Radium-223: the newest option in metastatic castration-resistant prostate cancer.

OS Radium-223 (Xofigo, Bayer and Algeta) is a boneseeking radiopharmaceutical that patients receive via injection. It is approved by the US Food and Drug Administration (FDA) to relieve pain and prolong survival in patients with metastatic castration-resistant prostate cancer (mCRPC) who have symptomatic evidence of bone metastasis. Because radium-223 selectively targets bone, it is not indicated for men who have visceral disease—which is the case for as many as one-quarter of men with mCRPC. Radium-223 is the third radiopharmaceutical to be approved by the FDA for use in mCRPC. The first was strontium-89, which was approved in 1993, and the second was samarium-153 (Quadramet, Jazz Pharmaceuticals), which was approved in 1997. Both strontium-89 and samarium-153 are beta emitters.