Ra-223 is an investigational alpha-pharmaceutical targeting bone metastases (mets) with high-energy, short-range alpha-particles. The recently completed phase 3, double-blind, randomized, multinational ALSYMPCA study showed that Ra-223 significantly improved over all survival (OS) in CRPC men with bone mets by a median increase of 3.6 months compared with placebo (median OS: 14.9 vs 11.3 mo; P < 0.001; HR = 0.69; 95% CI: 0.58-0.83). Men in this trial had progressive, symptomatic CRPC with ? 2 bone mets on scintigraphy and no known visceral mets; were receiving best standard of care (BSoC); and either previously received docetaxel, or did not because they were docetaxel ineligible, or refused