Real-world ARPI utilization patterns and outcomes in metastatic castration-sensitive prostate cancer.

119 Background: Intensification of androgen deprivation therapy (ADT) with androgen receptor pathway inhibitors (ARPIs) or taxanes is the standard of care for treating metastatic castration-sensitive prostate cancer (mCSPC). This study evaluated the real-world (RW) adoption of ADT intensification regimens and assessed outcomes in mCSPC patients (pts). Methods: A US-based deidentified RW database (Integra PrecisionQ) was used to identify mCSPC pts who initiated first-line (1L) therapy between 1-Jan-2020 and 31-Mar-2025. 1L treatment regimens and proportion of regimens that included an ARPI were analyzed by year (2020-2025). Baseline pt characteristics included age, payer type, region, and comorbidities. We compared time to next treatment (TTNT) and time to discontinuation (TTD) between ARPI-intensified ADT combinations and ADT monotherapy (mono), including the individual performance of each ARPI. TTNT was defined as the time from initiation of the 1L treatment to the start of subsequent treatment and TTD was defined as the time from initiation of 1L treatment to its discontinuation. Results: A total of 2300 pts received 1L treatment for mCSPC between 2020 and 2025, with a cohort median follow-up of 15 months after initiating IL treatments. Of 2300 pts, 1739 (74.6%) received ADT intensification and 1420 of 1739 (82%) received ADT intensification with ARPI. Use of ARPI combinations increased from 55.3% (198/358) in 2020 to 67.1% (349/520) in 2024. Use of the ARPI + docetaxel + ADT triplet increased from 0.8% (3/358) of total regimens in 2020 to 7.5% (39/520) in 2024. Median TTNT for ARPI-intensified doublet regimens compared to ADT mono is summarized in the table (n=1652: ADT mono, n=591 vs. ADT + any ARPI, n=1061). There were no large differences in median TTNT for each ARPI doublet. After adjusting for age at treatment, race, payer mix, and comorbidities, pts receiving ARPI doublet regimens were significantly more likely to stay on therapy compared to those on ADT mono (HR 0.79; 95% CI: 0.69, 0.91). Conclusions: In a large deidentified RW database mCSPC ADT-ARPI intensification is increasingly used. Irrespective of the type of ARPI intensification received, pts treated with ADT + ARPI stayed on therapy significantly longer than pts treated with ADT monotherapy. Despite the observed benefit with ARPI intensification, one-quarter of pts received ADT monotherapy. Median TTNT and TTD of selected 1L mCSPC regimens (N=1652 of 2300).* Regimen ADT Mono (n=591) ADT + any ARPI (n=1061) ADT + AA/P(n=379) ADT + Enzalutamide(n=412) ADT + Apalutamide(n=186) ADT + Darolutamide (n=84) Age at 1L treatment (yr) 70.2 70.8 70.4 70.3 70.2 70.1 Median TTD (mo) 12.1 19.5 19.1 18.9 21.3 24.1 Median TTNT (mo) 13.4 20.5 20.5 19.6 22.1 24.4 AA/P, abiraterone acetate/prednisone. *Other therapies (n=648) including ADT + docetaxel and ADT + docetaxel + ARPI were not part of the primary comparison and are not included in this table.