Radium Ra 223 dichloride in castration-resistant prostate cancer.

Radium Ra 223 dichloride (Xofigo®, formerly Alpharadin) is one of the representative α-particle-emitting isotopes that delivers radiation with a higher biological effect to a more localized area. Preclinical studies in mouse, rat and canine models have demonstrated that radium Ra 223 dichloride has a definite skeletal affinity and antitumor effect with a relatively low toxicity on bone marrow. More recently, in a large randomized phase III trial (ALSYMPCA), patients with bone metastasis and castration-resistant prostate cancer (CRPC) received six cycles of 50 kBq/kg of radium Ra 223 dichloride in 4-week intervals. In these men, radium Ra 223 dichloride improved the median overall survival by 3.6 months when compared to the placebo group. Collectively, these results suggest that radium Ra 223 dichloride is a promising candidate for managing bone metastases in patients with CRPC.