Abstract P4-22-19: Time on treatment of everolimus versus endocrine monotherapy or chemotherapy for early-line treatment of HR+/HER2- metastatic breast cancer: A retrospective chart review study in the US
Authors: Li N , Ohashi E , Koo V , Xie J , Hao Y , Tang DH 
Published: March 2017

Background:

Among postmenopausal women with hormone receptor-positive, human epidermal growth factor receptor-2-negative (HR+/HER2-) metastatic breast cancer (mBC) whose disease progressed on a non-steroidal aromatase inhibitor (NSAI), everolimus-based therapy (EVE), different endocrine monotherapies (ET mono), and chemotherapies (CT) are commonly used. Time on treatment is an outcome primarily determined by a therapy's combined efficacy and safety profile. This study assessed the real-world time on treatment (TOT) among patients receiving these treatments in early-line (i.e., 1st and 2nd) settings.

Methods:

A nationwide sample of postmenopausal HR+/HER2- mBC patients treated by community oncologists in the US was included in this retrospective chart review. Eligible patients for this study were required to fail NSAI and then receive EVE, ET mono or CT (index therapy) as an early-line therapy for mBC between July 1, 2012 and April 15, 2013. TOT was measured from index therapy initiation to physician-reported treatment discontinuation and compared among treatment groups using Kaplan-Meier analyses with log-rank tests and Cox proportional hazards models adjusting for the line of therapy and baseline characteristics including recurrent or de novo disease status, age, race, insurance type, Charlson comorbidity index, sites of metastases (e.g., bone, any other visceral site), ECOG performance status, previous CT treatment in the mBC setting, and duration from the initiation of the last adjuvant ET to mBC diagnosis.

Results:

A total of 145 patients treated with EVE, 217 patients treated with ET mono, and 102 patients treated with CT were included in the analysis. Baseline characteristics among the three treatment groups were similar, although EVE-treated patients had higher burden of metastases relative to ET mono-treated patients, but lower burden relative to CT-treated patients. TOT was longer among EVE-treated patients than ET mono- and CT- treated patients (log-rank tests: p=0.01 and p&lt;0.01). For patients who completed their index treatment, the median TOT among EVE, ET mono, and CT treatment groups were 8.9, 5.7, and 6.1 months, respectively. After adjusting for baseline characteristics, EVE was associated with significantly longer TOT compared with ET mono [hazard ratio (HR) = 0.62, 95% confidence interval (CI): 0.45 – 0.85] and with CT (HR = 0.32, 95% CI: 0.22 – 0.46).

Conclusions:

This real-world US chart review study of postmenopausal women with HR+/HER2- mBC showed that patients receiving EVE in line 1 or 2 experienced significantly longer TOT than those receiving ET mono or CT.

Citation Format: Li N, Ohashi E, Koo V, Xie J, Hao Y, Tang DH. Time on treatment of everolimus versus endocrine monotherapy or chemotherapy for early-line treatment of HR+/HER2- metastatic breast cancer: A retrospective chart review study in the US [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-19.