Midterm outcome of risedronate therapy for patients with Paget’s disease of bone in the central part of Japan

Although Paget’s disease of bone (PDB) is common in western countries, it is extremely rare in Asian ones including Japan. Recently, oral risedronate (17.5 mg once daily) was approved in Japan as a treatment of PDB besides calcitonin and etidronate. However, there are few data regarding the efficacy of this agent, dose for patients with PDB in Japan, or the durability of its effect. The purpose of this study was to evaluate the midterm outcome of oral risedronate (17.5 mg once daily) for patients with PDB in Japan. Seventeen patients with PDB were treated with risedronate (17.5 mg once daily) for 8 weeks. Efficacy and its durability were accessed based on serum total alkaline phosphatase (ALP) and symptoms. Risedronate effectively suppressed bone turnover evaluated with serum total ALP in all patients. In 8 of 10 patients with bone pain, risedronate reduced the pain. On the other hand, tinnitus and hearing loss did not disappear but somewhat improved. None of the patients suffered severe complications. Seven of 17 patients required readministration of oral bisphosphonate (risedronate, six; alendronate, one) due to elevated total ALP at 27 months (mean ranging from 9 to 39 months) after the initial administration of risedronate. Treatment of oral risedronate (17.5 mg once daily) for 8 weeks is safe and effective for patients with PDB in Japan. However, the durability of its effect is limited in some patients.