Lu-177-Prostate-Specific Membrane Antigen Ligand After Ra-223 Treatment in Men with Bone-Metastatic Castration- Resistant Prostate Cancer: Real-World Clinical Experience

We analyzed real-world clinical outcomes of sequential alpha-/beta-emitter therapy for metastatic castration-resistant prostate cancer (mCRPC). Methods: We assessed safety and overall survival in 26 patients who received Lu-177-prostate-specific membrane antigen ligand (Lu-177-PSMA) after Ra-223 in the ongoing noninterventional REASSURE study (Ra-223 alpha-Emitter Agent in Nonintervention Safety Study in mCRPC Population for Long-Term Evaluation; NCT02141438). Results: Patients received Ra-223 for a median of 6 injections and subsequent Lu-177-PSMA for a median of 3.5 mo (>= the fourth therapy in 69%). The median time between Ra-223 and Lu-177-PSMA treatment was 8 mo (range, 1-31 mo). Grade 3 hematologic events occurred in 9 of 26 patients (during or after Lu-177-PSMA treatment in 5/9 patients; 8/9 patients had also received docetaxel). Median overall survival was 28.0 mo from the Ra-223 start and 13.2 mo from the Lu-177-PSMA start. Conclusion: Although the small sample size precludes definitive conclusions, these preliminary data, especially the Lu-177-PSMA treatment duration, suggest that the use of Lu-177-PSMA after Ra-223 is feasible in this real-world setting.