Effects of denosumab on bone mineral density in men receiving androgen deprivation therapy for prostate cancer

Abstract

Purpose: In a recently completed 3-year, randomized, double-blind study, denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor kappaB ligand, significantly increased bone mineral density and decreased new vertebral fractures in men receiving androgen deprivation therapy for prostate cancer. We conducted subgroup analyses to evaluate the relationships between subject characteristics and the effects of denosumab on bone mineral density at multiple skeletal sites.

Materials and methods: A total of 1,468 subjects were randomized 1:1 to receive 60 mg subcutaneous denosumab every 6 months or placebo for 36 months. In these analyses we evaluated the effects of denosumab on bone mineral density at the lumbar spine, total hip and distal 1/3 radius (substudy of 309 subjects) during 36 months in specific subgroups according to age, duration and type of prior androgen deprivation therapy, bone mineral density T score, weight, body mass index, bone turnover marker levels and prevalent vertebral fractures.

Results: After 36 months denosumab significantly increased bone mineral density of the lumbar spine, total hip and distal 1/3 radius by 7.9%, 5.7% and 6.9%, respectively, compared with placebo (p <0.0001 for each comparison). Denosumab significantly increased bone mineral density to a degree similar to that observed in the overall analysis for every subgroup including older men as well as those with prevalent fractures, lower baseline bone mineral density, and higher serum C-telopeptide and tartrate-resistant alkaline phosphatase 5b. Mean increases in bone mineral density at each skeletal site were greatest for men with the highest levels of serum C-telopeptide and tartrate-resistant alkaline phosphatase 5b.

Conclusions: Denosumab significantly and consistently increased bone mineral density at all skeletal sites and in every subgroup, including men at greatest risk for bone loss and fractures.

Trial registration: ClinicalTrials.gov NCT00089674.

Figures

Figure 1

Forest plots of treatment effect of denosumab at 36 months in percentage change from baseline (±95% CI) in BMD at the lumbar spine. Results are presented as least squares means. Vertical bar represents 95% CI for percentage difference in lumbar spine BMD between denosumab and placebo for overall population at 36 months. Asterisk indicates p NS, not significant between subgroups.

Figure 2

Forest plots of treatment effect of denosumab at 36 months in percentage change from baseline (±95% CI) in BMD at total hip. Results are presented as least squares means. Vertical bar represents 95% CI for percentage difference in total hip BMD between denosumab and placebo for overall population at 36 months. Asterisk indicates p NS, not significant between subgroups.

Figure 3

Forest plots of treatment effect of denosumab at 36 months in percentage change from baseline (±95% CI) in BMD at distal 1/3 radius. Results are presented as least squares means. Vertical bar represents 95% CI for percentage difference in distal 1/3 radius BMD between denosumab and placebo for overall population at 36 months. Asterisk indicates p NS, not significant between subgroups.