• Jipan Xie, Yanni Hao, Nanxin Li, Peggy L Lin, Erika Ohashi, Valerie Koo, James E Signorovitch, Eric Q Wu, and Denise A Yardley.
• Analysis Group Inc. , New York, NY , USA.
• Curr Med Res Opin. 2015 Jun 1; 31 (6): 1095-103.

BackgroundEverolimus-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.MethodsThis 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.ResultsA 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.LimitationsLimitations 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.ConclusionsAmong 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.

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