Real-world use of bone-modifying agents (BMA) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) in the US.

95 Background: Most pts with prostate cancer with bone metastasis experience symptomatic skeletal events (SSEs) [PMID: 23884473], leading to increased morbidity and mortality. BMAs have been approved since 2007 and are recommended in mCRPC to prevent SSEs in pts with bone metastases or a high risk of osteoporotic fracture. Herein, we sought to assess the real-world trends of BMA administration in pts with mCRPC. Methods: We used the de-identified nationwide Flatiron Health electronic health record (EHR)-derived database to extract pt-level data. Inclusion criteria: pts with mCRPC with available date of diagnosis of mCRPC and information on receipt of BMA. Pts were categorized into 2 cohorts based on BMA receipt (e.g., bisphosphonates, denosumab, teriparatide, romosozumab) or not. Treatment trends of BMA by year of mCRPC diagnosis were summarized using frequency and percentages. Baseline characteristics at the time of mCRPC diagnosis (age, race-ethnicity, practice type, insurance) were compared between cohorts using the Wilcoxon rank-sum and Chi-squared tests. Results: Of 24,105 pts with metastatic prostate cancer in the dataset, 14,112 with mCRPC were eligible and included. 7,990 (56.6%) received BMA while 6,122 (43.4%) did not. In BMA receipt cohort: median age was 75 (IQR 67 – 81), majority were White (61%), treated in community practice (87%) and had commercial health plan (80%). In BMA non receipt cohort: median age was 75 (IQR 68 – 82), majority were White (61%), treated in a community practice (78%), and had commercial health plan (76%). The use of BMA decreased over time from 56% in 2013 to 46% in 2024 (Table). Statistically significant differences existed between cohorts in race-ethnicity, practice type, and insurance (p < 0.001) and will be presented at the meeting. Conclusions: Despite recommendations to use BMAs in pts with mCRPC and bone metastasis or high risk of osteoporotic fracture, our findings reveal a low utilization rate of BMAs in mCRPC setting with a notable decline over time. This highlights the need to incorporate the use of BMAs in clinical practice and improve access to these agents. Trends by year of mCRPC diagnosis in receipt of the first BMA and frequency and percentage of each agent. Year 2013N = 549 2014N = 1035 2015N = 1223 2016N = 1345 2017N = 1441 2018N = 1346 2019N = 1469 2020N = 1380 2021N = 1352 2022N = 1393 2023N = 1196 2024N = 383 Receipt of BMA, n (%) 316 (56) 674 (65) 792 (65) 837 (62) 886 (61) 766 (57) 816 (56) 766 (56) 692 (51) 713 (51) 556 (46) 176 (46) Denosumab, n (%) 190 (60.1) 450 (66.8) 557 (70.3) 599 (71.6) 606 (68.4) 533 (70) 526 (64.5) 488 (63.7) 410 (59.2) 414 (58.1) 290 (52.2) 94 (53) Zoledronic acid, n (%) 120 (38) 220 (32.6) 228 (28.7) 233 (27.8) 270 (30.5) 225 (29) 281 (34.4) 273 (35.6) 277 (40) 295 (41.4) 258 (46.4) 82 (47) Teriparatide, other bisphosphonates, n (%) 6 (1.9) 4 (0.6) 7 (1) 5 (0.6) 10 (1.1) 8 (1) 9 (1.1) 5 (0.7) 5 (0.7) 4 (0.5) 8 (1.4) 0