Treatment with tiludronate has a similar effect to risedronate on Paget's disease activity assessed by bone markers...

To compare the effects of tiludronate and risedronate on Paget's disease activity assessed by biochemical markers of bone turnover and quantitative bone scintigraphy.

An open-labeled non-randomized study was performed in 49 patients with Paget's disease who had completed treatment with tiludronate (400 mg/d) for 3 months (28 patients) or risedronate (30 mg/d) for 2 months (21 patients). Biochemical markers of bone turnover, including serum total alkaline phosphatase (TAP), bone alkaline phosphatase (BAP), procollagen type I N propeptide (PINP) and urinary N-terminal cross-linking telopeptide of type I collagen (NTX) were measured at baseline and at 6 and 12 months after the end of treatment. Quantitative bone scintigraphy at baseline and 6 months after the end of treatment was performed in all patients obtaining a scintigraphic activity index (SAI).

At baseline there were no significant differences in disease activity between both groups of patients, since markers of bone turnover as well as SAI were similar in both groups. The effects of tiludronate and risedronate in reducing the biochemical markers of bone turnover were comparable at 6 months (tiludronate vs risedronate: TAP -52% vs -43%; BAP -69% vs -56%; PINP -68% vs -63%; NTX -62% vs -59%) and at 12 months after the end of treatment (tiludronate vs risedronate: TAP -47% vs -36%; BAP -57% vs -46%; PINP -57% vs -52%; NTX -51% vs -52%). The effects of tiludronate and risedronate on SAI were also similar 6 months after the discontinuation of treatment. In addition, the percentage of patients who showed normalized serum TAP levels at 6 months after treatment were similar with both agents (74% with tiludronate and 70% with risedronate).

Tiludronate and risedronate given at the currently recommended dosages induce similar responses in Paget's disease activity.