Biological and radiological responses to oral etidronate and tiludronate in Paget's disease of bone.

Paget's disease of bone is characterized by a high bone turnover. Therefore, antiresorbing agents such as bisphosphonates are clearly indicated. However, as they accumulate in the pagetic lesions, they could produce some focal defects of bone mineralization. In a double-blind study, we have had the opportunity to compare the effects of tiludronate and of etidronate (both at a fixed dose of 400 mg/day orally) on the radiological changes of 12 patients suffering from Paget's disease of bone. After breaking the code, good agreement was observed between the radiological evaluations and the applied therapy: All positive bone balances were observed in the tiludronate group, except for three questionable densifications in the etidronate group, and the negative bone balances in the etidronate group. This confirms our previous experience with etidronate in Paget's disease when X-ray films of the lesions are followed sequentially during therapy.