LAUSR

88 Background: Abiraterone acetate + prednisone and enzalutamide are approved oral targeted therapies (OTT) for metastatic castration-resistant prostate cancer (mCRPC) which have significant clinical benefit. However, their impact on healthcare cost relative to docetaxel (DOC) is not well understood. Methods: This retrospective cohort study used combined claims data from Truven MarketScan Commercial and Medicare Supplement Plan databases. Males ≥18 years with ≥1 prostate cancer diagnosis and a subsequent metastasis diagnosis were indexed on the first claim date of DOC or OTT between 1/1/2012 and 12/31/2016. ≥1 claim for an androgen deprivation therapy during the 12-month continuous enrollment period prior to metastasis was required; patients with end stage renal disease or other primary cancer were excluded. All-cause per patient per year (PPPY) costs were estimated in 2016 US dollars. A generalized linear model was used to compare adjusted costs between DOC and OTT cohorts. Results: A total of 1,159 and 200 mCRPC patients initiated on OTT and DOC, respectively. Mean follow up time for both cohorts was 1.2 years. Mean age of OTT patients was 75.1 (Standard Deviation = 10.7) years and mean Quan-Charlson Comorbidity Index (QCI) was 3.2 (1.9). Mean age of DOC patients was 65.9 (9.1) years; mean QCI was 2.9 (1.8). 21% of OTT and 56% of DOC patients were commercially insured. Following treatment initiation, total mean unadjusted all-cause PPPY costs were $144,350 ($80,606) and $137,814 ($84,405) for OTT and DOC cohort, respectively. The primary cost drivers were utilization of treatments indicated for mCRPC, outpatient encounters and inpatient hospitalizations. Total adjusted PPPY costs were higher for OTT than DOC patients ($141,008 vs. $125,318, p = 0.0012), mainly due to higher costs of treatments indicated for mCRPC ($80,443 vs. $55,820, p < .0001). Medical costs (excluding mCRPC treatment) for OTT initiated patients were lower ($54,570 vs. $64,614, p = 0.0128). Conclusions: In a real-world setting, initiation on OTT was associated with higher overall cost of care for mCRPC compared with DOC. However, the cost of medical services was significantly lower when initiated on OTT.