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 docetaxel.The men were randomized 2:1 to receive 6 injections of Ra 223 or placebo and stratified by prior docetaxel use, baseline alkaline phosphatase level, and current bisphosphonate use.Nine hundred and twenty one men (921) were randomized (Ra-223, n = 614; placebo, n = 307) for the trial. Forty percent (40%) had >20 mets. The men receiving the Ra-223 experienced a significantly delayed response time to first SRE versus placebo by a median increase of 5.8 months (median time to SRE: 15.6 vs 9.8 mo; P < 0.001; HR = 0.66; 95% CI: 0.52-0.83).The analysis concluded that Ra-223 significantly delayed time to first SRE with a reduction in risk observed for all 4 SRE components. Despite the longer time at risk, Ra-223 patients had an approximately 50% reduction in risk for SCC.Ra-223 should become an effective therapy with a highly favorable safety profile if the FDA approves it.Clinical trial information:NCT00699751.

J Clin Oncol 31, 2013 (suppl 6; abstr 11); Nicholas J. Vogelzang, Chris Parker, Sten Nilsson, Robert Edward Coleman, C. Gillies O’Bryan-Tear, Minghua Shan, A. Oliver Sartor; Comprehensive Cancer Centers of Nevada, Las Vegas, NV; The Royal Marsden NHS Foundation Trust, Sutton, United Kingdom; Karolinska University Hospital, Stockholm, Sweden; Weston Park Hospital, Sheffield, United Kingdom; Algeta ASA, Oslo, Norway; Bayer HealthCare, Montville, NJ; Tulane Cancer Center, New Orleans, LA

Joel T. Nowak, M.A., M.S.W.