Clinical Trials Express: Fracture Risk Reduction with Denosumab in Japanese Postmenopausal Women and Men with Osteoporosis: Denosumab Fracture Intervention Randomized Placebo Controlled Trial (DIRECT)

Context: Denosumab 60 mg sc injection every 6 months for 36 months was well tolerated and effective in reducing the incidence of vertebral, nonvertebral, and hip fracture in predominantly Caucasian postmenopausal women with osteoporosis.

Objective: The objective of this phase 3 fracture study was to examine the antifracture efficacy and safety of denosumab 60 mg in Japanese women and men with osteoporosis compared with placebo.

Design And Setting: A randomized, double-blind, placebo-controlled trial with an open-label active comparator as a referential arm was conducted.

Patients: Subjects were 1262 Japanese patients with osteoporosis aged 50 years or older, who had one to four prevalent vertebral fractures.

Intervention: Subjects were randomly assigned to receive denosumab 60 mg sc every 6 months (n = 500), placebo for denosumab (n = 511), or oral alendronate 35 mg weekly (n = 251). All subjects received daily supplements of calcium and vitamin D.

Main Outcome Measure: The primary endpoint was the 24-month incidence of new or worsening vertebral fracture for denosumab vs placebo.

Results: Denosumab significantly reduced the risk of new or worsening vertebral fracture by 65.7%, with incidences of 3.6% in denosumab and 10.3% in placebo at 24 months (hazard ratio 0.343; 95% confidence interval 0.194-0.606, P = .0001). No apparent difference in adverse events was found between denosumab and placebo during the first 24 months of the study.

Conclusion: These results provide evidence of the efficacy and safety of denosumab 60 mg sc every 6 months in Japanese subjects with osteoporosis.