Everolimus use and associated factors among post-menopausal women with hormonal receptor positive/human epidermal growth factor receptor 2 negative metastatic breast cancer

Abstract

Background:Everolimus has been shown to be an effective HR+/HER2- mBC treatment in both clinical trials and real-world practice. The current study aims at understanding factors associated with everolimus use and how it is used in the real world.Methods:A retrospective chart review was conducted among postmenopausal HR+/HER2- mBC women who received everolimus, endocrine therapy (ET), or chemotherapy (CT) for mBC between 1 July 2012 and 15 April 2013 after an NSAI failure. Factors associated with everolimus use versus ET or CT were identified using multivariable logistic regressions. Reasons for prescribing everolimus and everolimus treatment patterns were described.Results:Liver metastasis and high tumor volume were associated with a higher likelihood of everolimus use versus ET (OR = 1.67, OR = 1.62) but a lower likelihood of everolimus use versus CT (OR = 0.43, OR = 0.30). Medicare-only insurance (OR = 0.30) as well as ECOG ≥2 (OR = 3.72) and prior CT in mBC (OR = 2.76) were associated with a lower and higher likelihood of everolimus use versus CT, respectively. The top reason for prescribing everolimus was efficacy (69–85%). About 15% and 29% of everolimus users in second line and third line or above received prior CT for mBC. Exemestane was the most common concomitant therapy with everolimus (56–87%). The majority of patients initiated everolimus at the labeled dose of 10 mg daily (>80%) and maintained this dose (>80%).Conclusions:In the real world, everolimus was used in more severe patients than ET but less severe patients than CT based on visceral metastasis, tumor volume, and performance status. The top reason for prescribing everolimus was efficacy. A large proportion of patients received first or second line CT before everolimus initiation. The majority of patients used everolimus according to the labeled combination and dose. Future studies are needed to determine optimal sequencing of everolimus, ET, and CT for HR+/HER2- mBC.