Bone mineral density response rates are greater in patients treated with abaloparatide compared with those treated with placebo or teriparatide: Results from the ACTIVE phase 3 trial

Background: Abaloparatide is a 34-amino acid peptide that selectively binds to the RG conformation of the parathyroid hormone receptor type 1. It was developed for the treatment of women with postmenopausal osteoporosis at high risk of fracture. In ACTIVE, an 18-month phase 3 study (NCT01343004), abaloparatide increased bone mineral density (BMD), decreased the risk of vertebral and nonvertebral fractures compared with placebo, and decreased the risk of major osteoporotic fractures compared with placebo and teriparatide. Here, we report a prospective, exploratory BMD responder analysis from ACTIVE. Methods: Proportions of patients experiencing BMD gains from baseline of > 0%, > 3%, and > 6% at the total hip, femoral neck, and lumbar spine at 6, 12, and 18 months of treatment were compared among the placebo, abaloparatide, and teriparatide groups in ACTIVE. Responders were defined prospectively as patients experiencing BMD gains at all 3 anatomic sites. Results: At months 6, 12, and 18, there were significantly more > 3% BMD responders in the abaloparatide group compared with placebo and teriparatide: month 6, 19.1% vs 0.9% for placebo and 6.5% for teriparatide; month 12, 33.2% vs 1.5% and 19.8%; month 18, 44.5% vs 1.9% and 32.0% (P < 0.001 for all comparisons of abaloparatide to placebo and to teriparatide). Findings were similar for the > 0% and > 6% responder thresholds. Conclusions: In postmenopausal women with osteoporosis, a significantly greater proportion of patients treated with abaloparatide experienced increases in BMD than did those treated with placebo or teriparatide.