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.

Keywords: metastatic castration-resistant prostate cancer; prostate cancer; real-world; treatment patterns.

Figure 1

Metastatic castration‐resistant prostate cancer (mCRPC) drug usage proportion. (A) 2000–2003 and 2004–2008 commercial claims cohorts^a; (B) 1‐year cohorts from 2010 to 2013 for LOT1; (C) 1‐year cohorts from 2010 to 2013 for LOT2+. LOT1, first line of treatment; LOT2, second line of treatment; LOT2+, beyond second line of treatment. ^aIn each of LOT1 and LOT2 settings, mCRPC drug usage proportion for each of these agents was significantly different (P < 0.0001) comparing the 2000–2003 and 2004–2008 commercial claims cohorts. ^bNo other claim of an mCRPC drug ±90 days from an mCRPC drug claim.

Figure 2

Metastatic castration‐resistant prostate cancer (mCRPC) usage proportion for LOT1 by age group. (A) individual year commercial claims cohorts from 2010 to 2013^a; (B) 2013 commercial claims and EMR cohorts. EMR, electronic medical record; LOT1, first line of treatment. ^amCRPC drug usage proportion in each of the age groups (44–64, 65–80, >80 years) was significantly different (P < 0.0001) for each of these agents comparing years 2010–2013.

Figure 3

Estimated median treatment duration of metastatic castration‐resistant prostate cancer (mCRPC) drugs^a in the 2000–2013 commercial claims cohort. (A) LOT1; (B) LOT2. LOT1, first line of treatment; LOT2, second line of treatment. Horizontal line = median; box = 25% and 75% quartiles, whisker = minimum and maximum values. ^aSipuleucel‐T was not included because of the fixed‐duration treatment course.

Figure 4

Metastatic castration‐resistant prostate cancer (mCRPC) drug usage proportion among docetaxel‐naïve and post‐docetaxel patients by age group in the 2010–2013 commercial claims cohort. In each of the age groups (44–64, 65–80, >80 years), the drug usage proportion of abiraterone acetate (P < 0.0001) and enzalutamide (P = 0.0003) was significantly different between the docetaxel‐naïve and post‐docetaxel settings, whereas the drug usage proportion of sipuleucel‐T (P = 0.40) and cabazitaxel (P = 0.42) was not significantly different between the docetaxel‐naïve and post‐docetaxel settings.