Impact of race on outcomes to 177Lu-PSMA-617 (LuPSMA) for metastatic castrate-resistant prostate cancer (mCRPC).

Abstract

27 Background: Prior work suggests that African American (AA) and other minority patients (pts) derive equal benefit from taxane chemotherapy and androgen receptor pathway inhibitors (ARPIs) for mCRPC as white pts. LuPSMA showed an overall survival (OS) benefit in mCRPC pts after prior taxane and ARPI. However, there are no data on racial differences in outcomes to LuPSMA. Methods: We queried an IRB-approved registry of all pts treated with at least 2 cycles of LuPSMA between June 2022 and August 2023 at two academic medical centers in Boston, MA. Clinical data, including self-reported race, was abstracted from the electronic medical record. Pts of AA, Hispanic/Latino and Asian race were categorized as minorities. Outcomes of interest were the proportion of patients with ≥50% decrease in PSA levels during LuPSMA therapy (PSA50) and OS, defined from the date of the first cycle of LuPSMA. PSA50 and OS between races were compared with the Chi-Square and log-rank tests, respectively. Results: A total of 156 pts were included. Median age at LuPSMA initiation was 73 years (range 53-92) and the median number of prior lines of therapy was 5 (range 2-12); all pts had received ≥1 taxane and ≥1 ARPI. 136 (87%), 10 (6%), 6 (4%) and 4 (3%) pts were White, AA, Hispanic/Latino and Asian, respectively. The median number of LuPSMA cycles received in the entire cohort was 4 (range 2-7), and median follow-up was 7.1 months. A numerically higher proportion of minority pts had visceral disease at baseline compared to White pts (50% vs. 31%, (X2 = 2.87, p=0.090). Overall, 86 pts (55%) had a PSA50, with PSA50 of 55% (n=75), 60% (n=6), 67% (n=4) and 25% (n=1) amongst White, AA, Hispanic/Latino and Asian pts, respectively. There was no significant difference in PSA50 between White and minority pts (X2 = 0.00, p=0.990). Median OS in the entire cohort was 12.9 months and was not significantly different between White and minority pts (12.9 months vs. 8.5 months, p=0.533). The Table summarizes outcomes by race. Conclusions: PSA50 and OS were comparable between minority and White pts receiving LuPSMA for mCRPC, despite minority pts tending to present with more visceral disease, a known adverse prognostic factor. Validation of these findings and efforts to widen access to LuPSMA amongst minorities are required, given that pts of all racial backgrounds appear to benefit equally from LuPSMA. [Table: see text]