Critical appraisal of denosumab in the treatment and prevention of postmenopausal osteoporosis and bone loss in patients undergoing hormone ablation

David L Kendler¹, Kenneth Shawn Davison^2
1Prohealth Clinical Research, University of British Columbia, Vancouver, British Columbia, Canada; ²Department of Medicine, Division of Immunology and Rheumatology, Laval University, Quebec, Canada

Abstract: Antiresorptive therapies are the mainstay for treating patients with excessively high rates of bone resorption. The receptor activator of nuclear factor-κB (RANK) ligand (RANKL), secreted by osteoblasts, binds to the RANK receptor on the surface of preosteoclasts and osteoclasts to elicit osteoclast formation, survival, and activity. Osteoprotegerin, also secreted by the osteoblast, acts as a decoy RANK receptor reducing RANKL binding to RANK and reducing bone resorption. Denosumab, a fully human monoclonal antibody, has a high affinity and specificity for RANKL. Denosumab rapidly decreases bone resorption and increases bone mineral density (BMD) at the lumbar spine, total hip, femoral neck, and one-third radius sites. In head-to-head trials, denosumab increased BMD and decreased bone resorption to a significantly greater degree than alendronate. In postmenopausal osteoporotic women, denosumab decreased the risk of vertebral fracture (68%), nonvertebral fracture (20%), and hip fracture (40%) over 36 months, compared to placebo. In patients with iatrogenic hypogonadism, denosumab rapidly decreased markers of bone resorption and increased BMD. In men treated with GnRH agonist for prostate cancer, treatment with denosumab led to a 62% decreased risk of new vertebral fracture over 3 years, as compared to placebo. In all trials completed to date, comparable adverse events have been observed in both denosumab and placebo or treatment groups.

Keywords: medication adherence, fracture, bone mineral density, bone turnover markers