Safety and Survival Outcomes of<sup>177</sup>Lu-Prostate-Specific Membrane Antigen Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer with Prior<sup>223</sup>Ra treatment: The RALU Study
Kambiz Rahbar, Markus Essler, Kim M. Pabst, Matthias Eiber, Christian la Fougère, Vikas Prasad, Philipp Rassek, Ergela Hasa, Helmut Dittmann, Ralph A. Bundschuh, Wolfgang P. Fendler, Milena Kurtinecz, Anja Schmall, Frank Verholen, Oliver Sartor
Abstract
The RAdium LUtetium (RALU) study evaluated the feasibility of sequential alpha and beta emitter use in patients with bone-predominant metastatic castration-resistant prostate cancer. Methods: This pre-planned, interim, retrospective analysis investigated safety and survival outcomes with lutetium-177-PSMA (<sup>177</sup>Lu-PSMA) in patients treated with prior radium-223 (<sup>223</sup>Ra). Results: Forty-nine patients were evaluated. Patients received a median of 6 <sup>223</sup>Ra injections; 59% of patients received ≥4 <sup>177</sup>Lu-PSMA cycles. Most (69%) patients received ≥4 life-prolonging therapies before <sup>177</sup>Lu-PSMA. Common Terminology Criteria for Adverse Events Grade 3–4 treatment-emergent adverse events during <sup>177</sup>Lu-PSMA therapy and a 30-day follow-up period included anemia (18%) and thrombocytopenia (2%). Median overall survival was 12.6 (95% CI 8.8–16.1) and 31.4 months (95% CI 25.7–37.6) from starting <sup>177</sup>Lu-PSMA or <sup>223</sup>Ra, respectively. Conclusions: <sup>177</sup>Lu-PSMA treatment was well tolerated in patients who had received prior <sup>223</sup>Ra. <sup>223</sup>Ra use before <sup>177</sup>Lu-PSMA is feasible and can be considered for future assessment of optimal treatment sequence.