Ji, Richard

ImportancePatients with metastatic castration–resistant prostate cancer (mCRPC) harboring BRCA1/2 alterations are eligible to receive poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors as single agents or in combination with an androgen receptor pathway inhibitor after these agents showed survival improvement in their landmark clinical trials. However, data are limited regarding the uptake of PARP inhibitors in these patients.ObjectiveTo investigate the use of PARP inhibitors in patients with mCRPC harboring BRCA1/2 alterations.Design, Setting, and ParticipantsThis retrospective cohort study used the deidentified Flatiron-Health electronic health record–derived database of US community and academic practices to extract patient-level data. The data cutoff date was May 31, 2024. Patients with mCRPC with evidence of harboring BRCA1/2 alterations and alive after August 15, 2020 (ie, 3 months after the approval of the first PARP inhibitor, rucaparib, in mCRPC) were included. Statistical analysis was performed from September 2024 to May 2025.ExposuresAge, race and ethnicity, insurance status, and practice type at the time of mCRPC diagnosis.Main Outcomes and MeasuresThe receipt of PARP inhibitors. Multivariable logistic regression was conducted to assess the association between the exposures and the main outcome.ResultsOf 24 105 patients with metastatic prostate cancer, 443 male patients (median [IQR] age, 72 [65-79] years) had mCRPC with BRCA1/2 alterations and were eligible and included in our analysis. Of these patients, 227 (51.2%) received a PARP inhibitor, whereas 216 (48.8%) did not. Compared with patients covered by a commercial health plan, those covered by Medicare were significantly more likely to receive a PARP inhibitor (odds ratio, 1.91; 95% CI, 1.02-3.66; P = .047). The odds of receiving a PARP inhibitor were not significantly higher in patients treated in community practice compared with those treated in academic centers (odds ratio, 1.64; 95% CI, 1.00-2.70; P = .05).Conclusions and RelevanceThis retrospective cohort study of patients with mCRPC and evidence of BRCA1/2 alterations found that approximately half of patients did not receive PARP inhibitors despite evidence of survival improvement in this population. These findings highlight the need to increase awareness of the survival data and access to life-prolonging therapies in patients with mCRPC.

108 Background: PARPi are approved for the treatment of pts with mCRPC either as single agents or as a combination with an androgen receptor pathway inhibitor (ARPI) [PMID: 37442702]. In a US Food and Drug Administration (FDA) pooled analysis, the benefit from PARPi appeared greatest for pts harboring BRCA1/2 alterations [PMID: 38484203]. However, real-world uptake of PARPi in pts with mCRPC with BRCA1/2 alterations is unknown. Herein, our objective was to assess the usage of PARPi in real-world pts with mCRPC harboring BRCA1/2 alterations. Methods: A de-identified nationwide Flatiron Health electronic health record (EHR)-derived database was used to extract pt-level data. Eligibility criteria: pts with mCRPC harboring alterations in BRCA1 or BRCA2 or both and alive after 8/15/2020 (i.e., 3 months following the approval of the first PARPi, rucaparib, in mCRPC) with available treatment information. The data cutoff date was 5/31/2024. Pts were categorized into two cohorts based on the receipt of any PARPi or not. Baseline characteristics at the time of mCRPC diagnosis, including age, race-ethnicity, and insurance plan, were collected in both cohorts. Results: Of the overall cohort of 24,105 pts with metastatic prostate cancer, 443 pts had mCRPC with BRCA1/2 alterations and were eligible and included in this analysis. 227 (51.2%) received a PARPi, while 216 did not (48.8%). Among the 227 pts who received a PARPi, 166 received it as a single agent (73.1%), 40 received it in combination with an ARPI (17.6%), and 21 received it in combination with other agents (9.3%). The median age was 72 in both cohorts (IQR 65 – 79 in patients receiving a PARPi and 66 – 78 in patients who did not). Other baseline characteristics in both groups are shown (Table). Conclusions: Despite PARPi demonstrating survival improvement in pts with mCRPC with BRCA1/2 alterations, a significant proportion of pts do not receive them. Our findings highlight the need to improve education among clinicians of level 1 evidence and improve access to life-prolonging therapies in pts with mCRPC. Baseline characteristics of pts with mCRPC who received vs. did not receive a PARPi. Characteristic Subgroup Pts who received a PARPiN = 227 Pts who did not receive a PARPiN = 216 Race-ethnicity, n (%) Asian 9 (4) 1 (0.5) Black 22 (9.7) 30 (13.9) Hispanic-Latino 10 (4.4) 10 (4.6) White 149 (65.6) 124 (57.4) Other and unknown 37 (16.3) 51 (23.6) Insurance, n (%) Commercial health plan 192 (84.5) 182 (84.3) Medicare-other government programs 31 (13.7) 18 (8.3) Medicaid 1 (0.4) 3 (1.4) Others and unknown 3 (1.3) 13 (6)

109 Background: C and Lu are associated with overall survival benefit and approved for pts with mCRPC after prior treatment with docetaxel and an androgen receptor pathway inhibitor (ARPI). However, in real-world settings, administering Lu requires coordination across specialties and resources [PMID: 36637862], which could delay its administration. Herein, we sought to compare the time from medication order to administering the first dose of C versus Lu. Methods: This study used pt level data from the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database. Inclusion criteria: availability of the date of the first order of single-agent C or Lu and the date of first administration of the drugs. The time between the first medication order to the administration of single-agent C or Lu was measured. Wilcoxon rank-sum test was used to compare the median days between medication order to administration between these 2 agents and a stratified analysis by practice type and insurance was performed. Results: Of 2,329 orders, 2,045 orders were for C between 1/1/2013 and 1/26/2024, while 284 were for Lu between 8/1/2013 and 12/6/2023. The time from medication order to administration was significantly longer with Lu (median 22 days, IQR 12-43) compared to C (median 7 days, IQR 3-14, p < 0.001). Time from medication order to administration of C and Lu by practice type and insurance is summarized (Table). At the time of the first order, pts in Lu cohort, compared to C cohort, were significantly older (median age 74 vs. 72, p < 0.001), more likely to be treated at an academic practice (27% vs. 15%, p < 0.001), and more likely to be covered by a commercial health plan (80% vs. 73%, p < 0.001). Conclusions: Our results show that it takes significantly longer to administer Lu compared to C across different practice types and most insurance plans. These results could inform healthcare policies aimed at improving access to Lu and guide treatment selection in the clinic. Time from medication order to administration of C and Lu by practice type and insurance. Category Subtype (number of orders for C/number of orders for Lu) CN = 2045 LuN = 284 p-value Practice type, mean (range) (days) Academic (315/77) 1.3 (0 – 59) 9.2 (0 – 55) < 0.001 Community (1730/207) 13 (0 – 243) 44 (1 – 282) < 0.001 Insurance, mean (range) (days) Commercial (1494/226) 11 (0 – 163) 32 (0 – 215) < 0.001 Medicare/other government programs (266/46) 10 (0 – 120) 46 (0 – 282) < 0.001 Medicaid (32/2) 9 (0 – 76) 28 (0 – 55) 0.8 Others (72/6) 12 (0 – 42) 21 (0 – 41) 0.2 Unknown (181/4) 14 (0 – 243) 76 (39 – 91) < 0.001