Health care resource utilization and costs in metastatic castration-resistant prostate cancer patients treated with enzalutamide or abiraterone acetate.

Abstract

232 Background: Cost of care is an important component of valuation of novel treatments in oncology. Enzalutamide (ENZA) and abiraterone acetate (ABI) are approved hormonal agents for the treatment of metastatic castration-resistant prostate cancer (mCRPC). This study compared healthcare resource utilization (HRU) and costs for patients treated with ENZA or ABI in the U.S. Methods: Adult mCRPC patients initiating ENZA or ABI before and or after cytotoxic chemotherapy were identified from the Truven MarketScan claims database (2012–2015). The first claim of ENZA or ABI was defined as the index date; continuous enrollment ≥6 months before and ≥3 months after the index date was required. HRU and costs were estimated during the post-index period for both cohorts. Generalized linear models compared HRU and costs between the cohorts and were adjusted for baseline demographic and clinical covariates. Analyses were separately conducted for chemo-naïve and chemo-experienced patients. Results: The study included 3230 chemo-naive patients (ENZA 920; ABI 2310) and 692 chemo-experienced patients (ENZA 262; ABI 430). Among chemo-naive patients, ENZA cohort was older (mean age: 74.5 vs 73.5; p=0.013), with a higher proportion of baseline comorbidities vs ABI cohort. During the post-index period, ENZA cohort had fewer all-cause inpatient admissions (IPA) [adjusted incidence rate ratio (IRR) 0.87; p=0.033], all-cause outpatient visits (OPV) [adjusted IRR 0.94; p=0.004], and PC-related OPV (adjusted IRR 0.92; p<0.001) vs the ABI cohort. Within 3 months of the index date, ENZA cohort was less likely to have an all-cause IPA (adjusted odds ratio [OR] 0.75; p=0.029). In addition, ENZA cohort had lower PC-related IPA and emergency department (ED) costs vs ABI cohort. The differences of HRU and medical costs between the 2 cohorts were not statistically significant for chemo-experienced patients. Conclusions: Despite a higher comorbidity burden at baseline, chemo-naive mCRPC patients treated with ENZA incurred less HRU and lower PC-related IPA and ED costs vs ABI cohort. Differences between the 2 cohorts were not statistically significant for chemo-experienced patients.