What is the role of radium-223 dichloride (Xofigo) in the treatment of hormone-refractory prostate cancer?

Updated: Dec 29, 2020
  • Author: Martha K Terris, MD, FACS; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

Radium-223 dichloride (Xofigo), formerly alpharadin, is an alpha-particle–emitting radioactive therapeutic agent that was approved by the FDA in May 2013. It is approved for men with castration-resistant prostate cancer (CRPC), symptomatic bone metastases, and no known visceral metastatic disease.

Approval was based on the ALSYMPCA trial (ALpharadin in SYMptomatic Prostate CAncer), which is the first randomized phase III trial to demonstrate improved survival of CRPC with a bone-seeking radioisotope. [40] The multinational trial was conducted in 19 countries and included 921 patients with prostate cancer that had progressed with symptomatic bone metastases and no known visceral metastases. The trial was halted early after a planned interim analysis found a survival benefit in favor of radium-223. Updated analysis demonstrated a 3.6-month survival advantage compared with placebo (14.9 vs 11.3 months,respectively).

In prespecified subgroup analysis from the ALSYMPCA trial, radium-223 dichloride was found to be equally effective whether or not the patient has previously received chemotherapy with docetaxel. Median overall survival with radium-223 was 14.4 months for patients who received previous docetaxel and 16.1 months for patients who did not. Correspondingly, median time to first symptomatic skeletal event was 13.5 months and 17.0 months, respectively, for the two groups. Compared with placebo, hazard ratios for the two groups of patients were 0.70 and 0.69, respectively, and both were statistically significant. [41]

In a separate analysis, time to first symptomatic skeletal event was assessed. Patients in the radium-223 treatment group went longer before the first symptomatic skeletal event than with placebo (median 15.6 months vs 9.8 months). The risks of external beam radiation therapy for bone pain and spinal cord compression were reduced with radium-233 compared with placebo. [42]


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