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Abstract
Objective:
This study aimed to compare time on treatment (TOT) among patients treated with everolimus and chemotherapy, two commonly used treatments for hormone-receptor-positive/human-epidermal-growth-factor-receptor-2-negative (HR+/HER2-) metastatic breast cancer (mBC).
Methods:
Postmenopausal women with HR+/HER2- mBC who initiated ≥1 new line of therapy for mBC during 20 July 2012–31 March 2014 after a non-steroidal aromatase inhibitor were identified from MarketScan and PharMetrics databases (2002Q1–2014Q2) using a claims-based algorithm. Patients were classified into treatment groups by regimen and line of therapy, and were followed until discontinuation of therapy, end of insurance eligibility, or data cut-off (30 June 2014). Discontinuation was defined as a treatment gap of ≥60 days; patients who did not discontinue were censored at the end of follow-up. TOT was compared between everolimus, chemotherapy, and capecitabine monotherapy using Kaplan–Meier analyses and multivariable Cox models adjusting for line of therapy, age, insurance, de novo mBC diagnosis, prior use of chemotherapy for mBC, sites of metastases, and Charlson comorbidity index.
Results:
Across the first four lines of therapies for mBC, a total of 940 everolimus, 3410 chemotherapy, and 721 capecitabine monotherapy regimens were included. Based on the different lines of therapies, the median TOT ranged from 5.5 to 7.2 months for everolimus, 4.3 to 4.7 months for chemotherapy, and 3.5 to 6.0 months for capecitabine monotherapy. Pooling all lines of therapies, everolimus was associated with significantly longer TOT compared to chemotherapy (multivariable-adjusted hazard ratio [HR] = 0.69, 95% confidence interval [CI]: 0.62–0.76) or capecitabine monotherapy (multivariable-adjusted HR = 0.73, 95% CI: 0.64–0.83). Longer TOT was consistently observed for everolimus for each line of therapy.
Limitations:
Proxies used for identifying HR + /HER2- mBC and treatment line, lack of certain clinical factors in claims data, generalizability limited to commercially insured patients in the US.
Conclusions:
This study found that HR+/HER2- mBC patients receiving everolimus experienced significantly longer TOT than those receiving chemotherapy overall or capecitabine monotherapy.
Transparency
Declaration of funding
Funding for this research was provided by Novartis Pharmaceuticals Corporation.
Author contributions: The study sponsor was involved in all stages of the study research and manuscript preparation, but all authors participated in the design of the study and contributed to the manuscript development. Data were collected by Analysis Group and analyzed and interpreted in collaboration with all other authors. Manuscript drafts were prepared by the authors with editorial assistance from a professional medical writer ultimately paid by the sponsor, Novartis Pharmaceuticals Corporation. All the authors vouch for the accuracy and completeness of the data reported and the adherence of the study to the protocol, and all the authors made the decision to submit the manuscript for publication.
Declaration of financial/other relationships
Y.H. has disclosed that she is an employee of Novartis Pharmaceuticals Corporation and owns stock/stock options. N.L., A.K., M.P., A.F., V.K., A.G., and E.Q.W. have disclosed that they are employees of Analysis Group Inc., which has received consultancy fees from Novartis Pharmaceuticals Corporation for this project. Analysis Group Inc. is a consulting firm that provides services to a variety of companies in the health care industry.
CMRO peer reviewer 1 has disclosed that he is a consultant to and has received grants from Novartis and Roche. CMRO peer reviewer 2 has no relevant financial or other relationships to disclose.
Acknowledgments
Medical writing assistance was provided by Ana Bozas PhD, an employee of Analysis Group Inc.
Previous presentation: A portion of the current research was presented in poster format at the 2015 San Antonio Breast Cancer Symposium, San Antonio, TX, USA, 8–12 December 2015.