To assess the clinical effect of radium 223 (Ra223) in patients with progressive symptomatic bone metastases on a background of metastatic castrate resistant prostate cancer (mCRPC).

347 Background: Ra223 is the first radiopharmaceutical shown in the ALSYMPCA trial to improve survival and achieve a tolerable safety profile in patients with symptomatic bone metastases. It remains unclear as to where Ra223 is best placed in the treatment pathway of CRPC. We assessed the effect of Ra223 in mCRPC in terms of biochemical and clinical response. Methods: Retrospective analysis of mCRPC patients treated with Ra223 via CDF between Dec 2013-May 2015. Clinical benefit assessed by pain response. Toxicities graded as per CTCAE V 4. Results: 58 patients, median follow up 11.6 (1.0-18.1) months. Median age 71 (54-84); median WHO PS 1 (0-2). 58 patients received 50kBq/kg, median number of cycles 5 (1-6). 43% and 33% completed 6 and 3 cycles respectively. Median number of previous treatments 3 (1-6). 52%, 17% and 5 % received prior Docetaxel, Bisphosphonates and Strontium respectively. Median time from radiotherapy for symptomatic bone metastases to initiation of Ra 223 was 433 days. Incidence of Grad...