Safety and Survival Outcomes of (177)Lu-Prostate-Specific Membrane Antigen Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer with Prior (223)Ra treatment: The RALU Study

The radium lutetium (RALU) study evaluated the feasibility of sequential α- and β-emitter use in patients with bone-predominant metastatic castration-resistant prostate cancer. Methods: This preplanned interim retrospective analysis investigated safety and survival outcomes with (177)Lu-PSMA in patients treated with prior (223)Ra. Results: Forty-nine patients were evaluated. Patients received a median of 6 (223)Ra injections; 59% of patients received at least 4 (177)Lu-PSMA cycles. Most (69%) patients received at least 4 life-prolonging therapies before (177)Lu-PSMA. Common Terminology Criteria for Adverse Events grade 3–4 treatment-emergent adverse events during (177)Lu-PSMA therapy and a 30-d follow-up period included anemia (18%) and thrombocytopenia (2%). Median overall survival was 12.6 mo (95% CI, 8.8–16.1 mo) and 31.4 mo (95% CI, 25.7–37.6 mo) from starting (177)Lu-PSMA or (223)Ra, respectively. Conclusion: (177)Lu-PSMA treatment was well tolerated in patients who had received prior (223)Ra. (223)Ra use before (177)Lu-PSMA is feasible and can be considered for future assessment of the optimal treatment sequence.