Abaloparatide plus alendronate reduces fractures, increases BMD in postmenopausal women
Twenty-four months of alendronate (ALN) after 18 months of abaloparatide (ABL) improves bone mineral density (BMD) of the lumbar spine, femoral neck and total hip, and lowers the risk of vertebral, nonvertebral, clinical and major osteoporotic fractures in women with postmenopausal osteoporosis, according to the ACTIVExtend study.
“Sequential ABL followed by ALN appears to be an effective treatment option for postmenopausal women at risk for osteoporosis-related fractures,” researchers said.
A total of 558 women from ACTIVE’s ABL group and 581 from its placebo group (92 percent of ABL and placebo completers) participated in the ACTIVExtend study.
Over the entire treatment period (43 months), 0.9 percent of women in the ABL/ALN group had a new radiographic vertebral fracture compared with 5.6 percent in the placebo/ALN group (relative risk reduction [RRR], 84 percent; p<0.001). [J Clin Endocrinol Metab 2018;103:2949-2957]
In Kaplan–Meier analysis, the ABL/ALN group had significantly lower incidence rates for other reported fractures compared with the placebo/ALN group (p<0.05 for all). Participants in ACTIVExtend further increased gains in BMD achieved during ACTIVE. For ACTIVExtend only, ABL/ALN vs placebo/ALN yielded an 87-percent RRR for vertebral fractures (p=0.001).
Furthermore, the two groups showed comparable adverse events. In a supplemental analysis for regulatory authorities, there were no hip fractures in the ABL/ALN group as compared with five in the placebo/ALN group.
“The results of ACTIVE and the completed ACTIVExtend trial in postmenopausal women at high risk for fracture demonstrate the effectiveness of a treatment sequence comprised of initial anabolic treatment with ABL for 18 months, followed by continuation of treatment with ALN for up to 2 additional years,” researchers said.
There are several reasons why a sequential treatment strategy with ALN after ABL is desirable, according to researchers. First, ABL delivers a prompt and consistent reduction in fracture risk, which is linked to increased BMD at vertebral and hip sites. It reduces the remodeling space and increases mineralization, thus improving bone mass. [JAMA 2016;316:722-733]
Second, while anabolic therapies are usually given for ≤2 years, ALN can be administered for a longer period. Its effect on BMD can last several years past the end of active treatment. [N Engl J Med 2004;350:1189-1199]
As a result, “an ABL/ALN sequence can provide a rapid and substantial initial benefit as well as a sustained favourable effect, employing a relatively inexpensive medication in the continuation phase,” researchers said.
The present study included women who completed ABL or placebo treatment in ACTIVE. Researchers assessed the incidence of vertebral and nonvertebral fractures and changes in BMD during the entire 43-month period from ACTIVE baseline to the end of ACTIVExtend and for the 24-month extension only.
This study had certain limitations. “It was not powered to demonstrate a significant reduction in nonvertebral fractures during the extension period; studies of greater size and duration would be needed to confirm the favourable trend observed,” researchers said.