Real-world characteristics of long-term survivors with metastatic castration-resistant prostate cancer (mCRPC) treated with radium-223 (Ra-223): An analysis of the global REASSURE study.

74 Background: Ra-223 is an alpha-emitting radionuclide approved to treat mCRPC with bone metastases. The REASSURE study (NCT02141438) assessed the long-term safety (~10 years yrs) and overall survival (OS) associated with Ra-223 in clinical practice. This was the most comprehensive and longest-term prospective study focused on safety and efficacy of a radiopharmaceutical in this setting. Methods: Patients (pts) with mCRPC with bone metastases were enrolled from 2014–2017 (final data cut-off: October 2024). We compared pts with extended OS to those without, using a 2-yr cutoff. We evaluated disease history, baseline characteristics, treatment patterns (including prior, concomitant and subsequent treatments), fracture rates, incidence of second primary malignancies (SPMs), and OS from diagnosis of castration resistance and Ra-223 initiation. Analyses were descriptive. Results: Of 1472 pts, 393 (27%) survived ≥2 yrs (median OS 38.1 months) and 1079 (73%) survived 20 lesions, % 28 / 13 15 / 23 Abiraterone: Prior / Concomitant / Subsequent, % 39 / 17 / 25 51 / 14 / 6 Enzalutamide: Prior / Concomitant / Subsequent, % 29 / 20 / 36 43 / 17 / 7 Docetaxel: Prior / Concomitant / Subsequent, % 26 / 1 / 35 44 / 2 / 12 Cabazitaxel: Prior / Concomitant / Subsequent, % 4 / 0 / 22 12 / 1 / 7 Bone Protective Agent: Prior / Concomitant, % 54 / 50 48 / 38 Completed 6 Ra-223 injections, % 92 48 OS from time of castration resistant cancer, median, months 56.2 27.4