Long term zoledronic acid during androgen blockade for prostate cancer.

OBJECTIVES

To evaluate the effect of zoledronic acid on androgen deprivation therapy in patients with hormone-sensitive prostate cancer by measuring the percentage change in lumbar-spine bone mineral density (BMD) at 12 and 24 months.

MATERIALS AND METHODS

An open-label, multicenter, randomized, two-phase study was conducted in patients with hormone-sensitive prostate cancer (N = 200) receiving 10.8 mg goserelin acetate with or without zoledronic acid (4 mg intravenously) every 3 months. In phase I, patients were randomized to goserelin acetate alone or goserelin acetate plus zoledronic acid for 12 months. In phase II, patients receiving goserelin acetate plus zoledronic acid continued treatment for up to a total of 24 months, whereas patients receiving goserelin acetate alone were randomized to goserelin acetate alone or goserelin acetate plus zoledronic acid for an additional 12 months. Lumbar-spine, femoral-neck, and total-hip BMD were assessed at 6, 12, and 24 months. Additional assessments included height change, laboratory studies, bone scans, radiographs, and computed tomography scans.

RESULTS

Significant BMD differences between patients receiving goserelin acetate alone and goserelin acetate plus zoledronic acid were observed at the 12-month (p <or= .01 for each site) and 24-month (p < .05 for each site) assessments. Initiating zoledronic acid after 12 months of goserelin acetate alone provided BMD benefits but was insufficient to completely restore BMD. Combining goserelin acetate and zoledronic acid was generally well tolerated.

CONCLUSIONS

Two years of zoledronic acid is well tolerated and can prevent bone loss in patients with prostate cancer undergoing androgen deprivation therapy.