Osteoporosis in men: epidemiology and treatment with denosumab

Abstract

Osteoporosis is a major public health care concern. Although often described as a disease affecting postmenopausal women, researchers and clinicians have emphasized its prevalence in men in recent years. The National Osteoporosis Foundation has stated that up to 25% of men over the age of 50 years will experience a fracture due to osteoporosis. Men who suffer from a major fracture have higher mortality rates than women. Pharmacologic therapy options for treating osteoporosis are limited for men as compared with women, so each medication approved for use in this population represents an important clinical option. In September 2012, the US Food and Drug Administration approved a new indication for denosumab to increase bone mass in men with osteoporosis at high risk for fracture. Denosumab is a fully human monoclonal antibody and novel antiresorptive agent that works by binding receptor activator of nuclear factor kappa-β ligand (RANKL) and inhibiting the signaling cascade that causes osteoclast maturation, activity, and survival. Ultimately, denosumab suppresses bone turnover and increases bone mineral density in both trabecular and cortical bone. Approval for treating osteoporosis in men was based on data from the ADAMO trial which displayed efficacy in increasing bone mineral density at the lumbar spine, total hip, femoral neck, hip trochanter, and one-third radius. Studies indicate that denosumab is effective and safe, and has superior adherence rates and patient satisfaction. Although long-term data and further research on fracture reduction rates in men should be explored, at this time denosumab is one of several appropriate first-line treatment options for men with osteoporosis.

Keywords: denosumab; men; osteoporosis; treatment.

Figure 1

Mechanism of action of denosumab. High affinity binding of denosumab to RANKL inhibits osteoclast maturation, activity, and survival by preventing RANKL from binding the RANK receptor on immature and mature osteoclasts. This decreases bone resorption and suppresses bone turnover. Abbreviations: RANKL, receptor activator of nuclear factor kappa-β ligand; RANK, receptor activator of nuclear factor kappa-β.