Efficacy, tolerability, and safety of risedronate in Japanese patients with Paget's disease of bone.

This study evaluated the clinical efficacy of treatment with oral risedronate (17.5 mg once daily) for 8 weeks in 11 Japanese patients with Paget's disease of bone (PDB). Risedronate suppressed the excessive bone turnover associated with PDB and improved several biochemical markers, including serum alkaline phosphatase (ALP), serum bone-specific ALP (BALP), urinary deoxypyridinoline (DPD), and urinary cross-linked N-telopeptide of type 1 collagen (NTX). These markers began to decrease within about 2 weeks after the initiation of treatment in most patients, and the response persisted for up to 40 weeks after the cessation of treatment. Risedronate reduced pain by week 24 in most patients. According to quantitative bone scintigraphy, the lesion with the highest radioisotope (RI) uptake showed a decrease of uptake from 12.7 +/- 6.8 to 6.0 +/- 2.3 (mean +/- SD) in week 24, although each lesion of patients with polyostotic disease had a different scintigraphic response. Overall, risedronate at a dose of 17.5 mg once daily was well tolerated by patients with PDB, even though the dosage was seven times higher than that approved for the treatment of osteoporosis in Japan (2.5 mg once daily). In conclusion, treatment with high-dose risedronate for 8 weeks resulted in clinically significant and sustained improvement of biochemical markers of bone turnover for 48 weeks in patients with PDB, and this improvement was associated with a decrease of RI uptake by Paget's bone lesions and with reduced pain.