Real world data of 177 Lutetium-PSMA-617 for metastatic castration resistant prostate cancer (mCRPC): Analysis of patients treated from 2 large reference centers.

e17050 Background: 177 Lu-PSMA-617 was recently approved for the treatment of patients with mCRPC in the USA. While treatment is associated with improved survival, responses to therapy are lower in patients with visceral metastasis and with FDG avid disease. In this study, we aim to characterize response to the therapy trying to optimize patient selection for 177 Lu-PSMA-617. Methods: Patients treated from 2020 to 2023 in 2 large oncology centers in Brazil were analyzed. Our primary endpoint was to investigate the PSA response rate. Secondary endpoints included overall survival (OS), time to next sequential therapies (TNST) and PSA response in patients with visceral disease. Patients were treated after being submitted to a double image consisting of PET-CT PSMA and a PET-CT FDG (as indicated by the TheraP trial, Hoffman et al.) confirming disease uptake without divergent disease. Results: A total of 32 patients with mCRPC were included in this analysis. The median age was 73 years. Median number of prior lines of therapy for mCRPC was 3 with 20 receiving more than one androgen receptor signaling inhibitor (ARSI) and 5 receiving more than one taxane. The percentage with a PSA response was 48,5% and visceral disease was present in 56,3% of patients. Response rate for pts with visceral disease versus non-visceral was 21,9% vs 43,8%. The Medians of TNST and OS were respectively 7 and 9,6 months. The characteristics of patients with and without a PSA response are detailed in the table. Conclusions: Our cohort, characterized by advanced age, extensive prior treatments, and elevated PSA values, exhibited a PSA response that aligns with patients treated in randomized trials. Notably, our patients with visceral disease demonstrated a lower PSA response. Table: see text