Lu-Prostate-Specific Membrane Antigen Therapy in Patients with Metastatic Castration-Resistant Prostate Cancer and Prior Ra (RALU Study).

Ra-dichloride (Ra) and Lu-prostate-specific membrane antigen (PSMA) are approved treatments for metastatic castration-resistant prostate cancer (mCRPC). The safety and effectiveness of sequential use of Ra and Lu-PSMA in patients with mCRPC are not well described. This study aimed to evaluate Lu-PSMA safety and efficacy in patients with mCRPC previously treated with Ra. The radium→lutetium (RALU) study was a multicenter, retrospective, medical chart review. Participants had received at least 1 Ra dose and, in any subsequent therapy line, at least 1 Lu-PSMA dose. Primary endpoints included the incidence of adverse events (AEs), serious AEs, grade 3-4 hematologic AEs, and abnormal laboratory values. Secondary endpoints included overall survival, time to next treatment/death, and change from baseline in serum prostate-specific antigen and alkaline phosphatase levels. Data were from 133 patients. Before Lu-PSMA therapy, 56% (75/133) of patients received at least 4 life-prolonging therapies; all patients received Ra (73% received 5-6 injections). Overall, 27% (36/133) of patients received at least 5 Lu-PSMA infusions. Any-grade treatment-emergent AEs were reported in 79% (105/133) of patients and serious AEs in 30% (40/133). The most frequent grade 3-4 laboratory abnormalities were anemia (30%, 40/133) and thrombocytopenia (13%, 17/133). Median overall survival was 13.2 mo (95% CI, 10.5-15.6 mo) from the start of Lu-PSMA. In this real-world setting, Ra followed by Lu-PSMA therapy in heavily pretreated patients with mCRPC was clinically feasible, with no indication of impairment of Lu-PSMA safety or effectiveness.

© 2023 by the Society of Nuclear Medicine and Molecular Imaging.

PMID: 37827838