(315) Economic burden of neutropenia among patients treated for HR+/HER2- and triple-negative metastatic breast cancer in the United States: a retrospective claims analysis

Background: : Neutropenia is a common adverse event associated with metastatic breast cancer (mBC) treatments. Little is known about the economic burden of neutropenia in mBC to US health systems.

Objective: : To evaluate all-cause and neutropenia-related costs and healthcare resource utilization (HCRU) among patients with HR+/HER2- and triple-negative (mTNBC) mBC.

Methods: : Patients with ≥1 ICD-10 diagnosis code for mBC were identified in IQVIA PharMetrics® Plus claims database from 9-2019 to 6-2024. Selection criteria included continuous enrollment 6 months before and ≥3 months after the index (diagnosis of mBC) date, receipt of mBC treatment post-index, and no diagnosis codes for other cancers ≤15 months pre-index. Study patients were categorized into HR+/HER2- mBC or mTNBC cohorts based on mBC treatment post-index using treatment-based proxies. All-cause and neutropenia-related HCRU and costs per patient per month (PPPM) were reported by treatment category across the duration of any line of mBC treatment.

Results: : Among HR+/HER2- patients with mBC (n=4,650; 98.1% female; mean age, 55 years; 94.0% NCI comorbidity index < 1), neutropenia was experienced by 48.5%, 32.4%, 24.8%, and 8.8% of patients over the duration of sacituzumab govitecan (SG) (n=68), chemotherapy (CT) (n=4,507), other targeted therapy (TT) (n=1,690), and endocrine therapy (ET) (n=3,325) regimens, respectively. Among patients with mTNBC (n=1,409; 99.4% female; mean age, 56 years; 91.1% NCI comorbidity index < 1), neutropenia was experienced by 43.9%, 36.1%, and 39.4% of patients over the duration of SG (n=246), CT (n=482), and TT (n=1,299) regimens. All-cause (and neutropenia-related, %) costs (PPPM) were $44,921 ($8,046, 18%), $13,386 ($1,502, 11%), $19,299 ($232, 1%), and $6,110 ($75, 1%) during receipt of SG, CT, TT, and ET regimens, respectively, for patients with HR+/HER2- mBC, and $44,568 ($7,720, 17%), $13,892 ($2,294, 17 %), and $25,980 ($1,825, 8%) over the duration of SG, CT, and TT regimens for patients with mTNBC. The proportion of patients making a neutropenia-related inpatient and outpatient visit was 18% and 35%, 5% and 31%, 2% and 24%, and 0% and 9% during receipt of SG, CT, TT, and ET regimens, respectively, for patients with HR+/HER2- mBC, and 9% and 40%, 8% and 34%, and 10% and 36% during the receipt of SG, CT, and TT regimens for patients with mTNBC.

Conclusions: : Neutropenia is a common adverse event with substantial impact to the overall economic burden among patients with mBC. An unmet need exists for treatments that balance costs of care with clinical benefit for these patients.

Sponsorship:: Daiichi Sankyo