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

Abstract

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. <b>Methods:</b> This preplanned interim retrospective analysis investigated safety and survival outcomes with ¹⁷⁷Lu-PSMA in patients treated with prior ²²³Ra. <b>Results:</b> Forty-nine patients were evaluated. Patients received a median of 6 ²²³Ra injections; 59% of patients received at least 4 ¹⁷⁷Lu-PSMA cycles. Most (69%) patients received at least 4 life-prolonging therapies before ¹⁷⁷Lu-PSMA. Common Terminology Criteria for Adverse Events grade 3-4 treatment-emergent adverse events during ¹⁷⁷Lu-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 ¹⁷⁷Lu-PSMA or ²²³Ra, respectively. <b>Conclusion:</b> ¹⁷⁷Lu-PSMA treatment was well tolerated in patients who had received prior ²²³Ra. ²²³Ra use before ¹⁷⁷Lu-PSMA is feasible and can be considered for future assessment of the optimal treatment sequence.