title: Comparative effectiveness of everolimus-based therapy versus endocrine monotherapy among postmenopausal women with HR+/HER2- metastatic breast cancer: a retrospective chart review in community oncology practices in the US.
abstract: BACKGROUND
  Everolimus-based therapy and endocrine monotherapy are used among postmenopausal women with hormone receptor-positive human epidermal growth factor receptor-2 negative (HR+/HER2-) metastatic breast cancer (mBC) whose disease progressed or recurred on a non-steroidal aromatase inhibitor (NSAI). However, limited evidence exists regarding the real-world comparative effectiveness of these agents.
  
  
  METHODS
  This retrospective chart review examined postmenopausal HR+/HER2- mBC patients in community-based oncology practices who received everolimus-based therapy or endocrine monotherapy (index therapy) as any line of therapy for mBC between 1 July 2012 and 15 April 2013 after NSAI failure. Time on treatment (TOT), progression-free survival (PFS), and time to chemotherapy (TTC) from index therapy initiation were compared using Kaplan-Meier analyses and Cox proportional hazards models adjusting for baseline characteristics.
  
  
  RESULTS
  A total of 243 and 270 patients received everolimus-based therapy or endocrine monotherapy in a quota-based sample. Patients treated with everolimus-based therapy had a higher proportion of visceral metastases, high tumor burden, and use of prior chemotherapies for mBC. After adjusting for baseline characteristics, everolimus-based therapy was associated with significantly longer TOT (HR = 0.67, 95% CI: 0.51-0.87) and PFS (HR = 0.75, 95% CI: 0.57-0.98) than endocrine monotherapy. No significant difference was found between everolimus-based therapy and endocrine monotherapy in TTC (HR = 0.81, 95% CI: 0.52-1.27). Results stratified by line of therapy were generally consistent with the overall results.
  
  
  CONCLUSIONS
  Limitations include recall and information bias with potentially absent or erroneous chart data, unobserved factors due to non-randomization, inability to measure outcome assessments paired with measuring outcomes prior to exposures, and potential patient selection bias associated with chart review.
  
  
  CONCLUSIONS
  Among a nationwide sample of postmenopausal HR+/HER2- mBC patients treated in community oncology settings, treatment with everolimus-based therapy was associated with significantly longer TOT and PFS compared to endocrine monotherapy.
authors.affiliation: Analysis Group Inc. , New York, NY , USA.
authors.forename: Jipan
authors.initials: J
authors.lastname: Xie
authors.forename: Yanni
authors.initials: Y
authors.lastname: Hao
authors.forename: Nanxin
authors.initials: N
authors.lastname: Li
authors.forename: Peggy L
authors.initials: PL
authors.lastname: Lin
authors.forename: Erika
authors.initials: E
authors.lastname: Ohashi
authors.forename: Valerie
authors.initials: V
authors.lastname: Koo
authors.forename: James E
authors.initials: JE
authors.lastname: Signorovitch
authors.forename: Eric Q
authors.initials: EQ
authors.lastname: Wu
authors.forename: Denise A
authors.initials: DA
authors.lastname: Yardley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D018572:Disease-Free Survival; D000068338:Everolimus / Q000008:administration & dosage; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy; D017698:Postmenopause; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D000068338:Everolimus; D018719:Erb-b2 Receptor Tyrosine Kinases
keywords: Breast cancer; Clinical outcomes; Endocrine therapy; Everolimus; HR+/HER2− metastatic breast cancer