Radium-223 dichloride (Ra-223) is a bone-targeting radioligand therapy shown to improve overall survival (OS) in patients with bone-metastatic castration-resistant prostate cancer (CRPC). This study aimed to evaluate the real-world safety and effectiveness of Ra-223 in Japanese patients with bone-metastatic CRPC.

This multi-institutional, retrospective study included men with bone-metastatic CRPC treated with Ra-223 across seven institutions. The primary endpoint was overall survival (OS), while secondary endpoints included changes in prostate-specific antigen (PSA) levels, incidence of adverse events, and time to clinical progression. Exploratory analyses assessed the association between clinical parameters and OS.

A total of 120 patients were enrolled. The median OS was 23.1 months. Anemia occurred in 4.1% of patients. Patients receiving ≥3 treatment cycles had significantly longer OS (median 30.2 months, p < 0.001), as did those with baseline hemoglobin levels ≥12 g/dL (median 31.5 months, p = 0.001). These factors were also prognostic determinants for clinical progression.

Ra-223 was effective and well-tolerated in real-world practice, with the number of treatment cycles serving as a predictor of overall survival. Additional case collection and further analysis incorporating data from the PEACE-3 trial will be presented.