Abstract PO2-05-03: Costs associated with adverse events in patients receiving treatment for hormone receptor positive/human epidermal growth factor receptor-2 negative metastatic breast cancer
Authors: Shah Anju , Sainski-Nguyen Amy , Moore Kristin , Rehnquist MK , Nanda Rita 
Published: May 2024

Abstract
Background:Adverse event (AE)-related health care resource utilization (HCRU) and costs are an important component in understanding the economic burden associated with managing patients (pts) with cancer and can inform treatment decision-making and access for pts, providers, and payers. At present, there are little data on AE-related HCRU and costs among pts receiving late-line treatment for hormone receptor positive (HR+)/human epidermal growth factor receptor-2 negative (HER2–) metastatic breast cancer (mBC). As such, the objective of this analysis was to describe the AE-related HCRU and costs among pts with HR+/HER2– mBC receiving chemotherapy (CT) who have received prior CT and endocrine-based therapies (ET). Methods: This retrospective study included pts who had at least 1 prior ET, had completed at least 2 CTs, had initiated their third (or greater) CT (post-ET) in the metastatic setting between Jan 2016 and Mar 2022, and were included in the Optum Research Database. The start date for the current line of CT was the index date. Pts were followed until disenrollment from health plan, study end date (Jun 2022), or death. AEs included in this study were based on clinical impact; these AEs were then organized into categories. AE-related HCRU and costs were reported as per pt per month (PPPM) and included outpatient visits, office visits, emergency room visits, inpatient stays, other medical costs (eg, laboratory/ancillary costs), and pharmacy costs. Costs were adjusted to 2021 US dollars using the Consumer Price Index. Results: A total of 769 pts were included with a mean age of 64 y (standard deviation: 13 y) and baseline National Cancer Institute comorbidity score of 0 (44%) or 1–2 (39%). 51% were commercially insured. A total of 715 (93%) pts had ≥1 AE during the follow-up period; the mean total PPPM cost associated with AEs was $7421 (Table 1) and the majority of costs were driven by ambulatory visits (office and outpatient visits: $3846 PPPM; Table 1) and inpatient stays ($3042 PPPM; Table 1). Among pts who experienced AEs, AEs that were associated with the highest mean total PPPM costs included infections, hepatoxicity, gastrointestinal toxicity and renal failure events. The costs associated with infections and renal failures were predominantly driven by inpatient stay costs ($5540 and $3298 PPPM, respectively; Table 1). Conclusions: This real-world analysis suggests that there is high prevalence of AEs associated with CTs in late-line (≥3 CTs) HR+/HER2– mBC, which may lead to a substantial economic burden and suboptimal treatment outcomes. Newer, effective therapies with manageable AE profiles may offer a better benefit-to-risk profile and improve outcomes compared with chemotherapies.

Citation Format: Anju Shah, Amy Sainski-Nguyen, Kristin Moore, MK Rehnquist, Rita Nanda. Costs associated with adverse events in patients receiving treatment for hormone receptor positive/human epidermal growth factor receptor-2 negative metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-05-03.