177 LuLu-PSMA-617 ( 177 Lu-PSMA-617) in combination with an androgen receptor pathway inhibitor (ARPI) versus 177 Lu-PSMA-617 alone for the treatment of metastatic castration-resistant prostate cancer (mCRPC): A real-world prostate cancer disease observation (PRECISION) data platform analysis.

78 Background: 177 Lu-PSMA-617 is currently under investigation in combination with an ARPI in those with metastatic hormone-sensitive prostate cancer (PSMAddition trial: NCT04720157). This observational study was performed to assess the effectiveness of 177 Lu-PSMA-617 in combination with an ARPI in patients with mCRPC in the real-world setting. Methods: This was a retrospective cohort study of adults with mCRPC in the PRECISION data platform, a comprehensive database of prostate cancer patients compiled from diverse clinical settings in the US. Patients who received 177 Lu-PSMA-617 during March 23, 2022–June 27, 2025 were identified, among whom two cohorts were selected for inclusion: those who had evidence of ARPI use (apalutamide, darolutamide, abiraterone, or enzalutamide) at any time during 177 Lu-PSMA-617 treatment (concomitant ARPI cohort), and those who had no other treatment for mCRPC during 177 Lu-PSMA-617 treatment (no concomitant therapy cohort). The index date was initiation of 177 Lu-PSMA-617. Patient characteristics and prostate-specific antigen (PSA) responses were evaluated descriptively. Progression-free survival (PFS), defined as the time from 177 Lu-PSMA-617 initiation to disease progression or death, was estimated using Kaplan–Meier analysis. Results: A total of 1,880 patients treated with 177 Lu-PSMA-617 were identified, 140 in the concomitant ARPI cohort and 1,740 in the no concomitant therapy cohort. The median age was 74 years. Demographic characteristics were balanced between the groups, except that median baseline PSA was lower in the concomitant ARPI cohort when compared with patients in the no concomitant therapy cohort (18 ng/mL vs. 32 ng/mL). Before 177 Lu-PSMA-617 initiation, 94.3% and 73.6% of patients in the concomitant ARPI and 80.9% and 56.7% in the no concomitant therapy cohort had received ≥1 prior ARPI and ≥1 prior taxane, respectively. PSA response rates were broadly comparable between cohorts. The median (95% confidence interval) PFS was 14.7 (11.7–21.3) months among patients in the concomitant ARPI cohort vs 12.5 (11.5–13.6) months in the no concomitant therapy cohort. Ongoing follow-up aims to evaluate the impact of combining ARPI with 177 Lu-PSMA-617 on long-term clinical outcomes, including overall survival. Conclusions: The results of this study demonstrate that 177 Lu-PSMA-617 delivers clinical benefits inpatients with mCRPC with or without ARPI; however, addition of an ARPI may potentially improve these benefits. Prospective randomized controlled studies are needed to confirm this.