2477P Real-world prostate-specific antigen (PSA) response with darolutamide or abiraterone in metastatic hormone-sensitive prostate cancer (mHSPC) triplet therapy

This retrospective chart review cohort study included adult pts with mHSPC in the US-based ConcertAI Patient360TM database who initiated DAR/ABI triplet therapy from 1/2020–1/2024. Endpoints were time to undetectable PSA (<0.2 ng/mL) and time to metastatic castration-resistant prostate cancer (mCRPC), by baseline PSA groups (low [Q1] ≤7.83 ng/mL; high [Q2–4] >7.83 ng/mL), and the relationship between undetectable PSA and time to mCRPC.

Of 242 evaluable pts (DAR n=141; ABI n=101), baseline characteristics were similar between cohorts. Median baseline PSA was 36 ng/mL in DAR pts and 22 ng/mL in ABI pts. Undetectable PSA was achieved by 66% of DAR pts and 53% of ABI pts. Regardless of baseline PSA group, DAR pts had a shorter time to undetectable PSA and longer time to mCRPC. In pts with high baseline PSA, at 12 months, the Kaplan-Meier (KM)-estimated probability of undetectable PSA was 61.9% for DAR (95% CI 51.0, 72.9) and 46.2% (95% CI 32.0, 63.0) for ABI; the probability of mCRPC was 21.1% (95% CI 13.8, 31.6) for DAR and 31.4% (95% CI 19.5, 48.1) for ABI. In pts with low baseline PSA, at 12 months, the KM-estimated probability of undetectable PSA was 93.8% (95% CI 75.3, 99.6) for DAR and 68.8% (95% CI 42.9, 91.1) for ABI; the probability of mCRPC was 5.0% (95% CI 0.7, 30.5) for DAR and 37.0% (95% CI 21.1, 59.5) for ABI. Among DAR pts, those with undetectable PSA had a lower risk of mCRPC vs pts who did not (7% vs 51%).

In this real-world study, DAR pts had a more favorable PSA response vs ABI pts, including higher undetectable PSA rates and shorter time to undetectable PSA, and a longer time to progression to mCRPC; these results were observed regardless of baseline PSA group. Undetectable PSA response with DAR was correlated with lower mCRPC risk.