Conference Coverage

Reduced fracture risk maintained in abaloparatide extension study


 

REPORTING FROM ASBMR 2017

– Sequential treatment with abaloparatide and alendronate was associated with reduced vertebral and non-vertebral fractures compared to placebo and alendronate among high-risk women with osteoporosis in a 3.5 year extension study of the ACTIVE trial.

The ACTIVExtend trial included 558 women in the abaloparatide group and 581 women in the placebo group of the original ACTIVE study (NCT01343004). In that double-blind trial, 2,463 postmenopausal women with osteoporosis were randomized to receive daily injections of abaloparatide (80 µg) or placebo, or open-label teriparatide (20 µg). After 18 months of treatment, patients in the placebo and abaloparatide groups were switched to alendronate 70 mg weekly for two years, Henry Bone, MD, director of the Michigan Bone and Mineral Clinic in Detroit, said at the annual meeting of the American Society for Bone and Mineral Research.

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From the beginning of ACTIVE to the end of ACTIVExtend, 5 women in the abaloparatide-alendronate group (0.9%) and 32 (5.6%) in the placebo-alendronate group had at least one new vertebral fracture (P less than .0001); 27 patients in the abaloparatide-alendronate group (5.0%), and 45 women (8.0%) in the placebo-alendronate group had a non-vertebral fracture (P = .038).

The abaloparatide-alendronate group had a 34% relative risk reduction for all clinical fractures compared to the placebo-alendronate group (P = .045). For major osteoporotic fractures, the abaloparatide-alendronate group had a 50% relative risk reduction compared to the placebo-alendronate group (P = .011).

Among women who had no new vertebral fractures during the first 18 months of the ACTIVE study, 2 women in the abaloparatide-alendronate group and 13 in the placebo-alendronate group had new vertebral fractures during ACTIVExtend.

Adverse events were similar in both arms of the study. There were no cases of atypical femur fracture or osteonecrosis of the jaw.The anabolic agent abaloparatide was approved by the Food and Drug Administration in April for the treatment of osteoporosis in women at high risk of fracture. Sequential treatment with the anti-resorptive agent alendronate aims to preserve the bone density gains from abaloparatide, as previous research has shown that improvements with anabolic agents can be lost once the drug is stopped.

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