Abstract P1-18-17: The economic burden of HER2-targeted therapy among metastatic breast cancer patients
Authors: Forero-Torres Andres , Anupindi Vamshi Ruthwik , Yeaw Jason , DeKoven Mitch , Feliciano Joseph , Richhariya Akshara 
Published: March 2020

Abstract
Background: There is limited information on the burden of metastatic breast cancer (mBC) with a central nervous system (CNS) metastasis in the literature. The objective of this study was to quantify the total all-cause healthcare resource utilization (HCRU) and costs among adult mBC patients administered HER2-targeted therapy with/without a CNS metastasis.
Methods: Retrospective study included continuously enrolled patients with a diagnosis (ICD-9 / ICD-10 codes) of BC and mBC (stage III/IV metastasis) and a pharmacy claim of anti-HER2 therapy (index date) between 1/1/12-9/30/17 identified from IQVIA’s Real World Adjudicated Claims – US Database. After excluding patients with breast-related surgery and radiation procedure in the 6-month baseline period, 3 mutually exclusive treatment groups were created: trastuzumuab (T), T + chemotherapy (TC [including capecitabine or taxanes]) and lapatinib group (L [with or without chemotherapy]), each further stratified by presence/absence of CNS metastasis (identified by diagnosis codes/brain radiation procedures). Overall treatment groups were propensity score matched 1:1:1. All-cause HCRU and costs were evaluated over the 1-year follow-up period.
Results: 5,895 HER2-targeted therapy patients were initially identified with 172 patients in each of the 3 treatment groups post-matching. Among these patients, 56.4%, 57.6% and 59.3% patients had a CNS metastasis in T, TC and L groups, respectively. The mean overall age of patients was 52.8, 52.3 and 52.6 years in T, TC and L groups, respectively, with a higher proportion of patients in the 55-64 age group. Majority of patients had arthritis/pain and cardiovascular diseases or were de novo metastatic in the baseline period. Baseline mean all-cause total costs were $77,069 among T group (CNS: $83,164; no CNS: $69,186), $62,164 among TC group (CNS: $66,906; no CNS: $55,733) and $81,007 among L group (CNS: $95,803; no CNS: $59,447). Costs were mainly driven by pharmacy (Rx)/outpatient (OP) setting. Over the 1-year follow-up period, mean total Rx costs were $115,453 (mean visits: 86.3), $81,091 (mean visits: 127.1) and $119,319 (mean visits: 83.3) among T, TC and L groups, respectively. This was followed by OP costs with $45,498 (mean visits: 189.2) in T, $62,263 (mean visits: 259.8) in TC and $69,654 (mean visits: 196.6) in L group. Inpatient (IP) costs were $13,319 (average hospital length of stay (LOS): 2.9 days), $18,177 (LOS: 2.2 days) and $10,239 (LOS: 1.4 days) among T, TC and L groups, respectively. CNS patients had higher mean total costs compared to the no CNS group among these treatment groups (T: $192,252 vs $153,784; TC: $237,376 vs $221,647 amd L: $205,637 vs $191,219).
Conclusions: Costs among mBC patients administered HER2-targeted therapy were highest for Rx, followed by OP and then IP over the 1-year follow-up period. Among each of the treatment groups, CNS metastasis patients incurred higher costs compared to patients without a CNS metastasis.
Table 1: HCRU and CostsCosts/HCRU (Mean (SD))T TC L Overall (172)CNS (97)No CNS (75)Overall (172)CNS (99)No CNS (73)Overall (172)CNS (102)No CNS (70)Total costs ($)175,479 (110,859)192,252 (117,801)153,784 (97,728)230,700 (118,127)237,376 (104,470)221,647 (134,688)199,769 (128,546)205,637 (123,428)191,219 (136,112)Rx visits86.3 (59.9)91.4 (66.0)79.6 (50.6)127.1 (51.4)130.5 (52.9)122.4 (49.3)83.3 (60.0)83.7 (60.5)82.6 (59.6)Total Rx costs ($)115,435 (90,443)118,388 (93,686)111,616 (86,543)149,609 (87,173)149,154 (84,852)150,226 (90,814)119,319 (99,587)119,754 (95,819)118,687 (105,539)OP visits189.2 (107.8)213.0 (119.0)158.4 (82.4)259.8 (97.5)269.6 (99.0)246.5 (94.5)196.6 (109.9)197.7 (102.1)195.0 (121.1)Total OP costs ($)45,498 (36,510)54,805 (41,792)33,462 (23,539)62,263 (40,151)69,685 (40,531)52,198 (37,607)69,654 (67,930)74,504 (68,010)62,588 (67,676)
Citation Format: Andres Forero-Torres, Vamshi Ruthwik Anupindi, Jason Yeaw, Mitch DeKoven, Joseph Feliciano, Akshara Richhariya. The economic burden of HER2-targeted therapy among metastatic breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-17.