Effects of Abaloparatide, a Human Parathyroid Hormone-Related Peptide Analog, on Bone Mineral Density in Postmenopausal Women with Osteoporosis

Context: Abaloparatide is a novel synthetic peptide analog of parathyroid hormone-related protein (PTHrP) that is currently being developed as a potential anabolic agent in the treatment of postmenopausal osteoporosis. Objective: This study sought to assess the effects of abaloparatide on bone mineral density (BMD) at the lumbar spine, total hip, and femoral neck in postmenopausal women with osteoporosis. Design: Multi-center, multi-national, double-blind placebo controlled trial in which postmenopausal women were randomly assigned to receive 24 weeks of treatment with daily sc injections of placebo, abaloparatide, 20, 40, or 80 mu g, or teriparatide, 20 mu g. A 24-week extension was also performed in a subset of subjects. Participants: Postmenopausal women with osteoporosis (n = 222). Main Outcome Measures: BMD by dual-x-ray absorptiometry and biochemical markers of bone turnover. Results: At 24 weeks, lumbar spine BMD increased by 2.9, 5.2, and 6.7% in the abaloparatide, 20-, 40-, and 80-mu g groups, respectively, and 5.5% in the teriparatide group. The increases in the 40and 80-mu g abaloparatide groups and the teriparatide group were significantly greater than placebo (1.6%). Femoral neck BMD increased by 2.7, 2.2, and 3.1% in abaloparatide, 20-, 40-, and 80-mu g groups, respectively, and 1.1% in the teriparatide group. The increase in femoral neck BMD with abaloparatide, 80 mu g was significantly greater than placebo (0.8%). Total hip BMD increased by 1.4, 2.0, and 2.6% in the abaloparatide, 20-, 40-, and 80-mu g groups, respectively. The total hip increases in the 40- and 80-mu g abaloparatide groups were greater than both placebo (0.4%) and teriparatide (0.5%). Conclusions: Compared with placebo, 24 weeks of daily sc abaloparatide increases BMD of the lumbar spine, femoral neck, and total hip in a dose-dependent fashion. Moreover, the abaloparatide-induced BMD increases at the total hip are greater than with the marketed dose of teriparatide. These results support the further investigation of abaloparatide as an anabolic therapy in postmenopausal osteoporosis.