Improvement of pagetic bone lesions with risedronate treatment: A radiologic study

Risedronate is a potent pyridinyl bisphosphonate in clinical development fo r treatment and prevention of osteoporosis, and has been recently approved for treatment of Paget's disease in the United States. An open-label study was conducted to determine the effect of risedronate treatment on pagetic b one lesions in patients with moderate to severe Paget's disease (mean serum alkaline phosphatase levels [ALP] approximately seven times the upper limi t of normal), Patients were treated with 30 mg/day oral risedronate for 84 days followed by a 112-day nontreatment period. This 196-day cycle was repe ated once in patients whose ALP did not normalize or who experienced relaps e, defined as a greater than or equal to 25% increase in ALP from the lon e st value measured. Radiographs of affected anatomical sites in 26 patients were collected at baseline, 6 months, and/or 12 months, Eleven patients rec eived one course and 15 patients received two courses of treatment. Radiogr aphs were examined by a skeletal radiologist who was blinded to their time sequence. Changes in pagetic lesions mere categorized as "improved," "deter iorated," or "no change." Between baseline and 6 months, 16 patients improv ed and 3 deteriorated; at 12 months, 11 patients improved and 2 deteriorate d. Most lesions remained unchanged between 6 and 12 months, Improvements we re noted in all skeletal sites (tibia, femur, humerus, forearm, pelvis, spi ne, and skull), but were most pronounced in weight-bearing long bones, In w eight-bearing bones, nine lesions had osteolytic fronts, Of these, seven im proved and two remained unchanged at 6 months; at 12 months, all but one le sion (which improved) remained unchanged. This radiographic assessment demo nstrates that oral risedronate, 30 mg/day in one or two 3-month courses, is highly effective for improving bone lesions in patients with Paget's disea se. Risedronate treatment had no deleterious effect on osteolytic lesions i n weight-bearing bones; indeed, the majority of lesions with osteolytic fro nts were improved after 6 months of risedronate treatment. (C) 2000 by Else vier Science Inc. All rights reserved.