Abaloparatide-SC, an injectable drug being studied for the treatment of postmenopausal osteoporosis, reduces the rate of new spinal fractures by 86%, as well as provide statistically significant reductions in the fracture rate at other parts of the body, according to data from the phase 3 ACTIVE fracture prevention trial (ACTIVE trial). Results from the ACTIVE trial were reported at the Endocrine Society’s 97th Annual Meeting in San Diego.
“The investigational drug abaloparatide-SC, if approved, may offer patients the potential to reduce their risk of fracture and increase bone density at all sites, even the most difficult to treat, such as the hip and wrist,” said lead investigator Paul Miller, MD, Medical Director of the Colorado Center for Bone Research in Lakewood.
Paul Miller, MD
Abaloparatide-SC is a new manmade form of human parathyroid hormone-related protein that is manufactured by Radius Health (Waltham, Massachusetts). The drugmaker is studying the medication in various forms, including a transdermal patch, in addition to the subcutaneous injection studied in the ACTIVE trial.
During the ACTIVE trial, researchers studied whether abaloparatide-SC can reduce fractures in postmenopausal women with severe osteoporosis who have a high fracture risk. The investigators compared rates of new fractures in 690 women who received a daily injection of abaloparatide-SC (80 mcg) and 711 women who received inactive placebo shots. Neither group of women knew which treatment they received. A third group of 717 women received a daily injection of teriparatide (20 mcg) in an unblinded fashion. All patients also received calcium and vitamin D supplements.
Over 18 months of treatment, the abaloparatide-SC-treated group had the greatest reduction in the rate of new vertebral fractures shown on x-ray, Dr. Miller reported. Compared with the placebo group’s new vertebral fracture rate of 4.2%, women who were treated with abaloparatide-SC had a new vertebral fracture rate of about 0.58%, representing an 86% reduction in the rate of broken bones at the spine, according to Dr. Miller.
“We believe this reduction seen in the abaloparatide-SC-treated group could be the largest reduction ever demonstrated in the vertebral fracture rate for any potential therapeutic drug being researched for the treatment of postmenopausal osteoporosis,” Dr. Miller said.
For nonvertebral fractures, Dr. Miller said abaloparatide-SC treatment had a 43% fracture-rate reduction compared to that of placebo. The rate of vertebral and nonvertebral fractures combined decreased by 45% in the abaloparatide-SC-treated group versus the placebo group. Additionally, the time to the first nonvertebral fracture was significantly delayed for women receiving abaloparatide-SC than for those who received a placebo, he said.
Results of patients’ bone mineral density tests also were compared between the two drug treatment groups. “Abaloparatide-SC resulted in more bone growth, at a faster rate, at more skeletal sites, and in more patients than teriparatide,” stated Dr. Miller.