OBJECTIVES: To estimate costs for metastatic castration-resistant prostate cancer (mCRPC) in order to assess the relative value of newer treatments approved for mCRPC.

METHODS: This retrospective cohort study used claims data from Truven MarketScan Commercial and Medicare Supplement Plan (Medigap) databases. Males ≥18 years with ≥1 prostate cancer diagnosis (ICD-9/10) and no end stage renal disease were indexed on the first observed mCRPC-specific treatment (proxy for mCRPC) claim date between 8/1/2011-6/30/2016. Patient characteristics during ≥6 months prior were described; 12-month post-index all-cause costs in 2016 US dollars were estimated. Generalized linear model was used to compare adjusted cost between abiraterone acetate + prednisone (AAP) and enzalutamide (ENZ) cohorts.

RESULTS: A total of 727 and 1,916 mCRPC patients from the commercial and Medigap databases were followed up for a mean of 668 and 696 days, respectively. Among commercially-insured patients, mean age was 59.7 (Standard Deviation=4.2) years; mean Quan-Charlson Comorbidity Index (QCI) was 7.0 (2.8). All-cause 12-month costs were $177,485 ($90,683) (mCRPC treatment: $96,910 [$58,854], medical care: $75,460 [$71,444], other pharmacy: $5,115 [$14,469]). Among Medigap patients, mean age was 77.0 (7.4) years; mean QCI was 6.7 (3.0). All-cause 12-month costs were $148,552 ($94,769) (mCRPC treatment: $86,927 [$46,421], medical care: $57,016 [$82,176], other pharmacy: $4,609 [$14,721]). Among 344 AAP and 110 ENZ commercially-insured patients, adjusted 12-month costs were $151,508 vs. $173,228 (p<.005). Among 1,081 AAP and 443 ENZ Medigap-insured patients, adjusted 12-month costs were $127,358 vs. $139,352, p <0.001. Lower total costs for ABI patients resulted mainly from lower outpatient and pharmacy costs.

CONCLUSIONS: Costs among mCRPC patients show significant variation, with patients initiating on AAP incurring significantly lower costs compared to ENZ over the first 12-months of treatment. Increased focus on improving quality outcomes and introducing new therapies across CRPC requires that we try to reduce the variation across the space.