Bisphosphonate efficacy and clinical trials for postmenopausal osteoporosis: Similarities and differences

In clinical trials, the bisphosphonates risedronate and alendronate have each been shown to reduce the risk of vertebral and nonvertebral fractures as early as 6 months (risedronate) and 12 months (alendronate). In contrast to risedronate and alendronate, ibandronate only reduces the risk of vertebral fractures, with no evidence for its efficacy in hip and nonvertebral fracture reduction. The antifracture efficacy of different bisphosphonates must rely on fracture data since bone mineral density measurements and changes in bone turnover markers appear to have no strict linear correlation with fracture risk reductions. The antifracture efficacy of different bisphosphonates ideally should be compared via head-to-head comparisons in fracture endpoint trials.