Overall Survival Associated With CDK4/6 Inhibitors in Patients With HR+/HER2- Metastatic Breast Cancer in the United States: A Seer-Medicare Population-Based Study

Authors

• Ravi K Goyal
• Hua Chen
• Susan M Abughosh
• Holly M Holmes
• Sean D Candrilli
• Michael L Johnson

Language

English

Publication Date

4-1-2023

Journal

Cancer

DOI

10.1002/cncr.34675

PMID

36760031

Abstract

Background: Evidence on overall survival (OS) with cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors is generally limited to data from clinical trials or a few observational studies with limited generalizability to Medicare population. The aim of this study was to determine OS benefits associated with CDK4/6 inhibitors in older Medicare patients with hormone receptor (HR)-positive and human epidermal growth factor receptor-2 overexpressing (HER2-) metastatic breast cancer (MBC).

Methods: In a retrospective cohort design, female patients aged ≥65 years with diagnosis of HR+/HER2- MBC from 2015 to 2017 who initiated first-line systemic therapy within 12 months of MBC diagnosis were selected from the Survey Epidemiology and End Results-Medicare database. The effect of treatment type (endocrine therapy [ET]+CDK4/6 inhibitor vs. ET alone) on OS was analyzed using Kaplan-Meier methods and multivariable Cox regression models. Adjusted hazard ratio (aHR) and 95% CIs were estimated.

Results: A total of 630 eligible patients were identified (169 patients treated with ET+CDK4/6 inhibitor and 461 patients treated with ET alone). In the Kaplan-Meier analysis, OS rate at 3 years after first-line treatment initiation was 73.0% for ET+CDK4/6 inhibitor versus 49.1% for ET alone (log-rank p < .0001). In Cox regression analysis, first-line ET+CDK4/6 inhibitor therapy was associated with 41% lower rate of mortality versus ET alone (aHR, 0.590; 95% CI, 0.423-0.823).

Conclusions: The findings of this real-world study demonstrate significant OS benefit associated with ET+CDK4/6 inhibitor therapy over ET alone in an older Medicare population of patients with HR+/HER2- MBC, largely consistent with the evidence from clinical trials.

Keywords

Aged, Female, Humans, Antineoplastic Combined Chemotherapy Protocols, Breast Neoplasms, Cyclin-Dependent Kinase 4, Kaplan-Meier Estimate, Medicare, Erb-b2 Receptor Tyrosine Kinases, Research, Retrospective Studies, United States, Cyclin-Dependent Kinase 6, Protein Kinase Inhibitors, Survival Rate, CDK4/6 inhibitors, SEER Medicare, metastatic breast cancer, overall survival, palbociclib

Published Open-Access

yes

Recommended Citation

Goyal, Ravi K; Chen, Hua; Abughosh, Susan M; et al., "Overall Survival Associated With CDK4/6 Inhibitors in Patients With HR+/HER2- Metastatic Breast Cancer in the United States: A Seer-Medicare Population-Based Study" (2023). Faculty, Staff and Student Publications. 3603.
https://digitalcommons.library.tmc.edu/uthmed_docs/3603