Dr. Den Discusses Bone-Targeting Agents in Prostate Cancer

Robert B. Den, MD, associate professor of radiation oncology, Thomas Jefferson University Hospital, discusses bone-targeting agents in prostate cancer.

About 90% of patients with prostate cancer who develop metastases will develop bone metastases. Zoledronic acid (Zometa), radium-223 dichloride (Xofigo), and denosumab (Xgeva) are agents designed to target the makeup of the bone. The bone is generally made up of calcium and phosphatase; zoledronic acid works through the phosphatase side, radium-223 works through the calcium side, and denosumab decreases the osteoclastic activity of the bone.

The bone is constantly on a balance beam, says Den, both building and destroying bone. This balance is based on the production of bone based on the osteoblasts, and the reduction of bone by the osteoclasts. While denosumab decreases the osteoclasts, radium-223 works as a calcium mimetic to cause uptake up radium into the bone, says Den. Thus, radium gets targeted toward areas of increased prostate cancer, he adds.