoledronic Acid

Using data from the Belgian Paget's Disease Registry of 142 patients treated with a 5 mg intravenous infusion of zoledronic acid, we examined disease remission over 3 years in 98 patients with Paget disease of bone (PDB) seen in routine practice. Median age was 76 years, most patients (60.2 %) were male, and all were Caucasian. Median time since PDB diagnosis was 11.5 years, few patients (5.1 %) had a family history of PDB, and 32.6 % had received prior bisphosphonate and/or other treatments. The most common pagetic locations were pelvis, spine, femur, tibia, and skull. The most common symptoms included pain, impaired mobility, bone deformities, and joint disease: 36.7 % of patients had comorbid osteoarthritis and 16.3 % comorbid osteoporosis. Response rates were 93.3 % at 1 year, 89.5 % at 2 years, and 91.6 % at 3 years, statistically similar to an extension study of the original zoledronic acid trials. Twenty-one patients experienced a relapse over the 3-year period at a median of 20.7 months posttreatment; of these, 13 regained remission by the end of the observation period. Relapse was not associated with osteoarthritis, osteoporosis, or other comorbidities. Safety data were similar to those reported elsewhere. In summary, in this somewhat frailer sample of patients with PDB, effectiveness and safety data were similar to those observed in the original trial populations. These findings, which are the first on the use of zoledronic acid for PDB in routine clinical practice, underscore the therapeutic benefits and relative safety of zoledronic acid in the management of PDB in "real-world'' clinical settings.