Treatment with once-weekly alendronate 70 mg compared with once-weekly risedronate 35 mg in women with postmenopausal osteoporosis: a randomized double-blind study.

UNLABELLED: Once-weekly alendronate 70 mg and once-weekly risedronate 35 mg are indicated for the treatment of postmenopausal osteoporosis. These two agents were compared in a 12-month head-to-head trial. Greater gains in BMD and greater reductions in markers of bone turnover were seen with alendronate compared with risedronate with similar tolerability.

INTRODUCTION: The nitrogen-containing bisphosphonates, alendronate and risedronate, are available in once-weekly (OW) formulations for the treatment of postmenopausal osteoporosis. A 12-month, head-to-head study was performed to compare these agents in the treatment of postmenopausal women with low BMD.

MATERIALS AND METHODS: A total of 1053 patients from 78 U.S. sites were randomized to OW alendronate 70 mg (N = 520) or risedronate 35 mg (N = 533), taken in the morning after fasting. Endpoints included BMD changes over 6 and 12 months at the hip trochanter, total hip, femoral neck, and lumbar spine (LS); percent of patients with predefined levels of change in trochanter and LS BMD at 12 months; and change in biochemical markers of bone turnover at 3, 6, and 12 months. Tolerability was evaluated by adverse experience (AE) reporting.

RESULTS: Significantly greater increases in hip trochanter BMD were seen with alendronate (3.4%) than risedronate (2.1%) at 12 months (treatment difference, 1.4%; p < 0.001) as well as 6 months (treatment difference, 1.3%; p < 0.001). Significantly greater gains in BMD were seen with alendronate at all BMD sites measured (12-month difference: total hip, 1.0%; femoral neck, 0.7%; LS, 1.2%). Significant differences were seen as early as 6 months at all sites. A greater percentage of patients had > or =0% (p < 0.001) and > or =3% (p < 0.01) gain in trochanter and spine BMD at 12 months with alendronate than risedronate. Significantly greater (p < 0.001) reductions in all biochemical markers of bone turnover occurred with alendronate compared with risedronate by 3 months. No significant differences were seen between treatment groups in the incidence of upper gastrointestinal AEs or AEs causing discontinuation.

CONCLUSIONS: In this 12-month, head-to-head trial of alendronate and risedronate, given in accordance with the approved OW regimens for treatment of osteoporosis in postmenopausal women, alendronate produced greater gains in BMD and greater reductions in markers of bone turnover than risedronate. The greater antiresorptive effect of alendronate was seen as early as 3 months, and the tolerability profiles were similar.