Predictors of systemic therapy sequences following a CDK 4/6 inhibitor-based regimen in post-menopausal women with hormone receptor positive, HEGFR-2 negative metastatic breast cancer

Abstract

Objective: To identify systemic treatment in the real-world following treatment with a cyclin-dependent kinase 4/6 inhibitor (CDKi) among post-menopausal women with hormone receptor positive, human epidermal growth factor receptor 2 Negative (HR+/HER2–) metastatic breast cancer (mBC).

Methods: Post-menopausal women with HR+/HER2– mBC were identified from MarketScan claims databases between January 1, 2012 and October 31, 2017. Eligible mBC patients who received a CDKi-based line of therapy following metastasis diagnosis were selected. A line of therapy ended at the earlier of systemic therapy discontinuation, switch to new treatment, or censoring.

Results: In total, 525 patients that received systemic therapy after a CDKi-based line were included (39.6% transitioned from use of a CDKi-based regimen in first line following metastasis diagnosis to any second line, and 60.4% shifted from a CDKi-based [second, third, or fourth line] to a subsequent line). Of post-CDKi second line regimens (n = 208), 38.0% were endocrine only, 35.6% were chemotherapy-based, 14.4% were everolimus-based, 9.6% were also CDKi-based line, and 2.4% were others. After adjusting for demographic and clinical characteristics, patients transitioning from a CDKi-based line to chemotherapy (vs others) had a trend of being more likely to have recurrent rapidly progressing disease, and were significantly less likely to have the prior CDKi-based line in combination with an AI (both p < .05).

Conclusions: This population-based study suggests that rapidly progressing disease, metastatic site location, age, and endocrine therapy partner may be predictive of subsequent systemic therapy regimen selection after progression on a CDKi-based line therapy in patients with HR+/HER2– mBC.

Keywords:

• Metastatic
• Breast cancer
• Sequences
• CDK 4/6 inhibitor
• Post-menopausal

Transparency

Declaration of funding

This study was sponsored and fully funded by Novartis.

Declaration of financial/other interests

Nicole Princic, David M. Smith, and William Johnson are employees of IBM Watson Health, which received compensation from Novartis for the overall conduct of the study and preparation of the manuscript. Derek H. Tang is an employee and owns stock with Novartis. Ayal Aizer and Aditya Bardia were consultants to Novartis in connection with the conduct of the study and manuscript development. CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

No assistance in the preparation of this article is to be declared.