865P - Treatment outcomes of 3rd treatment in a real-world metastatic castration resistant prostate cancer (mCRPC) population: Results from the Dutch CAPRI-registry

Data on outcomes of a 3rd line life prolonging drug (LPD) in patients with metastatic castration resistant prostate cancer (mCRPC) is lacking. Aim of this study was to evaluate outcomes of a 3rd LPD in a real-world cohort of mCRPC patients. mCRPC patients with a 3rd LPD before July 1st 2017 were retrospectively identified from the Dutch Castration-resistant Prostate Cancer Registry (CAPRI) and followed to December 31st 2017. Outcomes were overall survival (OS), treatment duration (TD) and PSA response. The association of potential risk factors with death was tested by Cox proportional-hazard models after multiple imputation of missing baseline characteristics. We identified 602 patients treated with a 3rd LPD. Baseline characteristics are listed in the table. Median OS was 7.8mo (IQR 4.4-14.0), median TD was 3.2mo (IQR 1.9-4.7) and PSA response (≥ 50% decline) was observed in 131 patients (22%). ECOG PS of 1 and >1 (HR 1.48, p