Response rate of bone mineral density to teriparatide in postmenopausal women with osteoporosis

Purpose: It is desirable for clinicians to know what bone mineral density (BMD) response they can expect in women treated with osteoporosis therapies. The focus of this analysis was to determine what percentage of women attained a lumbar spine BMD response to teriparatide that equaled or exceeded the least significant change (LSC) value of 3%. Methods: Data from three clinical trials involving postmenopausal women with osteoporosis were examined. The Fracture Prevention Trial was a double-blinded, placebo-controlled clinical trial examining the safety and efficacy of teriparatide 20 and 40 μg/day. The other two trials were double-blinded, head-to-head comparisons of alendronate 10 mg/day and teriparatide 20 or 40 μg/day, respectively. Only treatment-compliant women who had lumbar spine BMD measurements at all specified time points in these trials were included. For reference, we also examined the percentage of women with lumbar spine BMD responses to alendronate. Hip BMD responses that equaled or exceeded 3% were also examined. Results: According to the LSC criteria, 91% of the teriparatide 20 μg/day group and 94% of the teriparatide 40 μg/day group were lumbar spine BMD responders at 18 months in the Fracture Prevention Trial. In the teriparatide 20 μg/alendronate head-to-head trial, 94% of women receiving teriparatide had a lumbar spine BMD response that equaled or exceeded the 3% criterion at 18 months compared to 75% of those receiving alendronate 10 mg/day (p