Treatment evolution for metastatic castration-resistant prostate cancer with recent introduction of novel agents: Retrospective analysis of real-world data

Abstract

Despite increasing drug treatment options for metastatic castration-resistant prostate cancer (mCRPC) patients, real-world treatment data are lacking. We conducted retrospective analyses of commercial claims and electronic medical record (EMR) databases to understand how treatment patterns for mCRPC have changed in a US-based real-world population. Truven Health Analytics MarketScan® (2000-2013) and EMR (2004-2013) databases were used to identify patients with an index prostate cancer diagnosis (ICD-9 codes 185X or 233.4X) and prescription claims for an mCRPC drug (mitoxantrone, estramustine, docetaxel, sipuleucel-T, cabazitaxel, abiraterone acetate, enzalutamide, or radium-223). Regimen analyses for first line of therapy (LOT1), second line of therapy, and beyond were performed among cohorts based on year of first mCRPC drug usage. mCRPC drug usage and treatment duration were compared across cohorts and age groups within each cohort. The commercial claims cohort yielded 3437 evaluable patients. Most men (91%) commencing mCRPC treatment had docetaxel as LOT1 in 2010; this number had declined to 15% in 2013. In 2013, 67% and 9% of patients used abiraterone acetate and enzalutamide, respectively, as LOT1. Among both commercial claims and EMR cohorts, treatment pattern changes were most pronounced in men aged >80 years, and median treatment duration for some mCRPC drugs was shorter than expected based on available clinical trial information. These results demonstrate a shift in mCRPC treatments during the past 5 years, with greater use of newer noncytotoxic treatments than docetaxel. These real-world data aid in understanding the changing role of chemotherapy in the management of mCRPC. The use of cytotoxic drugs for metastatic castration-resistant prostate cancer (mCRPC) has declined dramatically during the past 5 years, with greater use of newer noncytotoxic treatments for mCRPC as both first line and second line of therapy. The shift away from cytotoxic therapy was most pronounced in elderly patients, likely due to the better tolerance of highly effective antiandrogen therapy (abiraterone acetate and enzalutamide). These changes in treatment patterns hold the potential of expanding the proportion of men able to receive treatment for mCRPC.