Abstract
Purpose of Review
To describe the clinical role of CDK 4/6 inhibitors in hormone receptor-positive (HR+) metastatic breast cancer (HR+ MBC) as well as current controversies and evolving areas of research.
Recent Findings
Palbociclib, ribociclib, and abemaciclib are each approved in combination with an aromatase inhibitor or fulvestrant for HR+ MBC. Abemaciclib is also approved as monotherapy for pre-treated patients. Key questions in the field include whether all patients with HR+ MBC should receive a CDK 4/6 inhibitor up front versus later line, impact on overall survival, role of continued CDK 4/6 blockade, mechanism of clinical resistance, and treatment sequencing.
Summary
The development of CDK 4/6 inhibitors has changed the therapeutic management of HR+ MBC. Additional research is needed to determine optimal treatment sequencing, understand mechanisms governing resistance, and develop novel therapeutic strategies to circumvent or overcome clinical resistance and further improve the outcomes of patients with MBC.
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Laura M. Spring has received compensation from Novartis for service as a consultant and participation on advisory boards.
Seth A. Wander has received compensation from Foundation Medicine and InfiniteMD for service as a consultant and from Eli Lilly for participation on advisory boards.
Mark Zangardi declares that he has no conflict of interest.
Aditya Bardia has received research funding (paid to his institution) from Genentech, Novartis, Pfizer, Merck, Sanofi, Radius Health, Immunomedics, Mersana Therapeutics, Innocrin, and Biotheranostics; has received compensation from Pfizer, Novartis, Genentech, Merck, Radius Health, and Immunomedics for service as a consultant and participation on advisory boards and steering committees; and has received compensation from Spectrum Pharmaceuticals and Taiho Pharmaceutical for service as a consultant and participation on advisory boards.
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Spring, L.M., Wander, S.A., Zangardi, M. et al. CDK 4/6 Inhibitors in Breast Cancer: Current Controversies and Future Directions. Curr Oncol Rep 21, 25 (2019). https://doi.org/10.1007/s11912-019-0769-3
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DOI: https://doi.org/10.1007/s11912-019-0769-3