Amgen (Nasdaq: AMGN) today announced that a pivotal, Phase 3, head-to-head trial evaluating denosumab versus Zometa® (zoledronic acid) in the treatment of bone metastases in 1,901 men with advanced prostate cancer met its primary and secondary endpoints. Denosumab demonstrated superiority over Zometa for both delaying the time to the first on-study skeletal related event (SRE) (fracture, radiation to bone, surgery to bone or spinal cord compression) (hazard ratio 0.82, 95 percent CI: 0.71, 0.95), and reducing the rate of multiple SREs (hazard ratio 0.82, 95 percent CI: 0.71, 0.94). Both results were statistically significant.
Overall rates of adverse events and serious adverse events, including infections, were generally similar between the two arms. Osteonecrosis of the jaw was infrequent (22 patients receiving denosumab as compared with 12 patients receiving Zometa) and there was no statistically significant difference between treatment arms. As with previous studies in advanced cancer patients, hypocalcemia was more frequent in the denosumab arm. Both overall survival and the time to cancer progression were balanced between treatment arms.