Durability of Response to Zoledronate Treatment and Competing Mortality in Paget's Disease of Bone.

There has been a marked secular trend in recent decades toward patients with Paget's disease presenting at a greater age and having less extensive skeletal involvement. Over a similar time frame more potent bisphosphonates with a long duration of effect have been developed, raising the prospect of many patients needing only once in a lifetime treatment. We studied a cohort of 107 patients who had been treated with intravenous zoledronate for the first time at a mean age of 76 years. Sequential measurements of the bone turnover marker procollagen-1 NT-peptide (P1NP) were made for up to 10 years. By 9 years, 64% showed some loss of zoledronate effect (defined as a doubling of P1NP from the nadir value after treatment), but only 14% had a biochemical relapse (defined as a P1NP value >80 μg/L). The mortality rate was substantially greater than the relapse rate-by 10 years more than half the cohort had died (p < 0.0001). We conclude that for the majority of older people with Paget's disease a single intravenous infusion of zoledronate will provide disease suppression for the remainder of their lives.