Men with prostate cancer are at risk of experiencing accelerated bone loss and fractures as a result of androgen deprivation therapy (ADT).
We evaluated the effects of denosumab, a fully human monoclonal antibody against RANKL, on preservation of BMD at 3 key skeletal sites (lumbar spine [LS], femoral neck [FN], and total hip [TH]) and the distal radius at 36 months both by responder category and individual responses in a waterfall plot analysis.
Design, Setting, and Participants
This phase 3, randomized, double-blind study of men with non-metastatic prostate cancer receiving ADT investigated the effects of denosumab on bone mineral density (BMD) and fractures. Patients were treated for 36 months.
Subcutaneous denosumab 60 mg (n=734) or placebo (n=734) every 6 months for up to 36 months. Patients were instructed to take supplemental Calcium and vitamin D.
Primary outcome measure: The percentage change from baseline to month 36 in LS, FN, and TH BMD was measured by dual energy x-ray absorptiometry. BMD at the distal 1/3 radius at 36 months was measured in a sub-study of 309 patients.
Results and Limitations
At 36 months, significantly more patients in the denosumab arm had increases of >3% BMD from baseline at each site studied compared with placebo (LS, 78% vs 17%; TH, 48% vs 6%; FN, 48% vs 13%; distal 1/3 radius, 40% vs 7%). The percentage of denosumab patients with bone loss at all 3 key BMD sites at month 36 was 1%, as opposed to 42% in placebo arm. At 36 months 69% of denosumab-treated patients had BMD increases at all three sites (LS, TH or FN) compared with 8% of placebo-treated patients. Lower baseline BMD was associated with higher magnitude lumbar spine, femoral neck, and total hip BMD responses to denosumab.
In men with prostate cancer receiving ADT significantly higher BMD response rates were observed with denosumab vs. placebo.
This study is registered with ClinicalTrials.gov with the identifier NCT00089674.