869P - Real-world use of radium-223 for treatment of metastatic castration resistant-prostate cancer (mCRPC): Results from the Dutch CAPRI registry

Radium-223 dichloride (Ra-223) is a targeted alpha-emitter that selectively binds to areas of increased bone turnover in bone metastases. In the ALSYMPCA trial an increased overall survival over placebo in both docetaxel pretreated (14.4mo) and docetaxel untreated (16.1mo) patients was shown. With multiple life-prolonging agents (LPD), data on treatment sequencing and outcomes in real-world practice are needed. The aim of this study was to investigate the use of Ra-223 and outcomes in daily practice in the Netherlands. Patients treated with Ra-223 in the CAPRI registry were included and followed until 01-01-2018. Subgroups were based on prior use of docetaxel (docetaxel naive, DOC-naïve; post-docetaxel, post-DOC). Outcomes were treatment sequence and overall survival from 1st Ra-223 injection. 288 patients treated with Ra-223 were included in this analysis. 90% were pretreated with one or more lines of LPD (38% 1line, 52% ≥1line). 33% of DOC-naïve patients were treated with Ra-223 as line 1. Baseline characteristics are shown in the table. DOC-naïve patients had prognostic favorable baseline characteristics compared to post-DOC patients, namely higher hemoglobin (7.9 vs 7.4mmol/L, p