Treatment of osteoporosis secondary to hypogonadism in prostate cancer patients: a prospective randomized multicenter international study with denosumab vs. alendronate.

BACKGROUND

Osteoporosis is a complication of androgen deprivation therapy (ADT) in men with prostate carcinoma. This is a multicenter, randomized, double-blind prospective study on use of denosumab versus alendronate in the therapy of secondary osteoporosis related to ADT.

METHODS

A total of 234 patients with diagnosis of osteoporosis underwent ADT for prostate cancer were enrolled. Patients were randomly assigned 1:1 to receive denosumab 60 mg subcutaneously every 6 months or alendronate (70 mg/week) for 2 years. All patient received supplemental vitamin D (600 IU/day) and supplemental calcium to maintain a calcium intake of 1200 mg per day. Effectiveness of therapy in both groups (denosumab group and alendronate group) was assessed by changes in bone turnover markers (BTMs), bone mineral density, fracture incidence, Visual Analogue Scale score for back pain, and Short Form-8 health survey score for health-related quality of life.

RESULTS

In the denosumab study group, level of BTMs for bone formation were significantly increased from baseline at all time points during the study (P<0.001); in the alendronate study group level of BTMs for bone formation were increased too (P>0.05). Mean changes in BMD at final follow-up differed significantly between two groups. BMD changes at the lumbar spine at 24 months were 5.6% with denosumab vs. -1.1% with alendronate (P<0.001).

CONCLUSIONS

Denosumab and alendronate showed similar clinical efficacy in the therapy of ADT-related osteoporosis in men with prostate carcinoma; both drugs provided significant improvements in back pain and general health conditions. Denosumab showed significant increase of BTMs and BMD than alendronate with lower rate of new vertebral fractures.