Nahle, Tarek

129 Background: Androgen receptor pathway inhibitors (ARPIs) improve metastasis-free and overall survival in men with non-metastatic hormone-resistant prostate cancer (nmHRPC). Apalutamide and darolutamide were approved by the Federal Drug Administration in 2018 and 2019, respectively, based on pivotal clinical trials showing similar efficacy. However, no head-to-head comparisons exist in real-world settings. We compared prescription patterns and survival outcomes between apalutamide and darolutamide in men with nmHRPC using the Surveillance, Epidemiology and End Results (SEER)-Medicare data. Methods: We identified men aged ≥66 years with localized or locoregional prostate cancer between 2000 and 2021 using the SEER-Medicare linked database. Eligible patients initiated apalutamide or darolutamide between January 2019 and December 2021, defined by Medicare Part D claims. The index date was the first prescription of either agent. Men with distant metastases, prior malignancies and age ≤65 were excluded. Baseline demographics and clinical characteristics were compared using chi-square and Wilcoxon rank-sum tests. Survival was assessed using Kaplan-Meier analysis with log-rank tests. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) for mortality. Results: Among 582 men with nmHRPC, 435 (74.7%) received apalutamide and 147 (25.3%) received darolutamide. The mean age at diagnosis was 73.8 vs 74.1 years (p=0.95). Most patients were White (84.6% vs 81.0%, p=0.21) and resided in metropolitan areas (85.0% vs 88.4%, p=0.39). Darolutamide use was more frequent in the Northeast (42.9% vs 24.6%, p<0.001), while apalutamide was more common in the South (28.7% vs 15.6%, p<0.001). Patients receiving darolutamide had higher-grade tumors (68.0% grade III vs 51.3%, p=0.002) and a longer median time from diagnosis to prescription (93 vs 64 months, p<0.001). Kaplan-Meier curves and adjusted Cox models showed no significant difference in overall survival (HR 1.00; 95% CI 0.51–1.98; p=1.00). Age was independently associated with mortality (HR 1.05 per year; 95% CI 1.00–1.10; p=0.04). Conclusions: Apalutamide and darolutamide demonstrated comparable real-world survival outcomes in nmHRPC. Geographic and clinical factors influenced prescribing patterns, but survival did not differ between agents. Treatment choice may therefore be guided by patient comorbidities, tolerability, and clinician preference. Variable Comparison HR (95% CI) P-Value Treatment Darolutamide vs Apalutamide 1.00 (0.51,1.98) 1.00 Age at Diagnosis 1.05 (1.00, 1.10) 0.04* Race White vs Non-White 0.71 (0.28, 1.80) 0.47 Marital Status Married vs Unmarried 1.29 (0.60, 2.75) 0.51 Geographic Region -Midwest vs West 1.18 (0.34, 4.15) 0.79 -Northeast vs West 1.92 (0.92, 3.88) 0.07 -South vs West 1.01 (0.43, 2.36) 0.99

Abstract Background Socioeconomic position (SEP) is a fundamental social determinant of health (SDoH) contributing to observed disparities in cancer and cardiovascular (CV) care among individuals with prostate cancer (PC). Understanding the influence of SEP on CV health is essential for addressing outcome inequities within this population. Methods We conducted a retrospective study utilizing Surveillance, Epidemiology, and End Results (SEER)-Medicare to evaluate CV outcomes in patients ≥65 years with PC from 2009 to 2017. We studied the impact of SEP on cardiovascular events (CVEs), cardiovascular mortality (CVm), PC-specific mortality (PCsm), and all-cause mortality. CVE, CVm, and PCsm were analyzed using competing risk models and all-cause mortality with Cox proportional hazards models. A subgroup analysis was performed in Non-Hispanic Black and Non-Hispanic White individuals. Results We included 141 242 patients of whom 76 844 were in high SEP areas (45.6%) and 64 398 in low SEP ones (54.4%). Both groups had a mean age of 72 years; patients in low SEP areas were 67.5% Non-Hispanic White, 34.4% having diabetes, 73.3% hypertension, and 67.7% dyslipidemia versus the high SEP group with 85.6% Non-Hispanic White, 30.4% diabetes, 69.9% hypertension, and 70.7% dyslipidemia. Patients in low SEP areas had higher risks of CVm (subdistribution hazard ratio [sHR] = 1.18, 95% CI = 1.12 to 1.25), PCsm (sHR = 1.12, 95% CI = 1.06 to 1.17), CVE (sHR = 1.07, 95% CI = 1.04 to 1.09), and all-cause mortality (HR 1.16, 95% CI = 1.13 to 1.20). Accentuated results were shown in the Non-Hispanic Black subgroup. Conclusion Adverse SEP plays a significant role in shaping outcomes among older patients with PC, contributing to elevated risks of adverse CV and survival outcomes.