Abaloparatide Decreased Fractures in Postmenopausal Women With Osteoporosis
The risk of new vertebral fractures dropped consistently in study participants randomized to receive abaloparatide, irrespective of baseline risk factors
BOSTON — Abaloparatide, an investigational parathyroid hormone-related protein (PTHrP) analog, reduced morphometric vertebral fractures, nonvertebral fractures, and major osteoporotic fractures when compared with placebo in postmenopausal women with osteoporosis.
These results, derived from the Abaloparatide Comparator Trial in Vertebral Endpoints (ACTIVE, ClinicalTrials.gov Identifier NCT01343004), a multicenter, randomized, double-blind, and placebo-controlled trial, were presented at ENDO 2016.
The primary outcome measure in the ACTIVE trial was the number of abaloparatide-treated patients who developed new vertebral fractures at 18 months compared with placebo. Secondary outcome measures included the efficacy of abaloparatide in increasing bone mineral density (BMD) in the lumbar spine, total hip, and femoral neck at 18 months when compared to teriparatide, and the efficacy of abaloparatide on incidence of nonvertebral fractures when compared with placebo.
The investigators found that study participants randomly assigned to receive abaloparatide had significant percentage increases in BMD from baseline in 3 areas when compared with those receiving placebo at 18 months (lumbar spine increased by 9.2%, total hip increased by 3.4%, and femoral neck increased by 2.9%; all P<.0001 vs placebo).
In participants treated with abaloparatide, morphometric vertebral fractures were reduced by 86% (P<.0001), nonvertebral fractures were reduced by 43% (P=.0489), and major osteoporotic fractures were reduced by 70% (P=.0004) when compared with placebo.
Major osteoporotic fractures were reduced by 55% in the abaloparatide treated group as compared with the teriparatide treated group (P=.0309).
After subgroup analysis, the authors found that the risk of new vertebral or nonvertebral fractures decreased uniformly among the study participants taking abaloparatide. This noted decrease appeared to be independent of baseline risk factors.
“Results of forest plots show consistent fracture reduction in the abaloparatide arm for new morphometric vertebral or nonvertebral fractures without any interactions caused by baseline risk factors. Furthermore, there were no interactions between any of the baseline risk factors and magnitude of BMD accrual by abaloparatide,” the authors noted.