Impact of Prior Treatments on Clinical Outcomes in Patients With Metastatic Castration-Resistant Prostate Cancer: A Real-World Analysis in the United States.

INTRODUCTION

Treatment intensification (combining androgen deprivation therapy [ADT] with an androgen receptor pathway inhibitor [ARPi]) and/or chemotherapy has demonstrated benefit over ADT-only treatment in prostate cancer settings before metastatic castration-resistant prostate cancer (mCRPC). This real-world analysis assessed the rates of treatment intensification before the mCRPC setting, first-line (1L) treatment patterns in mCRPC, and clinical outcomes in patients with mCRPC in the United States.

PATIENTS AND

METHODS

This noninterventional, retrospective cohort study utilized the Flatiron Health electronic health record database from 2016 to 2023 and included patients diagnosed with metastatic prostate adenocarcinoma on or after January 1, 2016, whoreceived 1L treatment for mCRPC. The primary objective was to describe mCRPC treatment patterns stratified by prior treatment(s) received. Secondary objectives included descriptive analyses of demographic and clinical characteristics at mCRPC diagnosis, median time to prostate-specific antigen progression or death (TTPD), and median overall survival (OS), stratified/grouped by prior treatment intensification.

RESULTS

Before mCRPC diagnosis, most patients (73.9% [3963/5361]) had not received treatment intensification; 867 (16.2%) had received prior ARPi only; 448 (8.4%), prior taxane only; and 83 (1.5%), both prior ARPi and taxane. The use of ARPi-only treatment before mCRPC diagnosis rose from 10.3% in 2018 to 34.8% in 2023. Over the study course, the majority (76.8%) of patients received an ARPi as 1L treatment for mCRPC. In the overall population, median TTPD was 12.1 months and trended lower for patients who had received prior ARPi-only treatment. Overall median OS was 24.6 months and trended lower for patients who received prior ARPi only or both prior ARPi and taxane.

CONCLUSION

Despite increased use of chemotherapy and ARPis prior to mCRPC, treatment intensification is underutilized. Clinical outcomes in patients receiving 1L treatment for mCRPC varied by prior treatment(s) received, highlighting the need for novel therapies and optimal treatment sequencing.