The cost impact of disease progression to metastatic castration-sensitive prostate cancer

Abstract

BACKGROUND: Metastatic prostate cancer (PC) is associated with declining survival rates and increased health care expenditure. However, there are few studies quantifying these increased costs. OBJECTIVE: To estimate overall health care resource utilization and costs associated with progression to metastatic disease in Medicare or commercially insured patients with nonmetastatic castration-sensitive PC (nmCSPC) or previously undiagnosed PC. METHODS: In this retrospective, observational cohort study, we used data from the IBM MarketScan Commercial and MarketScan Medicare Supplemental Databases. Included patients were aged 18 years or older, had 2 or more health care claims associated with a diagnosis of PC, and had a diagnosis of metastatic disease (index date) between January 1, 2014, and December 31, 2016. Patients with PC were identified at index as either progressing from a localized disease state (nmCSPC) without evidence of castration resistance (progressors) or de novo metastatic without a prior PC diagnosis. Unadjusted all-cause direct health care costs for the 2-year pre-index period and up to 2 years post-index were summarized. Metastasis-related incremental all-cause direct health care costs were estimated using regression modeling to adjust for patient baseline characteristics, follow-up duration, and possible selection bias. RESULTS: We identified 3,854 patients who met the criteria for CSPC at metastasis: 2,766 Medicare patients (mean age 78.8 ± 7.6 years) and 1,088 commercial patients (mean age 57.6 ± 4.3 years), with de novo patients accounting for 28.9% and 34.5% of the 2 analysis populations, respectively. Mean unadjusted total all-cause health care costs over the 24-month pre-index period among progressors were $52,661 (Medicare) and $43,111 (commercial); those among de novo patients were $39,756 (Medicare) and $22,090 (commercial). Mean unadjusted post-index costs for progressors were $100,331 (Medicare) and $127,374 (commercial) over a mean follow-up duration of 14.63 and 18.41 months, respectively, and $124,538 (Medicare) and $173,408 (commercial) over a mean follow-up duration of 14.14 and 17.29 months for patients with de novo disease. After multivariate adjustment, incremental cost increases due to metastasis in patients with CSPC pre-index were estimated at $104,051 (Medicare) and $93,334 (commercial), assuming data are available for 24 months post-index. Allowing for variation in the postindex observation period, estimates were $71,308 (Medicare) and $82,336 (commercial). Among de novo patients, cost increases due to metastasis were estimated at $180,932 (Medicare) and $215,397 (commercial), assuming all patients have data for 24 months postindex. Allowing for variable follow-up, estimates were $113,253 (Medicare) and $161,714 (commercial). CONCLUSIONS: Development of metastatic CSPC is associated with considerable costs over a 24-month follow-up period. Cost increases are greater for de novo patients than for those who progressed from localized disease. DISCLOSURES: Q.-D. Trinh received personal fees from Astellas, Bayer, and Janssen and grants from Intuitive Surgical. L. Passos Chaves, Q. Feng, J. Zhu, and T. Abbott are employees of Astellas Pharma Global Development, Inc. R. Sandin is an employee of, and holds stock in, Pfizer AB. This study was funded by Astellas Pharma Inc. (Northbrook, IL) and Pfizer Inc., the codevelopers of enzalutamide. Astellas Pharma Inc. was involved in the study design, data collection, analysis, interpretation of data, and decision to present these results.

FIGURE 1

Average Monthly Cost and Patient Count